Growth, yield, competition and economics of groundnut/cereal fodder intercropping systems in the semi-arid tropics of India

Intercropping legumes with non-legume crops during the rainy season (wet season) is a common practice in the semi-arid tropics of India. Of late, the concept of intercropping has also been utilized in irrigated (dry season) situations. In a 2-year field study during the dry season (February-May), we assessed yield, competition and economics in a groundnut/cereal fodder intercropping system compared with monocropped groundnut. Maize (Zea mays L.), sorghum (Sorghum bicolor (L.) Moench) and pearl millet (Pennisetum glaucum L.) were grown for fodder. One cutting for all and two cuttings (first at 50 days after sowing and second at 95 days after sowing) for sorghum and pearl millet were made. In intercrops one row of cereal fodder was sown between every three rows of groundnut (1:3). The green fodder yields and pod yield of groundnut were lower in intercropped than in monoculture plots. The highest green fodder yield in intercrops was recorded in pearl millet with two cuts (16.5 t ha(-1)) followed by pearl millet with one cut (11.8 t ha(-1)) and sorghum with two cuts (10.7 t ha(-1)). In intercrops the growth and yield of groundnut were affected by cereal fodder and intensity of cutting. A significant (*P < 0.05) reduction in leaf area index (LAI) and crop growth rate (CGR) was observed in the groundnut-pearl millet system over sole groundnut. Decrease in nodule mass at pod filling stages in groundnut ranged from 3.5 to 11.0% when intercropped with cereal fodders compared to sole groundnut crop. Groundnut yield was reduced more due to pearl millet and sorghum with two cuts. However, maize as the associated crop produced 9.0 t green fodder ha(-1) and affected the groundnut less with respect to pod yield (5.76% reduction), yield attributes, CGR, LAI and nodule dry mass. Of the two Cutting situations under intercropping, one cut gave 9.9% higher yield of groundnut as compared to two cuts. A higher land equivalent ratio (LER) and relative crowding coefficient (RCC) value leads to a crop yield advantage. Accordingly, yield advantage was greater in case of the groundnut/maize association. The competition ratio (CR) is a better indication of performance than RCC. The CRs of pearl millet and sorghum with two cuts were greater than maize but the corresponding CRs of groundnut were less. Thus, pearl millet and sorghum were more competitive, and groundnut under these two crops was affected more. The maximum monetary advantage was also recorded for the groundnut/maize intercropping system. (C) 2004 Elsevier B.V. All rights reserved.