Influence of Cropping Systems on Macrophomina phaseolina Populations in Soil

Cumulative effects of 15 crop combinations and rotations on populations of sclerotia of M. phaseolina in soil were studied during the fifth year of a Vertisol cropping system experiment at the International Crops Research Institute for the Semi-Arid Tropics Center in Patancheru, India. Higher counts of sclerotia were recorded in the intercropping systems of sorghum or cowpea with pigeon pea than in single-cropping systems. The highest counts of sclerotia were recorded in plots where sorghum was intercropped continuously with pigeon pea in both the rainy and postrainy seasons. An increase in the populations of sclerotia was also recorded when rainy season sorghum was followed by either safflower or chickpea (Cicer arietinum). Cropping systems with fallow in the rainy season, followed by sorghum or chickpea in the postrainy season, stabilized the inoculum density of M. phaseolina