妊娠猪舍氨气及氧化亚氮浓度测定与排放通量的估算

在北京选择一典型猪场,对不同季节妊娠舍的氨气及氧化亚氮浓度进行了为期1年的试验测定,并根据二氧化碳平衡原理,对猪场不同生长阶段的妊娠猪含氮气体的排放通量进行了估算。结果表明:冬季2004年11月氨气和氧化亚氮的平均浓度分别为(11．64±4．36),(1．17±0．2)mg／m~3,夏季7月舍内氨气和氧化亚氮的平均浓度分别为(3．31±2．67),(0．6±0．02)mg／m~3;妊娠猪饲养期间的氨气排放通量为每头(185．2～500．8)mg／h,氧化亚氮为(3．85～35．93)mg／h。     

猪舍氨气排放预测模型的研究现状

该文就氨气对环境的影响和猪舍氨气排放机制进行了简要的叙述，详细综述了氨气排放的机理模型和基于不同因素建立的经验模型。从中可以看出，国外对氨气排放的模型做了大量的研究，也取得了一定的研究成果，但是不同的研究结果有一定的差异。最后针对我国的实际情况，对我国氨气排放需进一步研究的问题进行了探讨。     

猪舍氨气排放预测模型的研究现状

该文就氨气对环境的影响和猪舍氨气排放机制进行了简要的叙述,详细综述了氨气排放的机理模型和基于不同因素建立的经验模型。从中可以看出,国外对氨气排放的模型做了大量的研究,也取得了一定的研究成果,但是不同的研究结果有一定的差异。最后针对中国的实际情况,对中国氨气排放需进一步研究的问题进行了探讨。     

育肥猪舍甲烷排放浓度和排放通量的测试与分析

畜禽养殖是重要的温室气体排放源,畜禽养殖的甲烷排放量受动物生长特性、粪便收集方式和气候条件的影响。为了探讨中国特有的饲养管理方式下育肥猪舍温室气体排放规律,为减少甲烷排放提供依据,该研究在北京选择一典型猪场,对不同季节育肥舍的甲烷排放浓度进行了试验测定,从2004年5月至2005年3月,每2个月一次连续采集72～80 h甲烷浓度和相关数据,并根据二氧化碳平衡原理,对猪场的甲烷排放量进行了估算。结果表明：育肥猪舍内甲烷浓度有明显的季节性和日变化特性,2005年1月舍内甲烷的平均浓度为(22.98±10.52)mg/m³,7月舍内甲烷浓度为(2.68±0.68)mg/m³;每日最低甲烷浓度出现在9:00 am～17：00 pm时段;冬季舍内二氧化碳浓度明显偏高,夜间比允许浓度高1倍;每头育肥猪饲养期间的甲烷排放量为68.10～207.01 mg/h,折合每标准动物单位排放量：436～1185 mg/h·(500 kg),在IPCC推荐的发展中国家猪呼吸代谢甲烷排放1.0 kg/(a·头)范围内。     

密闭箱处理蛋鸡粪的氧化亚氮氨气排放研究

采用密切箱处理蛋鸡粪的方法，研究了密闭箱内产生的氧化亚氮、氨气的排放规律、影响因子及两者存在的内在联系。结果表明，氧化亚氮的产生与有机质的含量以及蛋鸡粪内部的氧氧状况密切相关；氨气与氧化亚氮的逐日排放变化规律存在很大的相似性；蛋鸡粪的内部温度作用表现不明显，受外界气温影响很小。     

规模化笼养蛋鸡舍冬季氨气和颗粒物排放特征研究

畜禽养殖的氨气(NH3)和颗粒物(particulatematter,PM)排放已成为危害人畜健康,并可能造成环境风险的重大问题。该文选择北京郊区一典型规模化蛋鸡养殖舍,对典型冬季条件下蛋鸡舍的NH3和PM排放进行了连续8d的监测;并根据二氧化碳平衡原理,对NH3及PM的排放通量进行了估算。研究结果表明,蛋鸡舍出风口处NH3平均质量浓度为(4.58±3.29)mg/m3,每只鸡NH3排放通量为(32.2±12.5)mg/d。蛋鸡舍出风口处PM2.5、PM10和总悬浮颗粒物(total suspended particulates, TSP)质量浓度为(0.13±0.06)、(0.81±0.16)、(3.28±1.32)mg/m3,每只鸡PM2.5、PM10和TSP排放通量分别为(0.7±0.4)、(6.3±1.4)、(27.6±12.5)mg/d。氨气以及PM的排放均随着舍内1次/2 d的机械清粪频率呈现2 d的周期变化趋势。除清粪作业、鸡群日间活动等影响外,舍内PM2.5浓度一定程度上受舍外环境本底值影响。舍内PM2.5与PM10的比例在10.4%~20.4%之间。舍内PM2.5颗粒上所含的K+、Mg2+含量均显著高于舍外环境本底PM2.5(P0.05)。同时舍内及舍外PM2.5颗粒上解析出来的阳离子所带的电荷量均高于阴离子。研究结果可为畜禽养殖NH3和PM排放清单的编制提供基础参数;同时对畜禽舍PM的组分研究,可为后续开展二次无机气溶胶形成机理以及颗粒物源解析的研究提供支撑。     

影响氧化亚氮形成与排放的土壤因素

土壤中Ｎ２Ｏ形成、散发与地球温室效应有密切关系。土壤中Ｎ２Ｏ是通过硝化和反硝化过程形成的。由于硝化和反硝化过程中均产生Ｎ２Ｏ，故凡影响这两个过程的因素都会对Ｎ２Ｏ的形成发生作用。土壤通气状况、土壤水分含量、土壤氮素状况与氮肥施用、土壤ｐＨ、土壤有机物含量与组成、土壤质地结构及耕作利用等土壤因素都会影响Ｎ２Ｏ的形成与排放。     

农业土壤排放氧化亚氮的影响因素分析

氧化亚氮（Ｎ２Ｏ）是重要的温室气体之一。本文从施肥、灌溉、耕作、种植作物及土地用作改变等方面论述了农业活动对土矿氧化亚氮的影响，并总结限减排措施。     

农业土壤排放氧化亚氮的影响因素分析

氧化亚氮（N₂O）是重要的温室气体之一。本文从施肥、灌溉、耕作、种植作物及土地用途改变等方面论述了农业活动对土壤排放氧化亚氮的影响，并总结了减排措施。     

地面氧化亚氮排放静态箱测定技术

氧化亚氮是最重要的温室效应气体之一，国际科学界对其进行了大量的研究。开展氧化亚氮研究最重要的方面是测定技术，目前主要有静态箱法和微气象法，而以静态箱技术的使用最为广泛。静态箱技术也有其优点和缺点。文章从基本原理、取样箱设计、取样时间策略、自动采样箱设计、气相色谱测定技术参数、计算方法及自动测定系统等方面。系统介绍静态箱技术。我国在氧化亚氮研究上还较少，巳被测定的土地类型非常有限，文章将有助于促进我国在这方面的研究。     

典型潮土N2O排放的DNDC模型田间验证研究

利用典型潮土N2O排放的田间试验数据对脱氮-分解模型（DNDC）及其参数进行验证。结果表明,DNDC模型能较好地模拟田间实测到的冬小麦、夏玉米季土壤湿度和土壤日平均地表温度的动态变化。小麦和玉米季土壤N2O排放通量与土壤水分（WFPS）呈显著正相关,与土壤温度相关性不大。田间实测到的N2O排放高峰主要受降水和施肥的影响,在N2O排放峰的峰值和出现时间上模拟值与实测值较接近,但准确地捕捉N2O季节性的排放通量仍需对模型进行修正。通过比较施肥、土壤和田间管理等输入参数的改变对DNDC模型进行灵敏性分析,氮肥用量、施肥次数、土壤初始无机氮含量和土壤质地的改变对土壤N2O排放量均很敏感,其中氮肥用量和施肥次数的改变最为敏感。基于当地土壤特性和田间管理的校正,DNDC模型为评价农田生态系统N2O的排放提供了强有力的工具。     

Impacts of pellet pH on nitrous oxide emission rates from cattle manure compost pellets

Previous reports indicated that the emission of nitrous oxide (N₂O) when manure compost pellets (MCP) were applied to soil was greater than when ordinary manure compost or inorganic fertilizer was applied, but that applying pellets of nitrogen-enriched manure compost, a by-product of deodorizing manure during composting, resulted in N₂O emission rates less than those from MCPs. To investigate the mechanism by which N₂O emission rates and cumulative emissions were reduced in nitrogen-enriched manure composts pellets (N+MCP), we studied the impact of pellet pH on N₂O emission, because pH is different between MCP (pH 8.6) and N+MCP (pH 5.3). In an incubation experiment, the pH of pellets was adjusted to five levels (5.3, 6.0, 7.0, 8.0 and 8.6) with acid or alkaline solutions, and the pellets were incubated without soil in a beaker at 30°C for 90 d (MCP) or 42 d (N+MCP). A large peak in N₂O emission rate was observed soon after beginning the incubation (within 1–3 d) in the neutral and alkaline treatments for both MCP and N+MCP, and these peaks corresponded to a rise in the pellet nitrite contents. Thus, this N₂O emission peak might have been generated by the denitrification of nitrite in the pellets. In the acid treatments of MCP, the N₂O emission was distributed more in the later incubation period (14–90 d), when the reduction of nitrate in MCP occurred. This led to a significant increase in cumulative N₂O emission as compared with the alkaline treatments for MCP. Regarding the mechanism by which N₂O emission was reduced in N+MCP, although larger cumulative N₂O emission rates in the earlier stage (0–14 d for MCP and 0–7 d for N+MCP) were observed when the pellet pH was adjusted close to 7.0, lowering the pH of MCP to 5.3 (the pH of N+MCP) did not demonstrate a significant decrease in cumulative N₂O emission as compared with the original pH treatment (pH 8.6). These results indicate that pellet pH might not relate directly to the mechanism by which N₂O emission was reduced in N+MCP.     

规模化养猪场典型沼气工程各排放节点氨排放特征研究

为了解典型规模化猪场沼气工程的氨排放特性,选取长三角地区某规模化养猪场的典型沼气工程为研究对象,在沼气工程设施的不同氨排放暴露节点(集粪池、调节池和沼液池)设置监测点对氨排放进行连续3d的同步监测,测定处理设施各排放节点氨浓度,核算各排放节点粪便氨排放速率,分析各排放节点氨排放特征。研究结果表明,集粪池、调节池和沼液池的氨日均排放速率分别为1.48、3.08和1.47 g/(d·m2);各节点氨排放具有明显的日变化过程,大致表现为早晨氨排放呈波动增大趋势,午后开始降低,至夜间保持低值排放;集粪池、调节池在粪污周转时段出现日排放峰值;沼液池、集粪池和调节池静置阶段氨小时排放速率与温度呈正相关,与湿度呈负相关;集粪池、调节池和沼液池日氨排放量分别为13.44、38.72和5 275.4 g/d。     

New method for the estimation of nitrous oxide emission rates from an agricultural watershed

Abstract

We developed a new and improved method, the ‘high-emission-incorporation (HEI) method’, for estimating soil nitrous oxide (N₂O) emission rates at a watershed level based on nitrogen (N) input (consisting of fertilizer, manure, slurry and excreta N) and N surplus (calculated by subtracting the amount of crop yield and consumed N from the N input) of different sites in a livestock farm located in a watershed. The main characteristic of this method is the inclusion of extremely high N₂O emission rates, ‘outlier’, which are normally excluded from estimation. High N₂O emission rates were estimated using the regression model obtained from the measured N₂O values and the amounts of N surplus; normal N₂O emission rates were estimated using the regression model obtained from the measured values and the amount of N input. The probability of occurrence of a high flux was used to incorporate calculated high and normal N₂O emissions into one. The annual N₂O emission rate from the livestock farm in the watershed (467?ha), estimated using the HEI method, was 1156?±?147?kg?N?year^?1 over a 5-year period. The annual N₂O emission rates calculated using the site-specific emission factor (EF?=?0.0789) and the emission factor of the Intergovernmental Panel on Climate Change (EF?=?0.01) were 1838?±?585?kg?N?year^?1 and 673 (522–1103) kg?N?year^?1, respectively. The estimated value using the measure-and-multiply method, in which each land-use area is multiplied by the representative emission rate for each land-use type, was 964 (509–1610) kg?N?year^?1. The N₂O emission rates estimated by our newly developed method were consistent with the values calculated by the measure-and-multiply method and offered improvement over this measure because the new measure can also predict future N₂O emission rates from the watershed.     

Interactive effects of ammonium application rates and temperature on nitrous oxide emission from tropical agricultural soil

Emissions of nitrous oxide (N₂O), a potent greenhouse gas, from agricultural soil have been recognized to be affected by nitrogen (N) application and temperature. Most of the previous studies were carried out to determine effects of temperature on N₂O emissions at a fixed N application rate or those of N application rates at a specific temperature. Knowledge about the effects of different ammonium (NH₄⁺) application rates and temperatures on N₂O emissions from tropical agricultural soil and their interactions is limited. Five grams of air-dried sandy loam soil, collected in Central Vietnam, were adjusted to 0, 400, 800 and 1200 mg NH₄-N kg^–1 soil (abbreviated as 0 N, 400 N, 800 N and 1200 N, respectively) at 60% water holding capacity were aerobically incubated at 20°C, 25°C, 30°C or 35°C for 28 days. Mineral N contents and N₂O emission rates were determined on days 1, 3, 5, 7, 14, 21 and 28. Cumulative N₂O emissions for 28 days increased with increasing NH₄⁺ application rates from 0 to 800 mg N kg^–1 and then declined to 1200 mg N kg^–1. Cumulative N₂O emissions increased in the order of 35°C, 20°C, 30°C and 25°C. This lowest emission at 35°C occurred because N₂O production was derived only from autotrophic nitrification while other N₂O production processes, e.g., nitrifier denitrification and coupled nitrification-denitrification occurred at lower temperatures. More specifically, cumulative N₂O emissions peaked at 800 N and 25°C, and the lowest emissions occurred at 1200 N and 35°C. In conclusion, N₂O emissions were not exponentially correlated with NH₄⁺ application rates or temperatures. Higher NH₄⁺ application rates at higher temperatures suppressed N₂O emissions.     

规模化猪场机械通风水冲粪式栏舍夏季氨日排放特征

选取长三角地区典型机械通风水冲粪模式养猪场,针对不同生长阶段的肥猪栏舍和不同类型的母猪栏舍排放口氨排放进行同时监测(其中,育肥猪按质量分保育(24 kg)、育肥-Ⅰ(24~60 kg)、育肥-Ⅱ(60~120 kg)3个阶段,母猪分为妊娠猪与分娩猪2种类型),估算各栏舍氨排放通量,分析各栏舍氨排放特征,探讨各生长阶段对氨排放贡献。研究结果表明,保育、育肥-Ⅰ、育肥-Ⅱ、妊娠、分娩栏舍氨质量浓度分别为(0.97±0.40)、(3.37±0.70)、(5.45±2.30)、(2.19±1.06)、(1.44±0.48)mg/m3;各栏舍氨排放具有显著的日变化过程,早晨氨排放呈波动增大趋势,午后开始降低,至夜间保持低值排放;小时氨排放速率与温度呈极显著正相关,与湿度呈显著负相关;各生长阶段氨排放存在差异,保育、育肥-Ⅰ、育肥-Ⅱ、妊娠、分娩栏舍日排放速率分别为0.85、6.53、8.20、10.39和13.86 g/(头·d);保育、育肥-Ⅰ和育肥-Ⅱ阶段对肥猪氨排放的贡献率分别为3.64%、26.11%和70.25%,妊娠猪与分娩猪对母猪氨的贡献率分别为75.32%和24.68%,母猪的氨排放速率是肥猪的1.87倍。