Soil erosion is the major factor that has contributed to the reduction of soil fertility in the highlands of Ethiopia. This factor was reduced by soil and water conservation (SWC) practices. Hence, the study evaluated the effects of SWC practices and slope gradient on soil physicochemical properties in the Agemi watershed of northwestern Ethiopia. Farmland treated by SWC such as stone-faced soil bund (SFSB) and soil bund (SB), untreated farmland and slope gradient were identified in the study area. About 27 soil samples were collected from the treated farmland and untreated farmland with three slope classes, including lower (5-10%), middle (10-15%) and upper slopes (>15%). The soil physicochemical properties were analyzed by two ways analysis of variance (ANOVA) using SAS 9.2. The results of the study showed that the content of sand, clay, total porosity, pH, soil organic matter (SOM), total nitrogen (TN), available phosphorus (AP), exchangeable cations such as Ca²⁺, Mg²⁺, K⁺ and cation exchange capacity (CEC) were significantly affected (p<0.01) by SWC practices and untreated farmland with slope gradients. However, the content of silt, percent of base saturation (PBS) and exchangeable Na were statistically insignificant (p>0.05). Farmland treated with SFSB confirmed higher mean values of soil physicochemical properties than SB and untreated farmland. Moreover, the lower total porosity (TP) and higher bulk density (BD) were recorded on untreated farmland and upper slopes. This study concludes that farmland treated with SFSB improved soil physicochemical properties than farmland treated with SB followed by untreated farmland. Therefore, SFSB should be implemented on farmland to improve soil fertility in the study area.

Converting biowaste into biochar and subsequently putting it into the soil are considered to be an effective approach to sequestrate carbon (C). However, biochar will inevitably undergo the aging process in soil, which influences its stability, and ultimately threatens its carbon sequestration ability. This study selected CaCl2 as exogenous additive of sewage sludge and bone dreg to quantify both surface C and bulk C stability in Ca-rich biochars under three aging processes (dry-wet aging, freeze-thaw aging, and natural aging in farmland soil), and revealed the influence mechanisms of exogenous Ca on biochar stability. Results showed that after dry-wet aging (25 rounds), freeze-thaw aging (25 rounds), and natural aging in different farmland soils (5 months), oxidized surface C in Ca-rich biochar decreased by 10~23%, 28~41%, and 0~74%, respectively, compared to that in pristine biochar, while oxidized bulk C decreased by 6~10%, 0~1%, and 0~35%, respectively. Under three aging processes, the surface C and bulk C stability in Ca-rich biochar were superior to that in corresponding pristine biochar, which was attributed to the “protective effect” of Ca-containing crystals on biochar surface, including CaO, Ca5(PO4)3Cl, Ca5(PO4)3(OH), Ca8H2(PO4)6·H2O and Ca10(PO4)6(OH)2. These Ca-containing crystals could block the connection between biochar-C and the external oxidizing environment, intervening the oxidation of C-C/C=C in biochar, but also prevented aging from damaging C structure of biochar, reducing the generation of fragmented structure. By comprehensively assessing surface C and bulk C stability under three aging processes, final C sequestration in Ca-rich biochar increased to 27~80%, compared to that in pristine biochar (23~74%). Therefore, Ca-rich biochar is more dominant than pristine biochar, considering C sequestration potential during long-term aging in soil.

The possession and appraisal of agricultural fields have significant economic and social impacts. The objective of this study is to examine the perception of the factors that contribute to the value of agricultural fields and those that diminish their value in the appraisal process. The utilized quantitative methodology is based on a questionnaire administered to farmers in Huambo Province, Angola. The sample size consists of 644 respondents. The results allow concluding that the income generated from farming activities and the presence of infrastructure greatly facilitate the appraisal of agricultural fields. Conversely, the absence of legal ownership documentation and conflicts related to land ownership reduce the value of the fields. The exploratory factor analysis has identified seven determinant factors in the appraisal of agricultural fields: inherent location characteristics of the property, market dynamics related to agricultural fields, the availability of water on the property, proximity to tourist destinations, physical conditions of the fields, the positive externalities generated, and the advantages offered by the fields. We believe that this study will assist appraisers, farmers, and public administration in understanding the factors that positively and negatively impact the appraisal of agricultural fields.

Intercropping of maize (Zea mays L.) and peanuts (Arachis hypogaea L.) (M||P) significantly enhances crop yield. In a long-term M||P field experiment with two P fertilizer levels, we examined how long-term M||P affects topsoil aggregate fractions and stability, organic carbon (SOC), available phosphorus (AP), and total phosphorus (TP) in each aggregate fraction, along with crop yields. Compared to their respective monocultures, long-term M||P substantially increased the proportion of topsoil mechanical macroaggregates (7.6–16.3%) and water-stable macroaggregates (>1 mm) (13.8–36.1%), while reducing the unstable aggregate index (ELT) and the percentage of aggregation destruction (PAD). M||P significantly boosted the concentration (12.9–39.9%) and contribution rate (4.1–47.9%) of SOC in macroaggregates compared to single crops. Moreover, the concentration of TP in macroaggregates (>1 mm) and AP in each aggregate fraction of M||P exceeded that of the respective single crops (P<0.05). Furthermore, M||P significantly increased the Ca2-P, Ca8-P, Al-P, and Fe-P concentrations of intercropped maize (IM) and the Ca8-P, O-P, and Ca10-P concentrations of intercropped peanuts (IP). The land equivalent ratio (LER) of M||P was higher than one, and M||P stubble improved the yield of subsequent winter wheat (Triticum aestivum L.) compared with sole-crop maize stubble. P application augmented the concentration of SOC, TP, and AP in macroaggregates, resulting in improved crop yields. In conclusion, our findings suggest that long-term M||P combined with P application, sustains farmland productivity in the North China Plain by increasing SOC and macroaggregate fractions, improving aggregate stability, and enhancing soil P availability.

At present, farmland abandonment（FA）is a severe phenomenon in China, imposing a serious restriction on agricultural production. In this context, it is of great significance to explore the logical relationship between high-standard farmland construction (HSFC) and FA to optimize land resource allocation and guarantee national food security. Based on 838 samples of farmers in the main rice production area of the Yangtze River Basin in China, this paper employs the Tobit model, the mediating effect model, and the moderated mediating effect model to analyze the impact of HSFC on FA at the micro level. The results show that (1) HSFC inhibits FA, and FA proportion decreases by 1.14% for every 1% increase in HSFC proportion, and the robustness test and endogeneity treatment also yield consistent conclusions. (2) Agricultural socialization services (ASS) play a positive mediating role in the influence path. HSFC promotes farmers' purchase of ASS, which in turn inhibits FA. (3) The agricultural labor transfer distance (ALTD) plays a positive moderating role in the relationship between HSFC and FA. The farther the distance, the more likely HSFC can promote farmers' purchase of ASS and inhibit FA. The results provide enlightenment on how to precisely implement HSFC policy, that is, to inhibit FA by improving the construction of high-standard farmland and the post-construction management as well as protection system. Moreover, this study helps guiding the development of ASS and optimizing the institutional environment for agricultural labor transfer, creating conditions for agricultural scale management.

Farmland edge plants can support high butterfly richness. Our objective was determine if, even in farms under intensive cultivation, the diversity of plants (mostly native) in crop edges is enough to sustain a high species richness of butterfly. We characterized the vegetation on the edges of Medicago sativa farms in central Mexico and identified the species of diurnals butterflies (Rhopalocera) associated. Butterflies and plants were counted along transects at the edges of a cul-tivated field during 24 months. We found 2710 individuals of plants, belonging to 48 different species from 24 families; 1749 individuals of diurnal butterflies, belonging to 57 species from six families. Most than half of the plant species found were native flora of central Mexico and with ethnobotanical use. A similarity analysis test showed significant differences in floristic composi-tion between transects. The Canonical Correspondence Analysis between butterfly species and plant families showed three groups. Six butterfly species were migratory and four mexican en-demic species, most of them associated with a group formed by Amaranthaceae, Euphorbiaceae, Annonaceae Lamiaceae Apiaceae and Fabaceae families. The high diversity of plants in our agro-ecosystem plays an important role to sustain a high diversity of butterflies and could be useful as biological corridors.

In recent 40 years, the quantity and spatial patterns of farmland in Western Jilin have changed dramatically, which had great impact on soybean production potential. This study used one of the most advanced crop production potential models, the Global Agro-cological Zones model, to calculate the soybean production potential in Western Jilin based on meteorological, terrain, soil and land use data, and analyzed impact of farmland change on soybean production potential during 1975-2013. The main conclusions were the following. First, the total soybean production potential in Western Jilin in 2013 was 89.22 thousand tons. The production potential of eastern area was higher than the other areas of Western Jilin. Second, farmland change led to a growth of 33.03 thousand tons in soybean production potential between 1975 and 2000, and a decrease of 10.30 thousand tons between 2000 and 2013. Third, taking account of two situations of farmland change, the conversion between dryland and other categories, and the change of irrigation percentage led to the total soybean production potential in Western Jilin increased by 23.13 and only 2.87 thousand tons respectively between 1975 and 2000, and increased by 1.13 and 2.81 thousand tons respectively between 2000 and 2013. In general, the increase of soybean potential production was mainly due to grassland and woodland reclamation. The results of this study would be a good reference for protecting safe baseline of farmland, managing land resources, and ensuring continuity and stability of soybean supply and food security.

This study aimed at testing the effectiveness of novel combinations of chemical and physical methods to control Prosopis juliflora, an invasive weed in the Moshi and Simanjiro districts of Nothern Tan-zania. Six different treatments including manual uprooting, glyphosate, bark chop with chemical application, two separate chemical mixtures and control were tested in a total of 32 plots, which represented two land use types (grazing land and farmland) found in the two districts. Each plot covered 20m×30m plot area. Two response variables (stem count and tree volume) were recorded to compare weed population density before and after treatment six months later. An analysis of the untreated control plots, showed that the inherent growth potential of P. juliflora was higher in Moshi than in Simanjiro district. The number of stems increased during the experiment for all six treatments showing that the P. juliflora population had not yet reached the local carrying capacity. For the manual control treatment, the increase was reduced compared to the untreated control. For all other treatments, the increase in stem count was on par with that in the untreated control or even higher. Thus, we conclude that only manual uprooting had a controlling effect but not to the extent that it eradicated P. juliflora. Thus, it is for P. juliflora as for weed control in general: weed control must be an ongoing effort.

Based on the 2013–2017 Chinese Family Database and China Household Finance Survey, the study examines the impact of farmland transfer on the income structure of agricultural households. We observe a significant rise in the income of transferred-out households, while that of transferred-in households is unchanged. A further empirical decomposition of income shows a significant increase in both the wage and asset generated incomes of transferred-out households. Although the income generated by transferred-in households through agricultural production and management increases significantly, the decrease in wage income is larger. The study’s empirical designs are robustly tested with propensity score matching and instrumental variables. Moreover, we conduct a comparative analysis of the external constraints faced by the two groups to explore the reasons for the divergence of the income effect. The results show that transferred-in households face highly pronounced external constraints in terms of capital, technology, and farmland size, while transferred-out households face relatively fewer impediments to non-agricultural employment. Our empirical results imply that external constraints can limit the social welfare improvements of agricultural land reform, suggesting that other complementary measures would be required for future policy improvements to work better.

Agricultural activities are the second largest source of greenhouse gas emissions, and carbon emissions from agricultural land use (CEALU) have become a hot issue across the world. However, few scholars explored the impact of agricultural land policies on carbon emissions, such as the High-standard farmland construction(HSFC) in China.Thus，by relying on provincial panel data for China for the period 2005-2017, the effect of the high-standard basic farmland construction policy on carbon emissions from agricultural land use per unit area and its regional differences were quantitatively analyzed using the difference-in-difference (DID) model. The results showed that: 1) China's CEALU per unit area presented a fluctuating upward trend during the period 2005-2017, from 392.58 kg/ha to 457.72 kg/ha, with an average annual growth rate of 1.31%. 2) The high-standard farmland construction(HSFC) policy produced a significant carbon emission reduction effect in agricultural land use, and reduced the CEALU per unit area by 10.80% on average. With the promotion of this policy, its carbon emission reduction effect in agricultural land use presented an overall increasing trend. 3) The carbon emission reduction effect of the high-standard farmland construction policy in agricultural land use was significant in central China, but non-significant in eastern China and western China.

It is very difficult to accurately divide farmland and woodland in Gaofen 2 (GF-2) remote sensing image, because their single plant coverage is very small, and their spectra are very similar. The ratio of spatial resolution and one plant’s coverage area must be fully taken into account when designing the Convolutional Neural Network structure for extracting them from GF-2 image. We establish a Convolutional Encode Neural Networks model (CENN), The first layer has two sets of convolution kernels to learn the characteristics of farmland and woodland respectively, while the second layer is the encoder to encode the characteristics by transfer function, which can map the results to the corresponding category number. In the training stage, samples of farmland, woodland, and other categories are categorically used to train CENN, as soon as training is accomplished, CENN would acquire enough ability to accurately extract farmland and woodland from remote sensing images. The final extraction result is obtained by implementing per-pixel segmentation of images used to train the CENN. CENN is compared and analyzed with others such as Deep Belief Network (DBN), Full Convolutional Network (FCN), Deeplab Model. The results of experiments show that CENN can more accurately mine the characteristics of farmland and woodland, and it achieves its goal of extracting farmland and woodland with high precision from GF-2 images.