Volatilization of ammonia from manure as affected by manure additives, temperature and mixing

Ammonia (NH(3)) volatilization decreases the N-nutrient value of livestock manure slurries and can lead to soil acidification and eutrophication problems. In this study the effect of three manure additives (Euro Mest-mix (Mx), Effective Micro-organisms (EM), and Agri-mest (Am)) on NH(3) volatilization at three temperatures (4, 20, and 35 degrees C) was investigated. The manufacturers claim that Mx contains absorbing clay minerals and that applying Am and EM to slurry will reduce nitrogen losses, most likely by enhancing the biodegradation of manure slurry. Furthermore, the effect of mixing slurry on NH(3) volatilization has been investigated. Ammonia volatilization increased with increasing temperature and mixing of the slurries. However, at 35 degrees C mixing of manure reduced NH(3) emissions compared to non-mixing, which is related to a reduced crust resistance to gaseous transport at higher temperatures for non-mixing. Moreover, mixing introduces oxygen into the anaerobic slurry environment which will slow down microbial activity. The use of additives did not change manure characteristics (pH, dry matter, N(total), N(mineral), C/N, and C/N(organic)) and did not result in a significant (p<0.05) decrease in NH(3) emissions, except that at 4 degrees C and no mixing a significant decrease of 34% in NH(3) volatilization was observed, when Am and EM together, were applied to slurry.     

Effect of phenylphosphorodiamidate on urea hydrolysis,ammonia volatilization and rice growth in an alkali soil

Summary In order to improve nitrogen recovery by rice, the effect of a urease inhibitor phenylphosphorodiamidate (PPD) on the efficiency of fertilizer urea was studied in laboratory and greenhouse. Addition of PPD to urea (5% w/w) delayed urea hydrolysis by 3 to 4 days and reduced ammonia volatilization from 45% (without PPD) to 8.5% (with PPD). Ammonia volatilization obeyed first order kinetics. Urea hydrolysis was sufficiently strongly inhibited to match the nitrification potential of the soil. N application to rice by three different modes showed that a delayed mode (4 splits) was superior to two conventional modes (3 splits) in nitrogen recovery and fertilizer efficiency since it met nitrogen requirement of plants at reproductive stage. In 2 out of 3 modes of application, there was a 14% increase (relative) in grain yields and dry matter, and 6.8% increase in N uptake efficiency on application of PPD along with urea. The results indicate that urease inhibitors like PPD can be effectively used to block urea hydrolysis, reduce ammonia volatilization losses and improve N use efficiency by rice.     

A Determination and Comparison of Urease Activity in Feces and Fresh Manure from Pig and Cattle in Relation to Ammonia Production and pH Changes

Ammonia emission from animal production is a major environmental problem and has impacts on the animal health and working environment inside production houses. Ammonia is formed in manure by the enzymatic degradation of urinary urea and catalyzed by urease that is present in feces. We have determined and compared the urease activity in feces and manure (a urine and feces mixture) from pigs and cattle at 25°C by using Michaelis-Menten kinetics. To obtain accurate estimates of kinetic parameters V_max and K''_m, we used a 5 min reaction time to determine the initial reaction velocities based on total ammoniacal nitrogen (TAN) concentrations. The resulting V_max value (mmol urea hydrolyzed per kg wet feces per min) was 2.06±0.08 mmol urea/kg/min and 0.80±0.04 mmol urea/kg/min for pig feces and cattle feces, respectively. The K''_m values were 32.59±5.65 mmol urea/l and 15.43±2.94 mmol urea/l for pig feces and cattle feces, respectively. Thus, our results reveal that both the V_max and K''_m values of the urease activity for pig feces are more than 2-fold higher than those for cattle feces. The difference in urea hydrolysis rates between animal species is even more significant in fresh manure. The initial velocities of TAN formation are 1.53 mM/min and 0.33 mM/min for pig and cattle manure, respectively. Furthermore, our investigation shows that the maximum urease activity for pig feces occurs at approximately pH 7, and in cattle feces it is closer to pH 8, indicating that the predominant fecal ureolytic bacteria species differ between animal species. We believe that our study contributes to a better understanding of the urea hydrolysis process in manure and provides a basis for more accurate and animal-specific prediction models for urea hydrolysis rates and ammonia concentration in manures and thus can be used to predict ammonia volatilization rates from animal production.     

Managing ammonia emissions from dairy cows by amending slurry with alum or zeolite or by diet modification

Animal agriculture is a significant source of atmospheric ammonia. Ammonia (NH3) volatilization represents a loss of plant available N to the farmer and a potential contributor to eutrophication in low-nitrogen input ecosystems. This research evaluated on-farm slurry treatments of alum or zeolite and compared three diets for lactating dairy cows in their effectiveness to reduce NH3 emissions. NH3 emissions were compared using a group of mobile wind tunnels. The addition of 2.5% alum or 6.25% zeolite to barn-stored dairy slurry reduced NH3 volatilization by 60% and 55%, respectively, compared to untreated slurry. The alum conserved NH3 by acidifying the slurry to below pH 5, while the zeolite conserved ammonia by lowering the solution-phase nitrogen through cation exchange. The use of alum or zeolite also reduced soluble phosphorus in the slurry. NH3 loss from fresh manure collected from lactating dairy cows was not affected by three diets containing the same level of crude protein but differing in forage source (orchardgrass silage vs. alfalfa silage) or neutral detergent fiber (NDF) content (30% vs. 35% NDF). NH3 losses from the freshly excreted manures occurred very rapidly and included the urea component plus some unidentified labile organic nitrogen sources. NH3 conservation strategies for fresh manures will have to be active within the first few hours after excretion in order to be most effective. The use of alum or zeolites as an on-farm amendment to dairy slurry offers the potential for significantly reducing NH3 emissions.     

脲酶抑制剂和硝化抑制剂的协同作用对尿素氮转化和N2O排放的影响

根据培养试验,论述了脲酶抑制剂氢醌和硝化抑制剂双氰胺和碳化钙的不同组合在土壤正常水分和渍水的条件下对于土中尿素的水解及其释出的氨的吸附、氧化和挥发以及Ｎ２Ｏ生成的影响．文章指出,配合使用氢醌和双氰胺既能延缓土中尿素的水解并使水解后释出的氨在土中得以更多和更长时间的保持,还能减少土中硝酸盐的累积、氨挥发的损失及Ｎ２Ｏ的生成．这表明在脲酶抑制剂和硝化抑制剂间可能存在一定的协同作用．很好利用这一作用,将有益于提高尿素肥效和减少其Ｎ损失与环境污染．     

水氮互作对冬小麦田氨挥发损失和产量的影响

2015-2017年利用水肥渗漏研究池,以‘石麦15’(SM15)为材料,采用随机区组设计,设置2个氮肥类型(尿素和有机肥牛粪)、2个施氮水平(180和90 kg·hm^-2)、2个灌溉水平(500和250 mm)进行试验,探讨水、氮及其互作对冬小麦田土壤氨挥发损失量和籽粒产量的影响.结果表明: 施肥以后土壤氨挥发持续7 d左右.2015-2016年施肥后各处理土壤氨挥发损失总量为13.36～46.04 kg·hm^-2,氨挥发氮肥损失率为8.9%～41.1%,2016-2017年各处理土壤氨挥发损失总量为14.78～52.99 kg·hm^-2,氨挥发氮肥损失率为9.2%～45.8%;两年试验内氨挥发损失量最多的处理为W₂U₁(施尿素N 180 kg·hm^-2,灌溉量250 mm),氨挥发损失率最高的处理为W₂U₂(施尿素N 90 kg·hm^-2,灌溉量250 mm),合理的水氮管理可以显著降低土壤氨挥发损失率,施用尿素造成的土壤氨挥发损失为有机肥的2～3倍.两年试验均以W₁M₁(施牛粪N 180 kg·hm^-2,灌溉量500 mm)的小麦产量最高,灌溉量、肥料类型和施氮量互作对冬小麦产量影响极显著.综合氨挥发损失量和冬小麦籽粒产量,本试验条件下,水氮互作效应显著,冬小麦生育期内总灌溉量500 mm、施有机肥180 kg·hm^-2时冬小麦季土壤氨挥发损失率较低,产量最高,施用有机肥的增产效果优于尿素,可作为黄淮海地区冬小麦实际生产中增产增效的水肥优化管理方式.     

持续施用缓/控释尿素条件下水田土壤NH3挥发与N2O排放特征

以持续9年施用不同缓／控释尿素的水田棕壤为试验对象,以普通大颗粒尿素为对照,研究了持续施用不同缓／控释尿素条件下水田土壤NH₃挥发与N₂O排放特征.结果表明: 与普通大颗粒尿素(U)相比,除1% 3,4－二甲基吡唑磷酸盐(DMPP)+U处理 NH₃挥发增加了25.8%外,其他缓／控释尿素肥料处理对NH₃有明显的减排效果.树脂包膜尿素(PCU)对NH₃减排效果最明显,为73.4%,硫包膜尿素(SCU)为72.2%,0.5% N-丁基硫代磷酰三胺(NBPT)+1% DMPP+U为71.9%,1% 氢醌(HQ)+3% 双氰胺(DCD)+U为46.9%,0.5% NBPT+U为43.2%,1% HQ+U为40.2%,3% DCD+U为25.5%, 1% DMPP均与施用普通大颗粒尿素差异显著;所有缓／控释尿素处理与对照相比均可显著减少N₂O排放.1% DMPP+U对N₂O减排效果最明显,为74.9%,PCU为62.1%,1% HQ+3% DCD+U为54.7%,0.5% NBPT+1% DMPP+U为42.2%,3% DCD+U为35.9%,1% HQ+U为28.9%,0.5% NBPT+U为17.7%,SCU为14.5%,均与施用普通大颗粒尿素差异显著.比较0.5% NBPT+1% DMPP+U、SCU、PCU对NH₃和N₂O减排的综合效果,3种肥料作用相近,且均明显优于其他处理,但包膜材料的成本较抑制剂高数倍.因此,同时添加脲酶和硝化抑制剂的缓释尿素是减少水田氮素损失及环境污染的首选氮肥.     

几种控释氮肥减少氨挥发的效果及影响因素研究

采用“静态吸收法”和“土柱淋溶法”、室内模拟试验,研究几种控释氮肥施入土壤后的氨挥发损失情况、N溶出速率、土壤脲酶活性及pH值变化的关系．结果表明,施氮450mg·kg^-1土时,3种控释氮肥氨挥发损失氮总量分别比普通尿素减少49．7％、28．0％和71．2％;施氮600mg·kg^-1土时,3种控释氮肥氨挥发损失氮总量分别比普通尿素减少34．6％、12．3％和69．9％．控释氮肥能显著降低土壤氨挥发量,减少因施肥而引起的大气环境污染．控释氮肥氨挥发量与不同氮肥引起的土壤脲酶活性、pH值、土壤中氮溶出速率密切相关．土壤的氨挥发总量与肥料在土壤中溶出总量的相关系数达到0．9533,在肥料施入的前期土壤氨挥发量同土壤脲酶活性、pH值的相关系数达到0．9533和0．9908。     

Ammonia volatilization from a flooded tropical soil

Summary Ammonia volatilization, which follows upon the application of nitrogenous fertilizers to a flooded tropical soil, was directly measured in the greenhouse and in the field. Most of the ammonia volatilization losses occurred during the first 9 days after nitrogen application. Ammonia volatilization increased markedly with increases in soil pH. Nitrogen losses from ammonium sulfate applied to soils whose pH values were below 7.5 were very small. The losses from urea were much greater than those from ammonium sulfate. Mixing the fertilizer materials with the puddled soil reduced the losses. Ammonia losses from flooded soil were larger than from dry soil, and drying of a flooded soil reduced the duration and magnitude of ammonia volatilization. It is suggested that only a small amount of nitrogen is being lost through ammonia volatilization from many lowland rice soils. re]19750820     

Ammonia volatilization from tropical legume mulches and green manures on unlimed and limed soils

In the humid tropics, legumes are harvested and surface applied as mulch or incorporated as green manure. Studies on N dynamics and budgets from these systems report unaccounted losses of N. Ammonia volatilization may account for a significant percentage of these unexplained N deficits. The main objectives of this study were to: 1) determine the rate and amount of ammonia volatilization from organic amendments, both incorporated (green manure) and unincorporated (mulch), 2) compare ammonia volatilization of organic amendments on both acid (unlimed) and limed soils, and 3) correlate quality, i.e. polyphenolic and lignin concentration and carbon-to-nitrogen ratio, of the organic amendments with ammonia volatilization and net N mineralization. In an incubation experiment, ammonia volatilization losses and net N mineralization were measured from fresh leaflets of 10 legumes over a three-week period. Ammonia volatilization losses for the 10 species ranged from 3.4 to 11.8% of the total N applied in the organic amendment. Lignin content was negatively correlated to ammonia volatilization. Ammonia volatilized from mulches but not green manures, on both unlimed and limed soils, suggesting that ammonia volatilization is a surface phenomenon and not affected by soil pH. Net N mineralization was affected by species and soil pH, but was unaffected by placement (green manure or mulch). For the farmer in low-input agriculture where N tends to be limiting, volatilization losses of N from legume mulch systems could be on the same order of magnitude as crop removal.     

Patterns of ammonia volatilization from a forest soil

Summary Ammonia volatilization from urea-treated soils was estimated under field and laboratory conditions. Acid-washed filter papers were hung in the air in a spruce stand treated with N and P fertilizers in a factorial design. In the laboratory, moss sods were incubated to quantify ammonia volatilization.Ammonia volatilization increased with the level of N applied and more ammonia was absorbed by filter papers at 0.6 m above the ground than those at 1.2 m. Maximum rates of ammonia volatilization in urea-treated plots were observed between the third and fourth day after fertilizer application and similar absorption patterns were observed in areas not treated with urea. It is, therefore, suggested that ammonia volatilized from urea-treated plots can move to untreated areas. Addition of P along with urea significantly reduced ammonia volatilization under field conditions.Laboratory experiments showed that addition of urea to moss sods increased the pH of the organic layer from about 3.6 to 8.8. Sphagnum moss sods volatilized more ammonia (about 1.7 per cent of the added material) than feather moss sods (about 0.8 per cent). At higher incubation temperatures, however, the rate of ammonia volatilization decreased in sphagnum moss sods but increased in feather moss sods.     

生物炭配施硝化/脲酶抑制剂对亚热带水稻土活性氮气体排放的影响

探究施用生物炭和脲酶抑制剂/硝化抑制剂对亚热带水稻土氮素硝化过程的调控作用、氨挥发和N₂O排放的温室效应潜能的影响,确定生物炭与硝化和脲酶抑制剂的最佳组合,可为削减施用氮肥带来的活性氮气体排放对环境的负面风险提供理论依据。本研究采用室内好气培养试验方式,以单施尿素(N)为对照,设置7个试验处理[尿素+生物炭(NB),尿素+硝化抑制剂(N+NI),尿素+脲酶抑制剂(N+UI),尿素+硝化抑制剂+脲酶抑制剂(N+NIUI),尿素+硝化抑制剂+生物炭(NB+NI),尿素+脲酶抑制剂+生物炭(NB+UI),尿素+硝化抑制剂+脲酶抑制剂+生物炭(NB+NIUI)],观测生物炭与脲酶抑制剂(NBPT)/硝化抑制剂(DMPP)配施下土壤无机氮含量、N₂O排放及氨挥发的变化动态。结果表明: 1)培养期间,与N处理(5.11 mg N·kg^-1·d^-1)相比,NB处理的土壤硝化速率常数显著增加33.9%,N+NI处理显著降低22.9%;NB处理显著提高了氨氧化细菌(AOB)丰度,增幅达56.0%。2)与N处理相比,N+NI和NB+NI处理的NH₃累积排放量均显著增加约49%;N+UI处理降低了NH₃累积损失量,NB+UI处理抑制效果更明显。3)各处理的N₂O排放速率高峰均出现在施肥后前10 d;NB处理的N₂O排放高峰出现最早,N处理排放速率最高(5.87 μg·kg^-1·h^-1);硝化抑制剂与脲酶抑制剂配施减少土壤N₂O排放的效果最佳。综合计算各处理直接N₂O和间接N₂O(NH₃)排放产生的温室效应潜能(GWP)发现,N+NI和NB+NI处理较N处理分别增加了34.8%和40.9%,而NB和NB+UI处理的GWP显著降低了45.9%和60.5%。因此,生物炭与脲酶抑制剂配施对降低土壤活性氮气体排放所产生的温室效应潜能效果最佳。     

Prevention and control of losses of gaseous nitrogen compounds in livestock operations: a review

Nitrogen (N) losses from livestock houses and manure storage facilities contribute greatly to the total loss of N from livestock farms. Volatilisation of ammonia (NH3) is the major process responsible for the loss of N in husbandry systems with slurry (where average dry matter content varies between 3 and 13%). Concerning this volatilisation of NH3, the process parameters of pH and air temperature are crucial. During a period of approximately 10 years, systematic measurements of NH3 losses originating from a large variety of different livestock houses were made. One of the problems with NH3 emissions is the large variation in the measured data due to the season, the production of the animals, the manure treatment, type of livestock house, and the manure storage. Generally speaking, prevention and control of NH3 emission can be done by control of N content in the manure, moisture content, pH, and temperature. In houses for growing pigs, a combination of simple housing measures can be taken to greatly reduce NH3 emissions. In houses for laying hens, the control of the manure drying process determines the emission of NH3. Monteny has built an NH3 production model with separate modules for the emission of the manure storage under the dairy house and the floor in the house. Manure spreading is also a major source of NH3 emission and is dependent on slurry composition, environmental conditions, and farm management. The effects of these factors have been employed in a model. Losses via NO, N2O, and N2 are important in husbandry systems with solid manure and straw. The number of experimental data is, however, very limited. As N2O is an intermediate product of complex biochemical processes of nitrification and denitrification, optimal conditions are the key issues in N2O reduction strategies. We may expect that in the near future the emission of greenhouse gases will get the same attention from policy makers as NH3. Sustainable livestock production has to combine low emissions of gaseous N compounds with acceptable odour emissions, low emissions of greenhouse gases, and acceptable standards of animal welfare. For the entrepreneur, the strategy must be built on the regulations, the special conditions of his farm, and what is reasonably achievable.     

Biochar from animal manure: A critical assessment on technical feasibility,economic viability,and ecological impact

Animal manure has been used to manage soil fertility since the dawn of agriculture. It provides plant nutrients and improves soil fertility. In the last decades, animal husbandry has been significantly expanded globally. Its economics were optimized via the (international) trade of feed, resulting in a surplus of animal manure in areas with intensive livestock farming. Potentially toxic elements (PTEs), pathogenic microorganisms, antibiotic residues, biocides, and other micropollutants in manure threaten animal, human, and environmental health. Hence, manure application in crop fields is increasingly restricted, especially in hotspot regions with intensive livestock activities. Furthermore, ammonia volatilization and greenhouse gas (GHG) emissions during manure storage, field application, and decomposition contribute to air pollution and climate change. Conventional manure management scenarios such as composting and anaerobic digestion partially improve the system but cannot guarantee to eliminate sanitary and contamination risks and only marginally reducing its climate burden. Hence, this review discusses the potential of pyrolysis, the thermochemical conversion under oxygen-limited conditions as an alternative treatment for animal manure providing energy and biochar. Manure pyrolysis reduces the bioavailability of PTEs, eliminates pathogenic microorganisms and organic micropollutants, and reduces GHG emissions. Pyrolysis also results in the loss of nitrogen, which can be minimized by pretreatment, that is, after removing soluble nitrogen fraction of manure, for example, by digestion and stripping of ammonia–nitrogen or liquid–solid separation. However, conclusions on the effect of manure pyrolysis on crop yield and fertilization efficiencies are hampered by a lack of nutrient mass balances based on livestock unit equivalent comparisons of manure and manure biochar applications. Hence, it is essential to design and conduct experiments in more practically relevant scenarios and depict the observations based on the amount of manure used to produce a certain amount of biochar.     

脲酶抑制剂氢醌对土壤尿素氮转化的影响

本文根据用标记和非标记尿素进行的培养试验,论述了氢醌对于尿素的水解、氨的释出和挥发、硝化和反硝化作用以及生物固持的影响。得出的结论是:氢醌的作用不仅在于延缓尿素的水解和减少随之而来的氨的挥发,更重要的,是影响了尿素水解产物进一步转化的进程,增强了尿素氮对于作物的有效持续供应和减少了它的总损失。本文认为,在脲酶抑制剂的研究中,着眼点当不仅在于它们的直接作用,而更需要涉及对尿素氮转化的一系列过程的影响。这样,才能对抑制剂的作用机理有更深入的了解,对它的作用效果有更全面的评价。     

Simulation of Long-Term Carbon and Nitrogen Dynamics in Grassland-Based Dairy Farming Systems to Evaluate Mitigation Strategies for Nutrient Losses

Many measures have been proposed to mitigate gaseous emissions and other nutrient losses from agroecosystems, which can have large detrimental effects for the quality of soils, water and air, and contribute to eutrophication and global warming. Due to complexities in farm management, biological interactions and emission measurements, most experiments focus on analysis of short-term effects of isolated mitigation practices. Here we present a model that allows simulating long-term effects at the whole-farm level of combined measures related to grassland management, animal housing and manure handling after excretion, during storage and after field application. The model describes the dynamics of pools of organic carbon and nitrogen (N), and of inorganic N, as affected by farm management in grassland-based dairy systems. We assessed the long-term effects of delayed grass mowing, housing type (cubicle and sloping floor barns, resulting in production of slurry and solid cattle manure, respectively), manure additives, contrasting manure storage methods and irrigation after application of covered manure. Simulations demonstrated that individually applied practices often result in compensatory loss pathways. For instance, methods to reduce ammonia emissions during storage like roofing or covering of manure led to larger losses through ammonia volatilization, nitrate leaching or denitrification after application, unless extra measures like irrigation were used. A strategy of combined management practices of delayed mowing and fertilization with solid cattle manure that is treated with zeolite, stored under an impermeable sheet and irrigated after application was effective to increase soil carbon stocks, increase feed self-sufficiency and reduce losses by ammonia volatilization and soil N losses. Although long-term datasets (>25 years) of farm nutrient dynamics and loss flows are not available to validate the model, the model is firmly based on knowledge of processes and measured effects of individual practices, and allows the integrated exploration of effective emission mitigation strategies.     

Supplementation of Poultry Feeds with Dietary Zinc and Other Minerals and Compounds to Mitigate Nitrogen Emissions—A Review

One of the environmental challenges that the poultry industry has been faced with is ammonia emission from manure. One way to reduce nitrogen excretion and emissions is supplementing dietary trace minerals to inhibit the activity of microbial uricase, a key enzyme converting nitrogen compounds in the manure into ammonia. Several dietary minerals are commercially available as economic alternatives for reducing ammonia emissions in poultry. In this review, we discuss different mineral elements including zinc as feed amendment minerals that could be used to reduce ammonia emission. Issues discussed include potential for inhibiting microbial uricase, dietary supplementation levels, growth performance, toxicity, their influence on manure nitrogen emission, and potential mineral accumulation in soil. In addition, we discuss other minerals and compounds that have the potential to reduce ammonia volatilization by inhibiting microbial uricase and growth of uric acid-utilizing microorganisms.     

不同包膜控释尿素对农田土壤氨挥发的影响

为了探索包膜控释尿素土壤氨挥发损失规律特征和提高肥料氮素利用率,采用小麦玉米轮作田间试验,通过与普通尿素进行对比,运用土壤氨挥发原位测定方法——通气法系统研究了硫包膜和树脂包膜控释尿素的施用对小麦玉米轮作农田土壤氨挥发的影响.研究结果表明:在两种施氮量水平下(210 kg/hm2和300 kg/hm2),与普通尿素相比,硫包膜和树脂包膜控释尿素在小麦基肥期、小麦追肥期和玉米施肥期的施用均减少了土壤氨挥发的累积损失量,分别达35.1％-54.3％、59.6％-75.2％、65.6％-98.1％;有效降低了土壤氨挥发通量峰值且延迟其出现时间3-8 d,并能延缓土壤氨挥发主要阶段的时间分别为4-12 d、5-12 d.在小麦玉米轮作周年中,控释尿素土壤氨挥发累积损失量为28.39-43.35 kg/hm2,土壤氨挥发损失率为4.48％-5.63％,控释尿素时段土壤氨挥发通量比普通尿素降低了51.0％-70.8％;且树脂包膜控释尿素的施用降低小麦玉米轮作农田土壤氨挥发的效果优于硫包膜控释尿素.     

脲酶抑制剂氢醌对土壤脲酶活性,氨挥发和硝化的抑制动态

1.氢醌对土壤脲酶活性的抑制率及其持续的时间同氢醌浓度成正相关,与土壤脲酶活性成负相关。2.氢醌能有效地抑制施入土壤中尿素氨的挥发,而对铵盐和尿素的硝化强度产生强烈抑制。3.在麦秸还田土壤中,由于脲酶活性增高而提高了施入尿素的水解速度,故需提高氢醌用量;但由于麦秸的“氮因子效应”又固定了尿素分解产物及其氧化产物,从而弥补了氢醌失效后可能造成氮素的继续损失。     

Mitigation of ammonia,nitrous oxide and methane emissions from manure management chains: a meta‐analysis and integrated assessment

Livestock manure contributes considerably to global emissions of ammonia (NH₃) and greenhouse gases (GHG), especially methane (CH₄) and nitrous oxide (N₂O). Various measures have been developed to mitigate these emissions, but most of these focus on one specific gas and/or emission source. Here, we present a meta‐analysis and integrated assessment of the effects of mitigation measures on NH₃, CH₄ and (direct and indirect) N₂O emissions from the whole manure management chain. We analysed the effects of mitigation technologies on NH₃, CH₄ and N₂O emissions from individual sources statistically using results of 126 published studies. Whole‐chain effects on NH₃ and GHG emissions were assessed through scenario analysis. Significant NH₃ reduction efficiencies were observed for (i) housing via lowering the dietary crude protein (CP) content (24–65%, compared to the reference situation), for (ii) external slurry storages via acidification (83%) and covers of straw (78%) or artificial films (98%), for (iii) solid manure storages via compaction and covering (61%, compared to composting), and for (iv) manure application through band spreading (55%, compared to surface application), incorporation (70%) and injection (80%). Acidification decreased CH₄ emissions from stored slurry by 87%. Significant increases in N₂O emissions were found for straw‐covered slurry storages (by two orders of magnitude) and manure injection (by 26–199%). These side‐effects of straw covers and slurry injection on N₂O emission were relatively small when considering the total GHG emissions from the manure chain. Lowering the CP content of feed and acidifying slurry are strategies that consistently reduce NH₃ and GHG emissions in the whole chain. Other strategies may reduce emissions of a specific gas or emissions source, by which there is a risk of unwanted trade‐offs in the manure management chain. Proper farm‐scale combinations of mitigation measures are important to minimize impacts of livestock production on global emissions of NH₃ and GHG.