Influence of component crop densities and planting patterns on maize production in dry land maize/cowpea intercropping systems

An experiment was conducted to test the effect of four plant densities (10, 20, 30 and 40,000 plants ha-1) and four planting patterns (1rowM:1rowC, 1rowM:2rowsC, 2rowsM:2rowsC and 2rowsM:4rowsC) on the growth and dry matter production of a dryland maize/cowpea intercrop at three sites in Limpopo and North West province. The experiment was a split plot incorporated in randomized complete block design with four replications, where maize plant density was the main plot factor and subplot factor was the planting pattern. Sole maize flowered and reached physiological maturity later than intercropped maize, while sole cowpea flowered and matured earlier than under intercropping. Higher plant densities of 30 000 and 40 000 maize plants ha-1 delayed flowering and maturity of both component crops in sole and intercropped arrangements. Significant differences in maize and cowpea dry matter yields were observed at all trial sites. The 1rowM:2rowsC pattern and plant density of 30 000 plants ha-1 with 92 000 plants ha-1 of cowpeas was superior in maize dry matter production at all trial sites, whereas sole cowpea at 40 000 plants ha-1 gave the highest dry matter yield than the intercrop arrangements. The results of this study show that high plant density causes stress to plants and reduces plant growth, whereas intercropping has a negative influence on cowpea plant growth.