Destination or Distraction? Querying the Linkage Between Off-Farm Work and Food Crop Investments in Kenya

The relationship between off-farm work and farm input use in Sub-Saharan Africa has been documented, although results are mixed concerning the direction of effect. Here, we explore the robustness of this linkage by applying a range of econometric models to panel data collected in Kenya, using maize as an example because of its importance as a major food crop among smallholder farmers. We test the relationship between rates of fertilizer use and three types of off-farm earnings (labour on other farms, known as farm kibarua); income from self-employment and informal businesses and earnings from regular employment (salaries, pensions or wages). Consistent with previous research, we find a strong, negative linkage between non-farm work and rates of fertiliser use in maize production, indicating trade-offs in labour allocation and farm investments. However, the relationship between fertiliser use in maize production and earnings from farm kibarua appears to be positive, illustrating the role this type of work can play in easing cash constraints for destitute households. Adding to previous research, model comparisons illustrate the sensitivity of some estimated parameters to modelling assumptions. Further, the application of the general propensity score matching demonstrates that the magnitude of the marginal effects of non-farm income on fertiliser use rates varies as income changes. In the case of non-farm earnings, the response of fertiliser to additional income is negative at lower income levels, but positive at higher levels.