Effect of Row Arrangements on Sorghum-Cowpea Intercrop Yields in the Lowveld of Zimbabwe

Abstract

In the Lowveld of Zimbabwe, intercropping of cereals with legumes is a predominant feature in the cropping system which is practiced at small scale farms as a means of maximizing the use of limited farm lands as well as attaining food security by subsistence farmers. The usual intercropping system practice is a cereal-legume mixture, where millet and sorghum are widely used as a cereal component of intercropping with crops such as cowpea, groundnut and round nut. However, these interactions would possibly enhance productivity of intercrops if the cropping patterns were in their right proportions. A field trial was conducted during the 2019/2020 cropping season under rain-fed conditions at Chiredzi research station to determine the effect of intercropping on the yield and yield related traits of Sorghum and cowpea and the optimum row arrangement for the mixture of sorghum (SV4) with erect local cowpea (CBC2) for highest yield. The experiment comprised of six treatments; sole sorghum crop, sole cowpea and four spatial/row arrangements of 1:1, 1:2, 2:1 and 2:2 rows of sorghum alternated with cowpea. The treatments were arranged in a randomized complete block design with three replications. Land Equivalent ratio was used to evaluate the productivity. Intercropping sorghum with cowpea at different row arrangements had a highly significant effect on the yield per hectare of sorghum with sole sorghum giving the highest yield of 2455kgs/ha. Treatment 2 with 2rows of sorghum and 2rows of cowpea had the second highest yield of 1871kgs/ha. The intercropping patterns of 1Sorghum: 2Cowpea, 2Sorghum: 2Cowpea, sole cowpea and sole sorghum had LERs of 1.0199, 1.009, 1.000 and 1.000 respectively. The values of the land equivalent ratio (LER), however, indicated that there is no advantage of intercropping over pure stands. From this study, farmers in the Lowveld are advised to intercrop their sorghum and cowpea using the 2:2 row ratio at the onset of the first effective rains for considerable yields. This allows farmers to have a variety of nutrition sources and hence, enhanced food and nutrition security for both humans and livestock compared to mono cropping of sorghum or cowpea.