EFFECT OF NEEM (AZADIRACHTA INDICA) PRODUCT COATED UREA ON INCREASING THE NITROGEN USE EFFICIENCY AND PRODUCTIVITY OF RICE UNDER IRRIGATED ECOSYSTEM OF INDIAN SUBCONTINENT

摘要

Faculty of Agriculture, Bidhan Chandra Krishi Viswavidyalaya (Agricultural University), Mohanpur-741252, Nadia, West Bengal, India Abstract: A field experiment was carried to study the effect of different neem (Azadirachta indica) product coated urea on increasing the nitrogen use efficiency and growth and yield of rice during 2003 at Central Research Farm, Gayeshpur, Bidhan Chandra Krishi Viswavidyalaya, Nadia, West Bengal. India, in water logged condition. The experiment was layed out in a Randomized Block Design comprising eight treatments replicated thrice. The treatment included two (Neem kernel powder coated urea 100% and 80%) and another five treatments included either as sole application of urea as a source of nitrogen or in combination with different plant product (neem leaf, neem cake) as a source of nitrogen, as well as fertilizer check control. When nitrogen was applied through urea along with neem products (viz. neem cake, neem coated urea and neem kernel powder coated urea), it significantly increased yield attributing characters and yield of rice (grain yield 5.96 t/ha and straw yield 6.05 t/ha for neem cake coated urea and grain yield 5.96 t/ha & straw yield 6.18 t/ha for neem kernel powder coated urea) as compared to the treatments comprising urea nitrogen alone (grain yield 5.12 t/ha and straw yield 5.87 t/ha for sole urea as cent percent) or absence of nitrogen (grain yield 2.60 t/ha and straw yield 2.86t/ha). The maximum partial factor of productivity (59.60 kg grain /kg of nitrogen for neem cake coated urea and 59.50 kg-grain·kg~(-1) of nitrogen for neem kernel powder coated urea) and apparent nitrogen recovery (54.46% for neem cake coated urea and 54.09% for neem kernel powder coated urea) were recorded when nitrogen was applied in the form of urea + neem products which in turn increased the productivity. Though a decline of available N, P, K of soil was noted after the harvest of crop, it was minimum when neem products were used in the treatments. Uptake of N, P, and K was also recorded significantly higher in the treatments comprising neem products as compared to control or treatments based on urea alone. The benefit-cost ratios were also higher for neem kernel powder coated urea (2.54) and neem cake coated urea (2.53). The addition of neem based products along with chemical nitrogenous fertilizer urea has a definite beneficial role in checking the nitrogen loss from the soil and in improving the availability of nitrogen, which is ultimately reflected in higher uptake of nutrients and higher productivity and sustaining the environment.