Interlinked credit and farm intensification: evidence from Kenya

This paper addresses the potential for interlinked credit/input/output marketing arrangements for particular cash crops to promote food crop intensification. Using panel survey data from Kenya, we estimate a household fixed-effects model of fertiliser use per hectare of food crops, using an instrumental variables approach for addressing the endogeneity of participation in interlinked credit arrangements. Results indicate that households engaging in interlinked marketing programs for selected cash crops applied considerably greater fertiliser on other crops (primarily cereals) not directly purchased by the cash crop trading firm. These findings suggest that, in addition to the direct stimulus that interlinked cash crop marketing arrangements can have on small farmer incomes, these institutional arrangements may provide spill-over benefits for the productivity of farmers' other activities such as food cropping.     

Measuring the sustainability and economic viability of tropical farming systems: a model from sub-Saharan Africa

New technologies must be developed in sub-Saharan Africa which are sustainable and economically viable. This paper discusses a methodology for measuring the agricultural sustainability and economic viability of tropical farming systems for new technology evaluation. The approach is based on the concept of interspatial and intertemporal total factor productivity, paying particular attention to valuation of natural resource stock and flows. Agriculture is a sector which utilizes natural resources (e.g. soil nutrients) and the stock and flows of these resources affect the production environment. However, in many cases, the stock of these resources is beyond the control of the farmer and must be accounted for in an agricultural sustainability and economic viability measurement. For example, soil nutrients are removed by crops, erosion or leaching beyond the crop root-zone, or other processes such as volatilization of nitrogen. Agricultural production can also contribute to the stock of some nutrients by leguminous plants such as agroforestry systems. Using a data set available at the International Institute of Tropical Agriculture, we compute the intertemporal and interspatial total factor productivity indices for four cropping systems in southwestern Nigeria using stock of major soil nutrients as the natural resource stock. Results show that the sustainability and economic viability measures are sensitive to changes in the stock and flow of soil nutrients as well as the material inputs and outputs. Where the contribution of natural resource stock and flows are important (such as in the case of alley cropping), the measures provide markedly different results from conventional TFP approaches. The advantage of this approach is that interspatial and intertemporal total factor productivity measures are computed using only price and quantity data, thus eliminating the need for econometric estimation.     

Designating tree crops as forest: Land competition and livelihood effects mediate tree crops impact on natural forest cover in south China

The Chinese government applies the term ‘tree crops’ (jingjilin) to a bundle of tree species with uses other than timber production, defining this category as a component of national forest statistics. Tree crops may displace either farmland or forestland, and can be a promising livelihood option for smallholders. The overall impact of this particular policy on natural forest growth remained unanswered. In the general expansion trend of tree cover in southern China, tree crops could compete for land with natural forests, their cultivation may pose environmental trade-offs with natural forest cover. However, in a context of large labor flows from countryside to cities, tree crops could provide promising opportunities for dealing with on-farm labor shortages and generating income for disadvantaged populations remaining in rural communities, then promoting remaining natural forest quality through alternative livelihoods process. There is a knowledge gap to thoroughly investigate tree crops’ impact on natural forest change both conceptually and empirically, especially a mechanism verification of the alternative livelihood hypothesis. Thus, we construct a framework assessing land use competition and alternative livelihood effects together to assess overall impacts of tree crop cultivation on natural forests. Our dataset combines forest resource inventory data and provincial social-economic factors for a panel analysis of contributions to change in natural forest cover, density, and stock in China’s biodiversity-rich southern provinces. Results show tree crop cover is negatively associated with natural forest extent, but positive associated with change in natural forest density, while the relationship with change in natural forest stock is insignificant. Further tests of mechanisms support the hypothesis that tree crops benefit disadvantaged rural populations, providing an alternative livelihood. Defining tree crops as forest in China obscures important patterns, particularly a trade-off between tree crops and natural forest cover and a possible synergy with natural forest density mediated by alternative livelihood processes. Policy makers should enact specific policies to incentivize natural forest recovery in the southern collective forest zone and reconsider the appropriateness of defining tree crops as forest. Concentration and intensification of tree crop production on suitable lands may have the potential to benefit both forests and impoverished populations.     

Wholesale Market Feasibility Analysis for New Crop Development

Growers in developed as well as developing countries are seeking new or alternative crops to support rural employment, generate export earnings, and decrease crop surpluses in major crops. A key component of new crop development strategies is wholesale marketing feasibility. This article presents a model of how to analyze the feasibility of providing marketing services for new crops. The example used is a fresh-market, potato packing facility in Union County, New Mexico. The approach used in this study is applicable to growers in developing countries seeking to enter new or alternative crop markets.     

山东省粮经作物播种比例演变及结构优化研究——基于1986～2015统计数据

[目的]目前我国农业主要矛盾是结构性失衡,作为种植业大省的山东省的农业结构性矛盾更为突出,种植业供给侧结构性改革势在必行。[方法]选取山东省1987~2016年农业统计年鉴中有关1986~2015年粮食作物和经济作物以及同类作物不同品种的播种面积的统计数据,运用统计分析法、图表法和对比分析法,分析山东省粮经作物播种面积比例演变特点,以及粮食作物和经济作物各自内部播种面积比例演变特点。[结果]30年间,山东省粮食作物播种面积及占比呈缓慢下降趋势,而经济作物播种面积和占比则持续上升,但大豆、棉花等经济作物国际市场依存度持续走高。从粮食作物和经济作物具体品种来看,玉米、蔬菜、瓜果播种面积持续大幅度上升,而大豆、棉花播种面积连年下降。[结论]山东省应在遵循国家发展粮经饲统筹的"三元"种植结构的政策导向基础上,兼顾种植户的经济利益,顺应消费者需求变化,从种植制度与生产方式安排、农作物品种选择、农作物品质提升3个方面进一步优化种植业结构。     

Producer Experience, Learning by Doing, and Yield Performance

Current crop insurance rating procedures consider only performance for the individual crop in question. Recent farm legislation has given producers considerable planting flexibility and, as a result, many have shifted to new crops. Producers without a production history for the new crop may be offered levels of insurance that do not accurately reflect their expected yields. Likewise, premium rates may not reflect a producer's actual risk for a new crop. We examine the extent to which information about expected yields may be gleaned from a consideration of historical performance on other crops. We also consider the extent to which yield performance exhibits learning by doing such that yields improve with experience. Though the results are mixed, we generally find that yield performance tends to improve with experience. However, when yields are conditioned on historical yield performance for other crops, the importance of experience is diminished significantly. Yield performance is related to a number of farm characteristics. Finally, we examine the extent to which yield variability is correlated across crops for individual farmers. Implications for crop insurance rating practices are discussed. The results demonstrate robust correlation between a farm's historical yield on other crops and a newly produced crop—a factor largely ignored in current crop insurance contracts.     

An application of Target MOTAD Model to crop production in Zambia: Gwembe Valley as a case study

The Zambian Government encourages crop production in the Gwembe Valley without taking into consideration the risks involved. These risks mainly originate from the stochastic nature of rainfall. This paper, therefore, identifies optimal cropping patterns in the Gwembe Valley by using Target MOTAD Model. The results of the Target MOTAD Model indicate an optimal cropping pattern of growing sorghum, rice and soyabeans. This is different from the existing cropping pattern of sorghum, sunflower, cotton and maize. The overall policy implication of adopting the cropping pattern obtained from the model solution is that some resources allocated to the production of current crops have to be reallocated to the production of new crops. Moreover, since people in the Gwembe Valley are used to growing of cotton, sunflower and maize, the adoption of the suggested new crops will entail the education of the people (through extension services) in the crop husbandry of these crops.     

The economic determinants of cereal crop diversity on farms in the Ethiopian highlands

In less favoured areas such as the highlands of Ethiopia, farmers manage risk through land allocation to crops and varieties since they cannot depend on market mechanisms to cope. They also grow traditional varieties that are genetically diverse and have potential social value. Supporting the maintenance of crop and variety diversity in such locations can address both the current needs of farmers and future needs of society, though it entails numerous policy challenges. We estimate a model of crop and variety choice in a theoretical framework of the farm household model to compare the determinants of crop and variety diversity, revealing some of these policy considerations. Farm physical features and household characteristics such as wealth and labour stocks have large and significant effects on both the diversity among and within cereal crops, varying among crops. Policies designed to encourage variety diversity in one cereal crop may have opposing effects in another crop. Trade-offs between development-related factors and diversity in this resource-poor system are not evident, however. Market-related variables and population density have ambiguous effects. Education positively influences cereal crop diversity. Growing modern varieties of maize or wheat does not detract from the richness or evenness of these cereals on household farms.     

河南省县域农作物生产空间格局演变及专业化分区研究

[目的]河南省不同地区的光热水土条件存在较大差异,探索农作物种植的生产潜力最优区域,是新形势下提升河南省农作物产量和保障国家粮食安全战略的新思路。[方法]以县域为研究空间单元,选取河南省11种主要农作物为对象,借助空间经济学重心模型、专业化指数及空间自相关模型,通过地理信息系统(GIS)技术平台,揭示河南省农作物生产空间及专业化演变趋势。[结果]23年来,河南省县域农作物生产集聚及专业化水平持续提升,集聚空间呈"东进北上"演变趋势,其中麻类、烟草的生产集聚及专业化程度较高,谷物最低;蔬菜的生产集聚及专业化水平在2005年之后持续下降,水果在商丘东部形成了新的优势产区。基于此,将河南省11种农作物划分为绝对优势区、比较优势区、潜力优势区、不具优势区、优势衰退区和快速退出区6种类型生产空间,区域自然禀赋、制度政策、社会发展及农户个体意愿是河南省县域农作物生产空间演化主要驱动因素。[结论]基于农作物生产聚集及专业化水平演变趋势划定生产空间分区,引导农作物生产布局优化,对有效保障粮食安全具有重要意义。     

DO INCREASED COMMODITY PRICES LEAD TO MORE OR LESS SOIL DEGRADATION?

In this paper, a dynamic economic model is used to analyze the conflicting impacts of crop increasing/land degrading inputs with those of soil conserving/crop reducing inputs in problems of soil degradation in agriculture. Soil is a renewable resource that is generated naturally at a slow, essentially autonomous rate. Cultivation enhances crop production and degrades the soil, while conservation is unproductive for the crop but improves the soil resource. If the effects of cultivation dominate the effects of conservation in the soil dynamics, an increase in the price of the crop accelerates the rate of soil degradation In the short-run and decreases the long-run stock of the soil resource. On the other hand, if the effects of conservation dominate the effects of cultivation, an increase in the price of the crop decelerates the rate of soil degradation in the short run and increases the long-run stock of the soil resource. It is shown that subsidies on conservation activities or taxes on cultivation intensity may well decrease the long-run soil stock, although strong conditions must be satisfied for either of these results to hold. It also is shown that a reduction in the real discount rate or a direct per unit tax on soil losses is certain to increase the long-run soil stock and reduce the short-run rate of soil degradation.     

基于情景分析的烟草种植替代综合效应研究

[目的]烟草种植替代是从源头控制烟草消费的最有效措施,但在我国还未全面实施。文章分析研究不同情境下烟草种植替代可能产生的综合效应,以期推动我国烟草种植替代的实施。[方法]基于2018年湖北省利川市11种作物的成本收益、化肥使用量等数据,利用情景分析法,结合环境风险指数法和综合评价法对烟草种植替代可能产生的综合效应进行分析。[结果]（1）种植烟草高昂的人工成本使得其净利润为负,且在11种作物中最低,其现金收益仅高于粮食与油料作物,种植番茄或黄瓜的现金收益分别比烟草高7倍和6倍,烟草较高的价格可能是吸引农户种植的主要原因之一;（2）情景1种植烟草的氮肥使用环境风险较低,磷肥与钾肥使用的环境风险等级较高;情景2种植粮食作物可以减少化肥使用的环境风险,种植蔬菜等作物会增加化肥使用的环境风险;（3）在该文的3种情景中,粮食作物的固碳能力较强,经济作物的固碳能力较弱;种植烟草的固碳能力最弱,其综合效应仅优于油菜籽与烟草的组合,远低于种植蔬菜或烟草与蔬菜作物组合种植的综合效应。[结论]利川市可以选择番茄、黄瓜等蔬菜作物或是这些作物与烟草共同种植的方案来代替烟草种植,在履行《烟草控制框架公约》的同时能...     

Cash cropping and food crop productivity: synergies or trade‐offs?

The case for promoting export‐oriented cash crops in Africa has generally been based on their direct potential contribution to agricultural productivity and small farmer incomes. A relatively neglected avenue of research concerns the synergistic effects that cash cropping can have on other household activities, including food production. The conventional view that cash crops compete with food crops for land and labour neglects the potential for cash crop schemes to make available inputs on credit, management training, and other resources that can contribute to food crop productivity, which might otherwise not be accessible to farmers if they did not participate in cash crop programs. This article builds on previous research by hypothesising key pathways by which cash crops may affect food crop activities and empirically measuring these effects using the case of cotton in Gokwe North District in Zimbabwe. Analysis is based on instrumental variable analysis of survey data on 430 rural households in 1996. Results indicate that—after controlling for household assets, education and locational differences—households engaging intensively in cotton production obtain higher grain yields than non‐cotton and marginal cotton producers. We also find evidence of regional spill‐over effects whereby commercialisation schemes induce second round investments in a particular area that provide benefits to all farmers in that region, regardless of whether they engage in that commercialisation scheme. The study suggests that the potential spill‐over benefits for food crops through participation in cash crop programs are important to consider in the development of strategies designed to intensify African food crop production.     

A Case Study Approach to Comparing Weed Management Strategies under Alternative Farming Systems in Ontario

When research was initiated into comparing alternative method's of managing weeds in Ontario's major field cash crops, no field trial data existed. Twenty-five farmers were therefore surveyed for their production data on corn, beans and fall-seeded cereal grains, including weed management practices, input costs and wage rates, yields and product prices. Nine farmers were classified "conventional" because of their heavy dependence on synthetic herbicides, which were routinely broadcast on the three focus crops. Nine farmers were classified as "reduced input" if they placed reduce dependence on herbicides for at least one of the focus crops. Seven organic farmers placed zero reliance on herbicides, using instead substitutes such as crop rotations, smother crops, soil tillage and timeliness of field operations. Although organic farmers spent the most time and money on weed control, their overall direct costs of production were lowest for all three focus crops. Crop gross margins were highest on organic farms, partly because of lower production costs, but also because of higher product prices along with comparable crop yields. Linear programming model results for whole-farm analyses revealed highest net farm incomes on organic farms and lowest on conventional farms, in part due to lower overhead costs on organic farms, and in part due to greater enterprise diversification and to greater self-sufficiency in material inputs. These case study results need broader-scale testing to verify the conclusion that organic or reduced-input methods of weed management offer viable alternatives to conventional approaches.     

Input subsidies and crop diversity on family farms in Burkina Faso

Since their independence, many countries in sub-Saharan Africa have used input subsidies to increase agricultural productivity and improve food security. We analyse the effects of both a fertiliser and a seed subsidy on farming households' land allocation among crops and crop diversity in Burkina Faso. Although previous studies investigated either the impact of a fertiliser or a seed subsidy on targeted crops, few examined the effects of both subsidies combined. Applying a correlated random-effects model with a control function approach to nationally representative, 2-year panel data collected from farming households, we find that those with access to the fertiliser subsidy allocate more land to the crops it targets (rice, maize and cotton) than non-targeted crops. Focusing on a minor crop with key agronomic and nutritional attributes, we conclude that land allocation to cowpea as the primary crop and intercrop declined with the fertiliser subsidy. The fertiliser subsidy also negatively affects crop diversity. However, we find that the cowpea seed subsidy offsets the bias of fertiliser subsidy toward fertiliser-targeted crops and enhances diversity.     

Analyzing crop change scenario with the SmartScape™ spatial decision support system

Agricultural land use is increasingly changing due to different anthropogenic activities. A combination of economic, socio-political, and cultural factors exerts a direct impact on agricultural changes. This study aims to illustrate how stakeholders and policymakers can take advantage of a web-based spatial decision support system (SDSS), namely SmartScape™ to either test existing crop change policies or produce effective crop change decisions using tradeoff analysis. We addressed the consequences of two common crop change scenarios for Dane county in Wisconsin, United States, (a) replacing perennial energy crops with annual energy crops and (b) replacing annual energy crops with perennial energy crops. The results suggested that converting areas under grass and alfalfa production that were located on high quality soil and flat slope to corn promoted a net-income and availability of gross biofuel. Additionally, the model outcome proposed that converting areas under corn and soy production that were located on high slope to grass promoted net-energy, phosphorus loading, soil loss, soil carbon sequestration, nitrous oxide emission, grassland bird habitat, pollinator abundance, and biocontrol. Therefore, SmartScape™ can assist strategic crop change policy by comparing the tradeoff among ecosystem services to ensure that crop change policies have outcomes that are agreeable to a diversity of policymakers.     

Are farmers ‘efficient but poor’? The impact of crop choices on technical efficiency and poverty in Nigeria

We test the ‘efficient-but-poor’ hypothesis by estimating the determinants of smallholders' choice over cash or food crops and whether their crop choice affects technical efficiency and poverty using the national household panel data in Nigeria. We employ the stochastic frontier analyses correcting for sample selection about farmers' crop choice. Our results indicate that smallholders are generally efficient in their resource allocations. A treatment effects model is employed to estimate farmers' crop choice in the first stage and the impact of their choices on technical efficiency and poverty outcomes in the second stage. The results show that farmers' access to free inputs, non-farm income and the use of seeds from the previous growing season are important determinants of crop choice. The adoption of cash crops by food-crop producing households will not generally reduce poverty, although it will improve technical efficiency marginally. However, if cash crops are commercialised, poverty tends to decline.     

Changing the U.S. Sugar Program into a Standard Crop Program: Consequences under the North American Free Trade Agreement and Doha

We analyze the impact of continuing the existing U.S. sugar program, replacing it with a standard program, and implementing the standard program with multilateral trade liberalization. Under the North American Free Trade Agreement (NAFTA), duty-free sugar imports from Mexico could undermine the program's ability to operate on a "no-cost" basis to taxpayers as large public stocks of sugar could accumulate. The replacement of the current sugar program by one similar to other major U.S. crop programs would solve the problem of potential stock accumulation, accommodate further trade liberalization under a new WTO and future bilateral trade agreements, but would induce significant fiscal outlays through direct payments.     

基于最小距离法的RADARSAT-2遥感数据旱地作物识别

利用雷达遥感技术进行作物识别是当前作物遥感监测的研究热点之一,但利用雷达遥感技术进行旱地作物识别的相关研究较少,该文以RADARSAT 2雷达遥感数据对两种旱地作物玉米和棉花进行识别。以河北省枣强县为研究区,对其区域内的玉米和棉花进行识别。首先分析了与卫星过顶时刻同步采集的作物参数与后向散射系数之间的相关性发现,在植株高度、生物量、作物含水量、叶面积指数这四个作物参数中,植株高度与后向散射系数的相关性最大,其次是作物含水量;同时,通过最小距离法应用多时相、多极化雷达遥感数据进行作物识别,其精度可达到85%,通过与资源三号光学遥感数据结合,其作物识别精度提高到了93%。研究结果表明,雷达遥感数据应用于旱地作物识别是可行的,雷达遥感数据与光学遥感数据的结合能提高旱地作物识别的精度。该研究为应用雷达遥感数据进行旱地作物识别提供了参考。     

基于星载极化SAR数据的农作物分类识别进展评述

［目的］农作物播种面积信息不仅可为农情监测和作物估产提供重要的数据保障,还是国家制定粮食政策和经济计划的重要依据。快速、准确地获取农作物播种面积信息能为农业生产管理提供决策支持。极化SAR不受云雨天气的影响,在农作物遥感监测方面具有巨大的应用潜力,有效利用极化SAR数据进行农作物识别研究对促进雷达技术在国家农业遥感监测和农业供给侧结构性改革中发挥更大作用具有重要意义。［方法］以星载极化SAR技术的发展过程为论述主线,从单、双极化SAR数据,单、双极化SAR数据结合光学影像,全极化SAR数据三个发展阶段,对极化SAR数据在农作物分类识别中的研究与应用进行总结,并对比分析不同的识别特征、融合算法以及分类算法的优缺点。［结果］以往研究存在以下不足：当前研究多以识别水稻为主,对于难以识别的旱地作物研究较少;目前对旱地作物识别精度不高,平均识别精度不足85%;缺乏对不同作物散射机制及其随时相变化的研究,导致分类算法机理性不足,普适性较差。［结论］在今后的研究中,旱地作物散射机制的定量确定,如何利用散射机制及其变化来提高旱地作物遥感识别精度和普适性;目前分类算法大都是基于光学影像设计,如何利用SAR特殊的成像方式优化设计适用于极化SAR数据的分类算法,得到更高的分类精度;如何更好的跟光学遥感等多源数据（光学数据、GIS数据等）结合来提高精度,将成为未来极化SAR农作物识别中三个亟需重点解决的问题。     

基于无人机遥感可见光影像的农作物分类

[目的]无人机遥感具有高空间、高时间分辨率的优点,并可同时获得光谱和空间信息,因此在农作物分类中备受研究者的青睐。与侧重于从高分辨率RGB图像中提取纹理特征的分类方法不同,文章重点研究如何利用作物在光谱和空间维度上的联合特征尤其是作物高程特征,以实现农作物精细分类。[方法]首先,我们进行研究区域选择和地面实际情况调查,用无人机遥感系统进行可见光影像采集;其次,确定研究区域内农作物分类类别,分别对可见光遥感影像进行可见光植被指数计算及纹理滤波;针对数字表面模型(DSM)数据特点,对两期DSM数据进行差值处理,获得差异数字表面模型数据(DDSM),提取作物高度信息,并根据农作物冠层特性对差异数字表面模型进行滤波处理;最后,进行特征优选及组合,使用SVM方法进行农作物分类。[结果]确定最优分类特征为RGB、红波段对比度、绿波段二阶矩、蓝波段方差、DDSM、DDSM方差、DDSM对比度,分类精度由71.86%提高到92.30%,验证了由DSM影像提取的空间特征可以提高农作物分类精度。[结论]该研究探索了一种基于可见光及空间联合特征的农作物精细分类方法,方法简单可行,设备成本低,在基于无人机低空遥感的样方调查领域中有较大的应用前景。