Nutrient Optimization and Yield Intensification of Major Cereal Systems of Eastern India

India is the second largest producer of rice in the world with a production of 100 million tons in 2010-11. Rice occupies 44 Mha i.e. 22% of the total cropped area. However, at the current rate of population growth in India, the requirement of rice is estimated to be around 150 million tons within next fifty years. To make the India self sufficient in rice, it is needed to improve the productivity to a greater extent, compared to the existing condition. Food security in India (1.6 billion by 2050 that will require 450 Mt of food grain production) is a challenge ( Siddiq, 2000) and the options available are very limited. Among the various possible genetic approaches to achieve this target, hybrid rice technology is the most feasible and readily adaptable one which can increase 15% to 20% of food production (Peng et al., 1999, Siddiq, 1996). Commercial success of hybrid rice in China has clearly demonstrated the potential of this technology to meet the ever-increasing demands for rice over the world. Efforts to develop and use hybrid rice technology in India, through Indian Council of Agricultural Research (ICAR) started since 1989, with launching of a mission oriented project. Within a short span of seven years, half a dozen hybrids each from public and private sectors are made available for commercial cultivation. Hybrid rice has yield advantage of more than 30% over conventional varieties. In India, the area under hybrid rice was 2 million hectares i.e. approximately 5% of total rice area in 2011-2012 (The Hindu, 2012). Rice productivity is now at stagnant situation or declining in areas where N-fertilizer application is very high; It has also raised the concerns about sustainability of monoculture rice (Jeyabal and Kuppuswamy,2001). The hybrid cultivars are more responsive to higher doses of nutrients (Yuan, 1996 and Yuan, 1999) and thereby the yield potentiality is all high. Cultivation of high yielding varieties (HYV) of rice is the most popular practice for rice cultivation especially in the states of eastern India. There are major varieties (MTU 7029, Satabdi-IET 4786, IR 36, MTU 1010, IET 4094-Khitish, Sabita, Sashi, Ranjeet, Mahsuri, IR 36, IR 64, Ratna, Lunishree, Annada, Sabitri etc ) that are grown very popularly in eastern India especially during Kharif season. Out of total areas in West Bengal, 91.68% goes under HYV and nearly 5% area goes under hybrid rice (2007-08). The productivity of Rice at present is 2.485 tonne/ha for Kharif Rice and 3.039 tonne/ha for Boro Rice. The productivity is still far below the National average of 3.3 tonnes/ha for Rabi rice. For successful production of hybrid rice and HYV rice we need certain nutrient management plans. In the case of HYV, there are certain state recommendations for the nutrient management. However, these are mainly blanket recommendations. Blanket recommendations in most of the cases create unbalanced use of plant nutrients. On the contrary, with the increasing fertilizer price scenario efficient use of fertilizer is much more required. Moreover, there is no specific recommendation for the hybrid rice nutrient management. Therefore, farmers in general use the same nutrient management plan for HYV and hybrid rice. Sometimes the nutrient management totally depends on the assumptions by the farmers. However, hybrid rice produces higher yield (6.9 t/ha) in general compared to HYV (5.6 t/ha) and it is therefore expected that their nutrient management practices should also vary. Rice crop is the maximum consumer of nitrogenous fertilizer as nitrogen plays an important role in increasing the productivity of rice. However, nitrogen use efficiency (NUE) for rice is as low as 30-40%. The phosphorus and potassium fertilizers are also important for rice cultivation. The responses of N, P and K could be assessed by the “Omission Plots” trial techniques where a particular nutrient will be omitted considering the fact that the soil should be sufficient to provide other nutrients. Low response of crops to nitrogenous fertilizers is due to various nitrogen loss mechanisms,
namely, ammonia volatilization, leaching, surface run-off, and de-nitrification. Split application of the nitrogen fertilizer to rice may reduce the rapid nitrous oxide emission and increase NUE. Along with N, rice also needs application of P and K at right rate and time. However, at the present increase in P and K fertilizer prices, the application of these nutrients are reduced drastically. As a result the growth of the plants are hampered due to imbalanced fertilization. A relatively long-term study (three years) with continuous omission of N, P and K nutrients from selected plots respectively, might be a very good indication of the nutrient deficiencies. Maiti et al., 2006 reported that the growth attributes, yield components and grain yields increased with the increase in doses of chemical fertilizers alone as well as in combination with 5 tonnes FYM/ha in both the rainy seasons for both kharif and rabi season rice cultivation. In hybrid rice-hybrid rice cropping system, the application of 125% recommended doses of fertilizer along with 5 tonnes FYM/ha during rainy season followed by 100% recommended doses of fertilizer during summer season gave higher grain yield (12.0 tonnes/ha), net return (Rs 15,848/ha) and return/Re investment (Rs 1.34) compared with that of 100% recommended doses of fertilizer in both the seasons (10.45 tonnes/ha) grain yield, Rs 10,004/ha net return and Rs 1.23 return/Re investment. The status of organic carbon, nitrogen, phosphorus and potassium in the soil increased over the initial values after four consecutive croppings where FYM was applied in the rainy season. Xie et al., 2007 reported that according to NuDSS a “Nutrient Decision Support System (NuDSS)” for irrigated rice which was used to optimize nutrient management for two rice hybrid varieties, the optimal fertilizer N requirement for the target yields was about 150 kg/ha for Shanyou63 and about 120 kg/ha for Xieyou46, which were only about 70% of the fertilizer N application under current farmers’ practice. Comparing with farmers’ practice, there is great potential to increase actual rice yields and to reduce fertilizer N use rates by improving hybrid rice crop management practice. Proper P nutrition is critical for producing maximum rice yields. It promotes vigorous, early plant growth and development with strong root systems and profuse tillering, in addition to flowering, fruiting, and many other biochemical processes in the plant. However, its deficiency in rice is often referred to as a “hidden hunger” because its symptoms are hard to observe unless deficient plants are directly compared to sufficient plants (Dunn and Stevens, 2007). Pattanayak et al., 2008 suggested appropriate P application rates for rice through a soil test-based approach wherein application of the full recommendation was responsible for a 5.2 t/ha grain yield response which raised the potential of a two crop system to 13.9 t/ha. The soil test-based approach improved harvest index, increased the recovery efficiency of N and K, and the corresponding economic benefits from hybrid rice cultivation. Bezbaruah et al.,2011 reported that in Field experiments conducted during the wet seasons of 2006 and 2007 at the Agricultural Experimental Farm of the Indian Statistical Institute, Giridih, a part of eastern plateau region of India “CNRH-3” rice proved its efficiency in terms of grain yield that was also reflected in yield attributing characters such as number of productive tillers, number of grains per panicle, length of panicle, panicle weight, test weight and harvest index. Rice culti-vars grown with the application of inorganic fertilizers alone produced maximum grain yield and also recorded higher values of ancillary characters. The maximum amount of N, P and K was taken up by the “CNRH-3” rice, whereas maximum residual soil fertility was recorded in “Pro Agro 6201” rice. Maximum N, P and K uptake values were re-corded in inorganic fertilizers treatment. Higher nutrients uptake with the ap- plication of inorganic fertilizer might be due to higher
nutrient concentration along with higher biomass production (Swarup and Yaduvanshi, 2006, Banik et al., 2006). Presently, kharif rice followed by rabi rice followed by pulses is a very common crop rotation system in different districts of West Bengal. However, there is no certain nutrient management plan related to this Rice – Rice – Pulse (mung) cropping pattern. Present study will focus on the short term (one year) and long-term (three years) result of the soil and crop yield in this cropping system. Objectives of the Study: i. To evaluate the nutrient (N, P, K, S and Zn) supplying capacities of different soils under hybrid rice – high yielding rice - pulse cropping system. ii. To estimate the nutrient requirement of hybrid rice – high yielding rice - pulse cropping system. iii. To develop an optimum nutrient management strategy for sustaining high productivity in hybrid rice – high yielding rice - pulse cropping system. iv. To generate awareness among the farmers about improved nutrient management practices in the hybrid rice – high yielding rice - pulse cropping system. v. To study the effect of nutrient management on the economics of Hybrid rice and HYV cultivation in a hybrid rice – high yielding rice - pulse cropping system.