Quantifying the prevalence of (non)-response to fertilizers in sub-Saharan Africa using on-farm trial data

Poor and variable crop responses to fertilizer applications constitute a production risk and may pose a barrier to fertilizer adoption in sub-Saharan Africa (SSA). Attempts to measure response variability and quantify the prevalence of non-response empirically are complicated by the fact that data from on-farm fertilizer trials generally include diverse nutrients and do not include on-site replications. The first aspect limits the extent to which different studies can be combined and compared, while the second does not allow to distinguish actual field-level response variability from experimental error and other residual variations. In this study, we assembled datasets from 41 on-farm fertilizer response trials on cereals and legumes across 11 countries, representing different nutrient applications, to assess response variability and quantify the frequency of occurrence of non-response to fertilizers. Using two approaches to account for residual variation, we estimated non-response, defined here as a zero agronomic response to fertilizer in a given year, to be relatively rare, affecting 0–1 and 7–16% of fields on average for cereals and legumes respectively. The magnitude of response could not be explained by climatic and selected topsoil variables, suggesting that much of the observed variation may relate to unpredictable seasonal and/or local conditions. This implies that, despite demonstrable spatial bias in our sample of trials, the estimated proportion of non-response may be representative for other agro-ecologies across SSA. Under the latter assumption, we estimated that roughly 260,000 ha of cereals and 3,240,000 ha of legumes could be expected to be non-responsive in any particular year.

Organic Fertilizer Adoption, Household Food Access, and Gender-Based Farm Labor Use: Empirical Insights from Northern Ghana

This paper examined organic fertilizer adoption and its effects on two household food security indicators and gender-based farm labor use among smallholder farmers in Northern Ghana. An endogenous switching regression analysis shows that observed and unobserved farmer background factors determine farmers’ decision to adopt organic fertilizer as well as the outcomes from adoption. On average, adoption is associated with an 11% increase in per capita food consumption and a 55% reduction in household food gap duration. Adoption is also related to an increased labor use by 5.9 (90%) of female worker days and 1.3 (9%) of male worker days per acre, placing nearly all (82%) of the increased labor burden on female farmhands. We recommend mitigation of factors that hinder farmers from adopting the input and provision of female-user-friendly labor-saving devices for organic fertilizer use tasks.

Welfare Impact of Organic Fertilizer Adoption: Empirical Evidence From Nigeria

Soil fertility depletion is acknowledged to adversely influence agricultural productivity and welfare status of rural farming households. Studies have shown that organic fertilizer utilization tends to rejuvenate the soil, thereby enhancing its productive capacity. This study seeks to estimate the welfare impact of organic fertilizer adoption among agricultural households using the 2018/2019 Nigeria General Household Survey (GHS). The novelty of this study is in the use of propensity score matching (PSM) and endogenous treatment regression (ETR) to address biases that may arise from both observed and unobserved factors. Results show that the adoption of organic fertilizers positively and significantly impacts the welfare of farmers, particularly when sources of unobserved characteristics of agricultural households are accounted for. The heterogeneity impact results show that female household heads, agricultural households that had access to credit, and farm household residents in the southern region of Nigeria significantly gained more from the adoption of organic fertilizers. In addition, a check for time effect reveals that the adoption of organic fertilizers does not result in an immediate welfare effect; the effect is, however, positive and significant over time. This suggests that adoption does not only improve soil and mitigate against climate impact, but it also has a higher likelihood of providing long-term and sustainable welfare impact for agricultural households. The results point to the need for policies and programs to promote and sustain the adoption of organic fertilizers among agricultural households through addressing existing institutional barriers such as extension and credit facilities.

Determinants of smallholder farmers’ decisions on fertilizer use for cereal crops in the Ethiopian highlands

This study identified decision variables influencing fertilizer adoption and optimal fertilizer rates among smallholder farmers in the Ethiopian highlands. The fertilizer adoption and fertilizer use were examined in four regional states using a questionnaire survey, which was administered to 2880 farm households. A double hurdle model was used to analyze factors influencing the two independent decisions of adoption of fertilizers and use of fertilizers. The model estimates of the first hurdle revealed that the probability of fertilizer adoption increased by 1.2% as household education status improved, by 1.4% for an increased number of active family members, by 5.6% with improved access to credit, by 3.4% with cooperative membership, by 3.3% with an increase in farm size, by 4.6% when soil and water conservation practices are employed, and by 3.4% when agroecology of the farm is located in the medium to highland zone. Conversely, the probability of fertilizer adoption reduced by 0.9% for an increase in family size, 0.6% with 1 km distance from all-weather road, 1.6% for a kilometer further to farm plots, and 0.9% for an increase in number of parcels. The intensity of use of fertilizers was influenced by education status of the household head, family size, access to credit, membership to cooperatives, use of crop rotation, annual income, number of farm plots owned, use of soil and water conservation, and agroecology. Therefore, a concerted effort is needed to encourage fertilizer adoption and optimum fertilizer use intensity by improving households’ resource endowment, institutional capacity to deliver services, and infrastructure development.