Mitigating environmental externalities in livestock production through feed biotechnologies

New low phytate crop varieties have been heralded for their potential to assist animal producers manage phosphorus (P) as both an input cost and as an environmental externality. This paper investigates the economic viability of such biotechnologies under regulations that attempt to minimize fecal P pollution by limiting land application of manure. Such restrictions often require animal feeding operations to spread manure over larger areas, thus increasing cost. To assess the economics of P mitigation, the production, handling, spreading, and vegetative uptake of manure nutrients for a variety of livestock growing operations was simulated. The simulation concludes that low phytate crops can be effective at mitigating P in situations where manure spreading geography is significantly restricted. However, alternative technologies such as phytase appear to offer a lower cost mechanism for mitigating P in most situations.     

Agricultural intensification in the Sahel – The ladder approach

Agricultural intensification in the Sahel can be described as climbing a ladder. The capital, labour, management and institutional requirements increase when farmers climb the ladder, but the potential gains are also higher. The first step on this ladder are agricultural practices without any financial outlay but with increasing labour demand, such as organic fertilizer use, seed priming, water harvesting and harvesting grains at physiological maturity to improve fodder quality. The next step on the ladder is the use of micro-fertilising, popularly known as microdose, at the rate of 0.3 g NPK fertilizer per pocket in sorghum and millet. The following step is the development of improved crop/livestock systems characterized by use of higher rates of mineral fertilisers and manure, increasing cowpea density and improved animal fattening. The last step presented on the ladder is the development of more commercially orientated agriculture characterized by development of cash crops, milk production and/or agroforestry systems. Evidences from the field support the observation that farmers intensify their production in a sequential manner similar to the way described in this paper. The technologies presented can facilitate agricultural intensification by reducing the risks and minimising the cost in agricultural production.     

FARMFLOW—A dynamic model for phosphorus mass flow,simulating conventional and organic management of a Swedish dairy farm

A farm systems mass-balance calculation model, FARMFLOW, was applied to a case study comparing organic and conventional management of a Swedish experimental dairy farm, Öjebyn. Parameterisation of the model is implemented using detailed field data from the Öjebyn farm where the two management systems have been run parallel for more than 11 years. Simulations were made to compare the stocks, flows and resulting balances of phosphorus (P) in the two systems during six crop rotations (36 years). In addition, a maximum animal density scenario was tested, in order to analyse the effects of increased production intensity. Results show that FARMFLOW can be a useful tool for analysing the impact of management on internal farm P dynamics, as well as imports and exports. The organic management results in a higher proportion of internal P flows whereas the conventional system relies more on imports of P in feed and mineral fertilisers. In both management systems, the crop rotation cause large temporal and spatial variation in the application of manure P to the soil system. The resulting field specific soil P accumulation can indicate which fields to target with changed fertilisation management. In the maximum animal density scenario, both management systems led to an application rate of manure P in excess of crop demands.     

Water savings, nutrient leaching, and fruit yield in a young avocado orchard as affected by irrigation and nutrient management

This project was designed to determine the effect of fertilizer rate and irrigation scheduling on water use, nutrient leaching, and fruit yield of young avocado trees (Persea americana Mill. cv. Simmonds). Seven nutrient and irrigation management practices were evaluated: (1) irrigation based on crop evapotranspiration (ET) with 50% fertilizer at a standard rate (FSR); (2) ET irrigation with FSR (typical for avocado production in the area); (3) ET irrigation with 200% FSR; (4) irrigation based on exceedance of 15-kPa (SW) soil water suction with 50% FSR; (5) SW with FSR; (6) SW with 200% FSR; and (7) irrigation at a set schedule (based on timing and frequency typically used in local avocado production) with FSR. The SW with FSR treatment saved 87% of the water volume applied and reduced total phosphorus leached by 74% compared to the set schedule irrigation with FSR. The SW with FSR treatment had higher avocado fruit production, tree water-use efficiency, and fertilizer-use efficiency than the other six treatments. Thus, the use of soil water monitoring for irrigation management can substantially increase sustainability of young avocado orchards in southern Florida.     

Life cycle assessment of high- and low-profitability commodity and deep-bedded niche swine production systems in the Upper Midwestern United States

We used ISO-compliant life cycle assessment to evaluate the comparative environmental performance of high- and low-profitability commodity and deep-bedded niche swine production systems in the Upper Midwestern United States. Specifically, we evaluated the contributions of feed production, in-barn energy use, manure management, and piglet production to farm-gate life cycle energy use, ecological footprint, and greenhouse gas (GHG) and eutrophying emissions per animal produced and per live-weight kg. We found that commodity systems generally outperform deep-bedded niche systems for these criteria, but that significant overlap occurs in the range of impacts characteristic of high- and low-profitability production between systems. Given the non-optimized status of current deep-bedded niche relative to commodity production, we suggest that optimizing niche systems through improvements in feed and sow herd efficiency holds significant environmental performance improvement potential. Drivers of impacts differed between commodity and deep-bedded niche systems. Feed production was the key consideration in both, but proportionally more important in niche production due to lower feed use efficiencies. Liquid manure management in commodity production strongly influenced GHG emissions, whereas solid manure management increased eutrophication potential due to outdoor storage in deep-bedded niche production. We further observe an interesting but highly imperfect relationship between economic and environmental performance measures, where profitability tracks well with resource (in particular, feed) throughput, but only indirectly with emissions intensity.     

基于蝇蛆养殖技术的畜禽粪便处理模式

现阶段我国的畜禽养殖固体废弃物利用程度仍不高,堆肥是畜禽粪便无害化资源化的重要技术手段之一。但主要以低效益的常规单一有机肥生产为主,大量的畜禽养殖固体废弃物资源得不到有效利用,造成环境污染。蝇蛆是畜禽养殖固体废弃物的高效生物转化器,畜禽废弃物可经蝇蛆生物转化后生产蝇蛆蛋白和优质有机肥。该文针对传统堆肥经济效益低、辅料依赖性强、处理周期长和成本高等特点,结合主要畜禽粪的组分特征及理化特性,在现有的蝇蛆生物转化畜禽粪工艺基础上,通过对蝇蛆生物转化畜禽养殖固体废弃物的产业化共性关键技术和设备进行研究,实现畜禽养殖固体废弃物的生态治理和高值化利用。      

Assessing benefits of irrigation and nutrient management practices on a southeast Florida royal palm (Roystonea elata) field nursery

Many of the best management practices (BMPs) that are recommended for agricultural producers have not been scientifically evaluated for their conservation benefits considering the soil, climate, and hydrology of the proposed application location. The goal of this study was to compare royal palm (Roystonea elata) production in south Florida, USA, using tensiometer automated irrigation and reduced soil applications of nitrogen (N) and phosphorus (P), to that of traditional grower practices considering water savings, nutrient inputs, crop yield, crop nutrient status, soil nutrient status, and economic analyses. The study consisted of six treatments: (1) control (i.e., a grower irrigation rate and N and P fertilizer rates); (2) irrigation system automated to irrigate when soil water suction exceeded 5 kPa and the grower N and P rates; (3) irrigation system automated to irrigate when soil water suction exceeded 15 kPa and the grower N and P rates; (4) irrigation system automated to irrigate when soil water suction exceeded 15 kPa and 50% of the grower N and P rates; (5) the grower irrigation rate and 75% of the grower N and P rates; and (6) the grower irrigation rate and 50% of the grower N and P rates. Irrigation water volume applied, plant diameters, and plant heights were measured periodically throughout the study and plant tissue samples and soil samples were collected periodically for analysis of N and P content. Significant differences among treatments were only observed for the irrigation water volume applied. Automating the irrigation system to irrigate at soil suction exceeding 5 and 15 kPa resulted in 75 and 96% less water applied, respectively, than traditional irrigation scheduling practices used by a grower. Economic analyses suggested that all treatments would result in financial savings ranging from 7 to 34% per ha considering a 5-year, 2 ha investment. Thus, automating irrigation based on soil water suction for palm production in southern Florida, USA and similar locations will result in more sustainable agricultural production systems by benefiting the environment (less nutrients and water applied) and the grower (lower cost).     

Competing use of organic resources, village-level interactions between farm types and climate variability in a communal area of NE Zimbabwe

In communal areas of NE Zimbabwe, feed resources are collectively managed, with herds grazing on grasslands during the rainy season and mainly on crop residues during the dry season, which creates interactions between farmers and competition for organic resources. Addition of crop residues or animal manure is needed to sustain agricultural production on inherently poor soils. Objectives of this study were to assess the effect of village-level interactions on carbon and nutrient flows, and to explore their impact on the long-term productivity of different farm types under climate variability. Crop and cattle management data collected in Murewa Communal area, NE Zimbabwe was used together with a dynamic farm-scale simulation model (NUANCES-FARMSIM) to simulate village-level interactions. Simulations showed that grasslands support most cattle feed intake (c. 75%), and that crop residues produced by non-cattle farmers sustain about 30% of the dry season feed intake. Removal of crop residues (0.3-0.4 t C ha⁻¹ yr⁻¹) from fields of non-cattle farmers resulted in a long-term decrease in crop yields. No-access to crop residues of non-cattle farmers increased soil C modestly and improved yields in the long-term, but not enough to meet household energy requirements. Harvest of grain and removal of most crop residues by grazing cattle caused a long-term decline in soil C stocks for all farm types. The smallest decrease (−0.5 t C ha⁻¹) was observed for most fertile fields of cattle farmers, who manure their fields. Cattle farmers needed to access 4-10 ha of grassland to apply 3 t of manure ha⁻¹ yr⁻¹. Rainfall variability intensifies crop-livestock interactions increasing competition for biomass to feed livestock (short-term effect) or to rehabilitate soils (long-term effect). Prolonged dry seasons and low availability of crop residues may lead to cattle losses, with negative impact in turn on availability of draught power, affecting area under cultivation in consecutive seasons until farmers re-stock. Increasing mineral fertiliser use concurrently with keeping crop residues in fertile fields and allocating manure to poor fields appears to be a promising strategy to boost crop and cattle productivity at village level. The likelihood of this scenario being implemented depends on availability of fertilisers and decision of farmers to invest in rehabilitating soils to obtain benefits in the long-term. Adaptation options cannot be blind to what occurs beyond field and farm level, because otherwise recommendations from research and development do not fit the local conditions and farmers tend to ignore them.     

Control of Gaseous Emissions from Livestock Buildings and Manure Stores

Agricultural animal production is increasingly regarded as a source of gases which are both aggravating and ecologically harmful. An overview of the origin, number and quantity of trace gases emitted from animal housing and from manure stores is presented and possible means of preventing or reducing them are discussed.Of the 136 trace gases in the air of animal houses, ammonia and methane present the greatest risk to the environment. Quantitative information on concentrations found in air is available for only 23 of these gases. The gases are emitted principally from freshly deposited and stored excreta, from animal feed and from the animals themselves. Future work should determine sources and quantities of the gases emitted from animal housing more precisely and should aim to investigate the potential of these gases to cause damage to man, animals and environment.Total ammonia emissions from animal production in the former West Germany are estimated as approximately 300 000 to 700 000 t/a. It is calculated that between 10 and 23 kg/ha of nitrogen a year enters the soil via the air from these sources, the average of which is higher than the average "critical loads" for most natural habitats. However, there is still a shortage of satisfactory information on the extent of emissions, in particular on those from naturally ventilated animal houses. Ammonia has a direct effect on the trees in the area surrounding animal houses and is also transported long distances through the air causing eutrophication and acidification of water and soil. This frequently results in changes in plant ecology, hence reducing plant diversity.Reduction measures must begin with the housing and manure removal systems and with feeding and management. Factors such as the protein content of feeds, the pH value of slurry and feed additives, air temperature, air exchange rate and litter affect the extent of ammonia emissions from animal housing. Sustained reduction of emissions from outdoor stores is possible by using various coverings. The greatest research need is perceived to be in the area of feed practices which reduce nitrogen and the development of low emission housing and manure removal systems as well as in a detailed compilation of emission factors.As regards the environment, probably the most important carbon-containing gas is methane, which contributes to the "greenhouse effect". Emissions from animal husbandry in Germany are estimated at about 2Mt/a. This corresponds to 0·15% of the assumed global emission from all sources. There is still little knowledge about the quantities of the greenhouse gas nitrous oxide (N₂0) released from agricultural animals. It is estimated that agriculture in Germany emits between 5 and 23 kt/a.It will take some time for reduction measures to be put into practice and the possibility of reducing livestock numbers should also be included in the discussion. Ammonia emissions from animal production represent a considerable loss in valuable fertilizer nitrogen. A reduction in emissions is therefore necessary not only for environmental protection but also to minimize economic loss.     

Availability and use of feed resources in crop–animal systems in Asia

Feed resources and nutrition constitute the principal technical constraints to ruminant production in Asia. Four main categories of feed resources are potentially available for use in smallholder crop–animal systems. These are pastures (native and improved grasses, herbaceous legumes and multi-purpose trees), crop residues, agro-industrial by-products (AIBPs), and non-conventional feed resources (NCFRs). Priorities for the use of crop residues in terms of nutrient potential and animal species are indicated. Of the technologies developed to improve the nutritive value of crop residues, more attention has been given to chemical treatment of cereal straws than to supplementation. However, a failure to demonstrate cost-effectiveness has discouraged on-farm adoption. The production of fodder from food crop systems and the establishment of multi-purpose trees and shrubs are potentially important for insuring adequate feed supplies for ruminants and improving soil fertility, but there has been limited adoption on small farms to date. Equally, there is significant potential for the more effective use of locally-produced AIBPs and NCFRs, all of which are under-utilised currently.     

Dairy farm nutrient management model: 2. Evaluation of different strategies to mitigate phosphorus surplus

To reduce (P) surpluses on dairy farms and thereby the risk of P losses to natural waters we studied different management alternatives by a nutrient balance model described in the companion paper. The strategies evaluated mitigating the P surpluses were: mineral P fertilisation, dietary mineral P supplementation, replacement rate, animal density, production level, feeding intensity, dietary P concentration and nutrient efficiency in crop production. Responses to several interventions (e.g. mineral P fertilisation, purchased feed P, replacement rate) were similar to those observed in Finnish field studies. Reducing or completely giving up the use of purchased mineral P fertilisers was the most efficient measure to reduce P surplus. The slope between the amount of mineral fertilisers and P surplus was 0.98-0.99 (in the field data 1.0). Increased animal density resulted in a greater P surplus, but the slope between P input from purchased feed and surplus was considerably smaller (0.65) than that of P fertilisation. Increasing milk yield with improved genetic potential of the cows would have minimal effects on P surplus per unit of product, but it would increase P surplus per hectare. When the intensity of energy and protein feeding was increased, P surplus rose markedly both per unit of product and hectare. This is (1) due to increased dietary P concentration and (2) due to smaller marginal production responses than those calculated from feeding standards. Reducing dietary P concentration by constraining P excess per kg milk in least-cost ration formulation improved P efficiency in milk production and dairy farming system. However, feed cost increased as low P energy (sugar-beet pulp) and protein (soybean meal) supplements are more expensive than cereal grains or rapeseed feeds. Improving the nutrient use efficiency in crop production had a strong influence in the whole-farm efficiency and P surplus. The modelling results showed that Finnish dairy farms have a great potential to improve P efficiency and reduce P losses to the environment, even by increasing production intensity (milk/ha). It is concluded that the most cost-effective scenario to mitigate P surpluses at a dairy farm would be to reduce or give up the use of mineral P as fertilisers and supplements, and to improve the use of present soil P reserves.     

番茄叶片光合作用对水肥耦合的响应

研究了不同水肥因子对番茄叶片光合作用的影响。采用五元二次正交旋转组合设计,通过盆栽试验,建立了水分、氮、磷、钾和有机肥用量对番茄叶片光合速率的数学模型。随灌水量的增加,番茄叶片光合速率呈开口向下的抛物线状变化;光合速率随施氮量、施磷量、施钾量和有机肥用量的增加呈先减少后增加的变化规律。交互效应表现为,灌水量与施氮量和施磷量呈负的交互作用,有机肥用量与灌水量、施氮量和施钾量、施氮量与有机肥用量、施钾量与有机肥用量对光合速率的影响具有正交互作用。灌水和氮、磷、钾、有机肥施用对番茄叶片光合速率的影响既相互促进,又相互制约,只有合理的水肥管理措施才能提高番茄叶片的光合速率。     

不同有机肥对矿区复垦土壤磷素矿化特征研究

【目的】探究不同有机肥对采煤塌陷复垦土壤磷素的矿化特征。【方法】采用室内培养试验,以不施肥处理为空白处理(CK),研究了施用3种有机肥(鸡粪、猪粪、牛粪)对矿区复垦土壤速效磷的动态变化,并综合其矿化过程中的磷酸酶活性及磷转化强度,分析了不同有机肥对矿区复垦土壤磷生物有效性的影响。【结果】①在整个室内恒温培养过程中,各施肥处理的速效磷量均随培养时间延长呈下降趋势,不同培养时期速效磷量大致呈现出:鸡粪>猪粪≥牛粪>化肥>CK。培养结束时(105d),鸡粪、猪粪和牛粪处理较化肥处理显著提高了土壤速效磷量(18.56%~37.09%);鸡粪处理较猪粪和牛粪处理速效磷量显著提高了11.93%~15.62%,而猪粪和牛粪处理间差异不显著;②在整个室内恒温培养过程中,拟二阶动力学模型能较好地反映各施肥处理速效磷释放过程,其次为Elovich模型和幂函数模型,而粒内扩散模型拟合效果较差。③在整个培养时期施有机肥处理的磷酸酶活性显著高于化肥处理,提高幅度为39.14%~120.70%。④培养前期(0~14 d),猪粪处理与化肥处理对土壤有机磷转化强度影响较大,二者间差异不显著,且猪粪处理较牛粪、鸡粪处理能显著提高有机磷转化强度,分别提高了41.51%和86.52%;在培养中后期(42~105d)各施肥处理的有机磷转化强度差异均不显著。【结论】施用有机肥能促进矿区复垦土壤磷素矿化,其中鸡粪较猪粪和牛粪对提高土壤有效磷量作用更为明显。     

Improving water productivity in mixed crop-livestock farming systems of sub-Saharan Africa

In sub-Saharan Africa problems associated with water scarcity are aggravated by increasing demands for food and water, climate change and environmental degradation. Livestock keeping, an important livelihood strategy for smallholder farmers in Africa, is a major consumer of water, and its water consumption is increasing with increasing demands for livestock products. At the same time, current low returns from livestock keeping limit its contribution to livelihoods, threaten environmental health and aggravate local conflicts. The objectives of this review are to: (1) synthesize available knowledge in the various components of the livestock and water sectors in sub-Saharan Africa, (2) analyze livestock-water interactions and (3) identify promising strategies and technological interventions for improved livestock water productivity (LWP) using a framework for mixed crop-livestock systems. The interventions are grouped in three categories related to feed, water, and animal management. Feed related strategies for improving LWP include choosing feed types carefully, improving feed quality, increasing feed water productivity, and implementing grazing management practices. Water management for higher LWP comprises water conservation, watering point management, and integration of livestock production in irrigation schemes. Animal management strategies include improving animal health and careful animal husbandry. Evidence indicates that successful uptake of interventions can be achieved if institutions, policies, and gender are considered. Critical research and development gaps are identified in terms of methodologies for quantifying water productivity at different scales and improving integration between agricultural sectors.     

A package of water management practices for sustainable growth and improved production of vegetable crop in labour and water scarce Sub-Saharan Africa

A package of water management practices including pitcher irrigation method and water conserving techniques of manure application and mulching is experimented for sustainable growth and improved production of cucumber crop in Makanya village in North Eastern Tanzania. The increase in total yield due to package of water management practices is 203 per cent and water use efficiency obtained is 12.06 kg m⁻³. The seasonal water requirement of cucumber crop under package of water management practices ranges from 146.30 to 198.10 mm, which is on an average 4.19 times less as compared to control treatment of can irrigation. The irrigation interval in package of water management practices is 4.9 times higher than the can irrigation method. The water and labour uses are reduced by 75.9 and 73 per cent, respectively in package of water management practices. The results showed that the self-regulative nature of pitchers and moisture retention by water conserving techniques is helpful in mitigating water stress in crop root zone. The moisture retention period in soil is increased assisting reduction of labour hours required in irrigation. In local context, the water management practices included in the package are easy to understand, adopt, operate and maintain.     

基于北斗系统的大田智慧农业精准服务体系构建

农机精确导航技术正在中国大田种植领域规模化应用,但农机精准作业技术和农业生产精细管理技术的应用仍进展缓慢,精准农业技术、装备与服务体系尚未完成构建,节本增效和节能环保等农业生产目标的实现仍缺乏技术手段。随着物质、能量和信息三要素的不断融合,智能农机系统呼之欲出,将为农业生产提供安全、高效和科学的解决方案。基于智能农机系统的特点、中国农机社会化服务的特征及农业财政补贴的现状,本研究以节本增效和节能环保为主要目标,围绕农业生产组织、农机服务组织和农业主管部门等农机生产作业的核心参与者,融合农机社会化服务和农机精准化服务,建立了中国农机社会化精准服务体系。该体系预期可精确监测农机作业面积和肥药施用量等基本作业参数,可作为社会化服务结算和作业补助发放的精准依据。本研究为实现肥药双减等目标、帮助国家有关农业补贴政策调整和促进中国精准农业技术的全面应用提供了解决思路和技术手段。     

烤烟配方营养土定制化生产机械研制

在充分调查论证和反复试验基础上，确定以饼肥、菌渣、牛粪和钙镁磷肥的配方营养土替代传统烤烟火土灰配方营养土。根据饲料粉碎搅拌加工一体化原理，研制烤烟营养土加工机械。针对混制箱的堵塞问题，通过改进混制系统的粉碎和搅拌方式予以消除。试点机械化、规模化制作烤烟营养土，商品化供应烟农，简化烟农营养土制作工序，降低烟农营养土制作成本，满足烟叶生产规模化降本增效和烟叶生产绿色发展的需要，具有较好的社会和经济效益。      

有机肥施肥机的标校

由于畜牧业的迅速发展,畜禽粪便的产出量急剧增大。畜禽粪便是一种优质的有机肥源,有机肥还田不但提供了农作物生长需要的养分,还可以改善农业生态环境,降低粮食生产成本。因此,研制适合中国国情的有机肥施肥机具有重要的现实意义和应用推广价值。目前,我国对有机肥施肥机的研究才刚刚起步,本文以中机华丰(北京)科技有限公司研制的有机肥施肥机为研究对象,主要研究了有机肥施肥机的标校,包括施肥均匀度的测定与校验、工作幅宽的测定与校验以及部分试验结果,验证并回答了施肥过程中常遇到的几个问题。     

RZWQM: Simulating the effects of management on water quality and crop production

The interactive use of experimentation and modeling is an efficient way to devise and test new agricultural management systems. The Root Zone Water Quality Model (RZWQM) is a comprehensive simulation model designed to predict the hydrologic response, including potential for groundwater contamination, of alternative crop-management systems. The model is one-dimensional (vertical into the soil profile) and integrates physical, biological and chemical processes. It simulates crop development and the movement of water, nutrients and pesticides over and through the root zone for a representative unit area of an agricultural field over multiple years. RZWQM allows for a variety of management practices: tillage; irrigation, fertilizer, manure and pesticide applications; tile drainage and crop rotations. Several significant validation efforts have shown the usefulness of RZWQM for evaluating and developing management scenarios.     

不同生长条件下切花向日葵生产效益和碳足迹分析

为探究切花向日葵生产碳足迹和经济效益,通过调研切花向日葵生产企业,利用生命周期评价法评估露地,拱棚和日光温室3种不同生长条件下切花向日葵碳排放,核算生产成本和效益,结果表明：露地切花向日葵生产碳足迹为2174.46kg/hm2,生产成本51994元/ hm2,收入178608元/ hm2;拱棚向日葵生产碳足迹为2041.13kg/ hm2,生产成本59443元/ hm2,收入175973元/ hm2;日光温室向日葵生产碳足迹为2038.92kg/ hm2,生产成本58465元/ hm2,收入179544元/ hm2。3种不同生长条件下切花向日葵生产的主要成本均来自人工,种子,地租和肥料,碳排放最主要的来源均为厩肥和氮肥。在未来切花向日葵生产中,可通过优化生产技术提高肥料利用率,研发专用机械降低劳动力投入,增加轮作等途径来实现减排增收的目的。