Bias from Farmer Self‐Selection in Genetically Modified Crop Productivity Estimates: Evidence from Indian Data

In the continuing debate over the impact of genetically modified (GM) crops on farmers of developing countries, it is important to accurately measure magnitudes such as farm‐level yield gains from GM crop adoption. Yet most farm‐level studies in the literature do not control for farmer self‐selection, a potentially important source of bias in such estimates. We use farm‐level panel data from Indian cotton farmers to investigate the yield effect of GM insect‐resistant cotton. We explicitly take into account the fact that the choice of crop variety is an endogenous variable which might lead to bias from self‐selection. A production function is estimated using a fixed‐effects model to control for selection bias. Our results show that efficient farmers adopt Bacillus thuringiensis (Bt) cotton at a higher rate than their less efficient peers. This suggests that cross‐sectional estimates of the yield effect of Bt cotton, which do not control for self‐selection effects, are likely to be biased upwards. However, after controlling for selection bias, we still find that there is a significant positive yield effect from adoption of Bt cotton that more than offsets the additional cost of Bt seed.     

The economics of land fragmentation in the north of Vietnam*

Land fragmentation, where a single farm has a number of parcels of land, is a common feature of agriculture in many countries, especially in developing countries. In Vietnam, land fragmentation is common, especially in the north. For the whole country, there are about 75 million parcels of land, an average of seven to eight plots per farm household. Such fragmentation can be seen to have negative and positive benefits for farm households and the community generally. Comparative statics analysis and analysis of survey data have led to the conclusion that small‐sized farms are likely to be more fragmented, and that fragmentation had a negative impact on crop productivity and increased family labour use and other money expenses. Policies which allow the appropriate opportunity cost of labour to be reflected at the farm level may provide appropriate incentives to trigger farm size change and land consolidation. Policies which tip the benefits in favour of fewer and larger plots, such as strong and effective research and development, an active extension system and strong administrative management, may also lead to land consolidation.     

农业用水非农化对农户粮食生产用水行为的影响基于山东省728份农户调查数据

目的 农户作为微观经营主体,其节水技术的采用将提高粮食生产用水效率,达到节约水资源与保证粮食生产的双重目的。通过分析农户粮食生产用水行为,探讨水资源短缺约束对农户粮食生产技术采用的诱致效应。方法 文章基于2019年对山东省728份农户的调查问卷数据,以农户行为理论为基础,综合运用统计分析、Logit模型等方法,对农业用水非农化约束下农户的粮食生产用水行为进行分析。结果 在农业用水非农化态势下,作为理性经济人的农户倾向于采用节水技术,以保证粮食生产。农户年龄、家庭农业劳动力人数、灌溉水源与灌溉方式对其节水技术的采用影响显著为负,农业年收入、小麦及玉米种植面积对农户节水技术的采纳行为影响显著为正。结论 规模化经营是大型节水设施应用的基本条件,应当加快农地流转,推进粮食生产规模化经营,提高粮食灌溉的规模化和标准化水平;同时加快建立科学合理的农业水价改革制度,促进农民节约农业用水,以此实现水资源利用效率提高与粮食生产能力稳定的双重目标。     

Strategies to increase agricultural productivity and reduce land degradation: evidence from Uganda

This paper estimates a structural econometric model of household decisions regarding income strategies, participation in programs and organisations, crop choices, land management, and labour use, and their implications for agricultural production and soil erosion; based upon a survey of over 450 households and their farm plots in Uganda. Many factors have context-specific impacts and involve trade-offs between increasing production and reducing land degradation. Government agricultural extension and training programs contribute to higher value of crop production in the lowlands, but to soil erosion in the highlands. By contrast, non-governmental organization (NGO) programs focusing on agriculture and environment help to reduce erosion, but have less favourable impacts on production in the lowlands. Education increases household incomes, but also reduces crop production in the lowlands. Poverty has mixed impacts on agricultural production, depending on the nature of poverty: smaller farms obtain higher crop production per hectare, while households with fewer livestock have lower crop production. Population pressure contributes to agricultural intensification, but also to erosion in the densely populated highlands. Several household income strategies contribute to increased value of crop production, without significant impacts on soil erosion. We find little evidence of impact of access to markets, roads and credit, land tenure or title on agricultural intensification and crop production and land degradation. In general, the results imply that the strategies to increase agricultural production and reduce land degradation must be location-specific, and that there are few 'win-win' opportunities to simultaneously increase production and reduce land degradation.     

Yield Effects of Tissue Culture Bananas in Kenya: Accounting for Selection Bias and the Role of Complementary Inputs

We analyse yield effects of tissue culture (TC) banana technology in the Kenyan small farm sector, using recent survey data and an endogenous switching regression approach. TC banana plantlets, which are free from pests and diseases, have been introduced in East Africa since the late 1990s. Although field experiments show significant yield advantages over traditional banana suckers, a rigorous assessment of impacts in farmers’ fields is still outstanding. A comparison of mean yield levels between TC adopters and non‐adopters in our sample shows no significant difference. However, we find evidence of negative selection bias, indicating that farmers with lower than average yields are more likely to adopt TC. Controlling for this bias results in a positive and significant TC net yield gain of 7%. We also find that TC technology is more knowledge intensive and more responsive to irrigation than traditional bananas. Simulations show that improving access to irrigation could lift TC productivity gains to above 20%. The analytical approach developed and applied here and the finding of negative selection bias may also be relevant for the evaluation of other agricultural technologies.     

Land Invasions,Insecure Property Rights and Production Decisions

This paper investigates empirically the effect of land invasions on farm production decisions. The main hypothesis is that more invasions in a region are associated with lower investment, and in particular a bias towards annual crops as opposed to long‐term crops. We use a county‐level dataset for the state of Paraná, Brazil, from 2003 to 2007, with 1,995 observations. The panel data structure allows us to control for fixed effects, such as the formalisation of land titles and land concentration, which might be correlated with the intensity of invasions. An instrumental variable fixed effects model was estimated to avoid other sources of bias. Our main finding is that land invasions are associated with lower long‐term crop production and a higher percentage of annual crops, which could accelerate land degradation, and undermine environmental sustainability.     

Policy instruments for sustainable land management: the case of highland smallholders in Ethiopia

Degradation of land continues to pose a threat to future food production potential in many developing economies. Various approaches, mainly based on command‐and‐control policies, have been tried (with limited success) in the past to encourage adoption of erosion‐control practices by farm households. High transactions costs and negative distributional impacts on the welfare of the poor limit the usefulness of standards and taxes for soil and water conservation. One innovative approach is the use of interlinked contracts which create positive incentives for land conservation. This study analyses the social efficiency of such policies for erosion‐control in the Ethiopian highlands using a non‐separable farm household model. Incentive contracts linked with conservation seem to be promising approaches for sustainable resource use in poor rural economies. This may suggest that conservation programs should give greater consideration to better fine‐tuning and mix of policies that help achieve both economic and environmental objectives.     

The Amenity and Disamenity Impacts of Agriculture: Estimates from a Hedonic Pricing Model

The positive and negative externalities from farmland are increasingly a focus of public policy discussion about agriculture and land use. A GIS-based hedonic pricing model shows that agricultural open space increases nearby residential property values, but larger-scale animal operations and mushroom production have negative impacts. Animal production facilities with as few as 200 animal equivalent units reduce nearby property values, but larger facilities do not necessarily generate larger impacts. Because they tend to occur together, the negative impacts of animal agriculture and the positive impacts of open space must be simultaneously modeled to avoid omitted variable bias.     

Sequential Adoption of Site-Specific Technologies and Its Implications for Nitrogen Productivity: A Double Selectivity Model

This paper analyzes the sequential decision to adopt two site-specific technologies, soil testing and variable rate technology, and the impact of adoption on nitrogen productivity. The results indicate that while farm location was a key variable influencing adoption of soil testing, farm size, human capital, and innovativeness of farmers had a significant impact on adoption of variable rate technology in four Midwestern states. A double selectivity model applied to correct for sample selection bias shows that adoption leads to significant gains in nitrogen productivity for farms with below average soil quality but statistically insignificant gains for farms with above average soil quality.     

Agrobiodiversity,farm profits and land fragmentation: Evidence from Bulgaria

This paper presents an empirical analysis of the role of land fragmentation, crop biodiversity and their interplay with farm profitability. Original primary data are drawn from a survey conducted in the Plodiv region of Bulgaria. The econometric results stress the ambiguous role of land fragmentation on farm profitability. On one hand, land fragmentation reduces farm profitability. On the other hand, land fragmentation fosters crop diversification. We also find that crop biodiversity plays a beneficial role in farm profitability. Policies that aim to increase land consolidation and reduce fragmentation may overlook the positive link between diversity and plot heterogeneity. Policies that encourage land consolidation should, therefore, consider the crucial role that this has on other variables such as farm biodiversity.     

Land management,erosion problems and soil and water conservation in Fincha’a watershed,western Ethiopia

The knowledge of soil erosion processes, attitude towards rational use of resources and institutional support affect the capability of farmers to implement soil and water conservation (SWC) measures. This research was conducted to determine soil erosion problems and the factors that affect the adoption of SWC measures in Fincha’a watershed, western Ethiopia. A total of 50 farmers were interviewed using a semi-structured questionnaire, and two group discussions were held with 20 farmers. Moreover, transects were walked to classify erosion features, and a quantitative erosion survey was made on 19 farm plots during the rainy season of 2004. The results showed that crop fields are affected by annual soil losses ranging from 24 to 160 Mg ha⁻¹. Farmers are well aware of these erosion problems, and related the soil loss to steep slopes and a decline in soil fertility. However, they did not invest much in SWC measures, but apply soil management practices to sustain crop yields. The wealth status of farmers, land tenure arrangements and lack of access the farmers have to information are the major factors affecting SWC adoption. High labour demand of SWC measures, lack of short-term benefits and free grazing have negatively affected SWC adoption. Soil erosion problems in Fincha’a watershed have both on-site and off-site effects that require integrated SWC planning at watershed scale.     

土地流转背景下农户经营规模与土地生产率关系再审视——来自固定粮农和地块的证据

农户经营规模和土地生产率关系是发展经济学领域的经典议题之一。本文在土地流转加速发展的背景下讨论了我国农户经营规模扩大对土地生产率的影响以及测量两者之间关系面临的种种干扰。除了农户规模本身的作用外,理论和实证检验均表明存在土地流转市场时不同规模农户在土地生产率上的差异还可能源于农户和土地的异质性,譬如土地更多流向经营能力强的农户、流转多劣地等等。基于固定农户的固定地块数据可以有效控制异质性的实证策略,本文利用4个省两期跟踪调查数据对两者关系进行了再检验。研究发现,来自固定农户固定地块的证据表明农户土地经营规模扩大并不会影响粮食单产,而不控制固定地块时往往会得到两者负相关的伪结论,并且仅控制固定农户时上述伪结论更为明显。这一结果意味着不必担心规模经营会威胁粮食供给。     

Effect of off‐farm income on smallholder commercialization: panel evidence from rural households in Ethiopia

This article investigates how off‐farm income affects crop output market participation decisions and marketed surplus of smallholder farmers in Ethiopia. A double‐hurdle model is estimated using three waves of panel data from the Ethiopian Rural Household Survey. Unobserved heterogeneity is controlled for using a correlated random effect procedure and potential endogeneity of explanatory variables using a control function approach. The results show that off‐farm income has no significant influence on household crop output market participation. However, conditional on market participation, additional off‐farm earnings negatively affect the marketed surplus. This indicates that farmers use off‐farm earnings for consumption rather than for investment in agricultural production. Policy measures that promote rural investment may help increase returns to labor for land‐poor households participating in off‐farm work in the process of agricultural commercialization.     

EU‐wide Economic and Environmental Impacts of CAP Greening with High Spatial and Farm‐type Detail

In this paper we analyse the economic and environmental impacts of CAP greening introduced by the 2013 CAP reform using the CAPRI model. CAPRI captures the farm heterogeneity across the EU and it allows to depict the implementation of the greening measures in high detail while integrating the environmental effects and the market feedback of the simulated policy changes. The simulated results reveal that the economic impacts (land use, production, price and income) of CAP greening are rather small, although some farm types, crops (fallow land and pulses) and Member States may be affected more significantly. The CAP greening will lead simultaneously to a small increase in prices and a small decrease in production. Farm income slightly increases because the price effects offset the production decline. Similarly to economic effects, the environmental impacts (GHG emissions, N surplus, ammonia emissions, soil erosion, and biodiversity‐friendly farming practices) of CAP greening are small, although some regions may see greater effects than others. In general, the environmental effects at EU level are positive on a per hectare basis, but the increase in UAA can reverse the sign for total impacts. Overall, simulated GHG and ammonia emissions decrease in the EU, while the total N surplus, soil erosion and biodiversity‐friendly farming practices indicator slightly increase due to the CAP greening.     

Policy lessons from spatiotemporal enrollment patterns of payment for ecosystem service programs in Argentina

Payment for ecosystem services schemes (PES) are lauded as a market-based solution to curtail deforestation and restore degraded ecosystems. However, PES programs often fail to conserve sites under strong long-term deforestation pressures. Underperformance, in part, is likely due to adverse selection. Spatial adverse selection occurs when landowners are more likely to enroll parcels with low deforestation pressure than parcels with high deforestation pressure. Temporal adverse selection arises when parcels are enrolled for short time periods. In both cases, financial resources are allocated without having a sizeable impact on long-term land use change. Improving program performance to overcome these shortcomings requires understanding attributes of landowners and their parcels across large scales to identify spatial and temporal enrollment patterns that drive adverse selection. In this paper, we examine these patterns in Argentina’s PES program in Chaco forest, a global deforestation hotspot. Our study area covers 252,319 km². Results from multinomial logistic regression models showed that large parcels of enrolled land and parcels owned by absentee landowners exhibit greater evidence of spatiotemporal adverse selection than smaller parcels or parcels owned by local landowners. Furthermore, parcels managed under land use plans for conservation and restoration are more likely to be associated with adverse selection than parcels managed for financial returns such as harvest of non-timber forest products, silviculture, and silvopasture. However, prior to recommending that PES programs focus on land uses with higher potential earnings, a greater understanding is needed of the degree to which these land uses meet ecological and biodiversity goals of PES programs. We suggest that increased spatial targeting of enrollment, along with enrollment of local landowners and further incentives for land uses that support conservation and restoration, could promote long-term conservation of forest lands.     

Attaining Sustainable Farm Management Systems in Semi-Arid Areas in Kenya: Few Technical Options,Many Policy Challenges

Soils in arid and semi-arid lands (ASAL) are fragile, low in fertility and susceptible to erosion and leaching. To address these problems, activities were implemented in 1998–2003 to identify current problems, and design, test, implement, demonstrate and disseminate improved, integrated soil fertility management techniques. Current soil fertility management results in slightly negative nutrient balances, especially for phosphorus and potassium. Recycling of nutrients through crop residues and animal manure is inefficient, with evidently high losses. Due to the relatively high price of fertilisers and the high risks of crop failure, use of mineral fertilisers is restricted to market-oriented farms with access to irrigation facilities. Of the total farm household population, 35–85% lives below the poverty line. Applying higher rates of Farm Yard Manure (FYM) and/or fertilisers is unattractive and risky. Combinations of FYM and fertilisers give better financial returns than either of the two alone. Where irrigation is available, farmers adopt innovative farming systems that include higher application of mineral and organic fertilisers, and result in higher and more stable yields and higher financial returns. A set of specific policy measures for the semi-arid areas were identified to arrive at necessary changes in the economic environment, leading to a wider range of financially attractive technology options for smallholders.     

Adoption of new tobacco varieties in Greece: Impacts of empirical findings on policy design

Greece is a major international tobacco producer. Flue-cured tobacco varieties constituted the major alternative crop to Greek farmers growing certain oriental tobacco varieties. Diffusion of flue-cured tobacco was rapid due to its high yields and the depressed market for certain oriental tobacco varieties. Currently, the common organisation of the tobacco market is undergoing substantial changes, and the farmers' response will be a vital factor of success. A portfolio selection model reveals that the major factors influencing the adoption decision of tobacco growers are the size of the farm measured in annual work units, the farm's proximity to urban centres, the farm's diversification and the farmer's age. The number of contacts with institutions is, surprisingly, inversely related to adoption. Future tobacco policies impinging on factors influencing decisions to adopt new varieties or production practices may be more cost-effective.     

Challenging Small‐Scale Farming: A Non‐Parametric Analysis of the (Inverse) Relationship Between Farm Productivity and Farm Size in Burundi

We use a non‐parametric approach to investigate the (inverse) relationship between farm productivity and farm size. A kernel regression is used on data of mixed cropping systems to study the determinants of production including different factors that have been identified in literature as missing variables in the testing of the inverse relationship such as soil quality, location and household heterogeneity. Household data on farm activities and crop production were gathered from 640 households in 2007 in two Northern provinces of Burundi. Our results do not reject the findings of an inverse relationship between farm size and productivity. However, we find that size returns vary substantially with farm size, that is, between 0.2 for the smallest farms and 0.8 for the largest farms. Other factors that significantly affect production include soil quality. Finally, we find a significant positive association between food security and farm size.     

Resource use efficiency under self‐selectivity: the case of Bangladeshi rice producers

The paper jointly evaluates the determinants of switching to modern rice and its productivity while allowing for production inefficiency at the level of individual producers. Model diagnostics reveal that serious selection bias exists, justifying the use of a sample selection framework in stochastic frontier models. Results revealed that modern variety selection decisions are influenced positively by the availability of irrigation and gross return from rice and negatively by a rise in the relative wage of labour. Adoption of modern rice is higher in underdeveloped regions. Seasonality and geography/location does matter in adoption decisions. Stochastic production frontier results reveal that land, labour and irrigation are the significant determinants of modern rice productivity. Decreasing returns to scale prevail in modern rice production. The mean level of technical efficiency (MTE) is estimated at 0.82. Results also demonstrate that the conventional stochastic frontier model significantly overestimates inefficiency by three points (MTE = 0.79). Policy implications include measures to increase access to irrigation, tenurial reform and keeping rice prices high to boost farm returns and offset the impact of a rise in the labour wage which will synergistically increase the adoption of modern rice as well as farm productivity.     

Production Efficiency of Jasmine Rice Producers in Northern and North‐eastern Thailand

The paper jointly evaluates the determinants of switching to Jasmine rice and its productivity while allowing for production inefficiency at the level of individual producers. Model diagnostics reveal that serious selection bias exists, justifying use of a sample selection framework in stochastic frontier models. Results from the probit variety selection equation reveal that gross return (mainly powered by significantly higher Jasmine rice price), access to irrigation and education are the important determinants of choosing Jasmine rice. Results from the stochastic production frontier reveal that land, irrigation and fertilisers are the significant determinants of Jasmine rice productivity. Significantly lower productivity in Phitsanulok and Tung Gula Rong Hai provinces demonstrate the influence of biophysical and environmental factors on productivity performance. The mean level of technical efficiency is estimated at 0.63 suggesting that 59% [(100 ? 63)/63] of the productivity is lost due to technical inefficiency. Policy implications include measures to keep Jasmine rice price high, increase access to irrigation and fertiliser availability, as well as investment in education targeted to farm households which will synergistically increase adoption of Jasmine rice as well as farm productivity.