Productivity of yam under alternative cropping systems adopted by small-holder farmers of southeastern Nigeria

This study compares productivity of yam under mixed and sole cropping systems and determines the opportunity cost involved in the mixed cropping system preferred by small-holder farmers of southeastern Nigeria.The results show that output of yam per hectare, output/seed input ratio, as well as yield per yam crop stand, were all higher under yam sole cropping than under mixed cropping. Scarce resources of land, labour and capital were more productive under sole cropping. The opportunity cost of producing yam under a mixed corrping system was equivalent to

480·79 per hectare.Considering the labour and financial problems faced by the farmers, and given that the same level of social status is attainable by adopting either of the two cropping systems, it becomes rational to adopt sole cropping with less labour and cash requirements but higher output and returns.     

Application of a simulation model for assessing integration of smallholder shifting cultivation and sheep production in Yucatán, Mexico

Simulation models are effective tools to examine interactions between livestock, cropping systems, households, and natural resources. Our study objective was to use an integrated livestock and crop model to assess the outcomes from selected suites of management decisions observed in smallholder sheep-cropping systems of Yucatán, Mexico. The scenarios contrasted specialized systems versus mixed farming, and evaluated the outcomes of increased crop-livestock integration. Mixed enterprise scenarios involving sheep provided more income than specialized enterprises, and capitalized on a lower price of on-farm maize grain, efficient utilization of surplus labor, and availability of common land. Labor and management income was greatest for the unintegrated and partially integrated crop and livestock scenarios. It was more profitable for producers to sell excess grain and maize stover, and use common land to feed the livestock, suggesting that increased integration does not always result in improved outcomes. The results are consistent with a system not yet pushed to the point where integration is inevitable. For all sets of scenarios, the model structure was able to accommodate subtle management differences to produce appropriate biophysical, labor, and economic outcomes. We conclude there is potential to use similar model development methods to describe other crop-livestock systems, thus providing tools for learning, scenario analysis, and impact assessment.     

An economic and sociological analysis of mixed cropping in Menoua Division of Cameroon

This paper presents an economic and sociological analysis of the cropping systems of peasant agriculture in Menoua Division of Cameroon, in an attempt to determine their major merits and demerits. From the analysis, two major types of mixed cropping system emerged: a coffee-based and a food-crop-based system of cultivation.The results show that the cropping systems are location-specific: one around the homesteads and the other further away from the compounds.It is further shown that a major contributing factor to mixed cropping in Menoua is land scarcity and that, over the years, the practices have prevailed because of the benefits which the peasants have continued to derive from these systems of cultivation. Finally, evidence from the study shows that the annual farm incomes and land size cultivated are highly correlated and negatively skewed. The implications of these findings for further research are discussed.     

Ex-ante economic analysis of alternative mulch-based management systems for sustainable plantain production in Southeastern Nigeria

Due to rapid loss of soil fertility in traditional cropping systems and subsequent yield decline, plantain fields in Southeastern Nigeria are usually reverted to fallow after three years. This study investigates the potential of mulch-based systems for long term plantain production: alley cropping with Dactyladenia barteri and natural bush, and a cut-and-carry technique with Pennisetum purpureum. Model results simulate yields decline observed under traditional cropping systems due to a decrease in soil fertility. The adoption of mulch-based technologies is conditioned by capital availability. However, when adequate capital is available, mulch-based systems are quite profitable. Under baseline conditions, the alley cropping system with natural bush outperforms the other two improved technologies with a 154% and 72% increase in net returns over continuous and shifting traditional systems, respectively. The traditional system had the worst performance without fertilizer use. A sensitivity analysis shows that the increase in net return due to fertilizer in the alley cropping and traditional systems is at least 25%. This analysis indicates that credit programs that reach small farmers and land reform that gives them secure title are essential to widespread adoption of mulch-based plantain systems.     

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.     

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.     

Optimizing multiple cropping systems: Simulation studies

Tsai et al. (1987) developed a combined network optimization—simulation model for optimal sequencing of multiple cropping systems. Essentially, simulations were used to generate a deterministic activity network. Then an optimization technique (K Longest Path algorithm) was applied to solve optimal sequences of multiple cropping. Using north Florida as a study region, the model was utilized to investigate optimal multiple cropping sequences in an irrigated or non-irrigated field. The results indicated that, for a non-irrigated farm, winter wheat followed by either soybean, maize or peanut was the most profitable cropping rotation in a multiple cropping sequence. Especially favorable was the double cropping of wheat—peanut. For an irrigated farm, a peanut crop was found to be prominent. In the case where peanut was not considered in the rotation, inclusion of irrigated wheat—maize cropping could not be recommended as a profitable multiple cropping system. Instead, double cropping of maize—soybean was the main scheme under irrigation with the possible substitution of a wheat—soybean crop sequence. To obtain higher, stable net returns, a north Florida farmer with no irrigation capability should plan his production system according to multiple cropping sequences SQ2 or SQ4 in the study. Use of these results for real-time decision making requires that the optimization be evaluated to select each new crop using current farm status and future expected weather and market conditions.     

A bio-economic model of small-ruminant production in the semi-arid tropics of the Northeast region of Brazil: Part 2—Linear programming applications and results

Survey data covering production systems for mixed farms in the Northeast region of Brazil has been synthesized within a linear programming (LP) framework. The resulting model contains activities covering the production of cattle, sheep and goats, and a vector of alternative cropping activities. Farm resources include two categories of grazing land, planted forages, family labour, two categories of hired labour, and working capital. The major livestock activities represented in the region were included as production options.Initial results did not discriminate between categories of available grazing resources. Therefore, cattle, by virtue of their higher dressing percentages and higher price per kilogram, were the optimal livestock species. A series of adjustments was then carried out to reflect types of feed resources and patterns of animal species selectivity. Optimal farm solutions for a representative traditional-production unit found objective function levels close to those found by farm surveys, but discrepancies between model results and the actual farm situations for sheep and goat activities. Model results excluded small-ruminant breeding activities because of the low net offtake at weaning levels assumed in the model. Data that became available after these initial model runs showed a higher net offtake level, and these revised coefficients resulted in optimal LP results very close to those actually found on farms.The model was then used to simulate the response of activities and farm economic performance to ‘good’ and ‘bad’ years defined by ± half standard deviation from mean annual levels of precipitation. Model results indicated much higher variability of farm income in response to weather than that found with changes in levels of technical efficiency of sheep and goat production.     

绿洲灌区交替灌溉小麦间作玉米的产量及水分利用效率

在河西绿洲灌区,通过大田试验,研究了交替灌溉小麦间作玉米的产量及水分利用效率(WUE)。结果表明,交替灌溉小麦间作玉米的产量及WUE较单作显著提高。在低、中、高3个灌水水平下,间作土地当量比分别为1.30、1.35、1.38;净占地面积上间作小麦经济产量较单作小麦分别提高了20.96%、28.34%、33.10%,间作玉米经济产量较单作玉米分别提高了38.30%、41.65%、41.98%,间作增产作用显著;间作耗水量较相应单作耗水量的加权平均分别增加了5.37%、4.71%、4.18%;WUE间作较单作小麦和单作玉米分别提高了55.97%、63.86%、68.46%和8.29%、12.71%、14.02%,WUE间作与单作小麦差异显著,但与单作玉米差异不显著。     

利用NDVI指数识别作物及土壤盐碱分布的应用研究

利用监督分类、NDVI指数等遥感影像处理方法,在黄河上游的宁夏青铜峡灌区开展识别作物及土壤盐碱分布的应用研究。基于LANDSAT卫星遥感影像,依据NDVI指数推断作物及土壤盐碱分布,得到灌区作物及土壤盐碱分布状况和相应的估算结果。研究结果表明,灌区上、下游之间在作物长势上存在着较大差异,北部地区明显低于南部,土壤盐碱分布差别是造成该差异的主要原因之一。受盐碱影响的作物面积在年度内随气候条件的改变呈现出明显的季节性变化,灌区年内受土壤盐碱危害的面积约为100000hm2,近1/3的作物面积受到程度不一的土壤盐碱化影响,且灌区下游的盐碱地面积及盐碱化程度均高于上游。     

Evaluation of the water use efficiency of alternative farm practices at a range of spatial and temporal scales: A conceptual framework and a modelling approach

Water is the principal limiting resource in Australian broadacre farming, and the efficiency with which farmers use water to produce various products is a major determinant both of farm profit and of a range of natural resource management (NRM) outcomes. We propose a conceptual framework based on multiple water use efficiencies (WUEs) that can be used to gain insight into high-level comparisons of the productivity and sustainability of alternative farming practices across temporal and spatial scales. The framework is intended as a data aggregation and presentation device. It treats flows of water, biomass and money in a mixed farming system; economic inefficiencies in these flows are tracked as they are associated with a range of NRM indicators.We illustrate the use of the framework, and its place in a larger research programme, by employing it to synthesise the results from a set of modelling analyses of the effect of land use choices on long-term productivity and a range of NRM indicators (frequency of low ground cover, deep drainage, N leaching rates and rate of change in surface soil organic carbon). The analyses span scales from single paddocks and years to whole farms and have been carried out with the APSIM and GRAZPLAN biophysical simulation models and the MIDAS whole-farm economic model.In single wheat crops in one study, different land uses in preceding years affect grain yield primarily by affecting the harvest index. When the scale changes to cropping rotations, the critical factor affecting overall water use efficiency is found to be the proportion of stored soil water that is transpired by crops. When ordinated in terms of their water use efficiencies, a set of 45 modelled rotation sequences at another location are differentiated mainly by the proportion of pasture in the rotation; when rotations are ordinated using key NRM indicators, the proportion of lucerne pasture is the main distinguishing factor. Finally, we show that for whole crop-livestock farms at three different locations across southern Australia, the pattern of water use efficiencies in the most profitable farming systems changes in similar ways as cropping proportion is altered. At this scale, land use choices affect multiple water use efficiency indices simultaneously and commodity prices determine the balance of the resulting economic tradeoffs.Limitations to the use of the WUE framework arising from its relative simplicity are discussed, as are other areas of farming systems research and development to which it can be applied.     

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.     

The farmer-based small-farm schemes of the Ogun-Oshun River Basin Development Authority,Southwestern Nigeria

This paper analyses the strengths and weaknesses of the innovative small-scale farming scheme of the Ogun-Oshun River Basin Development Authority in southwestern Nigeria. Two project sites, Ofiki and Mokoloki, situated in contrasting ecological zones are used as case studies. In general the scheme has achieved a large measure of success in both areas, but, the future of the scheme appears brighter and more assured in the Ofiki area, situated in the economically depressed and rural savanna region, than in Mokoloki situated in the forest region where tree crop cultivation is prevalent and urban influence very strong. There are still many unresolved issues, solutions to which may determine the sustenance of the scheme. Such issues include the question of land rights; the negative attitude of the farmers to the system of sole cropping, pricing policy and payment of their share of farm proceeds; low initial returns from the projects; and operational bottle-necks.     

冬小麦、春玉米间作条件下作物需水规律

通过田间试验研究了冬小麦、春玉米间作条件下各生育期的作物需水规律.结果表明:与单作相比,第1个试验期内冬小麦全生育期内间作麦田土壤蒸发量增加34.63 mm,作物蒸腾量减小65.81 mm, 蒸发蒸腾量减小31.18 mm.第2个试验期内冬小麦生育期内间作麦田土壤蒸发量增加26.00 mm,作物蒸腾量减小64.81 mm, 蒸发蒸腾量减小40.81 mm.与单作春玉米相比,间作春玉米的土壤蒸发减少了40.94 mm,作物蒸腾增加了147.73 mm,ET值增加了106.79 mm.可为间作种植的水分管理提供参考.     

Energy minimised v. cost minimised alternatives for the US beef production system

A model of the US beef production system has been utilised to project tradeoffs between minimised cost of feeding and minimised fossil energy use to produce amounts of beef similar to 1976 consumption. Cost minimisation approaches the present actual beef production system, but suggests increases in bull feeding and the use of silage and grass finishing of cattle. Energy minimisation indicated energy savings could exceed the equivalent of 240 million barrels of crude oil/year. If energy costs increased three times the 1979 levels, energy and cost minimised solutions appear equivalent.USDA ‘Choice’ grade has been a cost effective strategy, even without consideration of price differentials for the higher quality beef. However, maintenance of current levels of ‘Choice’ beef production does not appear optimal from an energy efficiency standpoint. The model results for energy minimisation suggest an increase in grass finishing and feeding of large bulls, rather than steers, practices which could further reduce fossil fuel inputs, but would result in less ‘Choice’ quality meat. Each increase in energy efficiency in the beef system (other than simple elimination of waste) may be anticipated to have a cost penalty over current practice, given constant or moderately increasing energy costs.However, if energy prices were to reach three times their present level, the model suggests that national cost minimisation would require more energy efficient production systems, and the production of the higher quality beef grades would increase in relative expense. The beef industry does not, at present, minimise energy input because energy's apparent real cost has been low compared with other inputs.     

Conversion to organic arable farming in The Netherlands: A dynamic linear programming analysis

Several studies show that organic farming is more profitable than conventional farming. However, in reality not many farmers convert to organic farming. Policy makers and farmers do not have clear insight into factors which hamper or stimulate the conversion to organic farming. The objective of this paper is to develop a dynamic linear programming model to analyse the effects of different limiting factors on the conversion process of farms over time. The model is developed for a typical arable farm in The Netherlands central clay region, and is based on two static liner programming models (conventional and organic). The objective of the model is to maximise the net present value over a 10-year planning horizon. The results of the analysis of a basic scenario show that conversion to organic farming is more profitable than staying conventional. In order to arrive at the actual profitable phase of organic farming, the farmer has to pass through the economically difficult 2-year conversion period. Sensitivity analysis shows that if depreciation is 25% higher than conventional fixed costs due to machinery made superfluous by conversion, conversion is less profitable than staying conventional. Also the availability of hired labour, which can be constrained in peak periods, has a strong effect on the cropping plan and the amount of area converted. Further analysis shows that a slight drop (2%) in organic prices lowers the labour income of the farmer and makes conversion less profitable than conventional farming. For farmers, a minimum labour income can be required to ‘survive’. The analysis shows that constraint on minimum labour income makes stepwise conversion the best way for farmers to overcome economic difficulties during conversion.     

Irrigation modernization and water conservation in Spain: The case of Riegos del Alto Aragón

This study analyzes the effects of irrigation modernization on water conservation, using the Riegos del Alto Aragón (RAA) irrigation project (NE Spain, 123354 ha) as a case study. A conceptual approach, based on water accounting and water productivity, has been used. Traditional surface irrigation systems and modern sprinkler systems currently occupy 73% and 27% of the irrigated area, respectively. Virtually all the irrigated area is devoted to field crops. Nowadays, farmers are investing on irrigation modernization by switching from surface to sprinkler irrigation because of the lack of labour and the reduction of net incomes as a consequence of reduction in European subsidies, among other factors. At the RAA project, modern sprinkler systems present higher crop yields and more intense cropping patterns than traditional surface irrigation systems. Crop evapotranspiration and non-beneficial evapotranspiration (mainly wind drift and evaporation loses, WDEL) per unit area are higher in sprinkler irrigated than in surface irrigated areas. Our results indicate that irrigation modernization will increase water depletion and water use. Farmers will achieve higher productivity and better working conditions. Likewise, the expected decreases in RAA irrigation return flows will lead to improvements in the quality of the receiving water bodies. However, water productivity computed over water depletion will not vary with irrigation modernization due to the typical linear relationship between yield and evapotranspiration and to the effect of WDEL on the regional water balance. Future variations in crop and energy prices might change the conclusions on economic productivity.     

A synchronous and differential operational scheme for the NH3 application system in XAIC,China

The whole world is facing a new Industrial Revolution at the present time. How to meet the challenge of the ‘third wave’ is a difficult question in the forefront of agricultural production in developing countries. In the light of our study, one of the essential principles seems to be that people must pay great attention to the application of ‘soft science’, such as information theory and agricultural systems, while introducing or improving certain advanced and appropriate ‘hard technology’.Starting from this viewpoint, a simulation model has been developed to study the NH₃ direct application system in XAIC, China. The model uses experimental data from fourteen different districts in Xinjiang, plus the USA and Canada, and consists of a mixed integer program with goal programming variables. Its objective is to achieve maximum economic efficiency with minimum costs covering synthesis, transportation, storage and application, as well as lower energy consumption.Since a model only achieves real significance by being put into practice, an application of the model is described to show the effect of altering the composition of XAIC's N application from solid state only to 40% anhydrous ammonia and 60% solid N components. The sub-systems, running simultaneously at different levels, are controlled by computer feedback. The results have been satisfactory.     

Modelling water control needs for diversified cropping

The background and concepts of water control for crop diversification in rice-based irrigation systems are discussed. Water control is described in terms of the irrigation event volumes and intervals between irrigation events. The development of the WACCROD model to simulate these water control parameters under selected agroclimatic conditions is described. The simulation model can recommend irrigation event volumes and intervals for various dry season cropping patterns in rice-based irrigation systems. Also, the application of the model to a general situation at field level of a ‘typical’ rice based irrigation system is reported.     

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.