Gaseous Emissions from Solid Cattle Manure in Sloping-Floor Housing System

Additives Used with Straw Bedding Can Mitigate Ammonia and Greenhouse 1 Gaseous Emissions from Solid Cattle Manure in Sloping-Floor Housing System 2 Ghulam Abbas Shah , Ghulam Mustafa Shah, Muhammad Imtiaz Rashid Maqsood 3 Sadiq, Faheem Khan, Imran Mahmood, Zeshan Hassan, Adeel Anwar, Muhammad 4 Luqman, Zahid Hassan Tarar, Jeroen C. J.Groot, Egbert A. Lantinga 5 Department of Agronomy, Pir Mehr Ali Shah Arid Agriculture University Rawalpindi, 6 Punjab, 46300, Pakistan 7 Farming Systems Ecology Group, Wageningen University, Droevendaalsesteeg 1, 6708 PB, 8 Wageningen, the Netherlands 9 Center of Excellence in Environmental Studies, King Abdulaziz University, Saudi Arabia 10 Department of Environmental Sciences, COMSATS University, Islamabad, Sub-campus 11 Vehari, Pakistan 12 Department of Agricultural Extension, Pir Mehr Ali Shah Arid Agriculture University 13 Rawalpindi, Punjab, 46300, Pakistan 14 College of Agriculture, Bahauddin Zakariya University, Multan, Bahadur Sub Campus, 15 Layyah Pakistan 16 Agronomic Research Station, Khanewal, Pakistan 17 Soil and Water Testing Laboratory, Mandi Bahauddin, Pakistan 18 *Correspondence: shahga@uaar.edu.pk; shahjee1522@gmail.com 19 Abstract: We studied the influence of lava meal, zeolite and top layer of sandy soil as 20 bedding additives on gaseous C and N losses from a sloping-floor barn of naturally 21 ventilated animal housing. We selected four barn units where eight young bulls’ 22 group was reared in each barn. Chopped straw of wheat and barley applied daily at the 23 rate of 5 kg per livestock unit (LU) in bedding areas where one LU consisted of 500 24 kg body mass of live bulls. Zeolite, lava meal and sandy soil (18% clay + silt) applied 25 in barn at the rate of 10, 20 and 30% of straw dose, respectively. Static flux chamber 26 was used to measure gases emissions from the barn unit and mass balance calculation 27 was used to calculate straw manure total N (TN) losses during housing phase. On an 28 average, all bedding additives decreased 85% of the NH3 emission compared to 29 control; however, they did not influence CH4 emission. Zeolite decreased CO2 (35%) 30 and N2O (37%) emission rates. Subsequently, lava meal, sandy soil and zeolite 31 decreased 23, 37, and 50% of TN losses from barn manure, respectively. Overall, 32 measured N emissions through NH3-N and N2O-N from the barns was 11% of 33 calculated TN losses while remainder 89% was most probably attributed to di34 nitrogen (N2), a harmless gas. Hence, in straw-based cattle housings, zeolite could be 35 a promising additive for reduction of CO2, N2O and NH3 emissions and sandy soil can 36 be considered as cheap and readily available resource for reducing NH3 emission. 37


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The study was performed at Experimental and Training Organic Farm Droevendaal 129 (latitude 55°99'N and longitude 5°66'E), of Wageningen University and Research 130 Centre, which is situated in the north 1 km away from Wageningen city, the "Lava-Union ® " Germany, respectively. These companies also provided their chemical 142 composition (Table 1). The sandy [silt (14%), clay (4%), sand (82%)] textured soil 143 was sampled form the top 25 cm depth of the same farm where spring wheat was 144 cultivated previously, and then air dried. Soil chemical characteristics were presented 145 in Table 1.Bedding area of each barn unit consisted of 42 m2 with 21 m 2 manure alley. 146 Control and lava meal treatments were applied in the barn unit with slopes 6 to 8°, 147 and in case of zeolite and sandy soil treated barn these were 4 to 6° (see Fig. 1). Eight 148 beef bulls (young) were grouped to house in each barn unit. To avoid fight among 149 them, grouping was made according to their age. At the beginning of experiment, the 150 age of the bulls was ranged between 12 and 17 months where body weight of each 151 bull varies between 291 to 526 kg ( Table 2). The bulls' weight with empty stomach Where DMin shows the feed intake of DM (kg DM LU -1 day -1 ) per day, DMoff 178 indicates feed offered to bulls per day (kg DM LU -1 day -1 ). DMref represents feed 179 refusal by bulls per day kg DM LU -1 day -1 ), FNi indicates N intake from feed by bulls 180 per day (kg DM LU -1 day -1 ), TNoff shows TN present in feed offered to the bulls per 181 day (kg DM LU -1 day -1 ), as well as TNref represents TN found in feed refused by bulls 182 (kg DM LU -1 day -1 ). we used a scoring system to study the influences of bedding additives on bull dirtiness.

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The dirtiness scoring was carried out on day 38 and 78 of housing phase during the 189 weighing sessions by using scoring sheet (Scott and Kelly, 1989 indicates straw manure bedding surface area (7.07*10 -2 m 2 ) inside the flux chamber. Finally, the unaccounted N losses (UnNL) that are part of the established total N 303 losses from gases was quantified using following relation: Periodic total emission of NH3-N and N2O-N was estimated by taking the mean of 306 emission rates occurred between two successive sampling intervals and multiplied this 307 with day numbers amid these intervals (Chadwick, 2005). Afterward, TN emission 308 during whole housing phase was calculated by summing instantaneous emission rate 309 estimated between two sampling intervals.  CH4 and N2O as well as their relations with straw manure bedding thickness were 371 estimated by linear regression (Jeppsson, 1999). The data set for bulls' dirtiness was 372 obtained by summing 70 scores for every bull during each of the two measuring days.

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The summed value was treated as one replicate (Jeppsson, 1999).  Overall, during initial six weeks, rates of NH3 emission per LU fluctuated and then 389 these rates were stabilised (Fig. 3a). On the other hand, CH4, N2O, and CO2 emission 390 rates were low at initial stage and then increased to the end the housing experiment 391 (Figs. 3b-3d). The highest mean emission rates (g LU -1 day -1 and g kg -1 N) of CO2, 392 NH3, and N2O were observed in control and the lowest for zeolite treatment.

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Interestingly, rates of CH4 emission did not differ significantly among treatments (P > 394 0.05; Table 6). CO2 and N2O emission rates followed the same patterns (Figs. 3b and 395 3c), and there was a significant linear correlation (P < 0.001) between the emissions 396 rate of N2O and CO2 (Fig. 4). In general both CH4 and N2O show positive relationship with bedding thickness (Fig   399   5a, 5b). In case of CH4, the emission rate was greatly enhanced at bedding thickness 400 exceeded from 10 cm height (Fig. 5a). However, this increment was only higher (P < 401 0.05) for sandy soil than control. Gradual increase in N2O emission was observed with increasing thickness of bedding layer, which was established from trend lines 403 (Fig. 5b).  According to an old saying "too much of a good thing is bad", therefore, high clayey  We observed a significant direct linear 545 correlation (P < 0.001) between all 502 the data points of the rates of N2O and CO2 emission from animal manure exerted on 503 straw beddings (Fig. 4). This relationship was much similar to the relation between the aforementioned gases emitted after decomposition of plant residues in soil as 505 observed by Huang et al. (2004). In both studies, labile organic compounds from 506 organic matter (plant residues or manure) subjected to microbial decomposition and 507 nutrient mineralization which resulted to enhance the substrate (e.g. NH4 + ) for the 508 processes of nitrification and denitrification (Millar et al., 2004) (Table 5).
Generally, it is recommended to keep all animal hygiene, health, and 538 environment aspects in mind while working with bedding additives. Cleanliness of 539 bulls is considered as an important factor to ensure hygienic production of meat and 540 animal's well-being. We measured this parameter from all the treatments and found 541 that the bulls kept on the straw beddings mixed with zeolite and sandy soil were much 542 cleaner than those of lava meal mixed bedding were. This could be linked to the

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The results clearly indicated that using sandy soil, zeolite and lava meal as additives 553 in animal bedding has a great potential to reduce NH3 and total N losses from straw-