畜牧业中的甲烷排放及其减排调控技术

畜禽养殖规模的扩大使家畜胃肠道和粪尿的甲烷排放增加, 加剧了温室效应。本文通过分析中国畜牧业的现状、发展趋势及其对甲烷排放的影响以及甲烷的生成过程、产甲烷菌的结构特征和多样性, 提出减少胃肠道和粪尿甲烷排放的3种有效途径：一是改善日粮品质和结构以及培育高生产性能品种, 从而提高畜群生产力, 减少单位畜产品甲烷产量;二是通过调控瘤胃微生物区系, 抑制产甲烷菌的生长, 阻断甲烷生成途径, 降低个体甲烷产量;三是提出处理家畜粪尿的能源环保型和生态环保型管理模式, 以实现资源的充分利用, 减少甲烷排放。     

畜牧业中的甲烷排放及其减排调控技术

畜禽养殖规模的扩大使家畜胃肠道和粪尿的甲烷排放增加, 加剧了温室效应.本文通过分析中国畜牧业的现状、发展趋势及其对甲烷排放的影响以及甲烷的生成过程、产甲烷菌的结构特征和多样性, 提出减少胃肠道和粪尿甲烷排放的3种有效途径:一是改善日粮品质和结构以及培育高生产性能品种, 从而提高畜群生产力, 减少单位畜产品甲烷产量;二是通过调控瘤胃微生物区系, 抑制产甲烷菌的生长, 阻断甲烷生成途径, 降低个体甲烷产量;三是提出处理家畜粪尿的能源环保型和生态环保型管理模式, 以实现资源的充分利用, 减少甲烷排放.     

不同类型日粮奶牛体外消化性能与甲烷产生量比较

为控制动物甲烷排放提供参考依据,以奶牛为瘤胃液供体动物,采用体外消化法进行了日粮类型对CH4产生量及其与消化性能关系的研究。结果表明,日粮精粗比均为40∶60的条件下,粗料为玉米秸秆青贮日粮的CH4产生量、消化单位干物质（DM）的CH4产生量、单位消化能量的CH4产生量比粗料为干玉米秸秆日粮分别减少了30%、37%、32%,差异显著（P〈0.05）;粗料均为玉米秸秆青贮的条件下,精粗比60∶40日粮的CH4产生量、消化单位DM的CH4产生量、单位消化能量的CH4产生量比精粗比40∶60日粮分别减少了21%、23%、23%,差异显著（P〈0.05）。玉米秸秆经过青贮处理或适当增加日粮中精料比例可以显著减少甲烷的产生,同时可以提高干物质消化率和消化能比例。     

反刍动物瘤胃内甲烷的产生及营养调控

概述了反刍动物甲烷排放研究的意义、瘤胃内甲烷的产生机制和影响因素、及从营养控制方面减少甲烷排放量的几种方法。     

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。     

低温产甲烷菌群对玉米秸秆低温厌氧消化的生物强化作用

为研究产甲烷菌群对秸秆低温厌氧消化的生物强化作用,试研究将长期驯化的低温产甲烷菌群投加至秸秆厌氧消化体系中,对比不同添加剂量(3%、6%、9%、12%、15%和18%)对低温(20℃)批式厌氧消化性能的影响。对产甲烷性能、中间代谢产物进行统计学和动力学分析,评价生物强化效果,确定最佳剂量,结合微生物群落分析揭示生物强化作用机制,结果表明：生物强化可促进秸秆低温厌氧消化,提高甲烷率1.27～2.24倍,促进乙酸和丙酸的降解,避免酸抑制,相比对照组缩短厌氧消化时间(T₈₀)12～19d;动力学分析表明：生物强化可缩短厌氧消化的延滞期;统计学分析表明：强化甲烷产量的最佳剂量为12%,单位质量菌群强化甲烷产量的最佳剂量为6%;微生物群落分析显示生物强化促进低温厌氧消化的主要原因是提高了产甲烷菌Methanothrix和Methanosarcina相对丰度。     

水稻物质生产对稻田甲烷排放的影响

以研究水稻物质生产对稻田甲烷排放影响为目的的大田与盆栽试验于１９９４￣１９９５年在美国德克萨斯州进行。对同期观测的稻田甲烷排放量与水稻干物质积累资料的分析表明,在类似的气候,土壤及水稻栽培管理条件,稻田甲烷排放的季节总量随水稻生产力水平的提高而增加;甲烷日排放通量与水稻干物质积累呈正相关,水稻生长中,后期的物质生产对甲烷排放的贡献大于前期。     

固体浓度对猪粪厌氧消化甲烷产出特性的影响

利用自动甲烷潜力检测仪(AMPTS),在35℃条件下,设置TS2%、TS6%、TS10%和TS14%共4个总固体浓度的猪粪水进行厌氧消化试验,观测其日产气量及其甲烷浓度的变化过程。结果表明:各处理的日产气量均在第一天达到最高值,并随着消化天数的增加逐渐下降,固体浓度越高产气结束越晚。固体浓度越高初期产生的甲烷浓度越低,但随发酵时间延长高浓度处理的甲烷浓度逐渐提高,TS6%处理后期产甲烷浓度最高可达76.1%。在TS2%~10%时随固体浓度升高甲烷的总产量逐渐提高,而TS14%处理与TS10%处理的甲烷总产量无显著差异。计算表明,TS2%、TS6%、TS10%和TS14%处理的单位化学需氧量(CODcr)产甲烷率分别为311.5、409.7、488.8和357.4mL/g,单位挥发性总固体量(VS)产甲烷率分别为330.1、491.3、473.1和333.4mL/g,其中TS6%和TS10%处理的单位甲烷产率较高。说明固体浓度对猪粪厌氧消化过程及甲烷产率有较大影响,选择适宜的固体浓度有利于提高厌氧消化的甲烷产率。研究结果可为猪场沼气工程控制参数选择和粪便管理温室气体清单编制提供数据参考。     

温度对不同生态系统土壤甲烷氧化过程和甲烷氧化细菌的影响

温室气体的大量人为排放导致了近百年来的全球气候变化。甲烷是重要的温室气体,随着全球气温升高,甲烷排放量会随之增加,进一步加剧了全球温室效应。土壤是甲烷重要的源和汇,土壤中的甲烷氧化细菌在平衡甲烷的释放过程中发挥着关键作用。探究温度变化对土壤甲烷氧化能力的影响成为近年来的研究热点。本文综述了温度对土壤甲烷氧化过程以及甲烷氧化细菌的影响,分析了在不同温度下,各生态系统中的土壤甲烷氧化及甲烷氧化细菌响应特点和规律,比较了不同生态系统中土壤发生甲烷氧化的温度范围以及甲烷氧化菌株的生长温度范围。综述结果表明,不同生态系统能够发生甲烷氧化的温度范围不同;在能发生甲烷氧化的温度范围内,甲烷氧化速率随温度升高而增加;培养温度与土壤原位温度越相近时,甲烷氧化响应较为灵敏。与温度对甲烷氧化过程的影响类似,甲烷氧化细菌的丰度也随着温度升高而增加,并与增温幅度、优势甲烷氧化细菌的原位生长温度密切相关。土壤中的II型甲烷氧化细菌对温度较敏感,随着温度升高,II型甲烷氧化细菌丰度增加,因此,温度会通过影响甲烷氧化细菌的丰度和群落结构,从而影响甲烷氧化过程。但温度是否仅通过调控优势菌种更替来改变土壤甲烷氧化能力目前还尚未定论,未来需要进一步探究。本文讨论了土壤甲烷氧化过程对温度的响应及其微生物机制,可为全面解析全球变暖下的土壤甲烷氧化过程的变化提供参考。     

不同栽培措施对水稻田甲烷释放甲烷产生菌和甲烷氧化菌的影响

本文报道不同栽培措施下水稻田甲烷释放的特性和甲烷产生菌、甲烷氧化菌的数量、种类。结果表明，水稻田的甲烷释放，无论是早稻还是晚稻，成活期每天的释放量较少，随着生长逐渐增加，至分蘖期达到最高，随后又逐渐减少。长期淹水和高量氮肥或有机肥的施用可以明显地增加水稻田的甲烷释放量。产甲烷细菌的数量在干湿灌溉少氮处理的水稻田土壤中要少于其他各处理的土壤，其他各处理间无明显差异，早稻上生长前期较后期低２－３个数量     

中国畜牧业绿色全要素生产率演变及区域差异研究

绿色全要素生产率（TFP）是衡量经济发展方式转变的重要指标,畜牧业高质量发展提升绿色TFP尤为关键。现有文献在测算省域绿色要素生产率时忽视了各省份之间的异质性,生产率指数基于以自身为参照的距离函数,导致结果不能相互比较,无法为决策者提供准确的政策建议。本文提出了一种可以测算各省份经济增长和环境改善对提升全国绿色TFP贡献率的新方法,主要基于稳健型整体方向性距离函数和整体Luenberger绿色生产率指标,将中国整体作为统一的方向衡量各省份对全国要素生产率的贡献,使得各省份的效率值具有可比性。通过分析中国31个省份2001—2016年畜牧业绿色TFP的增长变化,研究发现：1）从整体上看,样本期我国畜牧业绿色TFP的年均增长率为5.01%,其中经济效率对畜牧业绿色TFP的贡献率达88.83%;技术进步对绿色TFP增长的贡献率高达78.65%。2）从区域上看,我国畜牧业区域发展不平衡,东部和中部地区畜牧业发展快于西部地区。3）我国畜牧业绿色TFP增长存在改进空间,且环境效率改进空间大于经济效率,东部地区经济效率改进空间趋小,畜牧业经济增长与碳排放出现弱脱钩状态;中部地区经济效率与环境效率均有很大的改进空间;西部地区经济效率及碳减排还有一定改进空间。因此,为实现畜牧业高质量发展,畜牧业绿色TFP应加快由依靠增加要素投入向注重环境改善转变,加强绿色科技创新的促进作用;同时要突破城乡及区域要素流动制度障碍,提高人均畜牧产值来推动畜牧业区域平衡发展。     

小麦根茎叶氧热比值的三角图与产量的关系

山西省水土流失面积10万平方公里,占总面积的64.1%。水土流失使土地生产力降低,水库淤积,河床抬高,水旱灾害频繁。根据当地的自然条件,建设“五层楼”的结构模式,修成水平梯田294公顷,造林906.4公顷,种草154.5公顷,取得了明显的经济效益和生态效益。开发山区的出路在于大力植树种草,发展畜牧业,加强农田基本建设,保证粮食稳产增收。治理小流域,必须建设基本农田粮食基地和多种经营商品基地,积极发展种植业。要注意解决边治理边破坏的问题。     

Multifaceted beneficial effects of rhizosphere microorganisms on plant health and productivity

Plant growth promoting microorganisms (PGPM) and biological control agents (BCA) are shown to possess secondary beneficial effects that would increase their usefulness as bio-inoculants, regardless of the need for their primary function. Indeed, PGPM, such as Rhizobium and Glomus spp., can promote plant growth and productivity (primary effect) but have now been shown to also play a role in reducing disease (secondary effect). Conversely, BCA, such as Trichoderma and Pseudomonas spp., can control disease (primary effect) but have recently demonstrated stimulation of plant growth (secondary effect) in the absence of a pathogen. Further work shedding light onto the precise mode of action and ecophysiology of these microorganisms would assist with their timely and appropriate use and potentially unleash their full promise as beneficial rhizosphere bio-inoculants for improved growth and health of plants. The potential increased use of these microorganisms afforded by their multifaceted beneficial effects may further help in reducing problems associated with the use of synthetic chemicals in agriculture.     

Productivity affects the density–body mass relationship of soil fauna communities

The productivity of ecosystems and their disturbance regime affect the structure of animal communities. However, it is not clear which trophic levels benefit the most from higher productivity or are the most impacted by disturbance. The density–body mass (DBM) relationship has been shown to reflect changes in the structure of communities subjected to environmental modifications, so far, mainly in aquatic systems. We tested how different seawater inundation frequencies and cattle grazing, which both disturbed and impacted the productivity of a terrestrial system, a salt marsh, affected the size structure of soil fauna communities, expressed by their DBM relationship. We hypothesized that either: (1) all the trophic levels of soil fauna would benefit from higher productivity (i.e., amount of litter mass), reflected by a higher Y-intercept of the DBM relationship; (2) only smaller animals would benefit, reflected by a lower slope of the relationship; (3) or only larger animals would benefit, reflected by a higher slope of the relationship. We collected a large range of soil fauna from different elevation levels in grazed and ungrazed areas, thence subjected to different levels of productivity, represented by litter mass, with the most inundated and grazed area as the least productive one. Considering that pore size must be smaller in inundated and grazed areas, productivity seemed to be a greater factor influencing species distribution than soil structure. We found slopes lower than −0.75, showing that large animals dominated the community. However, a difference between the DBM relationships of the most and least frequently inundated ungrazed sites indicated that higher productivity benefited the smaller animals. Our findings show that high productivity does not equally affect the different trophic levels of this soil fauna community, suggesting inefficient transfers of energy from one trophic level to another, as smaller species benefitted more from higher productivity.     

Mineral composition of bermudagrass as influenced by maturity and nitrogen in a cool,temperate environment

Abstract

Warm‐season grasses contribute substantially to herbage supply during summer in cool‐temperate environments, when the productivity of cool‐season grasses declines. Herbage digestibility as well as mineral concentration may limit the amount of essential nutrients available to meet grazing animal requirements. A field study was conducted to determine the productivity and quality of a new selection of bermudagrass [Cynodon dactylon (L) Pers.], RSl, which is capable of growth and persistence in areas where other cultivars of bermudagrass are likely to winterkill. Concentrations and uptake of mineral nutrients in RSl bermudagrass were determined in response to N levels (0, 120, 240, and 360 kg N/ha) and delayed initial harvest (advancing maturity) at 2, 4, and 6 weeks after active growth began. Concentrations of P, Ca, K, Mg, and S in early season growth generally declined with advancing maturity. Concentrations of elements showed mixed response to N levels, and generally were not affected by treatments late in the growing season. Early in the growing season, mineral uptakes increased with advancing maturity. Increasing N levels early and late in the growing season enhanced mineral uptake. Mineral ratios, such as N:S and K (Ca + Mg), were within critical limits for adequate animal nutrition, but the Ca:P ratio was less than 2:1 and could contribute to known mineral‐related disorders in male sheep. Herbage mineral concentrations of RSl generally met or exceeded mineral nutrient requirements for sheep and cattle in growing or lactating physiological states.     

Book Reviews

Growth, yield, and chemical composition responses of two faba bean cultivars due to foliar application of 28-homobrassinolide (HBR) and 24-epibrassinolide (EBR) were studied in two field experiments conducted at the Experimental Farm of Faculty of Agriculture, Cairo University at Giza, Egypt, during 2003/2004 and 2004/2005. The application of 0.10 mg l^?1 EBR improved the growth characters and yield of the two cultivars over the control. Treatment with 0.05 mg l^?1 EBR and 0.50 mg l^?1 HBR stimulated plant growth and productivity but less effectively than treatment with 0.10 mg l^?1 EBR. This increment was more pronounced in Sakha 1 cultivar as compared with Giza 40 cultivar. Application of 0.10 mg l^?1 EBR gave, along with a 28% rise in productivity of Sakha 1 cultivar and 21.8% rise in productivity of Giza 40 cultivar, a better quality of yield with regard to an enhancement in the concentration of N, P, K, Fe, Zn, Mn, Cu, protein, and total carbohydrates. These considerable effects of EBR and HBR on plant development and yield promotion, together with the environmentally safe aspects of these compounds, would mark a major development in the field of plant growth regulators, and would minimize the risks associated with agrochemicals by reducing environmental contamination.     

Suitable management options to improve the productivity of rice cultivars under salinity stress

Growing rice in saline soils by minimizing damage on growth and yield remains a challenge. We conducted field experiments in the Africa Rice research field located in the Senegal River delta (16° 11? N, 16° 15? W) to study the effects of three management options of fertilization e.g. (i) nitrogen, phosphorus, and potassium fertilization: NPK; (ii) NPK combined with zinc: NPK-Zn, and (iii) NPK combined with gypsum: NPK-gypsum on the soil salinity level, the nutrient uptake and the productivity of different rice cultivars. The whole objective of this study is to determine how zinc or gypsum associated to NPK fertilizer can improve the growth and productivity of rice crop in saline soil. Results showed that the initial soil salinity level was reduced rapidly in plots treated with gypsum. The leaf-K/Na ratio, agronomic nitrogen use efficiency (ANUE), and grain yield of rice cultivars under the salinity stress were improved by the NPK-gypsum and NPK-Zn options relatively to the NPK option, suggesting that NPK-gypsum and NPK-Zn are suitable management options in reducing adverse effect of low K/Na, low ANUE as well as to improve rice yield under salinity stress.     

Role of nutrient amendments in the success of half-moon soil and water conservation practice in semiarid Burkina Faso

The half-moon technique has been recently introduced in northern Burkina Faso as a method for the rehabilitation of sealed and crusted bare soils locally called zipellé. As this technique, like zaï and mulching practices, interested many farmers, a trial was conducted to study the effect on soil productivity of half-moon technique in association with different sources of nutrients. The experimental design consisted of treatments in which the half-moon was combined with organic or mineral fertilisers. The soil was a Ferric Lixisol with a rooting depth of 30 cm, low contents of organic matter (12 g kg⁻¹), nitrogen (0.6 g kg⁻¹) and available phosphorus (6.6 mg kg⁻¹). Applying compost or animal manure allowed yields from 900 to 1600 kg ha⁻¹ of sorghum grain, i.e. 20–39 times the yield obtained in the half-moon treatment without any amendment. Combining local rock phosphate to compost in the half-moon basins increased sorghum grain yield by 10% the first year and 26% the second year. This study showed that restoring favourable soil moisture conditions by breaking up the surface crust to improve water infiltration was not enough to improve sorghum production on the degraded zipellé. Removal of the water constraint by destroying the surface hard pan revealed the second major constraint, i.e. soil acidity and nutrient deficiency. Well-decomposed organic matter such as animal manure and compost supplied in the half-moons were good substrates that provided sorghum with the nutrients required for growth. Moreover, adding local rock phosphate to compost appeared to be an alternative for improving soil productivity. It is concluded that in the Sahelian zone, half-moon technique with appropriate nutrient management could be an effective method for the rehabilitation of degraded soil productivity.     

再生水灌溉条件下减量追氮对设施番茄根层土壤氮素利用的影响

为探讨再生水灌溉减量追氮对于设施番茄生产的可行性,以期确定再生水灌溉设施番茄合理氮肥追施量。通过田间小区试验,对再生水灌溉不同氮肥追施水平根层土壤氮素残留、 番茄生物量、 产量、 氮肥偏生产力及表观氮素损失量进行了对比分析。研究结果表明,设施番茄土壤矿质氮的消耗主要集中在30 cm以上根层土壤;与常规氮肥追施处理相比,减量追氮处理,可协调番茄营养生长和生殖生长平衡,番茄产量增加明显,同时显著提高氮肥偏生产力;番茄收获后,减量追氮处理的表观氮素损失量显著低于常规氮肥追施处理。因此,减少氮肥追施量辅以再生水灌溉可以实现番茄产量和氮肥偏生产力同步提升。     

Beneficial effects of silicon on abiotic stress tolerance in legumes

Soil salinity, drought, metal toxicity, and ultraviolet-B radiation were major abiotic stresses that limit plant growth and productivity by disrupting the plants' cellular ionic and osmotic balance; legumes, a diverse plant family, suffered from these abiotic stresses. Although silicon (Si) is generally considered non-essential for plant growth and development, Si uptake by plants could facilitate plant growth by reducing biotic and abiotic stresses. There is however, a lack of systematic study on Si uptake benefits and mechanism on legumes because legumes reject Si uptake. Here, we reviewed the beneficial role of Si in enhancing abiotic stress tolerance in legumes and highlighted the mechanisms through which Si could improve abiotic stress tolerance in legumes. Future research needs for Si mediated alleviation of abiotic stresses in legumes are also discussed.