Assessment of maize yield gap and major determinant factors between smallholder farmers in the Dedza district of Malawi

This study explored the effect of soil nutrient status, agronomic practices and socio-economic factors on maize yield attained by smallholder farmers in the Dedza District of Malawi. Results show that maize yield ranged between 0.4 and 12 t ha(-1) with a mean value of 4.1 t ha(-1). Observed high yields (>8.0 t ha(-1)) were associated with households using improved varieties combined with improved management practices such as NPK, urea and animal manure. With regards to soil factors, boron (B) and nitrogen (N) which are critically deficient in the area were significantly (beta = 21.1, p < 0.01) associated with maize yield increase. From agronomic factors, weeds, seed spacing, plant density and fertilizer application played significant role in maize yield. Weed rating inversely impacted yield (beta = -0.5; p < 0.001) where fields with the lowest weed rating had the highest yield (4.6 t ha(-1)) than those with the highest rating (2.3 t ha(-1)). Socio-economic factors such as household wealth, household members with off-farm employment, number of years the household head has been involved in farming decision making, access to agricultural advice and group membership also influenced agronomic practices and resulted in yield gap. Household wealth and off-farm employment contributed to increased yield while household head experience in farming had negative impact. Extension service impacted yield negatively which can be attributed to the low extension worker to farmer ratio. The study demonstrated that closing yield gap in maize mixed farming systems requires integrated approach to addressing agronomic, biophysical and socio-economic constraints.