Sorghum-pigeonpea intercropping and the effects of plant population density. 2. Resource use

The use of growth resources is examined in an intercropping combination of early sorghum (82 days) and later maturing pigeon pea (173 days) in a row arrangement of 2 sorghum:1 pigeon pea. Prior to sorghum harvest, light interception by the intercrop combination was almost as high as sole sorghum. After sorghum harvest, light interception by the remaining pigeon pea was very poor and it is suggested that pigeon pea yield could be increased by higher plant population density and better plant distribution. Soil water measurements indicated that this would increase the amount of water being transpired through the crop but would not increase the total evapotranspiration demand. Higher nutrient conc. in the intercrop pigeon pea compared with sole pigeon pea during this post-sorghum period suggested that yield of intercrop pigeon pea was not limited by nutrient stress, though the total uptake of nutrients by both crops was much greater from intercropping than sole croppin