| dc.description.abstract | This paper combines knowledge from soil science and economics to estimate economic determinants
of soil capital. Explaining soil capital facilitates a better understanding of constraints and
opportunities for increased agricultural production and reduced land degradation. The study builds
on an unusually rich data set that combines data on soil capital (represented by chemical and physical
properties) and economic data on household characteristics, labour supply, crop allocation and
conservation investments. The study yields both methodological and policy-relevant results.
On methodology, the analysis shows that soil capital is heterogeneous with soil properties widely
distributed across the farms. Likewise, farmers’ investment decisions and soil management vary
widely across farms. Hence simplifications of soil capital, which are common in the economics
literature, may have limited validity. On the other hand, soil science research limited to soils’
biological, physical and chemical characteristics fail to recognize that soil is capital owned and
managed by farmers. They thus run the risk of omitting important socio-economic determinants of soil
capital. They also exclude the possibility to explain some of the dynamics that are determined by its
stock character.
On policy, the study shows that farmers’ soil conservation investments, allocation of labour, manure
and fertilizer input, and crop choice indeed do determine variation in farmers’ soil capital.
Particularly strong positive effects on key soil nutrients (N,P,K) are observed for certain conservation
technologies. Extension advice shows unexpectedly no significant effects on soil capital. The wide
distribution of soil properties across farms reinforces the need to (i) tailor technical extension advice
to the specific circumstances in each farm, and (ii) enhance the integration of farmers’ knowledge and
experiences, expert judgment and scientific soil analysis at the farm level. | en |
