A bio-economic evaluation of the profitability of adopting subtropical grasses and pasture-cropping on crop-livestock farms

Pasture-cropping is a novel approach to increasing the area of perennial forages in mixed livestock and cropping systems. It involves planting annual cereals directly into a living perennial pasture. There is interest in using subtropical grasses for pasture-cropping as they are winter dormant and their growth profile is complementary with winter crops. The ability of subtropical grasses to maintain feed quality in summer is likely to be an important attribute. However, a wide range of factors can affect the uptake of such systems. This paper evaluates the farm-system economics of subtropical grasses and pasture-cropping. The research question is: what factors affect the profitability of a new technology such as (1) subtropical grass and (2) subtropical grass that is pasture-cropped. The analysis uses the MIDAS model of a central wheatbelt farm in Western Australia. The results suggest the profitability and adoption of subtropical grasses is likely to be strongly influenced by the mix of soil types present on the farm; the feed quality of the subtropical grass; whether the production emphasis of the farm is for grazing or cropping, and the level of production in summer and early autumn. The same factors are relevant to pasture-cropping, with the addition of yield penalties due to competition between the arable crop and the host perennial. The results were less sensitive to changes in the winter production of subtropical grass. Pasture-cropping was more profitable and likely to involve a larger area of the farm when a meat rather than a wool-dominant sheep system was present. However, there was little difference between the meat and wool flocks in their sensitivity to other factors in this analysis.     

Increasing animal productivity on small mixed farms in South Asia: a systems perspective

Smallholder crop–animal systems predominate in south Asia, and most of the projected future demands for ruminant meat and milk are expected to be met from the improved productivity of livestock in these mixed farming systems. Despite their importance in the sub-region, there is a paucity of information on research that incorporates animals interactively with cropping. Livestock research has tended to highlight component technologies, often treating diverse and complex mixed farming operations as a single system. Furthermore, little attention has been paid to social, economic or policy issues. Thus, many of the technological interventions have either failed to become adopted at farm level or their uptake has proved unsustainable. This paper reviews aspects of animal production in South Asia; the trends and forecasts for animal populations and products, constraints to productivity, research opportunities and some key examples of technologies that have failed to achieve their full potential on farm. A systems analysis of small-scale crop–livestock operations is advocated, as a precursor for targeting appropriate interventions at farm level to increase animal productivity and protect the natural resources base.     

我国秸秆加工机械的发展分析

随着国家恢复生态建设、实施禁牧圈养,秸秆对于牲畜的饲喂显得尤为重要.目前,我国每年生产的秸秆达6亿t多,占全世界秸秆总产量的20%～30%,是饲料的重要来源.近年来,我国畜牧业的快速发展对饲草的需求量急剧上升,有力地促进了饲草业的发展,同时也带动了饲草机械化的发展.大力发展牛、羊等食草动物,合理利用秸秆资源,促进饲草收贮和草产品加工技术,直接关系到国民经济的可持续发展.为此,论述了我国秸秆资源的利用情况,分析了秸秆加工机械及其发展现状,指出了秸秆加工机械的发展趋势.     

Simulation of production systems in East Africa by use of interfaced forage and cattle models

A forage model and a cattle production model were interfaced and adapted for tropical production conditions in East Africa. The objectives of the modelling were to structure and conceptualise a complex system for better comprehension, thereby determining constraints on a traditional African grazing system. The model was designed to simulate the physical linkages between the scarce resource of forage and the outputs of cattle, meat and milk. The effects of improved management practices were examined for a traditional village livestock grazing system. Verification and validation for the baseline village herd were carried out using several different sources of data. A combination of a restricted breeding season, supplemental feeding during the dry season and a seasonal sales policy resulted in a 40% increase in net revenue to village producers above the baseline for a ten-year period.     

Effects of silvopastoral areas on milk production at dual-purpose cattle farms at the semi-humid old agricultural frontier in central Nicaragua

In extensive cattle production systems, the composition of grazing areas may significantly influence productivity. In dual-purpose cattle production systems in the lowland tropics, pasture lands with trees, so-called silvopastoral areas, are considered as being important, particularly to facilitate the management of crossbred European native cattle. The aim of the study was to quantify the effects of silvopastoral areas on production at dual-purpose cattle farms in the semi-humid lowlands of central Nicaragua. The relationships between seasonal milk production and herd data, and the proportions of land use types were examined for 74 farms by stepwise regression analysis.     

青贮秸秆铡揉机的设计与试验

鉴于铡揉的青(干)玉米秸秆、麦秸等农作物秸秆及牧草物料适用于养殖牛羊牲畜及生物质能发电等领域,可有效推动粮改饲政策进一步实施,设计了一种青贮秸秆铡揉机。为此,提出了青贮秸秆铡揉机的设计方案,并对青贮秸秆铡揉机的输送喂入装置、铡揉装置及抛料装置进行优化设计,并通过试验数据计算得到青玉米秸秆的物料相对含水率平均值为55%,秸秆铡揉长度为1 060mm,秸秆破节率的平均值达91%,标准草长率为8 9%。设计的青贮秸秆铡揉机对于助推畜牧养殖业的产业化发展,提高畜牧养殖产品肉奶品质、避免秸秆资源浪费及减少环境污染具有重要的现实意义。     

A risk efficiency analysis of backgrounding and finishing steers on pasture in Saskatchewan, Canada

This paper combines an agricultural production decision support tool, GrassGro, with economic risk efficiency theory to examine several cattle feeding options that include various grazing systems for three climatic environments in Saskatchewan, Canada. Historical weather data were used to simulate a distribution of forage and cattle production data for each of several grazing systems during a 21-year period, 1978–1998. Price variability was included by varying year 2000 prices using historical price margin changes between the buying and selling weights of cattle. The risk efficiency analysis was completed using the Mean Standard Deviation (MSD) framework, and stochastic dominance principles.

Results of the study suggested that feeding systems, which included grazing, were economically competitive with traditional feedlot feeding systems and grain farming. Finishing cattle on pasture with the addition of a barley supplement was an attractive option, especially when high pasture productivity can be achieved. In all locations, more intense systems that included pasture fertilization and provision of an energy supplement, improved production and risk efficiency. Although the average net returns of all these feeding simulations were negative, the returns of traditional grain crops were even more negative. It is these negative returns in grain operations that lead to the incentive for producers to diversify into cattle production. Despite the negative net returns, the cash flow (range −$15.59 to $407.54 ha⁻¹) was mostly positive in all three locations.     

How much land is needed for global food production under scenarios of dietary changes and livestock productivity increases in 2030?

Growing global population figures and per-capita incomes imply an increase in food demand and pressure to expand agricultural land. Agricultural expansion into natural ecosystems affects biodiversity and leads to substantial carbon dioxide emissions.Considerable attention has been paid to prospects for increasing food availability, and limiting agricultural expansion, through higher yields on cropland. In contrast, prospects for efficiency improvements in the entire food-chain and dietary changes toward less land-demanding food have not been explored as extensively. In this study, we present model-based scenarios of global agricultural land use in 2030, as a basis for investigating the potential for land-minimized growth of world food supply through: (i) faster growth in feed-to-food efficiency in animal food production; (ii) decreased food wastage; and (iii) dietary changes in favor of vegetable food and less land-demanding meat. The scenarios are based in part on projections of global food agriculture for 2030 by the Food and Agriculture Organization of the United Nations, FAO. The scenario calculations were carried out by means of a physical model of the global food and agriculture system that calculates the land area and crops/pasture production necessary to provide for a given level of food consumption.In the reference scenario - developed to represent the FAO projections - global agricultural area expands from the current 5.1 billion ha to 5.4 billion ha in 2030. In the faster-yet-feasible livestock productivity growth scenario, global agricultural land use decreases to 4.8 billion ha. In a third scenario, combining the higher productivity growth with a substitution of pork and/or poultry for 20% of ruminant meat, land use drops further, to 4.4 billion ha. In a fourth scenario, applied mainly to high-income regions, that assumes a minor transition towards vegetarian food (25% decrease in meat consumption) and a somewhat lower food wastage rate, land use in these regions decreases further, by about 15%.     

Assessing the critical factors affecting the viability of small-scale dairy farms in the Punjab region of Pakistan to inform agricultural extension programmes

Agriculture in the Punjab province of eastern Pakistan benefits from one of the largest canal irrigation systems in the world. The typical mixed holding is a small, 5 ha mixed farm with three-quarters of its land used for cash crops, such as rice, wheat and sugarcane, and the remainder growing forages such as lucerne and berseem for dairy animals. Both cows and buffaloes are used for milk production, with the latter the more productive. Despite irrigation, productivity is constrained by a slow uptake of new technology such as fertilisers and new plant varieties, and poor livestock management, which leads to extended calving intervals, and a lack of available capital. This study used LP models, constructed with original local data on milk and crop production activities, to investigate the effect on profitability of alleviating the main constraints. The results demonstrate the powerful effect of using better, well managed dairy livestock, of increasing the uptake of simple technological improvements and of widening access to credit. They also show the synergy between these elements, for example the importance of finance as part of any intervention strategy. The results should enable agricultural development policy makers to rank the changes and devise better targeted programmes to deliver the changes on farm.     

Modelling the determinants of grassland stocking rates on dairy farms in England and Wales

An attempt has been made to provide a quantitative model of grassland management on a dairy farm which could be used for predictive purposes to establish appropriate stocking rates in relation to the resources available and the consequences of changing the level of resources used. The model takes into account the effect of rainfall, the available water capacity of the soil, soil drainage and fertiliser usage on grass production and the calving pattern, milk yield and availability of other feeds in determining grass requirements. Allowance is made for the fact that the response to unpredictable variation in grass production may be to under-stock. There was reasonably good agreement between predicted and actual stocking rates for a group of 33 dairy farms, but the predictions were too variable for acceptance of the model as a reliable aid in management planning on individual farms. Nonetheless, the model showed sufficient promise to suggest that it may be feasible to make predictions for individual farms in the future if a clearer understanding of a number of aspects of grassland management can be obtained: most notably, how farmers respond to risk, how managerial ability and financial constraints affect stocking intensity and how farmers integrate, in practice, grazing and conservation.     

A Review of Agronomic Factors Influencing Grass Silage Effluent Production in England and Wales

Silage effuent has a high biochemical oxygen demand (BOD) of about 60 000 mg/l. In 1991 it was estimated that the 29·7 Mt of bunker silage made per annum produced about 1·5 Gl of effluent. Silage effluent production is, however, extremely variable and may account for 25% of total agricultural water pollution incidents in wet years compared to 14% in dry harvest years. Incidents are highest in the grassland livestock areas of the west and least in eastern and south-eastern areas.A major factor in the increased pollution in recent years is the five-fold increase in the amount of silage made in the last 20 years. The average dry matter (d.m.) content of farm silages has also declined from about 270 to 250 g/kg in the past decade. Other reasons for increased pollution are inadequate and poorly maintained silos, crops being cut earlier and more late season aftermath cuts being taken in the autumn. There is evidence that increased use of nitrogen (N) fertilizer and N applied late produces grass with a low d.m. content. When this is ensiled with acid additives, effluent production is increased, but the effects of consolidation and mechanical pre-treatment are not clearly established. Large overfilled silos and poor silo design, structural deterioration and overflowing effluent tanks have also markedly contributed to silage effluent pollution.Effluent pollution could be reduced if crops were wilted to greater than 250g of d.m./kg. There are, however, difficulties in wilting in the wetter, western areas where rainfall and humidity are particularly high. The use of root and green crops together with higher d.m. crops for ensilage e.g. forage maize and whole crop cereals could potentially reduce effluent pollution; the present acreage is, however, very small in comparison with grass.     

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.     

Adapting to climate change: Agricultural system and household impacts in East Africa

The East African region exhibits considerable climatic and topographic variability. Much spatial and temporal variation in the response of different crops to climate change can thus be anticipated. In previous work we showed that a large part of this variation can be explained in terms of temperature and, to a lesser extent, water effects. Here, we summarise simulated yield response in two crops that are widely grown in the region, maize and beans, and investigate how the impacts of climate change might be addressed at two levels: the agricultural system and the household. Regionally, there are substantial between-country and within-system differences in maize and bean production responses projected to 2050. The arid-semiarid mixed crop-livestock systems are projected to see reductions in maize and bean production throughout most of the region to 2050. Yields of these crops in the tropical highland mixed systems are projected to increase, sometimes substantially. The humid-subhumid mixed systems show more varied yield responses through time and across space. Some within-country shifts in cropping away from the arid-semiarid systems to cooler, higher-elevation locations may be possible, but increased regional trade should be able to overcome the country-level production deficits in maize and beans caused by climate change to 2050, all other things being equal. For some places in the tropical highlands, maize and bean yield increases could have beneficial effects on household food security and income levels. In the other mixed systems, moderate yield losses can be expected to be offset by crop breeding and agronomic approaches in the coming decades, while more severe yield losses may necessitate changes in crop types, movement to more livestock-orientated production, or abandonment of cropping altogether. These production responses are indicative only, and their effects will be under-estimated because the methods used here have not accounted for increasing weather variability in the future or changes in the distribution and impacts of biotic and other abiotic stresses. These system-level shifts will take place in a context characterised by high population growth rates; the demand for food is projected to nearly triple by the middle of this century. Systems will have to intensify substantially in response, particularly in the better-endowed mixed systems in the region. For the more marginal areas, the variability in yield response, and the variability in households’ ability to adapt, suggest that, even given the limitations of this analysis, adaptation options need to be assessed at the level of the household and the local community, if research for development is to meet its poverty alleviation and food security targets in the face of global change.     

Bio-economic evaluation of dairy farm management scenarios using integrated simulation and multiple-criteria models

Appropriate selection of holistic management strategies for livestock farming systems requires: (1) understanding of the behaviour of, and interrelations between, the different parts of the system; (2) knowledge of the basic objectives of the decision maker managing such enterprise; and (3) understanding of the system as a whole in its agro-ecoregional context. A decision-support system based on simulation and mathematical programming techniques has been built to represent pastoral dairy production systems. The biological aspects (grass growth, grazing, digestion and metabolism, animal performance) are represented by simulation studies under a variety of management regimes. The outputs from the simulation runs (such as pasture utilisation, stocking rates, milk yields, fertilizer use, etc.) are used as data input to the multi-criteria decision-making models, and the latter have been used to select the management strategies which make the most efficient use of the farm's resources (i.e. land, animals, pastures). The paper discusses the effects and implications of different management scenarios and policies on the bio-economic performance of highland dairy farms in Costa Rica. Nevertheless, the model frameworks are generic and can be adapted to different farming systems or ruminant species. The effect of model formulation and sensitivity, different decision-maker objectives, and/or activity or constraint definitions on management strategy selection are also analysed.     

Steps toward sustainable ranching: An emergy evaluation of conventional and holistic management in Chiapas, Mexico

Conventional ranching in Chiapas, Mexico typically includes annual pasture burns and agrochemical use that decrease the biodiversity and forest cover of ranch lands. Members of a holistic ranching “club” in the Frailesca region of Chiapas, Mexico have moved away from this conventional management by eliminating burns and agrochemicals from their systems after decades of use because they believed that the land and their production process were growing unhealthy; they were further motivated by extension courses on holistic ranching. They have also implemented sophisticated systems of rotational grazing and diversified the use of trees. For this study all seven holistic ranchers and 18 neighboring conventional ranchers were interviewed about their cattle ranches and production strategies. An emergy analysis was conducted to compare the resource use, productivity and sustainability of the conventional and holistic ranches. Holistic ranches were found to have double the emergy sustainability index (ESI) values of conventional ranches, and the emergy yield ratio was 25% higher in holistic systems. Government assistance programs were found to have a negative impact on the ESI and were variably administered among holistic ranchers during the year of emergy evaluation. Overall improved emergy sustainability did not decrease milk nor cattle productivity. Transformities and specific emergies, the emergy of one type required to make a unit of energy (transformity) or mass (specific emergy) of another type, did not differ between conventional and holistic systems. Transformities for milk production ranged between 3.4E5 and 1.2E7 solar emjoules/joule (sej/J). Specific emergy for cattle production ranged from 3.5E10 to 1.5E11 sej/g. To improve the ESI assistance programs could be re-targeted toward incentive programs for increased forest cover in ranching systems and startup costs for holistic ranching. The results from this study show that productivity can be maintained as the sustainability of rural dairy ranches is increased. These results also show that local knowledge and understanding of the surrounding ecosystem can drive positive environmental change in production systems.     

Simulation of beef cattle production systems in the Llanos of Colombia: Part 2—Results of the modelling

Verifications and validations were conducted of a simulation model of beef cattle production on tropical ranges of the Colombian Llanos. Liveweight changes were simulated for individual cows sampled at random, for cow herds alternately grazing native savanna and molasses grass (Melinis minutiflora) and for steers grazing native savanna. Correlation coefficients between observed and simulated liveweight change were high. Simulations of the calving rates of cow herds from two experiments at Carimagua Research Station were also conducted and there was reasonably good agreement between observed and simulated data. Shortcomings of the model included an inability to simulate the heavy weight losses of grazing animals on molasses grass during the dry season and under-estimates of calving rates for the most productive herds. An experiment was conducted with the validated model from which it was concluded that grazing molasses grass and weaning of calves at 84 days of age would do little to increase calving rate.     

A quantitative framework for livestock development planning: Part 3—Feed demand and supply

The quantity and quality of feed available throughout the cycle of the seasons is a powerful constraint upon the rate at which livestock populations may expand and the rate at which they produce. To investigate this constraint in a national livestock development planning context it was necessary to develop an accounting system to interface feed demand with feed supply in what has been termed a Feed Balance Sheet. This presents feed deficits and/or surpluses within identified livestock production systems. The paper deals mainly with ruminant livestock populations grazing natural and improved grasslands and utilizing crop residues and agro-industrial by-products. The data illustrating the way in which the accounting system was developed are drawn from information on Sudanese livestock populations.     

Co-evolutionary scenarios of intensification and privatization of resource use in rural communities of south-western Niger

Agricultural production in the semi-arid agro-ecosystems of the Sahel centres on cereal staple crops and pastoralism with increasing crop–livestock integration. Animals mobilize soil fertility through manure production, graze crop by-products, and transfer nutrients from distant pastures to cropped areas. Yet in these systems various interacting factors, i.e. climate variability, poor soil fertility, poverty, and institutional constraints limit the capacity of agriculture to keep pace with the growing needs of an increasing human population.The major trends associated with population growth are (1) increasing area cropped at the expense of rangelands; (2) reduced availability of and access to good quality grazing resources, and (3) seasonal migration of labourers and transhumance of herds. These trends lead to co-evolution of farming systems towards increased privatisation of resource use.This study examines the implications of the development processes where farming systems co-evolve with their surroundings. It explores the impact of integrated management of livestock and crops in rural communities on both the livelihoods of differently endowed farms, and on the agro-ecosystem. Different scenarios explored the co-evolution of three sites situated in Western Niger with their environment. The sites differ in relative area cropped. The scenarios simulate the different future outcomes for varying socio-economic and biophysical criteria with either current or more intensive management.Explorative bio-economic models are used to compare a range of farm, livelihood and ecological indicators, and to reveal social and ecological trade-offs.If current agro-ecosystems and their environments co-evolve towards increased privatisation of grazing resources, then soil fertility is likely to deteriorate on the lands managed by the agro-pastoral groups. Soil fertility may improve on lands managed by the livestock-scarce farmers settled in villages, at the cost of declining farm incomes. The agro-pastoral groups are likely to resort to more distant pastures for feed. The village-based, livestock-endowed farms will resort to feeding on on-farm crop residues. Intensification, though associated with relative decreases in real incomes, will enhance food security in these new systems, except for the poorer settled farmers.     

基于放牧时空轨迹的天然草地利用评估模型

为了快速大范围获取草地利用情况,提出了一种基于放牧时空轨迹的天然草地利用评估模型。该模型根据牧群的放牧轨迹数据集,利用网格分析法计算牧群采食强度,通过模糊数学中的降半梯形、升半梯形及中间对称型分布,建立简单隶属函数对采食强度进行识别,进而获得草地利用分布情况以及不同利用强度下的草地有效利用面积。以2015年和2016年为实例,对新疆生产建设兵团农八师一五一团紫泥泉牧场草地利用情况进行估算,并对模型进行验证,模型精度达86.67%。结果表明,该评估模型能较好地反映草地利用情况;2015年和2016年研究区均有45%以上的草地未被利用,仅有3.7%左右的草地被适度利用;在被利用的草地中,2015年7月,76.53%的草地利用较差,仅有4.77%的草地利用较好;2016年7月,48.84%的草地利用较差,11.92%的草地利用较好。     

A general cattle production systems model. I: Structure of the model

A deterministic model for simulating beef cattle production under a wide range of management schemes and environments with cattle differing widely in genotypes for size, growth and milk production is described. In the model, genotypes are specified as production potentials, which are reached only if past and present planes of nutrition are adequate. Intake of forage and/or other feed is simulated as a function of the size and physiological status of the animals and the availability, digestibility and crude protein content of the feed. Animal performance is calculated from the nutrient intake and the animals' condition (fatness), degree of maturity and genetic potential. The model has been used for simulating beef cattle production under several widely differing sets of environmental and management conditions in Guyana, Colombia, Venezuela, Botswana, Texas and Mid-western United States and for simulating dairy-beef production systems in Colombia, Tanzania and Botswana. Results of simulations of existing conditions have coincided rather closely with actual production levels.