ARTICLE | doi:10.20944/preprints202306.0669.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: respirometry; cover crops; conservation systems; microbial biomass
Online: 9 June 2023 (04:44:20 CEST)
Soil quality is a factor which is directly related to the sustainability of agricultural production and can be compromised through the use of inadequate management practices. In this work, soil edaphic respiration and changes in microbial biomass promoted by cover crops in an integrated crop-livestock system (ICLS) were evaluated using soil quality indicators by the respirometry method. The design used was completely randomized in a 3x6 factorial scheme and multivariate principal components analysis (PCA) was performed according to MANOVA. The edaphic respiration was determined based on the respirometry technique. From the results, it was found that edaphic soil respiration was significant in the nine evaluation periods, demonstrating the importance of grass cover on this edaphic respiration arising from the biological activity of microorganisms, which is directly related to the amount of organic carbon in the soil. It was concluded that the use of cover crops contributed to producing organic matter in the soil and consequently greater microbial respiratory activity.
ARTICLE | doi:10.20944/preprints202305.1907.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: agricultural soil; food production ecosystems; soil quality indexes; physicochemical indicators; biological indicators
Online: 26 May 2023 (09:55:57 CEST)
As the global population grows, the demand for food increases and puts a strain on food production systems and agricultural productivity, causing soil degradation. Soil Quality Indexes (SQIs) have been developed to maintain and improve soil quality. However, due to the variety of soils and SQIs, analyzing and comparing results has been historically difficult. Therefore, in this study, we carried out a systematic review with meta-analysis focused on soil quality studies of agricultural soils under intensive agriculture using the unified weighted additive SQI methodology (SQIU). We analyzed 65 quality observations obtained from 22 studies. Chemical indicators were the most prevalent in the SQIUs, followed by physical and biological indicators. Conventional soil management had negative effects on soil quality (–7.55%). From the factors analyzed, the minimum database had a significant effect on the soil quality results, but not the number of indicators that made up the SQIU. The SQIU made up of chemical-biological indicators (CB) presented negatively overestimated measurements of soil quality (–32.53%), exaggerating the damage to the analyzed soils. The indicators that correlated most strongly with the size of the effect on agricultural soil quality were the cation exchange capacity (CEC), carbon to nitrogen ratio (C/N), and microbial biomass carbon (MBC). The SQIU is a feasible tool to interpret the quality of agricultural soils around the world, as it makes it possible to obtain a simple and generalized view of soil conditions.
Subject: Environmental And Earth Sciences, Soil Science Keywords: Soluble carbon; leaching loss; Water and fertilizer input; Soil carbon migration
Online: 26 May 2023 (09:41:15 CEST)
In order to formulate a reasonable water input model for cotton fields in southern Xinjiang, scientific and rational fertilization, reduce soil carbon leaching, and improve soil carbon sequestration capacity, the undisturbed soil column leaching test was used to simulate the current field management method in the study area. Two methods of drip irrigation and flood irrigation were set up, and three irrigation and three nitrogen fertilizer levels were used to carry out the undisturbed soil column leaching test. The results showed that the amount and mode of water and nitrogen input affected the distribution and leaching loss of organic carbon and inorganic carbon in soil. When the nitrogen application rate increased from 270 kg·hm-2 to 450 kg·hm-2, the leaching loss of soluble organic carbon and soluble inorganic carbon increased significantly. When the water input increased from 6000 m3·hm-2 to 9000 m3·hm-2, the leaching loss of DOC and DIC increased significantly. The carbon leaching loss under drip irrigation was higher than that under flood irrigation. The leaching rates of DOC and DIC were the fastest under the conditions of high water ( 9000 m3·hm-2 ) and high fertilizer ( 450 kg·hm-2 ). It shows that water and nitrogen input and irrigation methods are important factors affecting soil carbon leaching. In the case of excessive water input, long-term high-frequency irrigation is the main factor affecting carbon leaching.
ARTICLE | doi:10.20944/preprints202305.1739.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: Soil geochemistry pyrites; iron partitioning
Online: 25 May 2023 (05:24:51 CEST)
Baía de Todos os Santos is the second largest bay in Brazil and is home to important ecosystems, including estuarine systems and mangroves. However, studies on the seasonal variability of its soil properties and composition are still scarce. For this study, soil and leaf samples were seasonally collected from mangrove forests at four sites (Cacha Prego, Ponta Grossa, Ilha de Maré, and Pitinga), which are representative of different environmental conditions within the BTS. Soil physicochemical properties, soil composition and partition of Fe forms were determined, and analysis of minerals by Scanning Electron Microscope, was performed on soil samples. Isotopic ratios (δ13C, δ15N) were also determined on soil and leaf samples. Soils showed significant spatial and temporal changes affecting both their properties (pH, Eh) and their composition (TOC, pyrite and Fe oxyhydroxide contents). Clear spatial changes were observed in redox potential, significantly affecting the concentrations of the different geochemical forms of Fe, particularly the concentrations of crystalline oxyhydroxydes and pyrite in one of the studied sites. In three of the study sites, pyrite crystals showed clear evidence of degradation associated with sandy soils. Finally, δ13C and N/C ratios in soils seem to suggest a mixed origin of organic matter.
ARTICLE | doi:10.20944/preprints202305.1686.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: Forest; Hydraulic flume; Rill erosion; Root biomass; Root weight density; Unit stream power.
Online: 24 May 2023 (04:23:37 CEST)
Plant roots have significant effects on the soil erosion rates, since they can strongly change the soil detachment capacity (Dc). This study quantifies Dc at different flow rates in soils with Alnus subcordata species, compared to three other species (Brachythecium plumose, Gleditsia caspica and Sambucus ebulus species) in the Saravan forest park and develops regression equations for predicting Dc. Undisturbed samples collected from soils with the four tree species and subjected to five slopes (from 4.3 to 38.3%) and five water discharges (from 0.28 to 0.71 l m−1 s−1) using a hydraulic flume. The results showed that Dc was significantly lower in soils with Alnus subcordata species compared to Brachythecium plumose, Gleditsia caspica and Sambucus ebulus species, as the consequence of the changes in the root characteristics, so that Dc was negatively correlated with root weight density, root length and root biomass. The unit stream power had high accuracy for predicting Dc for all of the studied species. The lowest value of rill erodibility (Kr) was obtained in soils with Alnus subcordata species using regression relationship between the Dc and the shear stress of the soil. This experiment helped to show the importance of plant roots in reducing the soil detachment rates and provided a contribution in understanding the choice of appropriate species for soil conservation.
ARTICLE | doi:10.20944/preprints202305.1154.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: Phosphorus fertilizer; Nitrogen fertilizer; Organic fertilizer; Mean weight diameter; Meta-analysis; PLS-SEM
Online: 16 May 2023 (10:42:07 CEST)
Soil is an extremely significant resource for human survival, and agglomerates, as the basic unit of soil structure, not only enhance soil fertility and control the biological validity of nutrients, but also strengthen the soil's erosion resistance. The mass application of fertilizers may have a significant impact on crop growth and soil structure, and the rational application and dispensing of fertilizers will be an urgent issue to be addressed. Therefore, the effect of fertilizer application on the stability of water-stable soil aggregates needs to be studied under different meteorological and soil conditions to draw more general and feasible conclusions. Our Meta-analysis of data from 220 of 56 published studies found that fertilizer application increased mean weight diameter (MWD) by an average of 18% compared to the no-fertilizer treatment. Among the nitrogen (N), phosphate (P), and organic (OM) fertilizer treatments, the organic fertilizer treatment had a greater stimulatory effect on MWD (26%). Among the different fertilizer levels, low level of phosphorus (<40kg·hm-2·yr-1), high level of N (>120kg·hm-2·yr-1), and low level of organic fertilizer (<5000kg·hm-2·yr-1) increased MWD by 19%, 14%, and 41% respectively. Across soil types and land use types, the response to MWD was positive for red soils and paddy fields, and the stimulatory effect of organic fertilizer was more significant compared to chemical fertilizer. The regression model showed that the response ratio of MWD was negatively correlated with the response ratio of soil pH and bulk density (BD), and positively correlated with the response ratio of soil organic carbon (SOC) and microbial mass carbon (MBC). Meanwhile, the PLS-SEM model showed that average annual temperature was the main factor affecting the stability of soil aggregates, and the average annual rainfall is the secondary factor. Therefore, this study found that the long-term use of organic fertilizers in place of some chemical fertilizers was more effective than chemical fertilizer alone. Temperature and rainfall have greater effects on the response of fertilizer to soil aggregate stability.
ARTICLE | doi:10.20944/preprints202305.0957.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: enzyme degradation; nitrogen; phosphorus; protease; forest soil; tropics
Online: 12 May 2023 (13:45:17 CEST)
Soil enzyme activity can be affected by both production and degradation, as enzymes can be degraded by proteases. However, the impact of nutrient addition on enzyme activity is often solely attributed to changes in enzyme production without fully considering degradation. Here, we demonstrated that the activities of β-1,4-glucosidase (BG), β-D-cellobiohydrolase (CBH), β-1,4-Xylosidase (BX), and β-1,4-N-acetyl-glucosaminnidase (NAG) were comparable in nitrogen (N) and phosphorus (P) fertilized soils and the unfertilized control under field conditions, but the reduction in activity was substantially greater in the fertilized soils during short-term laboratory incubation. The results show that the interruption of the natural, continuous supply of organic matter or non-soil microbial-derived enzymes, which typically occurs under field conditions, leads to a more significant reduction in apparent enzyme activities in fertilized soils compared to unfertilized control. This may be attributed to the higher abundance of protease in fertilized soils, resulting in faster enzyme degradation. Interestingly, P fertilization alone did not have a similar effect, indicating that N fertilization is likely the main cause of the larger decreases in enzyme activity during incubation in fertilized soils compared to unfertilized control soils, despite our study site being poor in P and rich in N. These findings highlight the importance of considering enzyme degradation when investigating material dynamics in forest ecosystems, including the impact of nutrient addition on enzyme activity, as enzyme production alone may not fully explain changes in apparent enzyme activity.
ARTICLE | doi:10.20944/preprints202305.0873.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: synthetic fertilizer; dissolved organic carbon; phosphorus fractions; acidity; soil depth
Online: 12 May 2023 (03:32:40 CEST)
The influence of long-term chemical fertilization in paddy soils is based on the interaction between labile carbon and phosphorus fractions and how this influences soil organic carbon (SOC). Four soil depths (0–30 cm) were analyzed in this study. Easily oxidized organic carbon components, such as permanganate oxidized carbon (POXC) and dissolved organic carbon (DOC), and other physicochemical soil factors were evaluated. The correlation and principal component analyses were used to examine the relationship between soil depth and the parameter dataset. The results showed that Fe-P concentrations were greater in the 0–5 cm soil layer. DOC, inorganic phosphate fraction, and other soil physiochemical characteristics interacted more strongly with SOC in the 0–5 cm soil layer, compared to that in the 10–15 cm layer, influencing soil acidity. An increase in DOC in the 0–5 cm soil layer had a considerable effect on lowering SOC, consistent with P positively correlated with POXC, but negatively with SOC and water-soluble carbon (WSC). The changes in SOC could be attributed to the relationship between DOC and inorganic phosphate fractions (as Fe-P) under a specific soil pH condition. An increase in soil DOC could be caused by changes in the P fraction and pH. The DOC:Avai. P ratio could serve as a compromise for the C and P dynamic indicators. The soil depth interval is a critical element that influences these interactions. Agricultural policy and decision-making may be influenced by the P from chemical fertilization practices, considering the yields and environmental effects.
ARTICLE | doi:10.20944/preprints202305.0444.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: soil indicators; vegetation indicators; iron mining; ecological restoration
Online: 8 May 2023 (04:45:53 CEST)
Many ecosystems are being severely degraded, leading the United Nations to deem 2021-2030 as the Decade on Ecosystem Restoration. To be successful, this effort requires robust monitoring tools to assess land reclamation practices. Our study aimed to evaluate the quality of recovery efforts in mined areas by developing a Recovery Quality Index (RQI) based on soil and vegetation indicators. Using the heavily mined Iron Quadrangle region of Brazil as an example, we selected four local, undisturbed reference areas as restoration goals: Atlantic Forest (AF); ferruginous rupestrian grassland with dense vegetation (FRGD); ferruginous rupestrian grassland with sparse vegetation (FRGS); and quartzite rupestrian grassland (QRG). We also selected four areas that were directly or indirectly affected by mining, including an environmental compensation area set aside 5 years prior to the study (COMP-5), two sterile piles that had undergone recovery for 15 and 20 years (SP-20 and SP-15), and a cave area with 15 years of recovery (CAVE-15). The four recovery areas were grouped together with each individual reference area (making four combinations of sites), and measurements of 2 vegetation parameters and 34 soil attributes were used in a Principal Component Analysis (PCA) for each grouping. We determined the RQI for each group by summing weighted PCA scores for responsive indicators. Vegetative parameters had the lowest RQI weights in all four groups. Soil physical indicators tended to be the most important, except in AF, where chemical indicators were most relevant. RQI values were also lowest when AF was used as the reference, showing that the forest was a unique ecosystem, and the CAVE-15 site had lower RQI scores than the other restored sites, indicating the high degree of disturbance that occurred in that low-lying area. The SP-20 site tended to have higher RQI values than the SP-15, and similar values to the less disturbed COMP-5 areas, potentially indicating greater recovery of native soil properties during the longer recovery period. This RQI-based approach has excellent potential for robust assessment of the recovery of areas degraded by mining and can support decision-making during monitoring.
ARTICLE | doi:10.20944/preprints202305.0320.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: ECOSSE model; Permanent grasslands; Soil respiration; European grasslands
Online: 5 May 2023 (07:42:03 CEST)
This study used the ECOSSE model (v. 5.0.1) to simulate soil respiration (Rs) flux-es estimated from ecosystem respiration (Reco) for eight European permanent grassland (PG) sites with varying grass species, soils, and management. The main aim was to evaluate the strengths and weaknesses of the model in estimating Rs from grasslands, and to gain a better understanding of the terrestrial carbon cycle and how Rs is affect-ed by natural and anthropogenic drivers. Results revealed that the current version of the ECOSSE model may not be reliable for estimating daily Rs fluxes, particularly in dry sites. However, it could still be a valuable tool for predicting cumulative Rs from PG. Additionally, the model demonstrated accurate simulation of Rs in response to grass cutting and slurry application practices. The sensitivity analyses and attribution tests revealed that increased soil organic carbon (SOC), soil pH, temperature, reduced precipitation, and lower water table (WT) depth could lead to increased Rs from soils. The variability of Rs fluxes across sites and years was attributed to climate, weather, soil properties, and management practices. The study suggests the need for additional development and application of the ECOSSE model, specifically in dry and low input sites, to evaluate the impacts of various land management interventions on carbon sequestration and emissions in PG.
ARTICLE | doi:10.20944/preprints202305.0112.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: Atenolol; caffeine; sulfadiazine; dissolved organic matter; sewage; specific sorption; sorption competition
Online: 3 May 2023 (07:55:31 CEST)
Pharmaceutically active compounds (PhACs) enter soil with organic substrates such as manure. Such complex substrates differently affect PhACs’ soil sorption. To elucidate the effects, batch experiments were conducted using five selected chemicals as model constituents. Urea, KH2PO4, acetic acid, phenol and nonadecanoic acid (C:19) altered the sorption strength and/or nonlinearity of sulfadiazine, caffeine and atenolol in a topsoil. The nonlinear Freundlich model best described sorption. Overall, the PhACs’ sorption coefficients increased in the sequence urea<phosphate<phenol<C:19<acetic acid. The sorption nonlinearity also increased in most cases. The effects on sulfadiazine and caffeine were rather similar, but in many cases different from atenolol. Phosphate mobilized sulfadiazine and caffeine and urea mobilized sulfadiazine, which was explained by sorption competition resulting from specific preference of similar sorption sites. Soil sorbed phenol strongly increased the sorption of all three PhACs; phenolic functional groups are preferred sorption sites of PhACs in soil. The large increase in sorption of all PhACs by acetic acid was attributed to a loosening of the soil organic matter and thus the creation of additional sorption sites. The effect of C:19 fatty acid, however, was inconsistent. These results help to better understand the sorption of PhACs in mixtures of soil and manure.
ARTICLE | doi:10.20944/preprints202304.1018.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: soil quality assessment; minimum data set; soil quality index; principal component analysis
Online: 27 April 2023 (03:46:54 CEST)
Soil quality is related to food security and human survival and development. In recent years, due to the acceleration of urbanization and the increase of abandoned land, land degradation occurs, poor topsoil quality. In this study, the minimum data set (MDS) was constructed through principal component analysis (PCA) to determine the indicator data set for evaluating topsoil quality in Tieling County, China. In addition, the soil quality index (SQI) was calculated to analyze the spatial distribution characteristics and influencing reasons of topsoil quality in Tieling County. The re-sults showed that MDS included total potassium (TK), Clay, zinc (Zn), soil organic matter (SOM), soil water content (SWC), cation exchange capacity (CEC), pH, and copper (Cu). The MDS indicators can well replace all indicators to evaluate the topsoil quality in the study area. The overall soil quality of Tieling County showed a trend of low in the east and high in the west, and gradually increased from the hilly area to the plain area. The evaluation results are consistent with field research, which can provide reference for other topsoil quality evaluation, and it also provide a basis for the formulation of soil quality improvement measures.
ARTICLE | doi:10.20944/preprints202304.1007.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: SfM-MVS; SLAM; roadside erosion; low-cost erosion measurement; slope erosion
Online: 27 April 2023 (02:41:36 CEST)
Hillslope and mountain roads are often the source of erosion, which in turn can lead to larger landslides and other types of mass-movements. For this reason, low-cost repeat surveys that can be done by practitioners and not solely scientists and engineers is essential. To solve this issue the present contribution shows the testing and applicability of a mix of SfM-MVS and low-cost SLAM technology to provide erosion information. The low-cost SLAM generated between 300 ~ 900 points per square meter, while SfM-MVS created between ~11,000 to 900,000 points. The density is however a trade-off against a spatially varying error, although the variability at the road-cut scale only ranges from 2 cm vertically to 2.5 cm in x,y,z based on the C2C algorithm. Furthermore, this error tends to be more important in the higher section of the cutout (further away from the sensor and at a flatter angle). It is thus possible to measure small-scale roadside change, providing that the change is in the range of >5 cm (adding the maximum potential error twice) and providing that the road-cut is such that the sensors can be brought close to the surface (camera or sensor on a pole). The authors suggest that it can be a solution for state and agencies with limited funding and that cannot afford regular laser or for roadside that are difficult to access.
ARTICLE | doi:10.20944/preprints202304.0871.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: Fungicide; inoculant; insecticide; microbial enhancer; soil activator; soil conditioner; soil stimulant
Online: 25 April 2023 (03:26:11 CEST)
Field studies were conducted in 2016, 2017, and 2020 in south-central and the Coastal Bend regions of Texas to determine the effects of various biostimulants and soil additives on corn growth and yield. In south-central Texas, the use of pop-up fertilizer (9-30-0 + Zn) either alone or in combination with either 2% N, bifenthrin, or bifenthrin + pyraclostrobin resulted in the greatest corn vigor but a yield response was only noted with pop-up fertilizer alone at 28062 or 46771 ml ha-1 in one year. In the Coastal Bend region, leaf tissue analysis showed that only Fe was affected with the use of any soil additive. Bacillus licheniformis + bacillus megaterium + bacillus pumilus increased Fe leaf tissue content by 20% over the untreated check. Radicoat seed coating at 438 ml ha-1 reduced corn plant stand by 10% and Pseudomonas brassicaceanum reduced corn height when compared with the untreated check; however, no differences in test weight or yield from the untreated check were noted with any soil additive. Little if any impacts of the use of biostimulants or soil amendments were seen in these studies.
ARTICLE | doi:10.20944/preprints202304.0436.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: tillage operation; rainfall pattern; hydrological characteristics; surface rainfall; soil loss
Online: 17 April 2023 (09:50:43 CEST)
Many studies have focused on the impacts of rainfall duration and intensity while overlooking the role of rainfall patterns on intensive tillage erosion in hilly agricultural landscapes. The objective of this study was to determine the combined effects of rainfall patterns and intensive tillage erosion on surface runoff and soil loss on sloping farmland in the purple-soil area of China. Five simulated rainfall patterns (constant, rising, falling, rising-falling, and falling-rising) with the same total precipitation were designed, and the intensive tillage erosion treatment (IT) and no-tillage treatment (NT) were subjected to simulated rainfall using rectangular steel tanks (2 m × 5 m) with a slope of 15°. To analyse the differences in the hydrodynamic characteristics induced by tillage erosion, we calculated the flow velocity (V), Reynolds number (Re), Froude number (Fr), and Darcy-Weisbach resistance coefficient (f). The results indicate that significant differences in surface runoff and soil loss were found among different rainfall patterns and stages (P < 0.05). The falling pattern and falling-rising pattern had faster runoff-initiating times and larger sediment yields than those of the other rainfall patterns. f varied from 0.30 to 9.05 for the IT and 0.48 to 11.57 for the NT and exhibited an approximately inverse trend to V and Fr over the course of the rainfall events. Compared with the NT, the mean sediment yield rates from the IT increased the dynamic range of 8.34%–16.21% among different rainfall patterns. The net contributions of the IT ranged from 2.77% to 46.39% on surface runoff and 10.14%–78.95% on soil loss on sloping farmland. Surface runoff and soil loss were positively correlated with rainfall intensity, V, and Fr but negatively correlated with f irrespective of tillage intensive (P < 0.05). For varying-intensity rainfall patterns, soil and water loss fluctuated during rainfall events, suggesting that the changes in rainfall intensity and tillage intensity would result in drastic variations in soil hydrological characteristics and sediment transport mechanisms. The time sequences of rainfall intensity in each rainfall pattern significantly affected surface runoff, soil erosion, and their contribution rates to total soil and water loss. Moreover, tillage erosion effects on soil and water loss were closely related to rainfall patterns in hilly agricultural landscapes. Our study not only sheds light on the mechanism of tillage erosion and rainfall erosion but also provides useful insights for developing tillage-water erosion prediction models to evaluate soil and water loss on cultivated hillslopes.
ARTICLE | doi:10.20944/preprints202304.0255.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: Soil Organic Carbon (SOC); Mangrove; Myanmar; Blue carbon; coastal ecosystem; Soil organic carbon stock
Online: 12 April 2023 (08:03:07 CEST)
We investigated and quantified soil organic carbon (SOC) stock at the mangrove forest (Magyi, That Bot Khan and Wette) of Shwe Thaung Yan coastal region in Myanmar and estimated the SOC stock changes in Magyi mangrove forest over six years using repeated field measurements. The study sites were characterized by different mangrove vegetation, soil types, and sediment deposition from different water sources. Results showed that the mangrove preservation and restoration efforts had a significant effect on soil C storage, with soil carbon stocks in 2021 (1954.43 ± 33.24 ton/ha) being 2.7 times higher than the estimated carbon stock in 2015 (732.26 ± 6.99 ton/ha). The results also revealed slight differences in SOC between Magyi and the Tha-Bot-Khan and Wette areas, as the mangrove plants in the latter areas have an additional source of nutrients from Pho-Thoung-Gyi, a deep-sea bay near the forest. Our research findings are beneficial in understanding the role of Myanmar’s mangrove ecosystems in carbon sequestration and climate change mitigation efforts.
ARTICLE | doi:10.20944/preprints202303.0417.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: Coastal flow slides; critical angle; retrogressive breach failure; hydrodynamic sediment transport; Monte Carlo simulation; risk assessment
Online: 23 March 2023 (14:47:06 CET)
Breaching and liquefaction are two types of coastal flow slides proposed in the literature. While their final results are similar, liquefaction and breaching failure are two different processes, with breaching failure characterized by a different progression and sand movement mechanisms. In densely packed sand, breaching causes delayed sand grain discharge and negative excess pore pressures. Liquefaction, when a mass of soil suddenly behaves like a liquid, flow out over overly gentle slopes. Flow slides typically go unnoticed until the slope fails above ground because they start below the water. Without modern technology, diving equipment, risk assessment, and probabilistic and sensitivity assessments, flow slides inherently challenging. The authors developed a new sensitivity index to detect the susceptibility of coastal flow slides. It was established a sophisticated hybrid model that accommodates flow slides in sync with unpredictable variables employed in this new sensitivity index. Innovative hybrid model has three distinctive models. The Hybrid Hydrodynamic Model addresses wave, wind, current, climate change, and sediment transfer. The Monte Carlo Simulation analyses sensitivity, and the Bayesian Network calculates joint probability of coastal flow slide parameters of this new index that includes environmental characteristics, including climate change. With the assistance of these three models, researchers aim at a) presenting a methodology for coupling coastal flow slide projections with outcomes; b) distinguishing two flow slides; c) examining variables influencing flow slides. The use of such a hybrid model and risk index offers a robust and computationally efficient approach to evaluating the critical angle slope for breaching failure.
ARTICLE | doi:10.20944/preprints202302.0101.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: RUSLE model; GIS; soil water erosion; integrated approach; sustainable development; land degradation; vulnerable areas; soil loss rate
Online: 6 February 2023 (10:51:54 CET)
Soil erosion is one of the most important environmental problems which can have various negative consequences, such as land degradation affecting the sustainable development and the agricultural production, especially for developing countries like Tunisia. Moreover, soil erosion is a major problem around the world because of its effects on soil fertility by nutriment loss and siltation in water bodies. Apart from this, soil erosion by water is the most serious type of land loss in several regions both locally and globally. This study evaluated regional soil erosion risk through the derivation of appropriate factors, using the Revised Universal Soil Loss Equation (RUSLE), which was applied to establish a soil erosion risk map of the whole Tunisian territory and to identify the vulnerable areas of the country. RUSLE model take into account all the factors playing a major role in erosion processes, namely the erodibility of soils, topography, land use, rainfall erosivity and anti-erosion farming practices. The equation is thus implemented under Geographic Information System (GIS) “Arc GIS Desktop”. The results indicated that Tunisia has a serious risk of soil water erosion, showing that 6.43% of the total area of the country is affected by a very high soil loss rate estimated at more than 30 t/ha/year and 4.20% are affected by high mean annual soil loss ranging from 20 to 30 t/ha/year. The most eroded areas were identified in west southern, central and western parts of the country. The spatial erosion map can be used as a decision support document to guide decision-makers towards better land management and provide the opportunity to develop management strategies for soil erosion prevention and control in the global scale of Tunisia.
ARTICLE | doi:10.20944/preprints202212.0052.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: Vertisols; Volcanic Ash; Field Capacity; Air Porosity; Volumetric Swelling
Online: 2 December 2022 (13:44:59 CET)
The research aims to improve some of the physical and hydro-physical properties of some Vertisols in the southern region (part of the eastern Houran Plateau) in Sweda Governorate at the south of Syria. Using different quantities of volcanic ash, soil samples were collected from the Al-Thahallah village from a depth of (0-30) cm, The experiment was designed according to the complete random design with one factor that represents the ash quantity (1.25, 2.5, 5) %, with three replicates for each treatment in addition to the control treatment a0. The experiment was carried out within the plastic pots during agricultural season 2018/2019, in which the wheat of the Sham variety 3 were cultivated as a cover plant. The results showed that the addition of volcanic ash at the quantity of 5% led to a significant increase in the infiltration rate by (328.60) %,%, where the filtration rate increased from 0.42 cm/hr -1 to 1.80 cm.h-1, as well as for each of the air porosity by (89) % and the volume of infiltrate water by (40) %, compared with the control. The above-mentioned addition also resulted in a decrease in both dry bulk density, total soil porosity and volumetric swelling coefficient by (18.60, 5.80, 314) % Respectively, compared to the control. The addition also contributed to the reduce in the weighted moisture content when saturation and the field capacity, at the level of significance of 5%. The research recommends adding volcanic ash to the soil at a quantity of 5%, and adding enhancements with volcanic ash at various levels such as organic waste.
ARTICLE | doi:10.20944/preprints202209.0347.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: digital soil mapping; soil process units; soil parameter space; machine learning; unsupervised classification
Online: 22 September 2022 (15:08:05 CEST)
The national-scale evaluation and modelling of the impact of agricultural management and cli-mate change on soils, crop growth, and the environment require soil information at a spatial res-olution addressing individual agricultural fields. This manuscript presents a data science ap-proach which agglomerates the soil parameter space into a limited number of functional soil pro-cess units (SPUs) which may be used to run agricultural process models. In fact, two unsupervised classification methods were developed to generate a multivariate 3D data product consisting of SPUs, each being defined by a multivariate parameter distribution along the depth profile from 0 to 100 cm. The two methods account for differences in variable types and distributions and in-volve genetic algorithm optimization to identify those SPUs with the lowest internal variability and maximum inter-unit difference with regards to both, their soil characteristics and landscape setting. The high potential of the methods was demonstrated by applying them to the agricultural German soil landscape. The resulting data product consists of twenty SPUs. It has a 100 m raster resolution in the 2D mapping space, and its resolution along the depth profile is 1 cm. It includes the soil properties texture, stone content, bulk density, hydromorphic properties, total organic carbon content, and pH.
ARTICLE | doi:10.20944/preprints202209.0239.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: Hyperspectral Technology; Non-destructive Testing; Black Soil; Ensemble learning; Support Vector Machine
Online: 16 September 2022 (07:40:27 CEST)
For the soil in different regions, the nutrient fertility contained in it is different, and the detection and zoning management of soil nutrients before tillage every year can improve grain yield. In this paper, an integrated learning strategy model based on black soil hyperspectral data is designed for rapid classification of organic matter content classification of black soil. Soil hyperspectral image dataset of Xiangyang Experimental Base was collected; by changing the internal structure of the stacking model, an LSVM-stacking model with (MLP, SVC, DTree, XGBl, kNN) five classifiers as the L1 layer was built, and the simulated annealing algorithm was used for hyperparameter optimization. Compared to other stacking models, the LSVM-stacking metrics are significantly improved. The accuracy rate of hyperparameter optimization is improved by 38.6515%, the accuracy rate of the independent test data set is 0.9488, and the comparison of individual learners can improve the recognition classification accuracy of label"1" to 1.0.
ARTICLE | doi:10.20944/preprints202205.0351.v2
Subject: Environmental And Earth Sciences, Soil Science Keywords: Infiltration; GSA-HYBRID Algorithm; GSA Algorithm; Genetic Algorithms; Calibration; Characteristic Curve
Online: 27 June 2022 (11:18:05 CEST)
Among the various complex systems that we experience each day, there is the physical phenomenon of infiltration. Infiltration is considered as the dynamics of water flow in the subsurface soil that in this work is framed for the context of civil construction. This issue is approached with the use of mathematical models and stochastic techniques, however, there are hardships in collecting the samples in the field, the adoption of a scale type, the influence in soil layers interfaces, the effects of soil anisotropic characteristics and so on. In this study, methodology is proposed to deal with the soil sampling input such as the retro model, constitutive model and optimization algorithms. Additionally, an automatic calibration is set forth to fix parameters from the mathematical model submitted. Especially among the existing Optimization Algorithms there are Genetic Algorithms and the Generalized Simulated Annealing Algorithm (GSA). This work presents an overview of these optimization methods and a proposal for a more efficient and faster algorithm called GSA-HYBRID based on convergence gradient technique. The applied strategy depends on the type of case study considering its physical properties and constraints. In this sense, it is found that while Genetic Algorithms are able to replicate the optimization surface, Generalized Simulated Annealing is much more adequate in characterizing the system at an extremely low computational cost. Nevertheless, the hybrid technique GSA-HYBRID performed the fastest. Further research is necessary to implement the novel GSA-HYBRID algorithm due to its flexibility and higher speed, also, studying its application at different case studies.
ARTICLE | doi:10.20944/preprints202206.0281.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: phosphorous; inceptisols; fractions; soilproperties
Online: 21 June 2022 (04:27:28 CEST)
Total Twenty-Four Samples were collected from the Four different depths of Prayagraj, Uttar Pradesh near the bank of Yamuna River and determined Phosphorous (P) fractions and their relationship with soil properties, The soils were Neutral, low salinity and medium to rich in organic matter in the surface to subsurface horizons. Most of the soils showed Low range in nitrogen and phosphorous and high in potassium. Among the P fractions, the most predominant were Ca-P and followed by Fe-P > S-P > Occl-P > Red-P > Al-P. The Overall results showed that the available-P, organic-P and total-P decreases with increase the depth, Where the Ca-P was significantly positively correlated with pore space (r = 0.396*), Organic Carbon ( r = 0.555*), Available Nitrogen ( r = 0.55*) and significantly negatively correlated with Clay (r = -0.324*), pH ( r = -0.226*), EC ( r = -0.232*). Total-P and Occ-P are main contributing factors for the availability of P. The regression equations showed that soil pH was the main soil property that influences the different fraction of P. The Nutrient Index of available P for Inceptisols was found under medium to low category, about 60% of Inceptisols are likely to respond of P-fertilizer.
ARTICLE | doi:10.20944/preprints202205.0410.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: mugwort; perennial cropping; conventional rotations; sustainable agri-culture; soil microbial community
Online: 31 May 2022 (05:20:06 CEST)
Perennial cropping play vital roles in regulating soil carbon sequestration and thus mitigating climate change. However, how perennial cropping affects soil microbial community remains elusive. Using a field investigation, this study was conducted to examine the effects of mugwort cropping along a chronosequence (that is, wheat-maize rotation, 3-year, 6-year, and 20-year mugwort cropping) on soil microbial community in temperate regions of Northern China. The results showed that the highest total, actinomycetes, and fungi PLFAs were found in the 3-year mugwort cropping soils. All PLFAs of microbial groups were lowest in the 20-year mugwort cropping soils. All of the three cropping years of mugwort increased network complexity of soil microbial community. Changes in total nitrogen and phosphorus content as well as the ratio of ammonium nitrogen to nitrate nitrogen could be primarily explain the variations in soil microbial community along the mugwort cropping chronosequence. Our observations highlight the contrasting impacts of soil microbial community to short-term and long-term mugwort cropping compared to conventional rotations and would have critical implications for sustainable agricultural management under perennial cropping in temperate regions.
ARTICLE | doi:10.20944/preprints202203.0353.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: chlorothalonil; dissipation; enzyme activity; microbial community
Online: 28 March 2022 (03:46:35 CEST)
To get a better knowledge of the effects of residual chlorothalonil on soil characteristics and soil microbial communities, we evaluated the dissipation of chlorothalonil and the effects of different chlorothalonil concentrations on soil respiration, enzyme activities, and microbial community structure in yellow-brown loam soils. Bacterial and fungal soil communities were examined using traditional plate counting and polymerase chain reaction-denaturing gradient gel electrophoresis (PCR–DGGE) methods. Soil properties and the results of DGGE band analysis were both used to estimate the status of the soil microbial ecosystem. The results show that residual chlorothalonil has considerable effects on soil respiration, enzymatic activities, and microbial community structure. In particular, soil respiration and phosphatase activities were increased, while saccharase activity, microbial biomass, and microbial community diversity were decreased by increasing levels of chlorothalonil treatment. Correlation analyses revealed that the application of chlorothalonil was significantly correlated with the change of the soil respiration, urease activity, sucrase activity, soil culturable bacteria and culturable fungi biomass. We conclude that residual chlorothalonil is directly related to soil respiration, enzyme activities, and microbial community structure.
ARTICLE | doi:10.20944/preprints202203.0253.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: soil reflectance composites; digital soil modeling; soil organic carbon; GEOBIA, Landsat; terrain analysis
Online: 17 March 2022 (11:42:28 CET)
There is a growing need for an area-wide knowledge of SOC contents in agricultural soils at field scale for food security, monitoring long-term changes related to soil health and climate change. In Germany, large-scale SOC maps are mostly available with a spatial resolution of 250 m to 1 km2. The nationwide availability of both digital elevation models at various spatial resolutions and multi-temporal satellite imagery enables the derivation of multi-scale terrain attributes and Landsat-based multi-temporal soil reflectance composites (SRC) as explanatory variables. On the example of an Bavarian test of about 8000 km2, the scale-specific dependencies between the representativeness of 220 soil samples and different aggregation levels of the explanatory variables were analyzed for their scale-specific predictive power. The aggregation levels were generated by applying a region-growing segmentation procedure, the SOC content prediction was realized by the Random Forest algorithm. In doing so, established approaches of (geographic) object-based image analysis (GEOBIA) and machine learning were combined. The modeling results revealed scale-specific differences. Compared to terrain attributes, the use of SRC parameters lead to a significant model improvement at large field-related scale levels. The joint use of both terrain attributes and SRC parameters resulted in further model improvements. The best modeling variant is characterized by an accuracy of R2=0.84 and RMSE=1.99.
ARTICLE | doi:10.20944/preprints202202.0298.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: Sediment yield; runoff; SWAT; Watershed; Hydrological model; Hydrological Response Units; Critical area
Online: 23 February 2022 (14:38:00 CET)
Mahanadi is one of the major inter-state east flowing perennial rivers in peninsular India. Hamp watershed of Seonath Sub-basin of upper Mahanadi basin was considered for the study to estimate the sediment yield and nutrient loss-based identification of critical agricultural sub-watershed and its critical Hydrological Response Unit (HRU) using Soil and Water Assessment Tool (SWAT) in-terfaced with GIS i.e., ArcSWAT. The study area was divided into 14 sub-watersheds considering topographical parameters derived from DEM and drainage network. The land cover, soil layers, and DEM were used to generate 207 HRUs for analysis of annual runoff, sediment yield and nu-trient loss for 2004-2008 (calibration period) and 2010-2013 (validation period). The sediment yield, runoff estimation and nutrient loss matched consistently well with the monthly and seasonal measured values. On the basis of average annual sediment yield (18.18 t/ha), runoff (245.97 mm) and nutrient loss NO3-N (1.62 kg/ha), respectively, sub-watershed WS4 was categorized under high priority for critical are identification. The sub watershed WS4 comprises of 15 HRUs (No. 36 - 50) with four kharif crops viz rice, soybean, maize and sugarcane. Results showed that the crops soy-bean, maize and sugarcane reduced the average annual runoff by 18.1, 31.4 and 18.0 per cent, respectively whereas the sediment yield was increased drastically by 104.5, 37.5 and 5.7 per cent, respectively as compared to rice. Soybean and maize crops HRU generate significant amount of soil and nutrient loss and were found to be as the critical HRUs for the upper Mahanadi River basin
ARTICLE | doi:10.20944/preprints202112.0078.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: ESA CCI; soil moisture; EEMD; Mann-Kendall; temporal and spatial variation; Jiangsu water supply area (JWSA)
Online: 6 December 2021 (14:56:16 CET)
The South-to-North Water Transfer Jiangsu Water Supply Area (JWSA) is a mega inter-basin water transfer area (water source) that provides water resources from JiangHuai, combines drainage and flooding management, and regulates nearby rivers and lakes. Analyzing the spatiotemporal soil moisture dynamics in the area will inform agricultural drought and flood disaster assessment and early warning studies. Therefore, we evaluated the quality of European Space Agency Climate Change Initiative Soil moisture (ESA CCI_SM) data in the South-North Water Transfer JWSA. Then, we used ensemble empirical modal decomposition, Mann-Kendall tests, and regression analysis to study the spatiotemporal variation in soil moisture for the past 29 years. The CCI _SM data showed a high correlation with local soil measurements at nine sites. We then analyzed the CCI_SM data from three pumping stations (the Gaogang, Hongze, and Liushan stations) in the South-North Water Transfer JWSA. These stations had similar periodic characteristics of soil moisture, with significant periodic fluctuations around 3.1 d. The overall soil moisture at the three typical pumping stations showed an increasing trend. We then investigated whether there were abrupt soil moisture changes at each station. The spatial distribution of soil moisture in the South-North Water Transfer JWSA was characterized by “dry north and wet south”, with higher soil moisture in winter, followed by autumn, and low soil moisture in spring and summer. Although the linear trend of soil moisture in the South-North Water Transfer JWSA varied in significance, the overall soil moisture in the JWSA has increased over the past 29 years. The areas with significantly enhanced soil moisture are mainly distributed in the Yangzhou and Huai'an areas in the southeastern part of the study area. The areas with significantly decreased soil moisture are small in size and mainly located in northern Xuzhou.
ARTICLE | doi:10.20944/preprints202111.0007.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: African agriculture; Irrigation; Landsat; Remote Sensing; Reservoir.
Online: 1 November 2021 (11:26:45 CET)
Agriculture in Morocco has been extensive until the middle of the 20th century due to the distribution of rainfall and the availability of water. In the middle of the last century hydraulic works were built that allowed the transition to intensive agriculture by the increase of irrigated areas, allowing that in the territories where there is water for irrigation and the climate allows it, the crops adapt to the demands of the market. The objective of the study is to assess by satellite images the land cover between 1985 and 2020, analyzing the changes in cultivation areas, as well as the changes in desert, sub-desert and forest areas of the Oum Er Rbia hydrological basin in Morocco. Landsat satellite images have been used since 1984 by the US government (Aerospace and Geological Agencies). A series of vegetation indices (NDVI, RVI, TNDVI and EVI) have been used; among which TNDVI (Transformed Normalized Vegetation Index) stands out for its better accuracy, which has allowed us to distinguish vegetation in cultivated and forest areas, as well as arid zones. In addition, the study has compared the use of two methodologies to calculate changes in the coverage of the Earth’s surface, has used local image processing from the Sentinel Application Platform tool and has also used the Google Earth Engine tool. The latter being the most optimal, although at the moment it has great limitations. In both methodologies and in the different indices it has been possible to observe during these 35 years as the cultivated area has increased (related to the availability of water by the construction of reservoirs and canals), how plant cover has improved in forest areas, and a range of variations in arid areas.
REVIEW | doi:10.20944/preprints202110.0272.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: Climate Change; Soil; Sustainable Development Goals (SDGs)
Online: 19 October 2021 (11:52:34 CEST)
Climate change is a major threat to agricultural food production globally and locally. It poses both direct and indirect effects on soil functions. Thus, agricultural management practices has evolved to adaptation strategies in order to mitigate the risks and threats from climate change. The study concludes with a recommendation the coconut farmers should explore the idea of soil biodiversity in a bid to mitigate the potential negative impact of climate related risk on the farming. The study proffers the need for adopting sustainable agricultural practices to boost local coconut production. This can contribute to the simultaneous realisation of two of the Sustainable Development Goals (SDGs) of the United Nations: SDG 2 on food security and sustainable agriculture and SDG 13 on action to combat climate change and its impacts. The study findings has implications for tackling climate change in Sub-Saharan Africa and in particular Nigeria in order to boost local agricultural production and coconut in particular without negative environmental consequences and an ability to cope with climate change related risks.
ARTICLE | doi:10.20944/preprints202109.0410.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: Soil erosion; Defective sewer; soil science; soil engineering; soil
Online: 23 September 2021 (13:07:12 CEST)
Cases of road cave-ins have been reportedly increasing globally and reports have associated this phenomenon to underground soil erosion due to defective sewer pipes. As the sewer pipes age, they may develop some defects which may lead to cracks and crevices that will lead to infiltration of the soils surrounding the pipe into the pipe, leading to the formation of cavities around the pipe. Therefore, this study investigated the factors behind the causes of underground soil erosion due to defective sewer pipes and proffered solutions for combating underground soil erosion due to defective sewer pipes. The study objective included; (a) establishing how the soil particle sizes affect the internal soil erosion due to defective sewer pipes, (b) determination of the effect of defect sizes on the internal soil erosion due to defective sewer pipes, (c) establishing the effect of the embedment material used on the internal soil erosion due to defective sewer pipes, (d) investigation of the type of soil erosion mechanism in the presence of a buried sewer pipe defect caused by the groundwater infiltration process. The methodology of the study involved reviewing and analyzing secondary qualitative and quantitative data. The findings established that the defect size of the pipe, the type and characteristics of the soil and the type of embedment materials used affected erosion of soil around a defective sewer pipe.
ARTICLE | doi:10.20944/preprints202104.0365.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: Net Photosynthesis; Soil; Grassland; Mollic; Gelic; Eutric
Online: 14 April 2021 (10:05:19 CEST)
What is the ideal soil-grass combination for maximum photosynthesis? In this study, we investigated how soil and grassland types affect photosynthesis in the grasslands of Gannan, China. We divided the grasslands of Gannan into 166 study sites, each with a unique soil-grass combination by intersecting the soil and ecoregion maps using ArcGIS. We obtained 19 years of data on the Net Photosynthesis (PsnNet) of grasslands in the area from 2000 to 2018 and then divided them into “growing season” (June to September) and “non-growing season” (October top May). Between 2000 and 2018, PsnNet of grasslands showed a gradually increasing trend. The effect of soil type on PsnNet was not significant during the growing season. However, it was highly significant during the non-growing season. Among the soil types, grasses that grew in Mollic, Gelic, and Haplic soils had the highest rate of photosynthesis. The difference in PsnNet among the various grass types was highly significant during both seasons. However, Tropical and Subtropical succulent evergreen broad-leaf shrubs and Temperate meadows had the highest rate of photosynthesis. Additionally, there was a highly significant difference in PsnNet among the various soil-grass interactions. In the growing season, TStEgBLS growing Eutric soils had the highest PsnNet. However, SaDBLS growing in Gelic soils had the the highest.
ARTICLE | doi:10.20944/preprints202104.0030.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: micro minerals, selenium, deficiency, soil-plant relationship, Kosovo
Online: 1 April 2021 (16:17:35 CEST)
Minerals play many important functions in plant and animal metabolism. Therefore, we investigated the concentration of Se and other minerals and their relationships in soils and fodder plants in Kosovo. Seventy-three samples of each soil and fodder plants (grass, maize, and wheat) from 30 farms were collected. Both soil and plant samples, after processing and digestion, were analyzed for mineral concentration by ICP-MS. Mineral concentrations in soil and fodder crops, and the best predicting/explanatory models for micro minerals concentration, achieved by stepwise linear regression, are presented. Results showed very low concentration of Se in most of the soil and all fodder samples. In addition, the concentration of Co, Zn and Fe was not sufficient to satisfy requirements for all categories of farm animals. Plant Se concentration showed a positive relationship with Se concentration in soils. Plant Zn, Mo, Mn, Fe and Pb, in general, showed no significant relationship with their concentration in soil, while plant Co and Cd showed positive relationship only in maize, and Cu in wheat grain. Among the soil properties, pH had the highest effect on the concentrations of Co, Mo, Mn, Cd and Pb in fodder crops.
ARTICLE | doi:10.20944/preprints202102.0446.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: Soil; parameters; pit; composting; analysis; properties
Online: 19 February 2021 (15:05:33 CET)
During composting process, soils undergo many changes in their physical, chemical and biological properties. Composting has been widely known as an aerobic process during which organic matter is decomposed to humus like substances broken into many organic materials or compounds. The project aims to compare and analyze different combination of composting that yield different properties and nature of soils, and testing their soil physical properties. Dug three compost pits each 1.5 m in depth, labeled compost pit A consisting of potato peels – the only kitchen waste most common around the college hostels, compost pit B consisting of leaf litter and other garden trimmings and compost pit C consisting of cow dung and the other as a controlled experiment with no composting practices.
REVIEW | doi:10.20944/preprints202102.0236.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: goods and services; water-limited area; plant-water relationship; Soil water resource use limit by plants; Soil Water Carrying Capacity for Vegetation
Online: 9 February 2021 (11:49:54 CET)
The goods and services produced by forest and vegetation ecology system is the power by which human society can be promoted fast in high-quality and sustainable way. With the increase of population and economic development in water-limited regions, there is an increasing demand for the quantity and variety of forest vegetation ecosystem products and services. To meet the demands of this situation, most of the original forest has changed into farmland, non-native forest and grass land. As a result, water-plant relationship changed from equilibrium to non-equilibrium, which led to soil drought, soil degradation and vegetation decline in dry years or waste of soil water in rainy years in most of water-limited regions. In order to solve the questions and realize the sustainable utilization of soil water resources and the high quality and sustainable development of social economy, it is necessary to apply the utilization limit theory of soil water resources by plants and the theory of soil water carrying capacity for vegetation to adjust the relationship between plant growth and soil moisture to obtain the maximum yield and benefit of vegetation and serve high-quality and sustainable development.
REVIEW | doi:10.20944/preprints202012.0100.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: carbon stock; climate change; humus; organic wastes; soil management
Online: 4 December 2020 (11:11:47 CET)
The soil has lost organic matter in the past centuries. Adding organic matter to soils is one of the management practices applied to recover the levels of soil carbon of the past. Is it a good practice to reduce global warming? In fact, one of the practices promoted to combat climate change is increasing soil organic matter. However, the addition of organic residues to the soil could facilitate the liberation of CO2 and wastes could also have no positive effects on soil properties. In this sense, what it is important is: a) to know which is the expected effect of the organic matter added to the soil; b) how this application alters the soil processes; c) which are the management practices that should be applied; d) how much is the real amount of carbon sequester by the soil and; e) the balance at short and long period after the application of the organic matter. The adequate strategy should be to favour the increment of biologically stabilized soil organic matter considering medium and long time. However, it is necessary to adapt the strategies to the local environmental conditions.
ARTICLE | doi:10.20944/preprints202009.0695.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: clay minerals; limestone; biochar; trace elements; bio-availability; alkaline degraded soils
Online: 28 September 2020 (17:52:02 CEST)
Ca-bentonite (CB) alone and in a mixture with limestone (L), tobacco biochar (TB) and zeolite (Z) on the fixation, geochemical fractions and absorption of Cd and Zn by Chinese cabbage in smelter heavily polluted (S-HP) and smelter low polluted (S-LP) soils were investigated. The results showed that the CB+TB and CB+L+TB treatments significantly immobilized Cd up to 22.03% and 29.68%, respectively, and reduced uptake by Chinese cabbage shoot to 35.98% with CB+Z+L and 61.35% with CB+L in S-HP and S-LP soils compared with the control. The CB+ Z+ L+TB treatment mobilized Cd up to 4.45% and increased absorption in the shoot by 9.85% in S-HP soil. The greatest immobilization of Zn was 53.18% and 58.20% with the CB+Z+L+TB treatment, which reduced Zn uptake in the plant shoot by 9.94% with CB + L and 58.04 with CB+Z+L+TB in S-HP and S-LP soils. The CB+Z+TB and CB+TB treatments mobilized Zn up to 35.40% and 4.80%, respectively, in both soils. Furthermore, the uptake of Zn in plant shoot was observed by 58.96% and 7.82% with application of CB+Z and CB+TB treatments, respectively, in S-HP and S-LP soils. Overall, our results suggest that Ca-bentonite alone and in mixtures with different amendments can be used to reduce the phyto-extraction of Cd and Zn in Zn-smelter polluted soils.
ARTICLE | doi:10.20944/preprints202008.0132.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: reinforced soil; hexapods; layered inclusion; random inclusion
Online: 5 August 2020 (10:51:29 CEST)
Henry Vidal first introduced the concept of using strips, grids, and sheets for reinforcing soil masses. Since then, a large variety of materials such as steel bars, tire shreds, polypropylene, polyester, glass fibers, coir, jute fibers etc. have been widely added to the soil mass randomly or in a regular, oriented manner. In this investigation, a new concept of multi-oriented plastic reinforcement (hexa-pods), is discussed. A systematic and comprehensive laboratory tests were conducted on unreinforced and reinforced soil samples. Laboratory tests such as direct shear teat and California bearing ratio (CBR) test were analyzed on soil samples consisting of only soil samples, soil sample with random inclusion of hexapods and soil samples with layered inclusion of hexapods. From the results obtained through direct shear test it could be observed that cohesion value of both the soil sample has increased and the angle of internal friction has been decreased after reinforcing it with inclusions in both randomly and layered conditions. CBR test indicates that for same amount of compactive effort, both random and layered inclusions of hexapods show improvement in strength and stiffness. Random inclusions of hexapods give better resistance to penetration as compared to layered inclusions. The hexa-pods also changed the brittle behavior of unreinforced sand samples to ductile ones.
ARTICLE | doi:10.20944/preprints202003.0146.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: conventional agriculture; land degradation; small-holders; multinomial logistic regression; Nepal
Online: 9 March 2020 (01:24:35 CET)
Land degradation is a critical issue globally putting our future generations at risk. The decrease in farm productivity over the years is evidence of land degradation severity in Nepal. Among the many strategies in place, agroforestry, which is an integrated tree-based farming, is widely recommended to address this productivity issue. This paper thoroughly examines what influences the choice of agroforestry adoption by farmers and what discourages the adoption. For this, a total of 288 households were surveyed using a structured questionnaire. Two agroforestry practices were compared with conventional agriculture with the help of the Multinomial Logistic Regression (MNL) model. The likelihood of adoption was found to be influenced by gender; the male-headed households were more likely to adopt the tree-based farming practice. Having a source of off-farm income was positively associated with the adoption decision of farmers. Area of farmland was found being the major constraint to agroforestry adoption for smallholder farmers. Some other variables that affected positively included livestock herd size, provision of extension service, home-to- forest distance, farmers’ group membership and awareness of farmers about environmental benefits of agroforestry. Irrigation was another adoption constraint that the study area farmers were faced with. The households with means of transport and with larger family (household) size were found to be reluctant towards agroforestry adoption. A collective farming practice could be a strategy to engage the smallholder farmers in agroforestry.
REVIEW | doi:10.20944/preprints202002.0405.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: Systematic Review; Sustainable Agriculture; Climate Change; Resilience; Agro-Systems
Online: 27 February 2020 (12:23:04 CET)
In the last few decades, a lot has been written on the use of sustainable agriculture to improve ecosystem services for resilience to climate change. However, no tangible and systematic evidence exists on how this would participate in alleviating impacts on vulnerable rural communities. This paper provides a narrative systematic review (SR) integrated with a bibliometric analysis and a concept network analysis to understand how, in a changing climate, sustainable agriculture builds the resilience of agro-systems. The search was set from the date of the first relevant article until the end of 2018. Results generated have demonstrated that: a. Only single practices and methods have been studied to assess impacts on single ecosystem services. b. Soil quality and health are considered a key indicator of sustainable agriculture. c. Albeit the assessed practices and methods have shown to improve the biodiversity of agro-systems, which makes them more resilient to extreme climate events, we are still far from reaching interdisciplinary and multi-dimensional agriculture which integrates all management aspects and generates a full range of ecosystem services. In conclusion, the study addressed the following recommendations for the scientific community and for decision-makers to orient future research strategies and efforts: a. Integration of all agro-systems services into sustainable management using an ecosystem-based approach on a life-cycle basis using Life Cycle Assessment (LCA) method; b. Improving the scientific understanding of traditional knowledge for higher synergies and for further integration; c. Unification of assessment methods and indicators for the quantification of impacts; d. Creation of a platform to share, monitor, screen, and approve assessments and evaluations of sustainable agriculture by region.
Subject: Environmental And Earth Sciences, Soil Science Keywords: total P; bray 1 available P; P sorption; P saturation; P release; P fertilizer input; corn yield
Online: 21 February 2020 (07:14:59 CET)
High rates of phosphorus (P) currently being applied to soils for the production of vegetables in the Mekong Delta, Vietnam has led to the concern of its negative effect on the economics and the environment. This research presents a comprehensive study on the determination of P supplying capacity in this region of Vietnam to examine the possibility of reducing P fertilizer input. One hundred twenty (120) soil samples were collected to evaluate total P and Bray 1 available P in the soils. Phosphorus maximum sorption, degree of P saturation, P release, and the effect of P fertilizer on corn (Zea mays L.) yield in greenhouse and fields were also determined. Total P concentrations of 56.7% soil samples evaluated yielded high P concentrations (>560 mg P/kg), while 74.2% of the samples had high Bray 1 available P concentrations (>20 mg P/kg soil). Maximum P sorption ranged from 149 to 555 mg P/kg soil, respectively and has negative correlation to available P (r = - 0.63*), degrees of P saturation ranged from 0.63 to 5.46% correlated to available P (r = 0.98**) and maximum P release ranged from 1.2 to 61.9 mg P/kg soil, respectively correlated to available P (r = 0.96**). Corn grown in soils with available P concentrations >15 mg P/kg did not respond to P fertilizer in greenhouse or field experiments. We conclude that many farmers in this region can reduce P fertilizer input, thus increasing their profits and reducing negative environmental impacts associated with excess soil P for sustainable agriculture.
ARTICLE | doi:10.20944/preprints202002.0050.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: potato cultivation soil suitability; agricultural landscape categorisation; GIS
Online: 5 February 2020 (02:52:46 CET)
Growing potato demands considerable external inputs of pesticides due to its susceptibility to various pests and pathogens. Here we present an attempt to differentiate the Slovak rural landscape with respect to the possibility of effective potato cultivation and to characterise soil parameters of current potato cultivation areas with the aim to increase the sustainability of the potato production. The selection was based on soil climatic, production and economic parameters. By using the GIS tools and existing databases on soil characteristics in Slovakia, maps of soil suitability categories for potato cultivation were generated. In Slovakia, it was found that 12.3% of farmland is very suitable for potato cultivation and that as much as 43.1% is not suitable. Later the specified categories were characterised in detail and specified with respect to geographic, soil, climatic, production and economic parameters. Currently, most potato crops are cultivated on Eutric Cambisols (27%), Chernozems (20%) and Mollic Fluvisols (18%). Loamy soils (65%), soils without gravel (62%), deep soils (74%) and soil situated on plains (55%) are dominant in these regions. We suggest that potato cultivation should be concentrated on the most suitable areas, thereby increasing the economic profitability, improving the ecological stability of the country and supporting the sustainability of the agriculture.
ARTICLE | doi:10.20944/preprints201912.0214.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: geopolymers; metakaolin; biomass bottom ash; mechanical properties
Online: 16 December 2019 (11:15:41 CET)
In this research, the feasibility of using bottom ashes generated by the combustion of biomass (olive pruning and pine pruning) as a source of aluminosilicates (OPBA) has been studied, replacing the metakaolin precursor (MK) in different proportions (0, 25, 50, 75 and 100 wt. % substitution) for the synthesis of geopolymers. As alkaline activator an 8 M NaOH solution and a Na2SiO3 have been used. The geopolymers were cured 24 hours in a climatic chamber at 60 ° C in a water-saturated atmosphere, subsequently demoulded and cured at room temperature for 28 days. The results indicated that the incorporation of OPBA waste, which have 19.7 wt. % of Ca, modifies the characteristics of the products formed after alkaline activation. In general terms, the incorporation of increasing amounts of calcium-rich ashes results in geopolymers with higher bulk density. The compressive strength increases with the addition of up to 50 wt. % of OPBA with respect to the control geopolymers, contributing the composition of the residue to the acquisition of a better behaviour mechanical. The results indicate the potential use of these OPBA waste as raw material to produce unconventional cements with 28-day curing strengths greater than 10 MPa, and thermal conductivities less than 0.35 W/mK.
ARTICLE | doi:10.20944/preprints201908.0072.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: LULCC; SWC; soil erosion risk; Erer Sub-Basin; RUSLE; ArcGIS; SWC; MCDR
Online: 6 August 2019 (09:03:58 CEST)
Land use and land cover change (LULCC) is a critical factor for enhancing the soil erosion risk and land degradation process in the Wabi Shebelle Basin. Up-to-date spatial and statistical data on basin-wide erosion rates can provide an important basis for planning and conservation of soil and water ecosystems. The objectives of this study were to examine the magnitude of LULCC and consequent changes in the spatial extent of soil erosion risk, and identify priority areas for Soil and Water Conservation (SWC) in the Erer Sub-Basin, Wabi Shebelle Basin, Ethiopia. The soil loss rates were estimated using an empirical prediction model of the Revised Universal Soil Loss Equation (RUSLE) outlined in the ArcGIS environment. The estimated total annual actual soil loss at the sub-basin level was 1.01 million tons in 2000 and 1.52 million tons in 2018 with a mean erosion rate of 75.85 t ha–1 y–1 and 107.07 t ha–1 y–1, respectively. The most extensive soil loss rates were estimated in croplands and bare land cover, with a mean soil loss rate of 37.60 t ha–1 y–1 and 15.78 t ha−1 y−1, respectively. The soil erosion risk has increased by 18.28% of the total area, and decreased by 15.93%, showing that the overall soil erosion situation is worsening in the study area. We determined SWC priority areas using the Multi-Criteria Decision Rule (MCDR) approach, indicates that the top three levels identified for intense SWC account for about 2.50%, 2.38%, and 2.14%, respectively. These priority levels are typically situated along the steep slopes in Babile, Fedis, Fik, Gursum, Gola Oda, Haramaya, Jarso, and Kombolcha districts that need emergency SWC measures.
ARTICLE | doi:10.20944/preprints201906.0143.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: land cover maps; land cover scenario; Land Change Modeler (LCM); transition probabilities
Online: 15 June 2019 (16:13:07 CEST)
The results reveal CILSS as the most accurate data set with a Kappa coefficient of 68% and an overall accuracy of 83%. CILSS data shows a decrease of savanna and forest whereas an increase of cropland over the period 1975 to 2013. The increase of cropland area of 30.97% from 1975 to 2013 can be related to the increase in population and their food demand, while the losses of forest area and the decrease of savanna are further amplified by using wood as energy sources and the lack of forest management. The three datasets were used to simulate future LULC changes using the Terrset Land Change Modeler. The validation of the model using CILSS data for 2013 showed a quality of 50.94%, it is only 40.04% for ESA and 20.13% for Globeland30. CILSS data was utilized to simulate the LULC distribution for the years 2020 and 2027 because of its satisfactory performances. The results show that a high spatial resolution is not a guarantee of high quality. The results of this study can be used for impact studies and to develop management strategies for mitigating negative effects of land use and land cover change.
REVIEW | doi:10.20944/preprints201904.0123.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: social media; selfies; wild animals; wildlife tourism; wildlife trade
Online: 10 April 2019 (09:35:16 CEST)
Social media has become a powerful tool for spreading information and awareness campaigns on environmental issues, especially as they pertain to the conservation of wild animals. It is a double-edged sword, however, since it also facilitates the legal and illegal trade of wild animal species as well as the propagation of ‘wild animal selfies.’ This review presents some key literature to date which concerns the impact of social media on public perceptions of animals (such as through ‘viral’ videos), changing trends in animal encounters at wildlife tourism destinations, and the wildlife trade as it is facilitated by social media. Finally, avenues for future research are suggested with urgency, since the impact of social media on the welfare and conservation of wild animal species is most likely underestimated yet bears serious consequences.
ARTICLE | doi:10.20944/preprints201904.0109.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: soil organic carbon sequestration, climate, organic agriculture, cancer, earthworm, fire
Online: 9 April 2019 (12:28:54 CEST)
Shutdown for just six days enables land plants to entirely fix CO2 excess of +4 Gt C per yr. Rebuilding soil organic carbon (SOC) in worm-worked humus is the only practical carbon capture and storage (CCS) capable of freely offsetting annual anthropogenic emissions. A case is made to redirect all available resources towards proven, earthworm-based, organic husbandry. Priority is to safely combat mounting global threats due to irreversible species extinction, perilous climate change and deteriorating human wellbeing (mental/physical health). All three interlinked risks are underpinned by a relentless, yet largely ignored, critical loss of precious topsoil. A first step to topsoil recovery is vermi-composting all vegetable and animal ‘wastes’ for return to the field.
Subject: Environmental And Earth Sciences, Soil Science Keywords: orthodox soil science, alternative practices, corrective strategies
Online: 26 March 2019 (09:43:00 CET)
In Australia, orthodox soil scientists and alternative practitioners who promote ‘regenerative agriculture’ have not been communicating and engaging effectively with each other. Over many years scientists in CSIRO, state departments and universities have made significant achievements in mapping soil distribution, describing soil behaviour and identifying key soil properties and processes that are fundamental to healthy soil function. However, many alternative practitioners are dismissive of these achievements and highly critical of orthodox soil science. Yet many of the tools of soil science are essential to conduct evidence-based research towards elucidating how and why the exceptional results claimed by some alternative practitioners are achieved. We stress the importance of effective engagement and communication among all parties to resolve this ‘clash of cultures’.
ARTICLE | doi:10.3390/sci1010009.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: land cover; landscape change; habitat fragmentation; conservation planning; Oti-Keran-Mandouri; Togo
Online: 14 February 2019 (00:00:00 CET)
Biodiversity conservation planning is highly important in the current context of global change. Biodiversity conservation can be achieved by understanding changes in land use at the landscape scale. Such understanding is needed to reverse the unprecedented pressure on natural resources that has been reported by many studies conducted on biodiversity conservation within the Oti-Keran-Mandouri protected areas. Land cover maps reflecting different dates (1987, 2000, and 2013) and depicting different management systems, with overall accuracy ranging from 73% to 79%, were analyzed to understand the processes that lead to habitat degradation within these protected areas. The nature of change, within a given land cover class, was determined by comparing land cover maps on different dates using a decision tree algorithm that compares the number of patches, their areas, and their perimeters at different time periods (T1 and T2). Specifically, two time-periods were considered for this analysis: 1987–2000 and 2000–2013. Croplands and settlements increased at an average of 108.13% and 5.45%, respectively, from 1987 to 2000. From 2000 to 2013, croplands gained from all other land categories and continued to increase at a rate of 11.77% per year, whereas forests and savannas decreased at an annual average rate by 5.79% and 2.32%, respectively. The dominant processes of habitat change from 1987 to 2000 were the creation of forests, dissection of savannas, attrition of wetlands, and creation of croplands. Meanwhile, from 2000 to 2013, there was attrition of forests, as well as attrition of savannas, dissection of wetlands, and aggregation of croplands. In general, from 1987 to 2013, natural habitats regressed and were replaced by croplands; forests, savannas, and wetlands decreased at an average annual percentage 5.74%, 3.94%, and 2.02%, respectively, whereas croplands increased at an average annual rate of 285.39% of their own area. Aggregation, attrition, dissection, and creation were the main habitat change processes identified for the overall period from 1987 to 2013. There was habitat loss in forests and savannas and habitat fragmentation in wetland due to attrition and dissection, respectively. Identifying and understanding habitat change processes would enable the taking of appropriate biodiversity conservation actions.
ARTICLE | doi:10.20944/preprints201901.0224.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: land data assimilation; EnKF; EnOI; SMAP; SMOS; ESA CCI
Online: 22 January 2019 (12:33:58 CET)
A number of studies have shown that assimilation of satellite derived soil moisture using the ensemble Kalman Filter (EnKF) can improve soil moisture estimates, particularly for the surface zone. However, the EnKF is computationally expensive since an ensemble of model integrations have to be propagated forward in time. Here, assimilating satellite soil moisture data from the Soil Moisture Active Passive (SMAP) mission, we compare the EnKF with the computationally cheaper ensemble Optimal Interpolation (EnOI) method over the contiguous United States (CONUS). The background error-covariance in the EnOI is sampled in two ways: i) by using the stochastic spread from an ensemble open-loop run, and ii) sampling from the model spinup climatology. Our results indicate that the EnKF is only marginally superior to one version of the EnOI. Furthermore the assimilation of SMAP data using the EnKF and EnOI is found to improve the surface zone correlation with in-situ observations at a 95% significance level. The EnKF assimilation of SMAP data is also found to improve root-zone correlation with independent in-situ data at the same significance level; however this improvement is dependent on which in-situ network we are validating against. We evaluate how the quality of the atmospheric forcing affects the analysis results by prescribing the land surface data assimilation system with either observation corrected or model derived precipitation. Surface zone correlation skill increases for the analysis using both the corrected and model derived precipitation, but only the latter shows an improvement at the 95% significance level. The study also suggest that the EnOI can be used for bias-correction of the atmospheric fields where post-processed data are not available. Finally, we assimilate three different Level-2 satellite derived soil moisture products from ESA Climate Change Initiative (CCI), SMAP and SMOS (Soil Moisture and Ocean Salinity) using the EnOI, and then compare the relative performance of the three resulting analyses against in-situ soil moisture observations. In this comparison, we find that all three analyses offer improvements over an open-loop run when comparing to in-situ observations. The assimilation of SMAP data is found to perform marginally better than the assimilation of SMOS data, while assimilation of the ESA CCI data shows the smallest improvement of the three analysis products.
ARTICLE | doi:10.20944/preprints201811.0494.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: soil stoichiometry; soil nutrient; nutrient limitations; natural grassland; natural forest
Online: 20 November 2018 (09:35:23 CET)
The Loess Plateau is an important region for vegetation restoration in China, however, changes in soil organic carbon (SOC), soil nutrients, and stoichiometry after restoration in this vulnerable ecoregion are not well understood. Typical restoration types, including orchardland (OL), grassland (GL), shrubland (SL), and forestland (FL) were chosen to examine changes in the stocks and stoichiometry of SOC, soil total nitrogen (TN), and soil total phosphorus (TP) at different soil depths and recovery times. Results showed that SOC stocks first increased and then stabilized in OL, GL, and SL at 0–30 cm depth, while in FL, stocks gradually increased. Soil TN stocks first increased and then decreased in OL, SL, and FL with vegetation age at 0–30 cm depth, while soil TP stocks showed little variation between restoration types. In the later stages of restoration, the stocks of SOC and soil TN at 0–30 cm soil depth were still lower than those in natural grassland (NG) and natural forest (NF). The overall C:N, C:P, and N:P ratios increased with vegetation age. Additionally, the SOC, soil TN and soil TP stocks, and C:N, C:P, and N:P ratios decreased with soil depth. The FL had the highest rate of change in SOC and soil TN stocks, at 0-10 cm soil depth. These results indicate a complex response of SOC, soil TN, and soil TP stocks and stoichiometry to vegetation restoration, which could have important implications for understanding C, N, and P changes and nutrient limitations after vegetation restoration.
ARTICLE | doi:10.20944/preprints201612.0067.v1
Subject: Environmental And Earth Sciences, Soil Science Keywords: water in the soil; surface irrigation; water storage; irrigation modelling; soil hydrodynamics
Online: 13 December 2016 (09:55:18 CET)
An adequate representation of the water infiltration process in the soil allows improving the efficiency in application and the uniformity in surface irrigation. The Green and Ampt model has shown a good representation of the process, and researchers from the United States Department of Agriculture (USDA) determined the values of their parameters for soils of that country, which are shown in tables or through functional relationships and this information is used as reference in several parts of the world, although there is no certainty that they are representative of the soils in Mexico. In this study, the parameters of the Green & Ampt equation were determined and evaluated in some soils of agricultural importance in Mexico. The parameters were obtained in four ways: one of them applied a methodology adapted from Brooks and Corey to quantify the wetting front capillary pressure head and used an permeameter under constant hydraulic head to determine the saturated hydraulic conductivity, and the other three consisted in taking them from three studies reported by the USDA. The values of the parameters suggested in Mexico drastically underestimated the results with relative errors (RE) in a range of -49.0 to -94.0% and the most representative were those obtained with the methodology proposed in this research with RE of -15.0 to 6.0%.