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This study examines the impact of genetically modified maize on labour, cost and input substitutability for smallholders in South Africa. Producers of Roundup Ready® (RR) maize use significantly less child, female and male labour than non-RR producers, resulting in lower costs despite significantly higher herbicide, seed and fertiliser costs. A treatment effects model controlling for selection bias shows that the entire cost advantage and more can be attributed to the Roundup Ready® technology. These results are supported using a nonparametric kernel density estimator. Elasticities of factor substitution indicate strong substitutability among inputs; however, a lack of statistical significance limits the interpretation of the results.

This study examines the impact of genetically modified maize on labor, cost, and input substitutability for smallholders in South Africa. Data was collected during the 2009- 2010 maize production season from 184 households with a total of 212 maize plots in two regions, Hlabisa and Simdlangetsha, located in KwaZulu-Natal, South Africa. Producers of Roundup Ready® (RR) maize use significantly less child, female, and male labor than non- RR producers, resulting in lower costs in spite of significantly higher herbicide, seed, and fertilizer prices. An unrestricted cost function approach is used to evaluate the differences in cost between maize varieties, assuming that households use different input allocations to minimize cost while producing a fixed level of output. A treatment effects model used to control for selection bias shows that the entire cost advantage and more can be attributed to the Roundup Ready® technology. The treatment effects model reveals that RR maize producers have $102.44 (30%) lower costs per maize plot after taking into consideration the inverse Mills ratio, suggesting that the OLS model underestimated the cost-reducing effect of RR maize. Therefore, the entire cost advantage and more can be attributed to RR maize after isolating the effect of RR maize on total cost by disentangling the lower costs attributed to RR maize from those associated with farm and farmer characteristics. These results are confirmed using a nonparametric kernel density estimator. Elasticities of factor substitution indicate strong substitutability among inputs; however, lack of statistical significance limits interpretation of results.

Metadata only record Declines in crop yields (21% for sorghum and millet) and soil fertility (29% for C) have made conservation (CA) a significant management option for selected cropping systems of Mali. Baseline assessments and rapid rural appraisals have indicated that the classical CA components need to be modified, not only to remove permanent soil cover, but also to include capturing rainwater. The improved conservation agriculture production systems (CAPS) account for 40 to 70% running off rainwater and feeding cover crops and crop residues to cattle, which is a key component of local production systems. LTRA-8 (Improving soil quality and crop productivity through CAPS in West Africa)

The challenges one faces in trying to increase improving ecosystem services, improve yields and increase farm level profitability in West African countries largely revolve around the environmental and economic constraints. Improving ecosystem services with a focus on maintaining soil quantity, quality and moisture in West Africa will require the adoption of conservation agricultural practices (CAPS) such as legumes to fix nitrogen, a focus on reduced tillage and practices that maintain as much residue in the system as possible and integrated nutrient, water and pest management practices. LTRA-8 (Improving soil quality and crop productivity through CAPS in West Africa)

This poster describes the recent findings of the SANREM CRSP's Long-Term Research Activity 8 in the Upper West region of Ghana. This research team interviewed 358 farmers in 12 communities of 3 districts in Ghana in order to collect baseline socioeconomic data as well as to estimate farmer knowledge and perceptions regarding conservation agriculture. In addition to revealing crop productivity and marketing data, research results indicated that farmers were aware of the importance of soil conservation and expressed interest in learning more about conservation agriculture practices and integrated pest management. LTRA-8 (Improving soil quality and crop productivity through CAPS in West Africa)

Recent projections on the impact of climate change argue that eastern and southern Africa will be two regions around the globe that will experience dramatic reductions in maize yields by mid‐century. Absent from these projections is any consideration for farmer adaptation of cropping practices or land reallocation. This research quantifies risk, loss and ambiguity aversion for a sample of smallholder Kenyan farmers using framed field experiments. This behavioral information, directly elicited, is used to condition the selection of maize varieties differentiated by drought tolerance, pest resistance, maturity, and seed price. Overall, the willingness to pay for drought tolerance and other attributes is highly heterogeneous as determined through a Latent Class modeling approach. Failing to account for farmer heterogeneity biases the potential welfare gains from this technology. Secondly, willingness to pay estimates identify segments of farmers that are seed‐price sensitive and this elastic demand may limit technology purchase and the eventual impact of this adaptation strategy without seed market intervention.

The purpose of this research is to determine how technically efficient small-scale producers are in two provinces (North and South Kivu) in the Democratic of Republic (DR) of Congo at producing two different varieties of beans: bush and climbing beans. In addition to calculating the efficiency scores, this research attempts to identify what producer and field characteristics affect these scores. We hypothesize that bean producers will be more productive than producers in South Kivu and that climbing bean producers will be more productive than bush bean producers. Technical efficiency is estimated using a nonparametric approach. A tobit model is used to examine the effect of producer and field characteristic on the efficiency score. On average, farms were 66% technically efficient. North Kivu bean producers and climbing bean producers have, on average, a higher technical efficiency score than their counterparts. Implications from this research suggest that there is room for improvement in the technical efficiency scores for producers in DR of Congo. Based on the results, it may be more productive to continue focusing on improving the yield and nutritional content of climbing beans.

Controlling for spatial effects in micro-economic studies of consumer and producer behavior necessitates a range of analytical modifications ranging from modest changes in data collection and the definition of variables to dramatic changes in the modeling of consumer and producer decision-making. This paper discusses conceptual, empirical, and data issues involved in modeling the spatial aspects of economic behavior in data rich environments. Attention is given to established and emerging agricultural economic applications of spatial data and spatial econometric methods at the micro-scale. Recent applications of individual and household data are featured, including models of land-use change at the urban-rural interface, agricultural land values, and technological change and technology adoption.

Malaria and other transient illnesses have been recognized as factors constraining economic development in tropical countries. The purpose of this paper is to determine the direct and the indirect impact of transient illness shocks, caused primarily by malaria but also including other tropical illness, on family labor use in irrigated rice production in Mali. Family labor is the most important factor of production used in rice production in Mali and transient illness shocks may negatively impact labor supply, production and hence household welfare derived from agricultural income and consumption. Two labor demand models are estimated to determine whether illness does indeed reduce labor supply: one where the dependent variable only includes family labor and a second that combines family and hired labor. These models can be used to test two sets of hypotheses on the relationship between illness and labor supply. First, we hypothesize that short-term transient illness shocks affect household labor supply implying that intrahousehold coping mechanisms are not wholly effective. Secondly, we hypothesize that hired labor markets are ineffective in mitigating illness shocks. We find that direct and indirect health shocks reduce the effective supply of labor and that neither household nor market supply of labor can mitigate these shocks.

Recently, discussion had reemerged over the value of integrated pest and crop management training, through intensive approaches such as farmer field schools or participatory training, as a development approach (Feder et al, 2004). This paper develops a model of human capital accumulation through participatory research and tests several hypotheses on the effectiveness of this approach to increase the adoption of soil conservation and fertility management innovations and improve farm productivity in southeast Asia. Bivariate Probit models with treatment effects are estimated using full information maximum likelihood (Evans and Schwab, 1995: Trost and Lee, 1984) and covariates related to changes in land allocation and productivity, measured before project and after project intervention, are investigates. We follow Greene (1998) to control for simultaneity between adoption and impact by using the predicted adoption decision from the second set of regressions to calculate productivity differentials. Overall, we find that treatment affects associated with the participatory research activities are significant and positive in explaining the differential adoption rates of intercropping, hedgerows, contour ridging, the usage of farm yard manure and chemical fertilizer. The positive relationship between the adoption of soil conservation and fertility management techniques and participation, given very limited productivity impact, may indicated the "value" of the participatory approach to illustrate the social costs of land degradation, sensitize participants towards internalizing these costs, and demonstrate the importance of long-run strategies to preserve land productivity, or both. Secondly, we find that there are additional benefits to participatory research activities that are not embodied in the adoption of soil conservation or fertility management techniques.

This paper contrasts nonparametric data envelopment analysis (DEA) and free disposal hull (FDH) representations of dairy technology to determine whether factor indivisibilities and firm-specific location components affect economic performance. Location and capital structure variables, in addition to technology and firm structure, are used in a second-stage model to explain firm inefficiency using a Tobit estimator. Capital structure and location factors are correlated with firm efficiency in the DEA models but not the FDH indicating that the FDH representation may account for these factors in the in the first-stage efficiency modeling. Results indicate that failing to control for firm-specific spatial constraints and capital divisibilities will bias inefficiency estimates and overestimate the potential gains to economic policy designed to improve firm performance.

New crop varieties often have been promoted in developing countries based upon superior yield vis-a-vis locally available varieties. This research presents a hedonic model for upland rice by drawing upon the input characteristics and consumer good characteristics model literature. Model specification tests determine that a combination of production and consumption characteristics best explains the willingness to pay for new upland rice varieties. This non-separable household model specification determined that four traits explain the willingness to pay for new rice varieties: plant cycle length, plant height, grain elongation/swelling and tenderness. Yield was not significant explanatory variable for the willingness to pay for seed. The implications of this model are two-fold. First, varietal development and promotion must include post-harvest characteristics in addition to production traits when determining which varieties to promote for official release. Secondly, non-yield production characteristics such as plant height and cycle length are significant factors in producers' assessments of the value of a new variety. Overall, this paper provides an alternative explanation for limited adoption of modern upland rice varieties in West Africa: varietal evaluation programs have focused too narrowly on yield evaluation and have not promoted varieties with superior non-yield characteristics than locally available varieties.

This paper presents a dynamic model of land resource degradation and shifting rice cultivation in West Africa based upon Boserup and Dvorak. The model indicates the ex ante impact of research strategies to maximize the economic benefits of host plant resistance and land resource management and thereby stabilize yield decline and reduce land degradation.

This study integrates biophysical simulation data with a farm household model of intertemporal optimization, to investigate changing crop-livestock management practices in the Sudano-Guinean zone of Mali. Over a 15-yr time horizon we find that free grazing on the commons remains more attractive to the representative household than adopting more labor- and capitalintensive confinement systems, but that a relatively low level of pasture tax (around US$3 per livestock unit per year) would be sufficient to induce intensification. Because confinement raises output, the net cost of the tax to the household is only about US$1 per unit per year. Imposing pasture taxes to induce intensification could raise community welfare, if the value of commons resources liberated by reduced grazing pressure exceeds that level. © 1998 Elsevier Science B.V. All rights reserved.

In this study, we estimate production costs and elasticities of factor substitution for Zimbabwean smallholders, using a dual (cost function) approach with detailed data on prices paid and received by each of 65 farms across six survey sites over two years. We find that 95% of observed farm choices are consistent with optimal input use, and that there is moderate substitutability between labor, biochemical inputs and capital. These results indicate that farmers can substitute between factors as relative prices change, particularly to increase labor use as the rural population grows. By stratifying our sample, we investigate the degree to which production costs differ among the socioeconomic groups, tsting for higher costs among female-headed households (who might be subject to gender discrimination), resource-poor farmers without their own draft animals (who might have less timely operations), and isolated farms far from paved roads (who might have less access to markets and information). We find significant support only for the paved-roads effect, indicating the importance of rural infrastracture in determining production costs.

This study links intertemporal optimization to a biophysical crop growth model finding that agricultural intensification does not dramatically degrade soils in southern Mali. Productivity growth can be sustained through adoption of new techniques, particularly with policy reforms to reduce marketing costs and tax the use of common-property resources.

Metadata only record Analyses of sustainability generally focus on sustaining a specific resource using a specific set of agricultural techniques. This study uses new analytical tools to address a broader set of questions concerned with the sustainability of income or wealth, in the context of a dynamic sequence of farm activities chosen in response to changing environmental, economic and social conditions. Long-term field trials conducted in the Sudano-Guinean ecoregion of Mali provide some evidence regarding the dynamics of soil nutrients and crop yields, but provide limited insight about soil degradation processes under actual farm conditions. To simulate the long term evolution of soils under a variety of more realistic farming practices, a detailed biophysical model of crop growth is employed to derive quantitative estimates of important factors controlling yields and dynamic yield trends. The model indicates that severe water and soil temperature stress limit crop growth and hence nutrient uptake, particularly at the low plant densities used by farmers in response to low levels of soil moisture. To assess how farmer practices might change over time, the results of the biophysical simulation exercise are integrated into a dynamic mathematical programming model of household behavior. The model identifies adjustments in production, consumption and investment behavior, and captures their impact on the soil. Several experiments are conducted to determine the long run impacts of introducing new techniques including an improved sorghum cultivar, improved methods of crop residue management, and organic fertilizer production. Results indicate that the adoption of an improved sorghum variety can increase the supply of surplus marketed cereals by more than 30 percent. The long term impacts of various policy alternatives also are simulated including taxes on livestock grazing in communal areas and integration of product markets leading to greater producer specialization. Available in SANREM office, FS