共查询到20条相似文献，搜索用时 718 毫秒
1.
青藏高原纳木错高寒草原温室气体通量及与环境因子关系研究 总被引：6，自引：0，他引：6
青藏高原广泛分布着以高寒草甸和高寒草原为主的陆地生态系统。由于高寒草地生态系统异质性较大,对高寒草地主要温室气体通量的估算具有较大的不确定性。为研究高寒草原温室气体通量规律及其驱动因子,并为动态碳-氮耦合模式在高寒生态系统的参数化与检验提供数据支持,于2008年7-9月,使用静态箱-气相色谱法在位于青藏高原腹地的纳木错高寒草原开展了主要温室气体通量(CO2,CH4,N2O)及环境因子的同步观测。结果表明:纳木错高寒草原生态系统CH4,N2O通量和CO2排放分别为:-0.047 mg·m-2·h-1,0.49μg·m-2·h-1和208.2 mg·m-2·h-1;在季节尺度上,土壤温度与CO2排放呈显著正相关,与N2O和CH4通量线性关系不显著;土壤含水量与CH4和N2O通量呈正相关关系,但与CO2通量无显著相关。在日变化尺度上,土壤湿度稳定,土壤温度变化与N2O和CO2通量成正相关,对CH4通量影响不显著。 相似文献
2.
推动低碳发展建设研究,探讨实现碳达峰路径,并在此基础上实现碳中和目标,已成为当下我国应对气候变化和加强生态文明建设的首要任务。本研究以山东省烟台市某规模化猪场为研究对象,通过测算该猪场生猪生长过程和粪便贮存过程CH4和N2O排放量、粪便农田利用过程N2O排放量,以及能源消耗CO2排放量,对生猪养殖过程中各排放源的碳排放特性进行分析。结果表明：该猪场生猪肠道发酵CH4排放CO2当量仅占生猪生长过程温室气体排放总量的6.4%,而生猪呼出CO2排放占比高达93.6%;粪便贮存过程N2O排放CO2当量仅占粪便贮存过程温室气体排放总量的15.2%,占粪便贮存过程CH4排放CO2当量的17.9%;农田利用过程N2O直接排放量为间接排放量的10倍;耗煤、耗电、耗油CO2排放量分别占能源消耗CO2排... 相似文献
3.
为探讨湖北火烧坪三种土地利用方式下土壤温室气体排放的特征及其影响因子,以研究区农田、草地和天然林地为研究对象,采用野外原位静态箱-气相色谱法对其土壤温室气体通量动态变化进行监测,并对环境因子进行分析。结果表明：三种土地利用方式下土壤CO2均表现为排放,农田土壤CH4和N2O表现为排放,草地表现为吸收,林地不一致;土壤含水量抑制土壤CO2,促进土壤CH4产生,过氧化氢酶活性与土壤CO2和CH4的排放具有显著相关性,有机肥的施用影响土壤N2O的排放;全球增温潜势（Global warming potential,GWP）由大到小表现为草地 > 林地 > 农田,但草地由于生物量高光合呼吸作用强,向大气排放CO2的总量则较低。因此,人工草地的建造有利于降低研究区土壤温室气体的排放。 相似文献
4.
黄河口滨岸潮滩湿地CO2、CH4和N2O通量特征初步研究 总被引：3，自引：1，他引：2
2009年8月,运用静态暗箱-气相色谱法对夏季黄河口滨岸潮滩湿地CO2、CH4和N2O通量的日变化特征进行了原位观测。结果表明,夏季低潮滩沉积物-大气界面的CO2、CH4和N2O通量均具有明显日变化特征,日通量范围分别为-18.755～43.731,-0.070～0.224和-0.002～0.008 mg/(m2·h),均值为11.630,0.079和0.005 mg/(m2·h),全天表现为三者的排放“源”;中潮滩沉积物-大气界面CO2、CH4和N2O通量的日变化范围分别为-30.780～25.734,-0.111～0.100和-0.004～0.006 mg/(m2·h),均值为4.570,0.011和0.002 mg/(m2·h),全天亦表现为三者的排放“源”;中潮滩-大气界面CO2、CH4和N2O通量的日变化范围分别为46.253～102.637,-0.211～0.048和-0.008～0.008 mg/(m2·h),均值为76.656,-0.038和-0.002 mg/(m2·h),全天表现为CO2的“源”、CH4和N2O的“汇”。 本研究还发现,中潮滩的CO2通量与气温呈显著正相关(P＜0.05)关系,低潮滩沉积物的CH4通量与气温、地表温度和5 cm地温呈极显著正相关(P＜0.01)关系,而中潮滩的N2O通量与气温、地表温度和不同深度地温(5,10,20 cm)呈显著(P＜0.05)或极显著(P＜0.01)负相关关系;沉积物基质和翅碱蓬群落是影响CO2、CH4和N2O通量特征的重要因素,而水分、盐分对于三者通量特征的影响也不容忽视。 相似文献
5.
翻压紫云英对稻田土壤还原物质变化特征及温室气体排放的影响 总被引：1，自引：0，他引：1
采用室内培养试验监测紫云英翻压后土壤还原物质和温室气体的动态变化,旨在为紫云英还田造成水稻僵苗及带来的环境效应提供理论依据。结果表明,翻压紫云英显著增加土壤还原性物质总量、活性还原性物质含量、Fe2+和Mn2+含量,显著降低土壤氧化还原电位(Eh)。与对照(CK)相比,翻压紫云英15000(M1)、30000(M2)、45000 kg·hm-2(M3)处理土壤还原性物质总量平均值分别增加0.34、0.80、1.16 cmol·kg-1,土壤活性还原性物质含量平均值分别增加0.14、0.35、0.52 cmol·kg-1,Fe2+含量平均值分别增加87.91、182.91、280.61 mg·kg-1,Mn2+含量平均值分别增加10.12、12.77、15.73 mg·kg-1,Eh平均值分别降低32.88、47.98、57.26 mV。还原性物质均在培养近15 d时达到高峰,M3处理Fe2+含量最高超过400 mg·kg-1,已达到水稻幼苗中毒浓度。翻压紫云英显著增加CO2、CH4排放,降低N2O排放,增加了全球增温潜势(GWP)。与CK相比,M1、M2、M3的CO2排放速率平均值分别增加7.67、12.48、20.54 mg·kg-1·d-1,CO2累计排放量分别增加171.63、293.42、498.45 mg·kg-1,CH4排放速率平均值分别增加0.04、0.09、0.21 mg·kg-1·d-1,CH4累计排放量分别增加0.36、0.69、1.77 mg·kg-1,N2O排放速率平均值分别降低0.46、0.64、0.72 μg·kg-1·d-1,N2O累计排放量分别降低10.00、13.02、14.36 μg·kg-1,M1、M2、M3的GWP平均值分别是CK的1.59、2.04、2.91倍。CO2、N2O排放主要集中在培养前期,CH4排放主要集中在培养后期。还原性物质含量与CO2、CH4的排放呈显著正相关,与N2O排放呈显著负相关。综上,翻压紫云英增加还原性物质含量,促使CO2、CH4排放,抑制N2O排放,增加GWP。实践中翻压紫云英可增加水稻产量,探索适宜紫云英翻压量确保单位水稻产量下的GWP不增加实现增产和环境效应的双赢具有重要实践意义,但这需要通过盆栽和大田试验验证。 相似文献
6.
田间盆栽试验研究了不同降水格局下填闲种植对冬小麦农田夏闲期土壤温室气体排放的影响。试验采用控制降水格局(自然降水和减半降水)和填闲作物(黑麦草单播、长武怀豆单播、黑麦草和怀豆混播、裸地对照)双因素处理设计, 利用静态箱-气相色谱法对土壤CO2、N2O和CH4排放通量进行观测。结果表明:1)各处理土壤是CO2、N2O的排放源, 是CH4的弱吸收汇。2)降水格局和填闲种植对土壤温室气体排放均具有显著影响。与自然降水相比, 减半降水的土壤CO2日均排放通量降低了33%, N2O日均排放通量降低了17.9%, 但对CH4通量影响不大。3)与裸地对照相比, 单播黑麦草、长武怀豆和二者混播日均CO2排放通量提高了140.8%、135.6%和137.7%, 不同填闲处理间差异不显著。而日均N2O排放通量分别降低了8.0%、21.8%和27.4%, 其中单播长武怀豆和混播处理与单播黑麦草处理差异显著。单播长武怀豆处理土壤日均CH4吸收通量较裸地对照、单播黑麦草和混播处理分别降低了65.8%、63.7%和68.9%。4)与自然降水相比, 减半降水农田综合增温潜势平均下降了26.1%, 温室气体排放强度平均提高了47.2%。而与裸地对照相比, 单播黑麦草、单播长武怀豆和二者混播处理综合增温潜势平均分别提高了67.9%、65.5%和67.8%, 且各填闲作物处理间差异不显著。与单播黑麦草和混播处理相比, 在冬小麦夏闲期单播长武怀豆具有更高的地上生物量和更低的温室气体排放强度, 在自然降水条件下能够兼顾经济效益与生态效益, 适宜在本地区加以推广种植。 相似文献
7.
黄土高原雨养农业区不同种植模式土壤温室气体排放特征 总被引：1，自引：0，他引：1
研究陇中黄土高原旱作农田,设置了苜蓿-苜蓿(L-L)、苜蓿-休闲(L-F)、苜蓿-小麦(L-W)、苜蓿-玉米(L-C)、苜蓿-马铃薯(L-P)和苜蓿-谷子(L-M)6个处理,采用静态箱-气相色谱法和碳通量测量系统LI-8100对苜蓿后茬轮作不同作物土壤温室气体排放动态及其影响因素进行了测定与分析。研究结果表明,农田土壤表现为CO2源、N2O源和CH4吸收汇,且呈现夏秋高,春冬低的季节性变化特征。L-L处理的CO2累积排放量最高,L-W处理较之降低了42.43%;L-C处理的N2O累积排放量最高,L-P处理最低;CH4吸收量以L-M处理最高,较L-F和L-L分别增加了62.71%和31.87%,综合增温潜势表现为L-L>L-M>L-C>L-P>L-F>L-W。相关分析结果表明,CO2、CH4、N2O排放量与脲酶、过氧化氢酶活性及土壤温度呈极显著相关(P<0.01),与土壤水分在不同土层有显著相关性;逐步回归分析发现,土壤温度、过氧化氢酶是CO2和CH4排放的主导因素,土壤温度极显著影响气体排放,N2O排放主要受到环境因子的影响。综合来看,与长期苜蓿连作相比,黄土高原地区苜蓿种植一定年限之后轮作粮食作物能减少土壤温室气体排放量,减弱农田温室气体的增温效应,其中以小麦效果最佳。 相似文献
8.
为揭示不同类型和剂量氮沉降下青藏高原高寒草地N2O排放速率的响应规律，本研究对83组N2O排放速率研究数据开展整合分析，结果表明：模拟氮沉降实验极显著增加高寒草地N2O排放速率，增加幅度和平均效应值分别为148.43%和0.91。高寒草甸和高原草原N2O排放速率增加幅度依次为115.98%和190.96%(P<0.05)。就不同类型氮素添加的平均效应值而言，硝酸钾>家畜粪便>硫酸铵>尿素>硝酸铵>家畜尿液>氯化铵>硝酸钠，其中后两者对青藏高原高寒草地N2O排放速率影响最低，增加幅度依次为43.33%和34.99%。低剂量、中剂量和高剂量氮素的平均增加幅度分别为40.49%,197.13%和339.29%。氮沉降平均效应值受氮素剂量、土壤硝态氮含量、全氮含量、年均气温和地上生物量的显著性影响，前三者分别可以解释28.32%,12.94%和11.17%的效应值变异。未来氮沉降增加情景可能显著增加青藏高原高寒草地N2 相似文献
9.
三江源区草地退化严重威胁我国的生态安全,因此,研究恢复措施对草地的影响有重要意义。本研究以青海省果洛藏族自治州轻度退化高寒草甸为研究样地,通过三种不同类型氮素(尿素CH4N2O、硫酸铵(NH4)2SO4和硝酸钾KNO3)的九种组合配施,分析氮素配施后退化高寒草甸群落特征和土壤养分的变化,以探究不同类型氮素配施对退化高寒草甸恢复效果。研究结果表明,与对照相比,氮素配施显著提高了群落初级生产力(P<0.05),且生物量随着氮素配施量呈先增加后降低趋势,但对植物群落多样性无显著影响;土壤中速效氮和硝态氮呈现降低趋势(P<0.05),但有机碳、全氮、全磷和铵态氮含量无显著变化;利用主成分分析,通过综合评价植被指标和土壤指标,筛选出恢复该区域退化高寒草甸的最佳氮素配施量为47.2 g·m-2硫酸铵+72.2 g·m-2硝酸钾+21.6 g·m-2尿素,为退化高寒草甸的恢复提供理论依据。 相似文献
10.
为探讨草地温室气体通量对不同刈割强度的响应情况、优化草地利用方式及强度,本研究通过在晋西北赖草（Leymus secalinus）草地构建不同强度的刈割试验,采用静态箱/气相色谱法定量研究了不刈割、轻度刈割、中度刈割和重度刈割对3种温室气体（CO2,CH4和N2O）通量的影响及温室气体通量与主要环境因子的关系。2017年和2018年生长季及非生长季观测结果表明,不同刈割强度下的草地均表现为CO2和N2O的源、CH4的汇;刈割于2018年生长季显著影响CH4和N2O通量（P<0.05）;3种温室气体通量与土壤温度呈显著指数相关（P<0.05）,CO2通量与土壤体积含水量、N2O通量呈显著线性相关（P<0.05）。本研究为采用合理的草地刈割强度提供一定的参考和理论依据。 相似文献
11.
Mitigation of nitrous oxide (N2O) emission from swine wastewater treatment in an aerobic bioreactor packed with carbon fibers 
下载免费PDF全文
下载免费PDF全文 Takahiro Yamashita Ryoko Yamamoto‐Ikemoto Hiroshi Yokoyama Hirofumi Kawahara Akifumi Ogino Takashi Osada 《Animal Science Journal》2015,86(3):358-368
Mitigation of nitrous oxide (N2O) emission from swine wastewater treatment was demonstrated in an aerobic bioreactor packed with carbon fibers (CF reactor). The CF reactor had a demonstrated advantage in mitigating N2O emission and avoiding NOx (NO3 + NO2) accumulation. The N2O emission factor was 0.0003 g N2O‐N/gTN‐load in the CF bioreactor compared to 0.03 gN2O‐N/gTN‐load in an activated sludge reactor (AS reactor). N2O and CH4 emissions from the CF reactor were 42 g‐CO2 eq/m3/day, while those from the AS reactor were 725 g‐CO2 eq/m3/day. The dissolved inorganic nitrogen (DIN) in the CF reactor removed an average of 156 mg/L of the NH4‐N, and accumulated an average of 14 mg/L of the NO3‐N. In contrast, the DIN in the AS reactor removed an average 144 mg/L of the NH4‐N and accumulated an average 183 mg/L of the NO3‐N. NO2‐N was almost undetectable in both reactors. 相似文献
12.
青藏高原高寒湿地温室气体释放对水位变化的响应 总被引：1，自引：0，他引：1
为了探究水位变化对青藏高原高寒湿地温室气体释放的影响,以高原东部若尔盖典型高寒湿地为研究对象,采用“中型实验生态系”的技术手段,研究了两种不同水位情形 [稳定水位(SW,0 cm)和波动水位(DW,从0 cm下降到45 cm,再复原到0 cm)] 对高寒湿地二氧化碳(CO2)、甲烷(CH4)和氧化亚氮(N2O)三种温室气体释放的影响。结果表明,1)高寒湿地水位变化对土壤(0~10 cm)可溶性有机碳(DOC)没有显著影响;水位从0 cm下降到45 cm,再复原到0 cm,对铵态氮(NH 4 + O 3 -
13.
Keiko MINATO Yasuyuki KOUDA Masaaki YAMAKAWA Satoshi HARA Tadashi TAMURA Takashi OSADA 《Animal Science Journal》2013,84(2):165-177
We developed a system for measuring emissions from stored slurry by using a floating dynamic chamber. CH4, CO2, N2O and NH3 emitted from the storage tank of a dairy cattle farm in eastern Hokkaido were measured during summer 2008 (7/16–8/6), fall 2008 (10/2–10/26), spring 2009 (6/2–6/21) and winter 2009 (3/11). Average daily gas emission rates in summer, fall and spring were, respectively, 54.8, 54.2 and 34.3 g/m2 for CH4; 602, 274 and 254 g/m2 for CO2; 55.4, 68.2 and trace mg/m2 for N2O; and 0.55, 0.73 and 0.46 g/m2 for NH3. CH4, CO2 and NH3 emission rates during the brief measurement period in winter were reduced to 1/4, 1/23 and 1/2, respectively, of summer emission rate levels. All gas emissions showed diurnal fluctuation and were greatest during the daytime, when the ambient temperature rose. CH4, NH3 and CO2 emissions increased significantly during the daytime, and the daily emission (in grams) of each gas was positively correlated with maximum daily temperature. According to the combined spring, summer and fall measurements, the CH4, N2O and NH3 annual emission factors were 1.42% (g CH4/g volatile solids), 0.02% (g N2O‐N/g total N) and 0.43% (g NH3‐N/g total N), respectively. 相似文献
14.
Comparison of ammonia and greenhouse gas emissions during the fattening of pigs, kept either on fully slatted floor or on deep litter 总被引：7，自引：0，他引：7
Five successive batches of fattening pigs were raised, each during a four month period, on a totally concrete slatted floor in one experimental room and on straw based deep litter in another. The rooms were automatically ventilated to maintain a constant ambient temperature. Available floor space was of 0.75 m2 per pig kept on the slatted floor and 1.20 m2 per pig kept on the deep litter. With this last system, about 46 kg of straw were supplied per pig throughout a fattening period. The slurry pit was emptied and the litter removed after each batch. Once a month, the emissions of ammonia (NH3), nitrous oxide (N2O), methane (CH4), carbon dioxide (CO2), and water vapour (H2O) were measured continuously for 6 consecutive days by infra-red photoacoustic detection.The performance of the animals was not significantly different according to the floor type.Gaseous emissions from pigs raised on the slatted floor and on the deep litter were, respectively, 6.2 and 13.1 g per pig per day for NH3, 0.54 and 1.11 g per pig per day for N2O, 16.3 and 16.0 g per pig per day for CH4, 1.74 and 1.97 kg per pig per day for CO2 and 2.48 and 3.70 kg per pig per day for H2O. Except for the CH4 emissions, all the differences were significant (P < 0.001). Thus, pig fattening on deep litter releases nearly 20% more greenhouse gases than on slatted floor, with 2.64 and 2.24 kg of CO2-equivalents, respectively (P < 0.001). Whatever the floor type, emissions increased from the beginning to the end of the fattening periods by about 5 times for NH3, 4 times for N2O, 3 times for CH4 and 2 times for CO2 and H2O. Correlation coefficients between CO2-emissions and H2O, NH3 and CH4 emissions were, on average for both floor types, 0.82, 0.77 and 0.74, respectively.Although rearing pigs on straw generally has a good brand image for the consumer, this rearing system produces more pollutant gases than keeping pigs on slatted floors. 相似文献
15.
青藏高原草地生态系统碳循环研究进展 总被引：7，自引：0，他引：7
青藏高原属于气候变化的敏感区和生态脆弱带,对气候变化和人类活动扰动十分敏感,在未来全球碳循环调控中发挥着重要的作用。为增进对青藏高原高寒草地生态系统碳循环的理解,综述了近10年来气候变化、氮沉降和人类活动干扰下青藏高原温室气体排放、土壤碳库变化以及模型模拟应用等方面的最新研究进展。概括出高寒草地生态系统碳循环研究的草地类型主要包括高寒草原、高寒草甸、灌丛草甸草原、沼泽化草甸以及高寒湿地等。阐述了温室气体产生的机理、青藏高原高寒草地碳循环的源汇关系,指出温度升高、放牧、氮沉降是影响青藏高原温室气体排放、土壤碳库变化最重要的外界扰动,但是温室气体排放、土壤碳库对这3个因子之间协同作用的响应目前还不清楚。现有的高寒草地生态系统碳循环模型,主要以植被类型为基础,大多只考虑了水热因子,很少包含土壤因子和生物因子及其协同作用的影响。在此基础上,指出未来拟加强的研究重点: 1)冻融交替过程土壤温室气体排放研究; 2)非生长季土壤呼吸作用研究; 3)碳循环和植物物候耦合研究; 4)高寒草地生态系统碳循环模型的开发。 相似文献
16.
本文以千日红组培苗为试验材料,研究培养基中氮形态及含量对千日红试管苗生长和开花诱导的影响。结果表明,1)相对于铵态氮(NH4+),硝态氮(No3-)作为唯一氮源更有利于千日红试管苗生长和开花诱导,但千日红在NH4+和NO3-同时存在的培养基中表现最佳。2)在20 mmol/LNH4+(NO3-)和5 mg/L PP333存在的条件下,试管苗生长基本随着培养基中NO3-(NH4+)含量的增加而增加,并在含40 mmol/L NO3-+20 mmol/L NH4+(即MS培养基中氮含量)的培养基中株高达到最大值5.91 cm;而叶片数和开花率则随着培养基中NH4+和NO3-含量的增加呈现先增加后下降的趋势,并在20 mmol/L NO3-+5 mmol/LNH4+培养基中达到最大值,分别为10.7片/株和38.89%。3)氮含量及形态配比结果表明,千日红试管苗开花率在培养基中氮总量为5 mmol/L、NO3-/NH4+为4/1时达到最大值39.95%,而株高和叶片数在氮总量为35 mmol/L,NO3-/NH4+为4/1时达到最大值8.52 cm和13.38片/株。千日红试管苗开花率与培养基中NO3-/NH4+显著正相关,而与氮总量及株高之间显著负相关。此外,培养基中氮含量及形态配比还显著影响无菌苗根系生长。 相似文献
17.
Cheatgrass (Bromus tectorum L.) is an exotic annual grass causing ecosystem degradation in western US rangelands. We investigated potential mechanisms by which crested wheatgrass (Agropyron cristatum L. Gaertn., Agropyron desertorum [Fisch. {Ex Link} Scult.]) suppresses the growth and invasibility of cheatgrass. Research focused on monthly mineral soil N availability and the proportional concentration of NH4+-N in a crested wheatgrass community by microsite (crested wheatgrass, unvegetated interspace, shrub subcanopy) and soil depth (0–15, 15–30 cm) over a 1-yr period. Mineral soil N in crested wheatgrass microsites ranged from 0.24 to 1.66 mmol · kg-1 and was not appreciably lower than the other microsites or other ecosystems we have measured in the Great Basin. The molar proportion of NH4+-N in the mineral N pool of crested wheatgrass averaged over 85% for the year and is significantly higher than the other microsites and far greater than other plant communities we have measured in the Great Basin. We conclude that crested wheatgrass does not suppress cheatgrass by controlling mineral N below a threshold level; rather, we hypothesize that it may limit nitrification and thereby reduce NO3--N availability to the nitrophile cheatgrass. 相似文献
18.
《The Journal of Applied Poultry Research》2014,23(1):41-50
Distillers dried grains with solubles (DDGS), an important ethanol industry co-product, has been used as a high-protein feed in poultry production. Limited studies exist on their effect on air emissions, however. In the current study, 4 diets (2 × 2 factorial design: 0 or 20% DDGS + inorganic or organic mineral sources) were fed to Hy-line W36 hens from 50 to 53 wk of age and the effects of DDGS level and mineral sources on air emissions were monitored continuously for a 23-d period in environmentally controlled chambers. The NH3, H2 S, CH4, nonmethane hydrocarbons, N2 O, CO2, and CO2-equivalent emissions ranged from 0.51 to 0.64 g/day-hen, 0.71 to 0.84 mg/day-hen, 33.9 to 46.0 mg/day-hen, 54.1 to 60.0 mg/day-hen, 66.0 g to 72.2 g/day-hen, and 83.1 to 92.1 g/day-hen, respectively. Feeding DDGS to laying hens resulted in 14% decreased NH3 emissions but a 19% increase in CH4 emissions without affecting other gaseous emissions. More than 30% of N, 80% of P, 80% of K, and 50% of Ca was retained in the manure. In conclusion, feeding laying hens a diet containing 20% DDGS may be beneficial for the environment. Substitution for organic trace minerals did not affect hen performance or air emissions. 相似文献
19.
N. Vera C. Gutiérrez R. Allende P. Williams C. Fuentealba 《Acta Agriculturae Scandinavica, Section A - Animal Sciences》2018,68(4):181-189
ABSTRACTThis study assessed the potential of a pine bark extract (PBE) to decrease methane (CH4) and ammonia nitrogen (NH3-N) production in vitro. Dietary substrates, mixed hay, soybean meal and corn grain, were supplemented 0, 2, 4 and 6% of PBE and incubated in an in vitro batch culture for 24-h. Incubations were run three times. Total gas production (GP) was determined at 6, 12 and 24-h and gas samples were analysed for CH4. Samples were collected for volatile fatty acids (VFA) and NH3-N analysis. Treatments were compared by polynomial contrasts for PBE concentration. Increasing PBE caused linear decreases in NH3-N, microbial biomass production and digestibility, whereas the degradation rate was quadratically reduced. Total VFA were decreased but total GP and CH4 production and kinetics were unaffected. The inclusion of 2% PBE in ruminant feed has the capability to reduce NH3-N concentration by 50%, without affecting diet digestibility or CH4 production. 相似文献