Evaluation of Maize Nutrient Contents in a Maize/Cowpea Intercropping Systems in South Africa

Abstract

Field experiments were carried out at three localities in North West and Limpopo provinces at South Africa to assess the effects of planting density and planting patterns and their interaction effects on residual soil nutrient contents in maize/ cowpea (M/C) sole and intercropped systems. The trial consisted of four planting densities (10000; 20000; 30000 and 40000 plants ha -1 ) and six planting patterns (1 rowM:1rowC; 1rowM:2rowsC; 2rowsM:2rowsC; 2rowM:4rowC; sole maize and sole cowpeas) at three sites. The experiment was a split-plot incorporated in randomized complete block design with four replications where maize plant density was the main factor and subplot factor was the planting pattern. The obtained results were as following: 1) Maize N, P, K, Ca and Mg concentration level showed a decreased pattern as the planting density increased at both trial sites. 2) Maize N content in planting density ranged from 1.28 to 1.65% at both locations. 3) Plant density of 10 000 plants ha -1 had higher N yield of maize by 22 and 11% relative to 40 000 plants ha-1 at Potchefstroom and Taung, respectively. However, N concentration in maize was significant at Taung, the 2rowsM:4rowsC pattern had higher N concentration and was 1.75% compared to all other intercropping planting patterns and sole maize. 4) The interaction of all intercropping planting patterns and plant density of 10 000 plants ha -1 gave higher nutrient concentration level than at higher plant density. 5) Sole cowpea had higher residual soil N-NO3- yield of 1.92, 1.66 and 1.23 mgkg -1 , whereas residual soil N-NH +4 was 3.28, 3.44 and 3.34 mgkg -1 at Syferkuil, Potchefstroom and Taung, respectively, compared to all intercropping planting patterns and sole maize. 6) Cowpea has the ability to fix atmospheric N into the soil for subsequent crop use. and 7) The study indicates that intercropping system and lower plant density up to 30 000 plants ha-1 of maize had the potential of improving crop productivity and soil fertility status depending on the climate and available N in the soil.