Productivity analysis of aerobic rice + legume intercropping system

Abstract

The field experiment entitled ‘Productivity analysis of aerobic rice + legume intercropping system’ was carried out at College of Agriculture, Padannakkad during December, 2021 to May, 2022 with an objective of analysing the productivity of the system of aerobic rice intercropped with legumes (cowpea and black gram) under varying levels of nitrogen. The experiment was laid out in Randomized Block Design with 9 treatments and 3 replications. The treatments imposed were, T1: Sole crop of black gram, T2: Sole crop of cowpea, T3: Sole crop of aerobic rice, T4: Intercrop of black gram + aerobic rice with recommended dose of nitrogen (RDN), T5: Intercrop of black gram +aerobic rice with 75% RDN, T6: Intercrop of black gram +aerobic rice with 50% RDN, T7: Intercrop of cowpea + aerobic rice with RDN, T8: Intercrop of cowpea + aerobic rice with 75% RDN, and T9: Intercrop of cowpea + aerobic rice with 50% RDN. The crop varieties used for the study were Sharada, Sumanjana and PGCP 6 of aerobic rice, black gram and cowpea, respectively. The significant results of the study are as follows. The treatments had significant effect on number of tillers/ hill in aerobic rice. The treatments T4 and T3 recorded highest number of tillers/ hill at 60 DAS (29.27) and at harvest (24.40), respectively. Treatments showed significant effect on root volume of aerobic rice. T3 and T6 recorded highest root volume at 60 DAS (41.67 cm3) and at harvest (60.00 cm3), respectively. T1 recorded the highest plant height, root length and root volume at 30 DAS. At the time of harvest, T6 had the highest root length, while T5 had the highest root volume. The effective nodules per plant were significantly high in T4 and T6 at 30 DAS and at harvest, respectively. The plant height and number of effective nodules of cowpea were significantly high in sole crop of cowpea (T2). The root length and root volume were high in T8 and T7 respectively at 30 DAS. The root length, number of leaves and number of effective nodules were high in T9 at harvest. The relative growth rate of aerobic rice was significantly high in T4 between 30-60 DAS. Black gram and cowpea recorded significantly high leaf area index in T5 and T9, respectively. The number of productive tillers were high in T4. The number of spikelets/ panicle and number of filled grains/panicle were significantly high in T5. Sole crop of aerobic rice (T3) recorded significantly higher grain yield (1052 kg ha-1) and T5 (Intercrop of black gram + aerobic rice with 75% RDN) was the best among intercropping treatments. The grain yield (2429 kg ha-1), stover yield (1873 kg ha-1) and HI (0.57) of black gram were significantly high in sole crop (T1). Among the intercropping treatments, T6 recorded the highest grain yield. The number of pods per plant and weight of pod of cowpea were significantly high in T8. There was no significant differ between the treatments with respect to the grain yield of cowpea. However, the higher yield was recorded by sole crop (2319 kg ha-1), followed by T9. The land equivalent ratio was high in T7. The competition ratio and aggressivity values of aerobic rice were more than unity and zero, respectively when intercropped with black gram which shows that aerobic rice was dominant over black gram. The relative crowding coefficient of legume was significantly high in T9. The actual yield loss (AYL) of aerobic rice was significantly high in T5 and that of legumes was high in T9 and the total AYL was significantly high in T7. The higher net returns, gross returns and BCR were recorded by sole crop of black gram. Cowpea when intercropped with aerobic rice at 50 % RDN recorded highest gross returns (180065 ₹ ha-1), net returns (103858 ₹ ha-1) and BCR (2.36). The overall results on agro-economic evaluation of aerobic rice + legume intercropping system under varying levels of nitrogen revealed that intercropping of aerobic rice with a legume component, either cowpea or black gram, was more productive than sole cropping of aerobic rice. The study shows the positive influence of legume crops in the cropping system as evidenced in yield attributes and yield of aerobic rice, even at lower levels of N. Economic analysis also reveals that lowering N levels in aerobic rice + legume intercropping system can be recommended. The experiment was laid out in Randomized Block Design with 9 treatments and 3 replications. The treatments imposed were, T1: Sole crop of black gram, T2: Sole crop of cowpea, T3: Sole crop of aerobic rice, T4: Intercrop of black gram + aerobic rice with recommended dose of nitrogen (RDN), T5: Intercrop of black gram +aerobic rice with 75% RDN, T6: Intercrop of black gram +aerobic rice with 50% RDN, T7: Intercrop of cowpea + aerobic rice with RDN, T8: Intercrop of cowpea + aerobic rice with 75% RDN, and T9: Intercrop of cowpea + aerobic rice with 50% RDN. The crop varieties used for the study were Sharada, Sumanjana and PGCP 6 of aerobic rice, black gram and cowpea, respectively. The significant results of the study are as follows. The treatments had significant effect on number of tillers/ hill in aerobic rice. The treatments T4 and T3 recorded highest number of tillers/ hill at 60 DAS (29.27) and at harvest (24.40), respectively. Treatments showed significant effect on root volume of aerobic rice. T3 and T6 recorded highest root volume at 60 DAS (41.67 cm3) and at harvest (60.00 cm3), respectively. T1 recorded the highest plant height, root length and root volume at 30 DAS. At the time of harvest, T6 had the highest root length, while T5 had the highest root volume. The effective nodules per plant were significantly high in T4 and T6 at 30 DAS and at harvest, respectively. The plant height and number of effective nodules of cowpea were significantly high in sole crop of cowpea (T2). The root length and root volume were high in T8 and T7 respectively at 30 DAS. The root length, number of leaves and number of effective nodules were high in T9 at harvest. The relative growth rate of aerobic rice was significantly high in T4 between 30-60 DAS. Black gram and cowpea recorded significantly high leaf area index in T5 and T9, respectively. The number of productive tillers were high in T4. The number of spikelets/ panicle and number of filled grains/panicle were significantly high in T5. Sole crop of aerobic rice (T3) recorded significantly higher grain yield (1052 kg ha-1) and T5 (Intercrop of black gram + aerobic rice with 75% RDN) was the best among intercropping treatments. The grain yield (2429 kg ha-1), stover yield (1873 kg ha-1) and HI (0.57) of black gram were significantly high in sole crop (T1). Among the intercropping treatments, T6 recorded the highest grain yield. The number of pods per plant and weight of pod of cowpea were significantly high in T8. There was no significant differ between the treatments with respect to the grain yield of cowpea. However, the higher yield was recorded by sole crop (2319 kg ha-1), followed by T9. The land equivalent ratio was high in T7. The competition ratio and aggressivity values of aerobic rice were more than unity and zero, respectively when intercropped with black gram which shows that aerobic rice was dominant over black gram. The relative crowding coefficient of legume was significantly high in T9. The actual yield loss (AYL) of aerobic rice was significantly high in T5 and that of legumes was high in T9 and the total AYL was significantly high in T7. The higher net returns, gross returns and BCR were recorded by sole crop of black gram. Cowpea when intercropped with aerobic rice at 50 % RDN recorded highest gross returns (180065 ₹ ha-1), net returns (103858 ₹ ha-1) and BCR (2.36). The overall results on agro-economic evaluation of aerobic rice + legume intercropping system under varying levels of nitrogen revealed that intercropping of aerobic rice with a legume component, either cowpea or black gram, was more productive than sole cropping of aerobic rice. The study shows the positive influence of legume crops in the cropping system as evidenced in yield attributes and yield of aerobic rice, even at lower levels of N. Economic analysis also reveals that lowering N levels in aerobic rice + legume intercropping system can be recommended.