EFFECT OF DIFFERENT NUTRIENT MANAGEMENT PRACTICES ON GROWTH, YIELD AND QUALITY OF RICE

Abstract

The Green Revolution has played an important role in global food security. However, at the same time, the Green Revolution also encouraged the use of chemical pesticides and fertilizers. The negative impact of these chemical fertilizers is causing health problems in humans and animals, reducing soil fertility, and endangering the environment subsequently. Under such situations, it is essential to limit the utilization of these chemicals while sustaining the crop's productivity. Using diverse available organic resources and agricultural wastes, it is possible to reduce the application of these synthetic fertilizers and subsequently retain soil fertility. However, crop production capacity and soil productivity of various organic materials are not completely known. Keeping this in mind the research work carried out to evaluate the performance of different organic. Inorganic and INM of organic and inorganic on rice (PR-114) quality and productivity, soil fertility and system sustainability. For this purpose, the field experiments were conducted in the years 2014 and 2015 at the demonstration farm of the Department of Water Resources Development and Management, Indian Institute of Technology Roorkee, Uttarakhand in sandy loam soil. The experiment was laid out in Randomized Block Design (RBD) with 8 treatments and 3 replications comprising different combinations of inorganic fertilizers and organic manures viz., T1 - control, T2 - recommended dose of chemical fertilizers (RDCF) @ 120:60:60, T3 - FYM @ 20 tha–1, T4 - vermicompost (VC) @ 5 tha–1, T5 - 50% FYM + 50% RDCF, T6 - 50% VC + 50% RDCF, T7 - 50% VC + 50% FYM and T8 - 25%VC + 25% FYM + 50% RDCF. Significant changes in plant height, number of leaves, leaf length, leaf width and leaf area index (LAI) at different intervals (30, 60 and 90 DAT) were observed in both years. Inorganic treatment T2 was performed well over all other treatments. INM treatments (T5, T6 and T8) performed well over organic treatments (T3, T4 and T7) but less than inorganic treatment T2. The number of tillers was significantly different among treatments at 30 DAT only in both years, whereas, no difference was observed in the number of tillers at 60 and 90 DAT in both years. The inorganic treatment T2 performed well over all other organic and INM treatments in all respects of grain yield and yield attributes. Response of INM was observed better than organic treatments. The mixed INM treatment T8 was found superior among all INM treatments. There was a mixed response of organic treatments T3 (FYM) and T4 (vermicompost). In some yield attributes the performance of FYM was observed better than vermicompost and in others, vermicompost showed well. Significant difference was observed in hulling, head rice recovery and grain chalkiness due to different nutrient management in both the years. Hulling and head rice recovery was higher in inorganic treatment T2 compared to all other organic and INM treatments. Among INM, mixed INM treatment T8 produce more hulled and head rice than T5 and T6. Vermicompost treated T5 produced more hulled and head rice than FYM treated T3 and mixed organic treatment T7. All organic treatments produced a similar amount of chalked grain whereas, mixed INM treatment T8 produced the least chalked grain among all INM treatments. Inorganic treatment T2 produced the least chalked grain among all treatments. Organic treatments produced a high amount of ash, fat and carbohydrate and less amount of fiber and protein in comparison to inorganic and INM treatments. INM treatments produced more fiber and protein in comparison to their counterpart organic treatments but less than inorganic treatment T2. Soil pH was significantly affected by different nutrient management in the soil in the year 2014 only whereas, no significant difference was observed on soil EC in both the years. Soil organic carbon, available nitrogen, extractable phosphorus and exchangeable potassium were significantly different in experimental plots due to different soil nutrient management in both the years. All organic treatment increased the soil organic content followed by INM treatment compared to inorganic treatment T2. Higher residual nitrogen has remained in mixed organic treatment T7 followed by FYM treatment T3 and INM treatment T5, which may be due to the bulkiness of FYM in such treatments. High residual phosphorus was retained by the FYM treatment T3 followed by mixed INM treatment T8. FYM treatment alone or in INM performed better to retain soil phosphorus in comparison to vermicompost treatment either applied alone or in INM. High residual potassium was retained by the FYM treatment T3 followed by mixed organic treatment T7. Other treatments except inorganic treatment T2 retained almost similar amounts of potassium in the soil. Inorganic treatment T2 retained the least amount of soil macronutrients in comparison to organic and INM treatments. Significant differences in soil trace elements were recorded due to different nutrient management in the soil in both years except for exchangeable copper in year 2015. The mixed response of organics FYM and vermicompost was observed in retaining soil trace elements in the soil. FYM retained a higher amount of zinc, iron and manganese but a low amount of copper in comparison to vermicompost. Vermicompost incorporated INM treatment T6 retained more amount of copper and manganese whereas, a low amount of zinc and iron in comparison to FYM incorporated treatment T5. Mixed organic treatment T7 retained a higher amount of trace elements in comparison to mixed INM treatment T8. Inorganic treatment T2 retained a low amount of trace elements in soil compared to organic and INM treatments. The pooled data of cultivation economics shows that vermicompost treatment is the least economical among all treatments due to its high cost of production (BCR-0.95) whereas, CF treatment T2 was the most economical with BCR- 1.72. FYM treatment BCR was higher than vermicompost treatment either applied alone or in combination with chemical fertilizers in INM. The mean BCR of all organic treatments was 1.05 whereas, the mean BCR of INM treatment was 1.41 which was even lower than CF treatment T2 (BCR-1.72). The result shows that chemical fertilizers cannot be replaced with organic manures to avoid the economic sustainability of farmers. FYM may be a great choice for organic rice production due to its low cost in comparison to vermicompost. Pooled data from two years shows that all organic and INM treatments were able to sustain yield, soil fertility and crop nutritional quality in various capacities. Only chemical fertilizer and unfertilized control retained a lower value of SI, indicating these systems are not capable of maintaining sustainability in all aspects. Vermicompost treated T4 (1.05) retained the highest SI value followed by its counterpart INM treatment T6 (1.04). There was a very small and non-significant difference between SI of FYM treatment T3 (10.4) and Vermicompost treatment T4 (1.05) showing that both can be used in place of each other’s and sustain crop yield, soil fertility and nutritional quality of rice in the same manner. The SI of CF-INM treatments was lower than organic treatments showing that although INM is sustainable for crop yield and nutritional quality but somehow less sustainable for soil fertility in comparison to organics. The overall conclusion of the study is that the use of organic and INM may sustain soil fertility for the long term and increase yield and nutritional quality gradually.