Crop Rotation of Leguminous Crops as a Soil Fertility Strategy in Pearl Millet Production Systems

Abstract

Crop rotation represents one strategy of the crop and soil fertility management practices being implemented in Namibia to improve soil fertility and crop yield per area of land cultivated. Experiments are being conducted at four research stations in the northern Namibia communal area where Pearl millet is predominantly grown. During the 2005/2006 cropping season, different crops used in rotation with Pearl millet became well established and 3.82 t/ha of Lablab (Lablab purpureus) was recorded at Bagani Research station with 0 t/ha recorded at Okashana and Omahenene. Different rainfall figures were recorded per location. Bagani recorded the highest average rainfall of 890 mm in 2005/2006 and 540 mm in 2006/2007, while Okashana recorded the lowest with 63 mm during the same year. When all the plots were treated with Pearl millet, the yield of Pearl millet dropped slightly from 2.70 to 2.18 t/ha at Omahenene in the plots where Pearl millet was planted previously and 2.63 t/ha was recorded in the plot where Lablab was previously planted. At Bagani a higher yield of Pearl millet was recorded in plots where Lablab was planted and a lower yield where Sorghum was planted with 2.49 t/ha and 1.56/ha, respectively. A higher yield of Pearl millet at Mannheim was recorded in plots where nothing was planted (fallow) with 1.63 t/ha and a lower yield was recorded where Pearl millet was grown previously with 1.40 t/ha. Soil samples taken for fertility analysis revealed that the soils at all four research stations lack major elements such as P and K. This project is expected to end during the 2009/2010 growing season.