Influence of sorghum-legume association on soil properties and crop yields in Swaziland

摘要

Intercropping is a common farming practice prevalent among small-scale farmers in the tropics. Since the farmers do not have money to buy fertilizers with which to improve soil fertility and crop yields, one way of accomplishing the same goal would be to plant crops in association with leguminous companion crops, which could fix nitrogen in the soil. Many Swaziland farmers do not practise intercropping of sorghum and legumes, because of lack of knowledge regarding which grain legume would be the best companion crop to the cereal. If an investigation showed the superiority of one legume over another, such information would be beneficial to sorghum growers. Sorghum (Sorghum bicolor L.) was grown as a sole crop and in association with groundnut (Arachis hypogaea L.) and sugar bean (Phaseolus vulgaris L.) to assess the influence of the pulses on soil properties and yield of sorghum. Results showed that when planted in association with groundnut, sorghum yielded 17.2% higher than sole sorghum; when intercropped with sugar bean, sorghum yield was much depressed, being 60.4% lower than that of sole sorghum, and 88.0% lower than the yield of sorghum associated with groundnut. The yield differences were not statistically significant. Groundnut improved organic matter content of the soil better than sugar bean. It is recommended that sorghum be grown in close association with groundnut.