Assessment of productivity variables of cowpea (Vigna unguiculata) varieties in cowpea-maize (Zea mays) strip intercropping in Limpopo Province, South Africa

Abstract

Farmers’ traditional cropping practice in Limpopo Province is to mix and broadcast crops at planting without definite row arrangement. Although this practice is very easy and cost-saving, it is not productive because of its low plant density, hindrance to farm input application, low crop yields and poor return on investment. However, strip intercropping, where crops are planted with definite row arrangement, reduces interspecies competition, optimizes plant population, and increases crop yield. An experiment was conducted during cropping seasons of 2016–17 and 2017–18 at University of Limpopo, South Africa using five cowpea varieties, TVu 13464, IT86D-1010, Glenda, IT82E-16 and IT87K-499-35, and maize to assess the performance of these crop mixtures under strip intercropping, monocropping, and mixed intercropping as a control. The experiment was laid using split-plot design with three replicates during two seasons (1st year and 2nd year). Agronomic variables such as date of maturity, plant height, number of pods per plant, grain and fodder yields were measured. Results indicate that significant interactions were obtained between the cowpea varieties and the cropping systems in most of the variables measured. Cowpea sown in the strip intercropping performed better as compared to those sown in mixed intercropping. Cowpea varieties IT86D-1010 during 1st year and IT87K-499-35 during 2nd year exhibited more grain yield under monocropping than under strip intercropping and mixed intercropping. The financial benefits (profit and benefit cost ratio) was highest in strip intercropping plots. The land equivalent ratio (LER) of strip intercropping during the two years ranged between 1.00 and 2.98 and was higher as compared to mixed intercropping, which ranged between 0 and 1.72. Therefore, strip intercropping is a more productive cropping system and is recommended as a cropping practice for farmers in the Limpopo Province.