A review on the effects of mineral fertilizer, manure and water management in improving sorghum grain yields in semi-arid areas

Sorghum grain yield is constrained commonly by soil nutrient deficiency and water stress in semi-arid areas across Africa. Grain yields ranges from 500 to 650 kg ha-1 in some parts of African and even below 500 kg ha-1 in some countries like Mozambique and Zimbabwe without using any nutrient amendments. The use of mineral fertilizer supply nutrients readily in the soil and increasing their availability to crops and improve crop yields. Farmers in rural communities are resources constraint and not able to buy adequate mineral fertilizers and they need to amend mineral it with manure. Application of manure improves soil physiochemical properties and nutrient availability which play an important for plant growth and increasing yields. However, cattle manure commonly used by smallholder farmers is rich in plant residues and require decomposers to use a lot of mineral nitrogen as sources of energy for decomposition hence nitrogen becomes unavailable to plants. Combining mineral fertilizer and manure has a potential of improving yields from 500 to 5000 kg ha-1 depending on soil type and rainfall received in the area. However, semi-arid regions are associated with low and erratic rainfall which causes soil water stress and reduce yields. There is need to combine water management with mineral fertilizer, and organic manure to create a sustainable sorghum production in marginalized areas. This paper reviews the effects of mineral and organic fertilizer in improving sorghum production in semi-arid region and come up with way forward to meet food demand in these areas.