Performance of mung bean as component crop in pearl millet -mung bean intercropping as influenced by nitrogen application

摘要

Response of pearl millet - mung bean intercropping system to applied N was evaluated under good (409 mm) and sub-normal seasonal rainfall (193 mm) situations at Central Arid Zone Research Institute, Jodhpur. The mean seasonal rainfall (100 years) of experimental station is 310 mm. Treatments consisted of intercropping of mung bean [Vigna radiata (L.) Wilczek] in pearl millet [Pennisetum glaucum (L.) R. Br.] planted in two systems viz., paird planting (2 rows of pearl millet at 30 cm apart and 2 suchpairs at 70 cm apart) and uniform planting (50 cm), at two level of pearl millet population (1.6 x 10~5 and 1.0 x 10~5 plants ha~(-1)) and four levels of nitrogen (0, 30, 60 and 90 kg N ha~(-1)). Grain yield of pearl millet (principal crop) was many-foldhigher in good rainfall season as compared to sub-normal rainfall season although the rainfall in good season was 111% more only. The yield of component crop (mung bean) in general was lower in good rainfall season compared to sub-normal season. Poor yield of mung bean in good season indicated competition for some factor other than moisture. Planting system did not influence the yield of both component crops significantly in both types of seasons yet the paired planting indicated a trend of better yields in sub-normal season. This system gave 18.4% higher yield of principal crop (pearl millet) and 8.7% yield of component crop (mung bean). Application of nitrogen to principal crop favourably influenced the grain yield of principal crop irrespective ofplanting system and rainfall. Increasing levels of nitrogen significantly increased the mean yield of pearl millet up to 60 kg N ha~(-1) in both seasons. The yield of pearl millet in intercropping system was however; lower than that with sole cropping atevery level of nitrogen application. Although N was applied to principal crop, pearl millet, it reduced the yield of legume component in the system. Increasing N application to the principal crop steadily reduced the yield of mung bean, irrespective ofrainfall. The yield of pearl millet in intercropping system at no nitrogen application level was 1744 kg ha~(-1) in good season and 153 kg ha~(-1) in sub-normal season as against 1976 and 314 kg under sole cropping at that level of nitrogen, respectively. This indicated that intercropping of legume did not impart any advantage to associated cereal (pearl millet) under any rainfall situation. In a good season, 2188 kg ha~(-1) pearl millet yield-equivalents were harvested when no nitrogen application wasmade to principal crop. Application of 30, 60 and 90 kg N ha~(-1) to principal crop enhanced the benefit by 24, 51 and 57% over no nitrogen. In sub-normal rainfall season no such enhancements in yield-equivalents due to N application were recorded. In agood season, the land equivalent ratio (LER) up to 1.46 and in subnormal season LER up to 1.20 was recorded which indicated better land utilization by 20-46% due to intercropping. A maximum change of 7 mm in moisture use was caused by planting system andpopulation level. Application of N resulted in greater moisture use by the system. Enhancing the N application rate by every 30 kg ha~(-1) led to increase in moisture use by 4-5 mm in both types of seasons. Application of N resulted in ensuing greater stability in production irrespective of planting system or population. The maximum sustainable yield index of 0.31 was achieved with the application of 90 kg N ha~(-1) in paired planting which indicated that 31% of maximum observed yield over years is assured with high probability in intercropping system, as against 17% in sole cropping system at that level of N application.