Potential of field edge rainwater harvesting, biomass transfer and integrated nutrient management in improving sorghum productivity in semi-arid regions: a review.

Sorghum has been promoted in arid and semi-arid areas due to its drought tolerance which makes it survive under harsh environmental conditions, but grain yields are very low, e.g., averaging 514 kg ha⁻¹. The use of field edge rainwater harvesting techniques of tied contours and infiltration pits can be suitable options to capture rainfall and reduce runoff on the soils. Furthermore, integration of field edge rainwater harvesting with appropriate soil fertility management practices can potentially increase sorghum yields. The use of biomass transfer of nitrogen fixing trees such as Leucaena leucocephala is an agroforestry practice which can improve soil fertility through increasing mineral nitrogen, cation exchange capacity and porosity, water retention, and reduce soil bulk density. Other appropriate soil fertility management include integrated nutrient management (INM) where organic fertilisers such as cattle manure are mixed with inorganic fertilisers. These technologies are examples of climate smart agricultural practices that have the potential to increase sorghum yields. The integration of rainwater harvesting techniques and INM show improved sorghum yields ranging from 750 to 2100 kg ha⁻¹ with potential of increasing yields in clay soils. However, currently there is little data available on the implementation of these technologies in semi-arid areas. This paper reviews and analyses the potential effect of integration rainwater harvesting, biomass transfer and INM on sorghum yields in semi-arid areas of Zimbabwe. [ABSTRACT FROM AUTHOR]