Field and village nutrient balances in millet cultivation in northern Burkina Faso: a village case study

Millet cultivation in the Sahel may be unsustainable as it contributes to soil degradation, particularly via nutrient depletion. The flow of nitrogen and phosphorus in millet cultivation has been assessed from empirical and literature data in order to construct a simple nutrient balance model. Whereas most nutrient balances refer to single fields, balances for a village territory have also been calculated. The results suggest that nitrogen and phosphorus are lost from fields, the amount depending on soil type and millet yield. With boundaries at the village territory, the balances show a negligible output of nitrogen and an input of phosphorus to the village. The combination of two different spatial scales suggests that millet cultivation is more sustainable than generally believed. Further, the balances serve to identify the important nutrient flows, and can be used as a tool in nutrient management.