Evaluating crop-livestock-based farming systems: A village level study in the dry zone rainfed district of Sri Lanka

In Sri Lanka cropping enterprises interact with livestock production on peasant farms. This analysis of the crop-livestock farming system aims at understanding the existing constraints and interactions between crops and livestock in these farms. The main objective of the study is to describe the crop-livestock integrated farming systems in three rainfed villages in the Moneragala district of Sri Lanka, and to evaluate these systems in terms of maximizing farm incomes from the different crop and livestock components of the systems. A field survey was conducted to collect data from 153 farming families for the Maha season of 1982/83. A linear programming model was formulated to test the hypothesis.The results show that in general the activities for lowland rice, highland rice, sugar cane, labour, farm cash cost, and MVP (compost) are higher in the optimal farm plan than in the actual farm situation. The livestock in the optimal plan is mainly confined to milch cattle. However, with the present high level of manutrition among rural livestock industry emphasis should be placed on the expansion of the rural livestock industry in the study villages. The optimal plan also suggests the use of crop residues as a substitute for compost for farm crops. Hence, in the context of escalating prices of chemical fertilizers, research is required to find the suitability of crop residues and household residues as substitutes for compost. Increases in supplementary irrigation may result in the expansion of the farm area and hence the farm income. Other methods of increasing farm income include: replacing hired labour with non-utilized family labour, increased agricultural research, and extension activity regarding the use of modern inputs by farmers on crops.     

The promising impact of ley introduction and herd expansion on soil organic matter content in southern Mali

In southern Mali, cultivated area and herd size increase together with population growth. Consequently, periods of natural fallow shorten and traditional farming and animal husbandry techniques lead to a decrease of soil organic matter (SOM) content. Between 20 and 45% of the land is cultivated while less than 60% is arable area. To increase efficiency of natural fallow, a reduction in livestock herds is often proposed. By means of a linear programming model, the feasibility of maintaining actual SOM content in two villages in different agro-ecological zones was investigated. By adjusting animal numbers and cropping pattern, the model maximized: (1) SOM content under the condition of positive farm labour income; or (2) farm labour income under the condition of a positive SOM content. The model results suggested that maintaining SOM content requires the use of cereal crop residues for animal feed and for manure through bedding in kraals, but also higher animal densities. The last was feasible only through: (1) herding cattle of several farms together to overcome labour constraints; and (2) introducing P-fertilized leys, for grazing in the dry season. Grazing of the leys together with crop residues allowed animal densities up to 44 tropical livestock units (TLUs) km⁻², while less than 16% of the produced rangeland fodder was grazed. In such conditions, a positive SOM balance and higher income was obtained with a minimum of 16.7% of ley in the crop rotation. Limiting the area cropped with cotton stabilized income and contributed to a positive SOM balance. Zero-grazing during the warm season allowed SOM surpluses to be achieved with 12.5% of ley. However, as income decreased, seasonal zero-grazing could only be adopted for high-producing animals and small herds.     

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.     

A simulation-based analysis of productivity and soil carbon in response to time-controlled rotational grazing in the West African Sahel region

In the Sahel region of West Africa, the traditional organization of the population and the grazing land avoided overexploitation of pastures. Since independence in the 1960s, grazing lands have been opened to all without specific guidance, and the vulnerability of the pastures to degradation has increased. Rotational grazing is postulated as a possible solution to provide higher pasture productivity, higher animal loads per unit land, and perhaps improved soil carbon storage. The objective of this study was to conduct a simulation-based assessment of the impact of rotational grazing management on pasture biomass production, grazing efficiency, animal grazing requirement satisfaction, and soil carbon storage in the Madiama Commune, Mali. The results showed that grazing intensity is the primary factor influencing the productivity of annual pastures and their capacity to provide for animal grazing requirements. Rotating the animals in paddocks is a positive practice for pasture protection that showed advantage as the grazing pressure increased. Increasing the size of the reserve biomass not available for grazing, which triggers the decision of taking the animals off the field, provided better pasture protection but reduced animal grazing requirements satisfaction. In terms of soil carbon storage, all management scenarios led to reduction of soil carbon at the end of the 50-year simulation periods, ranging between 4% and 5% of the initial storage. The differences in reduction as a function of grazing intensity were of no practical significance in these soils with very low organic matter content, mostly resistant to decomposition.     

Systematic design and evaluation of crop rotations enhancing soil conservation, soil fertility and farm income: a case study for vegetable farms in South Uruguay

Rapid changes in the social and economic environment in which agriculture is developing, together with the deterioration of the natural resource base threatens sustainability of farm systems in many areas of the world. For vegetable farms in South Uruguay, survival in the long term depends upon the development of production systems able to reduce soil erosion, maintain or improve physical and biological soil fertility, and increase farmer’s income to socially acceptable levels. We propose a model-based explorative land use study to support the re-orientation of vegetable production systems in South Uruguay. In this paper we present a new method to quantitatively integrate agricultural, environmental and socio-economic aspects of agricultural land use based on explicit design objectives. We describe the method followed to design and evaluate a wide variety of land use activities for Canelón Grande (South Uruguay) and we illustrate the usefulness of this approach in an ex-ante evaluation of new farming systems using data from 25 farms in this region. Land use activities resulted from systematic combination of crops and inter-crop activities into crop rotations, different crop management techniques (i.e., mechanisation, irrigation and crop protection) and animal production. We identified and quantified all possible rotations and estimated inputs and outputs at crop rotation scale, explicitly considering interactions among crops. Relevant inputs and outputs (i.e., soil erosion, balance of soil organic matter and nutrients, environmental impact of pesticides, labour and machinery requirements, and economic performance) of each land use activity were quantified using different quantitative methods and following the target-oriented approach. By applying the methodology presented in this paper we were able to design and evaluate 336,128 land use activities suitable for the different soil types in Canelón Grande and for farms with different availability of resources, i.e., land, labour, soil quality, capital and water for irrigation. After theoretical evaluation, a large subset of these land use activities showed promise for reducing soil erosion, maintaining soil organic matter content of the soil and increasing farmer’s income, allowing improvement of current farming systems in the region and providing a widely diverse set of strategic options for farmers in the region to choose from. This method can be used as a stand-alone tool to explore options at the field and farm scale or to generate input for optimisation models to explore options at the farm or regional scale.     

A method for exploring sustainable development options at farm scale: a case study for vegetable farms in South Uruguay

The methodology presented in this paper aims at analysing whether there is room for improvement of vegetable farmers’ income in Canelón Grande (Uruguay), while reducing soil erosion and improving physical and biological soil fertility, and to gain insight in the influence of farmers’ resource availability on the opportunities for sustainable development. The (generic) approach we developed to support re-design of farming systems in this region is unique in dealing with complex temporal interactions in crop rotations and spatial heterogeneity on farms in one integrated method, while revealing trade-off between economic and environmental objectives. Rather than an arbitrary sub-set, all feasible crop rotations were generated, using a tool named ROTAT. The crop rotations were combined with a range of production techniques according to pre-defined design criteria to create a wide variety of alternative production activities at the field scale. We used process-based simulation models supplemented with empirical data and expert knowledge to quantify inputs and outputs of production activities. We developed a mixed integer linear programming model (MILP), named Farm Images, to allocate production activities to a farm with land units differing in soil quality, while maximising or minimising socio-economic and environmental objectives, subject to constraints at the farm level. Production activities comprised current practices as well as activities new to the area. We used Farm Images to design farm systems for seven existing farms in Canelón Grande with different resource availability. The farm systems designed by the model had higher family income than current systems for six of the seven farms studied. The estimated average soil erosion per ha decreased by a factor of 2–4 in the farm systems proposed compared to the current systems, while the rate of change of soil organic matter increased from negative in the current systems to +130 to +280 kg ha⁻¹ yr⁻¹ in the proposed farm systems. The degree to which the objectives could be achieved was strongly affected by farm resource endowment, i.e., particularly by the fraction of the area irrigated, soil quality and labour availability per ha. The study suggests that decreasing the area of vegetable crops by introducing long crop rotations with pastures and green manure during the inter-crop periods and integrating beef cattle production into the farm systems would often be a better strategy than the actual farmers’ practice.     

On farm testing of integrated nutrient management strategies in eastern Uganda

This paper reports on a Participatory Learning and Action Research (PLAR) process that was initiated in three villages in eastern Uganda in September 1999 to enable small-scale farmers to reverse nutrient depletion of their soils profitably by increasing their capacity to develop, adapt and use integrated natural resource management strategies. The PLAR process was also used to improve the participatory skills and tools of research and extension personnel to support this process. The farming systems of the area were characterised for socio-economic and biophysical conditions that included social organisations, wealth categories, gender, crop, soil, agro forestry and livestock production. Farmers identified soil fertility constraints, their indicators, and causes of soil fertility decline, and suggested strategies to address the problem of soil fertility decline. Soil fertility management diversity among households indicated that most farmers were not carrying out any improved soil fertility management practices, despite previous research and dissemination in the area. Following the diagnosis stage and exposure visits to other farmer groups working on integrated soil fertility projects, the farmers designed 11 experiments for on-farm testing. One hundred and twenty farmers then chose, for participatory technology development, sub-sets of these 11 experiments, based on the major agricultural constraints and the potential solutions identified and prioritised by the farmers. Quantitative and qualitative results from the testing, farmer evaluation and adaptation, training, dissemination strategies and socio-economic implications of these technologies are discussed.     

Communicating complexity: Integrated assessment of trade-offs concerning soil fertility management within African farming systems to support innovation and development

African farming systems are highly heterogeneous: between agroecological and socioeconomic environments, in the wide variability in farmers’ resource endowments and in farm management. This means that single solutions (or ‘silver bullets’) for improving farm productivity do not exist. Yet to date few approaches to understand constraints and explore options for change have tackled the bewildering complexity of African farming systems. In this paper we describe the Nutrient Use in Animal and Cropping systems - Efficiencies and Scales (NUANCES) framework. NUANCES offers a structured approach to unravel and understand the complexity of African farming to identify what we term ‘best-fit’ technologies - technologies targeted to specific types of farmers and to specific niches within their farms. The NUANCES framework is not ‘just another computer model’! We combine the tools of systems analysis and experimentation, detailed field observations and surveys, incorporate expert knowledge (local knowledge and results of research), generate databases, and apply simulation models to analyse performance of farms, and the impacts of introducing new technologies. We have analysed and described complexity of farming systems, their external drivers and some of the mechanisms that result in (in)efficient use of scarce resources. Studying sites across sub-Saharan Africa has provided insights in the trajectories of change in farming systems in response to population growth, economic conditions and climate variability (cycles of drier and wetter years) and climate change. In regions where human population is dense and land scarce, farm typologies have proven useful to target technologies between farmers of different production objectives and resource endowment (notably in terms of land, labour and capacity for investment). In such regions we could categorise types of fields on the basis of their responsiveness to soil improving technologies along soil fertility gradients, relying on local indicators to differentiate those that may be managed through ‘maintenance fertilization’ from fields that are highly-responsive to fertilizers and fields that require rehabilitation before yields can improved. Where human population pressure on the land is less intense, farm and field types are harder to discern, without clear patterns. Nutrient cycling through livestock is in principle not efficient for increasing food production due to increased nutrient losses, but is attractive for farmers due to the multiple functions of livestock. We identified trade-offs between income generation, soil conservation and community agreements through optimising concurrent objectives at farm and village levels. These examples show that future analyses must focus at farm and farming system level and not at the level of individual fields to achieve appropriate targeting of technologies - both between locations and between farms at any given location. The approach for integrated assessment described here can be used ex ante to explore the potential of best-fit technologies and the ways they can be best combined at farm level. The dynamic and integrated nature of the framework allows the impact of changes in external drivers such as climate change or development policy to be analysed. Fundamental questions for integrated analysis relate to the site-specific knowledge and the simplification of processes required to integrate and move from one level to the next.     

Tactical management of pasture fallows in Western Australian cropping systems

Agricultural systems in the Western Australian wheatbelt are increasingly moving towards specialist crop production due to elevated cereal prices, depressed markets for livestock products, and ongoing labour scarcity. However, the profitability of crop-only farms is threatened by increasing levels of herbicide resistance and declining soil fertility. This study determines the value of ungrazed pasture fallows grown tactically between crop phases to address these agronomic constraints. A novel metaheuristic optimisation technique, compressed annealing, is used to determine profitable flexible land-use sequences in a complex simulation model. Tactical use of single-year, ungrazed pasture phases is found to be more valuable than the use of break crops in crop-only systems. In contrast to previous analysis, it is identified that rotation of short periods of crop and pasture is more profitable than extended phases of both. Effective weed control without dependence on selective herbicides is the key agronomic characteristic determining the value of intermittent pasture phases. Accordingly, the number of single-year pasture phases employed in a sequence should increase with the severity of herbicide resistance. Compressed annealing is shown to be a practical method of identifying profitable land-use sequences that respond to information that unfolds dynamically.     

Integrated crop–livestock simulation models for scenario analysis and impact assessment

Despite the fact that many smallholder farming systems in developing countries revolve around the interactions of crop and livestock enterprises, the modelling of these systems using combinations of detailed crop and livestock models is comparatively under-developed. A wide variety of separate crop and livestock models exists, but the nature of crop–livestock interactions, and their importance in smallholder farming systems, makes their integration difficult. Even where there is adequate understanding of the biophysical processes involved, integrated crop–livestock models may be constrained by lack of reliable data for calibration and validation. The construction from scratch of simulation models that meet the needs of one particular case is generally too costly to countenance. As for all modelling activity, the most efficient way to proceed depends on the nature of the systems under study and the precise questions that have to be addressed. We outline a framework for the integration of detailed biophysical crop and livestock simulation models. We highlight the need for minimum calibration and validation data sets, and conclude by listing various research problems that need attention. The application of robust and trustworthy crop–livestock models is critical for furthering the research agenda associated with animal agriculture in the tropics and subtropics.     

南部非洲的保护性农业

可持续性和可盈利性 保护性农业以实现可持续的和可盈利的农业为目标,实现该目标要通过以下三方面：最小土壤扰动,永久土壤覆盖和作物轮作。这种方法对于不同规模的农田和农业生态系统都有巨大的使用潜力,但是最迫切需要采取这个方法的还是小农户,尤其是那些劳动力严重短缺的农户。这是一个结合可盈利农业生产、环境保护和可持续生产的方法,     

Crop yields under the traditional cropping patterns in a middle-belt savanna agro-ecological zone of Nigeria

A farming systems study was carried out from 1983 through 1985 among the rural farmers of the Middle-Belt agro-ecological zone of Benue State in Nigeria. The study aimed at providing the baseline data needed for evaluating the traditional cropping patterns and for assessing the magnitude of their effects on yields and returns from farms. Crop yields were found to be affected by several components of traditional cropping systems: fallow length, crop combinations in inter-cropping patterns, crop sequences and dates of planting. Variation of crop performance is such that the development in the area of well articulated farming systems research through ‘on the farm’ experimentation will provide a framework for improving the farmers' yields through modifications to the farming system.     

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.     

Water productivity in rainfed systems: overview of challenges and analysis of opportunities in water scarcity prone savannahs

Addressing the Millennium Development Goals on food and poverty over the coming decade puts enormous pressure on the world’s finite freshwater resources. Without water productivity (WP) gains, the additional freshwater in agriculture will amount to 5,600 km³ year⁻¹ in 2050. This is three times the current global irrigation use. This paper focuses on the underlying processes and future opportunities of WP gains in water scarcity prone and poverty stricken savannah regions of the world. The paper studies the consumptive (green) WP dynamics rainfed farming systems, and shows that the often assumed linear relationship between evapotranspiration (ET) and yield (Y) does not translate into constant WP over a wide range of yields. Similarly, crop transpiration (T) and Y show non-linearity under on-farm and low yield conditions. This non-linearity is validated against several on-farm research experiments in semi-arid rainfed farming systems. With integrated soil and water management, focusing on dry spell mitigation and soil fertility can potentially more than double on-farm yields, while simultaneously improve green (ET) WP and productive green (T) WP. Through the adoption of appropriate soil and water management in semi-arid smallholder farming systems, crop yields improve and result in improved livelihoods and WP gains.     

The whole-farm benefits of controlled traffic farming: An Australian appraisal

Controlled traffic farming (CTF) uses a range of technologies to confine traffic-induced compaction to permanently defined tramlines within a farm’s cropping area. CTF concentrates and improves trafficability whilst simultaneously supporting soil structure improvement between tramlines, thereby raising crop yields and offering other advantages such as reduced overlap that saves on crop inputs. This study uses whole-farm modelling to assess the profitability and role of CTF in different farming systems in Australian dryland agriculture. Farming system scenarios with and without the CTF are compared. Stepwise analysis, combined with sensitivity analysis, reveals the characteristics of CTF that most affect its value. Results indicate that the most valuable aspect of the technology is its beneficial impact on the yield and quality of crops grown on soils most subject to compaction. Hence, on farms dominated by these soils and where their faming system emphasizes cropping, CTF forms an especially valuable role. For a typical farm in the study region, employing conservative measures, farm profit increases by around 50% through use of CTF. Hence, CTF represents a remarkably profitable innovation for farming systems, offering input savings and output increases.     

Crop–animal systems in Asia: implications for research

The importance of crop–animal systems in Asia, the multiple roles played by animals and the opportunities for increasing their contribution to these systems justifies continued research effort. An assessment of the role of livestock in mixed farming systems in 14 countries has identified priority systems, technical constraints and weaknesses in the national organisations. Future research needs to focus on the rain-fed production systems, where most of the livestock are found. There is an overriding need for a farming systems perspective to the research agendas that involves inter-disciplinarity and community-based participation. Such an approach will be more complex, require concentrated effort and more efficient resource use, but will be associated with considerable benefits due to a greater integration of effort.     

Crop–animal systems in Asia: socio-economic benefits and impacts on rural livelihoods

Traditionally, small farmers in Asia have practiced mixed farming. To improve crop and animal productivity, increase farm incomes and maintain the ecological balance, several technology options have been developed through on-station and on-farm research by international organisations and national agricultural research systems. However, a review of the research reveals a paucity of information, particularly in South Asia, on the socio-economic benefits and impacts of these technologies and interventions for poor farming households. This paper presents the few case studies available which document the benefits of new technologies to improve crop–animal systems. Additionally, the paper suggests reasons for the neglect of socio-economics in these studies, and ways to strengthen this dimension.     

Factors influencing potential scale of adoption of a perennial pasture in a mixed crop-livestock farming system

Evaluating the potential scale of adoption of a technological innovation or management practice at the farm business scale can help gauge the potential size of an industry for the purposes of prioritising resources for research and development. In this paper we address the question of quantifying the potential area of adoption of a perennial pasture, lucerne (Medicago sativa L.), in dryland mixed farming systems in Australia. Lucerne pastures play a significant role in dryland farming systems in the wheat-sheep zone of southern and western Australia. While there are benefits of integrating lucerne into cropping systems there will inevitably be additional costs, and the scale of adoption of lucerne will depend largely on the increase in farm profit resulting from the introduction of lucerne. Whole-farm economic models of representative farms in the Australian wheat-sheep belt were used to determine the key drivers for the scale of adoption of lucerne.For a particular farming system the optimal area of lucerne which maximises whole-farm profit is found to depend on production, price and cost conditions. Generally, no more than 30% of a farm was allocated to lucerne according to those conditions and location of the farm. For most scenarios examined the response of profit was flat around the optimal area. This implies that lucerne could be grown on areas greater than the optimum, in order to reduce groundwater recharge (and thereby reduce the risk of dryland salinity), without greatly reducing whole-farm profit. The optimal area of lucerne in all regions was limited by the area of suitable soil types and proportion of lucerne in the most profitable lucerne-crop sequences.At all price levels assumed in this study lucerne remained as part of the optimal enterprise mix for all farm types examined. Lucerne productivity was also a major determinant of the optimal area of lucerne. The sensitivity of profit to changes in winter and/or summer production varied between regions and for different livestock enterprises. The differences were driven by the timing of energy demands and supply of feed in individual farming systems.In all regions the optimal area and profitability of lucerne varied with livestock enterprise. The analyses showed that changing from wool production to meat production enabled greater economic benefit to be realised from lucerne. This was consistent across farm types and demonstrated the value of lucerne as a source of high quality feed for finishing prime lambs in summer.The results of this study demonstrate that lucerne is profitable in a range of environments on a significant proportion of the farm area, but that this area is small relative to that required to significantly influence in its own right the environmental issue of salinity.     

Development and evaluation of an integrated simulation model for assessing smallholder crop-livestock production in Yucatán, Mexico

Mixed farming systems constitute a large proportion of agricultural production in the tropics, and provide multiple benefits for the world’s poor. However, our understanding of the functioning of these systems is limited. Modeling offers the best approach to quantify outcomes from many interacting causal variables in these systems. The objective of this study was to develop an integrated crop-livestock model to assess biophysical and economic consequences of farming practices exhibited in sheep systems of Yucatán state, Mexico. A Vensim™ dynamic stock-flow feedback model was developed to integrate scientific and practical knowledge of management, flock dynamics, sheep production, partitioning of nutrients, labor, and economic components. The model accesses sheep production and manure quantity and quality data generated using the Small Ruminant Nutrition System (SRNS), and interfaces on a daily basis with an Agricultural Production Systems Simulator (APSIM) model that simulates weather, crop, and soil dynamics. Model evaluation indicated that the integrated model adequately represents the complex interactions that occur between farmers, crops, and livestock.     

A simulation model for managing perennial grass pastures. Part I—structure of the model

A simulation model has been structured to facilitate stochastic evaluations of grazing management systems on perennial grass pastures. The output data, stored in a direct-access data set, can be used as input to statistical programs which will perform desired statistical analyses of the data.The model was originated to provide a practical method for estimating the effects of grazing frequency, duration, and grazing rate on the performance of grazing systems for perennial grass pastures. The model provides 32 different attributes for characterizing the performance of a grazing system.