Conventional Cropping Systems for Alfisols and Some Implications for Agroforestry Systems

ICRISAT's work on conventional annual cropping2048systems for Alfisols is summarized, and the implications for agroforestry systems examined. The importance of intercropping system is emphasized as a means of increasing cropping intensity above that of a sole crop. Data from sorghum/pigeonpea and millet/groundnut intercropping systems are presented to illustrate the concepts of "temporal" and "spatial" complementarity between crops. It is reasoned that both these concepts are equally applicable in agroforestry systems. Experiments on sorghum/groundnut are presented to indicate the possibilities of greater relative advantages of intercropping systems under conditions of moisture stress. But the dangers of increasing total plant populations under such conditions (e.g., by adding a tree species) are also highlighted. The limitations on nitrogen contributions from annual grain legumes used as intercrops are discussed, and it is suggested that there might be scope for much greater contributions from leguminous trees in agroforestry systems. The possibilities of improved pest or disease control, and of greater yield stability in intercropping systems are considered.