Assessment of the nitrogen requirements of planted maize (<I>Zea mays </I>L.) in the semi-arid areas of Zimbabwe

Abstract

The optimum planting dates for maize under dry land agriculture are within the first rains. Late planting of maize results in low yields. However, a lot of communal area farmers plant well after the first rains because of shortages of draught power. In some cases the first planting rains delay resulting in delayed planting. Information on the effect of late planting and its interactions with inorganic fertilizers on crop yields in the semi-arid areas is scarce. The CERES-maize model (v3.1) was validated using data collected from Chivi Communal Area and Chiredzi Research Station and the model was used to evaluate the effect of planting dates on the yield of maize. The model over predicted grain yield by 1.5% and had a slope coefficient of 0.89 of the estimated equation and an r2 value of 0.81. Both the 1995/6 and 1996/7 simulated yields from the planting dates scenarios show that planting can be extended to early December, late December, early January and late January without a significant decrease in yield by adding no nitrogen, 15, 30 and 60 kg ha-1, respectively.


UNISWA Jnl Agric Vol.10 2001: 5-11