Ammonia loss from soil during incubation and drying

Abstract

The loss of ammonia by volatilization during incubation and soil drying and contamination of soil samples during drying were studied in the laboratory. Aqua ammonia placement treatments produced a range of soil nitrate and ammonium levels, which produced different amounts of ammonia upon incubation and drying. Recovery of applied N as mineral N and volatilized N in acid traps was virtually complete, indicating that ammonia volatilization was the only significant N loss process. When aqua ammonia was applied to the surface, 57% was volatilized, compared with only 2% when the fertilizer was deep placed. Ammonia volatilization decreased with time; most of the loss occurred during the first day after fertilizer application and ammonia loss was virtually complete within 8 days of incubation. Regression analysis indicated loss of ammonia on soil drying could be explained by the initial ammonia concentration and the time from fertilizer application; approximately 40 days from fertilizer application were required for complete chemical adsorption of ammonia (i.e. no ammonia loss on drying).

Unfertilized soils absorbed up to 66 mg N/kg of the ammonia volatilized from fertilized soils when dried together in the same oven. We conclude that where accurate ammonium analysis is required on recently fertilized soil, undried soil should be used. This eliminates ammonia loss during drying and cross‐contamination of samples. Drying of soil did not affect the recovery of nitrate N, as nitrate was not volatilized or denitrified.     

Ammonia emissions from fields treated with green manure in a Mediterranean climate

The ammonia flux from a green manured field was measured at a site in southern Italy. The green manure was provided by ploughing in about 66 and 78 t ha⁻¹ of broad beans at the flowering stage during the spring in 1995 and 1996. The NH₃ flux was estimated by means of the micrometeorological simplified aerodynamic method with the ammonia concentration measured at two levels above soil surface. Ammonia concentration was measured over a 2–3 h sampling period by trapping air NH₃ in a H₂SO₄ solution and analysing this sample in the laboratory with the colorimetric method using the Nessler solution. About 70% of the total amount of ammonia was emitted in the first two days immediately after manuring. The NH₃ flux was regulated by the same mechanism as the water vapour transport. Seventy percent of the daily ammonia was emitted around noon. The ammonia emission stopped during rainy and cold days and started again as soon as solar radiation, soil and air temperature increased, following plant decomposition. The total amount of ammonia emitted in the experimental period (28 days in 1995 and 18 days in 1996) was about 13 kg ha⁻¹ for both years.     

滇池流域原位模拟降雨条件下不同有机肥用量的农田氮素流失研究

在滇池流域的花卉(呈贡县大渔乡)、粮食(晋宁县晋城镇)及蔬菜(晋宁县新街乡)3种土地利用类型,应用原位模拟人工降雨设备,对其施用不同数量的有机肥后,地表径流和渗漏水中的水溶性总氮和总氮的浓度、数量变化特征进行了研究.所用的有机肥为未腐熟新鲜有机肥(鸡粪),模拟降雨量为120 mm,雨强采用40 mm/h模拟渗漏流失过程和120 mm/h模拟径流流失过程,有机肥用量分别为0、15、30、75、150 t/hm~2.结果表明:不同土地利用类型径流与渗漏水量存在显著差异;径流和渗漏两种流失途径下,总氮(TN)和水溶性总氮(DTN)的流失浓度、流失量均与有机肥间存在显著线性相关,渗漏水与径流水中的TN、DTN平均浓度与有机肥用量间的相关系数为0.999 3、0.981 3、0.994 6和0.982 0,渗漏与径流途径的TN、DTN流失总量平均值与有机肥用量间的相关系数为0.990 5、0.984 5,0.997 3和0.989 5.且不同土地利用类型,径流和渗漏流失的TN、DTN量平均值也表现出集约化蔬菜及花卉农田高于大田.DTN是滇池流域氮的主要流失形态.     

除氨菌系对牛粪堆肥氮素转化的影响

为了减轻牛粪堆肥过程中NH3释放对环境的污染及氮素损失,在牛粪堆肥时添加除氨菌系,研究其对氮素形态转化的影响。加除氨菌系处理的NH4+-N、NH3较对照分别降低20.47%和61.21%,全氮、NO3--N较对照分别提高11.63%和65.01%,酸解有机氮、氨基酸态氮、酰胺态氮和氨基糖态氮含量分别提高12.42%、11.26%、16.92%和19.51%。表明除氨菌系在牛粪堆肥过程中,能够固定NH4+-N向有机氮各组分转化,减少NH3挥发,具有较好的保氮作用。     

华北地区施用有机肥对土壤氮组分及农田氮流失的影响

为研究有机肥施入土壤后引起的土壤氮组分含量变化对农田氮流失的影响,采用小区试验,并结合田间原位模拟降雨试验,分析施用的有机肥中氮组分的量、土壤氮含量、农田氮素流失浓度及流失量三者间的关系。结果表明:有机肥中酸解氨基酸氮、酸解铵态氮含量占全氮比例分别为28.6%～40.6%,21.3%～33.2%,平均为35.4%、26.4%,是有机肥氮的主要组分;随着单位面积施入农田的有机肥中酸解氨基酸氮、酸解铵态氮(均为可矿化氮)的量增加,0～20 cm土层土壤可矿化氮含量也增加,二者呈极显著正相关;随着耕层土壤中可矿化氮含量增加,农田渗漏液中总氮、水溶性总氮、硝态氮浓度增高,二者呈显著或极显著正相关;随着施用有机肥中可矿化氮的量增多,径流液中总氮、水溶性总氮流失量增加,渗漏液中总氮、水溶性总氮、硝态氮浓度及流失量增高,分别呈显著和极显著正相关。因此,农田中高量施入有机肥,可造成土壤可矿化氮含量增加,农田氮素流失风险也随之增大。     

Ammonia volatilization and carbon dioxide emission from poultry litter: Effects of fractionation and storage time

Abstract

In many poultry producing areas, the amounts of poultry litter generated exceeds the amounts needed for application to soil, as fertilizer, at environmentally safe rates. To reduce the amounts of litter produced, Ndegwa et al. (1991) proposed fractionating the litter to generate a fine fraction that could be used as fertilizer, and a coarser fraction that could be recycled into poultry houses as bedding material. Because the fine fraction may need to be stored for several months before land application, knowledge of the changes that occur during storage would be important from the point of view of litter utilization. The objective of this study was to monitor water and inorganic nitrogen (N) contents, as well as potential ammonia (NH₃) volatilization and carbon dioxide (CO₂) emission in samples of whole litter and fine fraction stored in an unheated building for 16 weeks. Potential NH₃ volatilization and CO₂ emission were measured at unamended water contents and at a water content of 0.5 kg kg^‐1. Water and inorganic N contents of the whole litter and fine fractions showed some fluctuations during the first 4 weeks, but remained relatively stable from weeks 4 to 16. At unamended water contents, potential NH₃ volatilization and CO₂ emission were relatively low and similar for the whole litter and the fine fraction. Also, potential NH₃ volatilization remained stable whereas CO₂ emission decreased with time. Increasing the water content to 0.5 kg kg^‐1significantly increased potential NH₃ volatilization and CO₂ emission in the whole litters and fine fractions, with larger increases usually observed in the fine fractions. At 0.5 kg kg^‐1, both potential NH₃ volatilization and CO₂emission decreased with time. These results suggest that the fine fraction and the whole litter should be stored at relatively low water contents to prevent N losses through NH₃ volatilization and possibly denitrification.     

塑料薄膜覆盖对牛粪便温室气体排放的影响

为控制短期贮存畜禽粪便的温室气体排放,该文研究了塑料薄膜覆盖对肉牛粪便短期贮存过程中温室气体排放量的影响。试验采用静态箱-气相色谱法观测了秋季(日均22.87℃)肉牛粪便自然露天堆放(对照组)和塑料薄膜覆盖堆放(覆盖组)时温室气体的排放通量。结果表明:秋季覆盖塑料薄膜贮存粪便可使N2O和CO2的日均排放通量分别降低94.85%(P0.01)和88.85%(P0.01),并在试验前期(0~9 d)使CH4的日均排放通量降低了43.37%(P0.05),但随后的10~30 d,覆盖组粪便CH4的日均排放通量极显著高于对照组(P0.01)。结论:当环境温度在17.23~30.35℃时,覆盖塑料薄膜可以降低堆放贮存(0~30 d)粪便N2O和CO2的排放通量以及堆放初期(0~9 d)CH4的排放通量。因此,塑料薄膜覆盖贮存法可显著降低粪便堆放初期的温室气体排放。     

Hydrogen sulfide assessment in shallow-pit swine housing and outside manure storage

In Saskatchewan, some recent incidents have lead us to believe that certain manure management activities can potentially release high concentrations of H2S into the atmosphere of shallow-pit barns. The objectives of the monitoring project reported here were to evaluate worker exposure to H2S during the completion of the following tasks: emptying of in-barn shallow manure pits, power washing of barn rooms, and agitation and emptying of outdoor manure storage facilities. In-barn monitoring was performed in gestation, farrowing, nursery, and grow-finish sections in the summer of 2001 and the winter of 2002 on four different farms. Plug pulling can generate very high concentrations of H2S. The maximum values recorded during some of the monitored events reached 1,000 ppm. The H2S released as a plug is being pulled does not follow a predictable pattern when considering the level that will be reached, the concentration variations during the event, and the time at which the peak concentration will be observed. Power washing generated lower H2S concentrations than plug pulling. However, as the task to be performed generally takes time, the 15 min time-weighed average of 15 ppm (STEL) can be reached after the task started and can be exceeded for a long period of time, which for some of the monitored events was more than 30 min. Finally, monitoring at the storage facilities showed that the risks of exposure to excessive H2S concentrations during the agitation and emptying of outside manure storage facilities were very limited. Results from this study suggest that pig production buildings involving short-term storage of liquid manure may present H2S exposure risks that have been underestimated until now. All workers should be provided with an H2S monitor and safety equipment to ensure that workers are protected when the H2S concentration rises. As well, engineering controls have to be developed to prevent H2S formation in the manure or H2S emission into the worker/pig space.     

规模化养猪场粪污全量收集及贮存工艺设计

基于全量收集的粪污贮存技术具有粪尿收集方便、运行成本低廉和养分利用率高等特点,在欧美等发达国家得到了普遍应用,是一种适合在中国华北、西北等地区和土地匹配较充足的区域进行推广的粪污处理与还田利用技术。文章以规模化养猪场尿泡粪全量贮存技术为研究对象,分析了尿泡粪收集量、贮存工艺控制参数、贮存设施设计和投资运行成本等内容,旨在为该技术的推广应用提供参考。结果表明：每头生猪整个饲养周期内尿泡粪收集量为0.70 m3;粪污贮存设施分为舍内贮存池和舍外贮存罐2种,粪污贮存方法可采取舍内贮存、舍外贮存和舍内结合舍外贮存3种。粪污pH值酸化至5.5～6.5,氨排放量最高可减少80%;粪肥还田前一般要求存储时间为6个月。以存栏5 000头规模养猪场为例,舍内贮存池所需容积为6 600 m3,投资660万元;舍外贮存罐所需容积为4 118 m3,投资206万元;舍内结合舍外贮存设施所需容积为8 214 m3,投资651万元;粪污处理成本为3.83万元/a,施肥成本为10.8万元/a;全部粪肥还田可满足133 hm2农田用肥,节省化肥6.0万元/a,该研究可为粪污贮存及利用提供参考。     

覆盖材料和厚度对堆存牛粪氨气和温室气体排放的影响

为了研究锯末和稻草2种材料覆盖以及不同厚度的锯末覆盖对牛粪堆存过程中氨气(NH3)和温室气体(N2O、CH4和CO2)排放量的影响,采用静态箱的方法测试了不同覆盖厚度(1、3和5 cm)和2种材料(锯末和稻草)覆盖下牛粪NH3、N2O、CH4和CO2排放量。结果表明,在不同厚度锯末覆盖的试验中,与不覆盖处理组相比,覆盖降低了牛粪NH3和CO2累积排放量,但覆盖显著增加了牛粪N2O和CH4累积排放量(P0.05);3个覆盖处理组内,NH3、N2O和CO2排放量随着覆盖厚度的增加而下降,然而,CH4排放量随着覆盖厚度的增加而升高;1、3和5 cm厚锯末覆盖的牛粪总温室气体排放量分别为108.61、103.57和101.36 g/kg,与1 cm锯末覆盖相比,3和5 cm厚锯末覆盖的牛粪总温室气体排放量显著降低(P0.05)。在相同质量的锯末(2 cm厚)和稻草(6 cm厚)2种材料覆盖的比较试验中,2种材料覆盖都显著降低了牛粪NH3和CO2的累积排放量(P0.05),但同时也显著增加了CH4的累积排放量(P0.05);锯末覆盖增加了牛粪N2O累积排放量(P0.05),而稻草覆盖则降低了牛粪N2O累积排放量(P0.05)。与锯末覆盖相比,稻草覆盖显著增加了CH4的累积排放量(P0.05),但同时显著降低了牛粪CO2的累积排放量(P0.05);锯末覆盖和稻草覆盖牛粪总温室气体排放量分别为101.51和109.46 g/kg,与锯末覆盖相比,稻草覆盖显著增加了牛粪总的温室气体排放量。试验结果表明,较厚的锯末(3和5 cm)覆盖对牛粪NH3和温室气体的减排效果更好。     

典型双季稻田基施碳酸氢铵和尿素的氨挥发损失研究

采用密闭室连续抽气法研究了湖南典型双季稻田,尿素和碳酸氢铵基施后的氨挥发特征。结果表明,基施碳酸氢铵(NC)稻田初始氨挥发强度和氨挥发总量大于基施尿素(UR)稻田。早稻季NC处理稻田氨挥发排放量为45.19 kg·hm-2,损失率达30.12%,UR处理氨挥发排放量为32.93 kg·hm-2,损失率达21.95%;晚稻季NC处理稻田氨挥发排放量为70.91 kg·hm-2,损失率达31.93%,UR处理氨挥发排放量为61.78 kg·hm-2,损失率达27.04%。基施尿素能够显著降低稻田氨挥发排放,减少氮素损失。     

添加硫酸对羊粪堆肥进程及氮素损失的影响

为研究不同浓度硫酸对羊粪堆肥进程及氮素损失的影响,以羊粪和小麦秸秆为堆肥材料,分别配置浓度为1、2、3 mol/L的硫酸作为添加剂,采用条垛式堆肥进行50 d的试验,监测堆肥过程中的温度、pH值、EC值、种子发芽指数、C/N及氮损失率。结果表明：添加硫酸处理的堆体温度升到50℃以上需要的时间比未添加硫酸的CK处理缩短4～6 d,堆体的高温保持时间随加入硫酸浓度的升高而延长,EC值、种子发芽指数随硫酸浓度的升高而增大,硫酸浓度为2和3 mol/L处理的种子发芽指数分别为83.0%和84.2%,堆肥产品的全氮含量分别比CK处理提高16.32%和13.16%。硫酸浓度为2 mol/L时,总氮损失率最低为24.03%,保氮效果最好。羊粪条垛堆肥过程中,分别在第0、10、20 d添加浓度为2 mol/L的硫酸2 L/m3,不仅可以加快堆肥腐熟进程,而且可以提高堆肥产品的全氮含量,保氮效果显著。本研究为硫酸添加剂应用于畜禽粪污堆肥生产优质有机肥提供理论依据。     

滇池流域人工模拟降雨条件下农田施用有机肥对磷素流失的影响

应用田间原位人工模拟降雨的方法,在滇池流域不同作物类型农田上研究了有机肥（猪粪）不同用量水平对农田磷素流失的影响。结果显示,随着有机肥（猪粪）施用量的增加,农田流失液中各形态磷素的平均浓度提高,两者间呈显著正相关,相关系数均达到0..9以上。径流方式下,颗粒态磷是主要流失形态;渗漏方式下,有机肥用量水平低时颗粒态磷是主要流失形态,有机肥用量达到中等至较高水平时水溶性是流失的主要形态。同一有机肥用量水平下,不同作物类型农田流失液中各形态磷素的平均浓度均表现为:蔬菜田花卉田粮田。     

The origin and loss of fractal scaling in simulated soil aggregates

A growing body of evidence supports the use of fractals to approximate the heterogeneous structure of soil. Fractal models of transport processes in soil indicate that the fractal dimension and the upper limit to fractal scaling (denoted ξ) determine flow rates and scaling properties. A two-dimensional Monte Carlo simulation of soil aggregation is used to identify the key processes which may lead to fractal-like scaling in the soil matrix. A bonding law is developed which parameterizes the relative importance of chemical bonding to binding by microbial by-products and fungi. We investigate the sensitivity of the fractal dimension and ξ to the nature of the bonding law, and to aggregate fragmentation, initial particle size distribution and mechanical restructuring. Fractal-like structures result from the aggregation process. However, the measured fractal dimension is insensitive to the detailed form of the bonding law. The factor that most sensitively influences the fractal dimension is found to be mechanical restructuring such as would arise from the action of roots, soil fauna and natural weathering. By contrast, ξ is most sensitive to the bonding law. The results suggest that the fractal dimension and characteristic diameter of aggregates should be uncorrelated, and that increased binding by microbial by-products and fungi should produce larger, less dense, aggregates.     

An evaluation of furrows for managing soil and water loss from a shallow Alfisol under simulated rainfall

Furrows are widely used in rainfed areas of semi-arid India for soil and water conservation. The orientation of furrows, either down or across slope, and their spacing influence the effectiveness of furrows as soil and water conservation measures. We evaluated treatments with furrows aligned down and across 3% sloping land at spacings of 90, 60 and 30 cm under simulated rainfall intensities of 80 and 100 mm/h on a shallow Alfisol. A bare plot without any furrows was considered as a control. A large (24 m × 3 m) rainfall simulator developed at the Central Research Institute for Dryland Agriculture (CRIDA), Hyderabad, was used for this controlled study. Run-off was measured by a calibrated tipping bucket run-off recorder. The effects of the treatments on peak flow rate (L/s), sediment loss with run-off water (kg/ha/mm), peak sediment concentration (g/L), run-off (per cent rainfall) and time to peak (min) were investigated. When compared with the control (no furrows), across slope furrowing with 60- and 30-cm spacing reduced sediment yields by 19.9 and 21.3 kg/ha/mm of run-off, respectively, under a rainfall intensity of 80 mm/h and 24 and 25.3 kg/ha/mm of run-off, respectively, under a rainfall intensity of 100 mm/h. For the control, sediment loss was 50.72 kg/ha/mm run-off and 56.68 kg/ha/mm run-off for rainfall intensities of 80 and 100 mm/h, respectively. Similar trends were recorded from observations of peak flow, time to peak and peak sediment concentration. Run-off hydrographs demonstrated the conservation value of across slope furrowing by delaying run-off initiation, reducing run-off and slowly releasing the run-off after the cessation of rainfall. The results show that furrow orientation has major effects on reducing run-off, whereas furrow spacing has insignificant effects.     

添加剂对猪粪秸秆堆肥的氮素损失控制效果

为减少堆肥过程中的氨气挥发和氮素损失,该文以新鲜猪粪和玉米秸秆为原料,采用强制通风静态垛堆肥装置进行35 d的好氧堆肥试验,研究2种固氮添加剂(过磷酸钙+氢氧化镁、磷酸+氢氧化镁)对猪粪秸秆堆肥过程中的氮素损失控制效果。结果表明:添加适量的固氮剂均可降低堆肥化过程中氨气的排放率。过磷酸钙+氢氧化镁处理相比较对照和磷酸+氢氧化镁处理,氮素固定率较高,固氮效果较好。与对照处理相比,该处理在整个堆肥过程中的累积氨气挥发量和总氮损失分别降低了41.78%和13.27%;在堆肥结束时,铵态氮和硝态氮含量分别提高了60.00%和24.66%。最终堆肥产品的种子发芽率指数为97.22%~115.86%,表明所有处理在堆置35 d后均达到腐熟。X射线衍射分析证实了添加固定剂处理的堆肥产品中均有鸟粪石(Mg NH_4PO_4·6H_2O)的存在,说明通过添加过磷酸钙+氢氧化镁、磷酸+氢氧化镁2种固定剂可以改变堆肥的理化性质,促进堆肥的降解和腐熟。     

有机肥种类对土壤有效磷累积量的影响及其流失风险

为研究不同有机肥种类对土壤有效磷累积量的影响,采用鸡粪、猪粪、牛粪3种有机肥,于2008~2009年间在河北省廊坊进行了大田试验。结果表明:在总磷量相同条件下施入不同种类有机肥,耕层土壤中水溶性磷和有效磷含量显著不同。施入牛粪、鸡粪、猪粪的土壤0~5 cm土层中土壤水溶性磷分别为15.64、12.06、9.95mg/kg,有效磷含量分别为91.87、73.47、65.26 mg/kg;综合0~20 cm土层,施入牛粪、鸡粪、猪粪的土壤水溶性磷分别为6.42、4.84、4.41 mg/kg,有效磷含量分别为47.60、35.50、35.14 mg/kg。表现出有机肥中有效磷含量高则表层土壤中水溶性磷和有效磷含量也高。由于表层土壤的高量水溶性磷和易溶性磷在降雨条件下易于造成农田磷素流失,在确定环境友好的有机肥施用量时,不仅要考虑有机肥带入的总磷量,还要重视有机肥中有效磷含量对农田表层土壤水溶性磷和易溶性磷富集的影响。