Effect of component densities on the performance of pearl millet - Mung bean intercropping system under different rainfall situations in an arid environment

A field study on pearl millet and mung bean component densities in intercro pping was assessed under three cropping season rainfall situations, viz., a bove normal (409 mm), normal (301 mm) and below normal (190 mm) having 24, 14 and 8 effective rainy days, respectively. The soil was sandy loam having 10.5 and 2.5% moisture content (w/w) at field capacity and -15 bar tension s, respectively. Decreasing the density of pearl millet (principal crop) fr om 20 to 13.3 plants m(-2) increased its yield, but further decrease to 10 plants m(-2) decreased the yield at all levels of intercrop component densi ties irrespective of the type of season. The yield of component crops depen ded more on the effective storage of moisture in the, soil profile and avai lability of moisture at reproductive stage (weeks 8-12) rather than quantum of rainfall during the season. Component density combination of 13.3 plant s m(-2) of pearl miller with 5 plants m(-2) of mung bean was optimum and re sulted in the highest grain yield, LER and WUE in all seasons. Moisture str ess in below normal season and the availability of radiation in lower half of the canopy in good rainfall situation was a limiting factor for pearl mi llet yield. Higher consumptive use (214-254 mm) was recorded in moisture st ress free seasons compared to below normal rainfall season (150-157 mm). On an average, harvest index was lower (0.24) in moisture stress season (due to differential influence of terminal drought on grain and total dry matter yield) as compared to normal and above normal rainfall seasons (0.42). Hig h sustainable yield index for pearl miller under optimum component density (0.37) compared to sole cropping (0.23) indicated better stability of pearl miller production due to intercropping in arid environment.