The effect of planting combinations and weeding on the growth and yield of component crops of maize/bean and maize/pumpkin intercrops

Abstract

A diagnostic survey carried out in 1997 to obtain baseline information on the farming situation in Transkei area of South Africa, showed that agriculture in this area was characterized by low technological inputs which invariably led to low agricultural outputs. The main farming system of the majority of the farmers (98%) was based on intercropping involving maize, beans and pumpkin combined in an haphazard fashion.Based on the above findings, two field experiments were set up in 1998 designed to bring out the best planting combinations for maize/beans and maize/pumpkin intercrops which could be introduced to the farmers. Effect of weeding on the intercrops was also investigated.In both intercrops, intercropping adversely affected the plant heights and circumferences of the component crops. Also, the yield of the individual crop in each intercrop was depressed by intercropping compared with its sole yield. In maize/beans intercrop, the yield of maize was depressed by 15% and that of beans by 13%. However in both intercrops, productivity as measured by Land Equivalent Ratio (LER) was the highest with maize at 10000 plants/ha combined with beans at 150000 plants/ha (2·60) with weeding while the combination with the best LER (1·50) in maize/pumpkin intercrop was at 30000 plants/ha of maize combined with pumpkin at 2500 plants/ha, with weeding. However, before any final recommendation is made, the profitability of each combination has to be considered.Weeding was found to enhance intercrop yields in maize/bean combination by 35% and by 30% in maize/pumpkin combination.