Effect of In-Situ Green Manuring on Soil Fertility, Growth and Yield of Rice Under Organic Farming PDF

J.Res. ANGRAU 47(1) 28-39, 2019 EFFECT OF INSITU GREEN MANURING ON SOIL FERTILITY, GROWTH AND YIELD OF RICE UNDER ORGANIC FARMING GANAPATHI and M.Y. ULLASA* Organic Farming Research Centre, University of Agricultural...

J.Res. ANGRAU 47(1) 28-39, 2019 EFFECT OF INSITU GREEN MANURING ON SOIL FERTILITY, GROWTH AND YIELD OF RICE UNDER ORGANIC FARMING GANAPATHI and M.Y. ULLASA* Organic Farming Research Centre, University of Agricultural and Horticultural Sciences, Shivamogga -577204 Date of Receipt: 19.12.2018 Date of Acceptance:28.02.2019 ABSTRACT The experiment was conducted to study the effect of insitu green manuring on soil fertility, growth and yield of rice under organic farming during kharif season for three consecutive years from 2012-13 to 2015-16.It was observed that the application of 100 kg Nequivalent FYM for preceding dhaincha (Sesbania aculeata) has produced higher green biomass yield (21.55 t ha-1) as compared to other green manuring crops with or without manuring. Incorporation of green manuring crop fertilized with 100 kg N equivalent FYM along with recommended dose of FYM (10 t ha-1) for succeeding rice crop has recorded significantly higher growth, yield attributes, grain (50.49 q ha-1) and straw yield (80.60 q ha-1). Also, the microbial population and final nutrient status of soil was found highest in the treatment which received 100 kg N equivalent FYM for dhaincha crop during sowing along with application of recommended dose of FYM for rice (10 t ha-1) during incorporation of dhaincha. The continuous application of FYM along with green manure for four consecutive years enhanced the soil chemical and biological properties. INTRODUCTION production (CAGR) of Rice during 2001-2011 is less Rice is a staple food for nearly half of the (1.78 %) as compared CAGR of 1980-90 (3.62 %). world’s population with more than 90 per cent of it There is a drastic reduction in fertilizer use efficiency being consumed in Asia itself. Rice production in from 1970 (13.8 kg/kg NPK) to 2010 (3.7 kg/kg NPK). Asian countries has increased considerably by virtue Lack of inclusion of organic manures, crop residues, of the green revolution, providing solutions to food manures and green manuring crops, as nutrient shortages and reducing poverty. sources especially under intensive cropping system is leading to decline in productivity of food crops in India is one among the major rice producing general and rice in particular in the country. An countries in the world. In India, the rice yield per unit efficient organic nutrient management approach area increased from 668 kg ha-1 in 1951 to 2404 kg needs to be developed for increased productivity of ha-1 in 2016 and rice harvested area increased from rice under submerged conditions, in a sustainable 31 mha in 1951 to 43 mha in 2016. However, annual manner. Organic nutrient management represents rice production increased nearly five-fold from 20 m an important strategy for increasing the productivity tons in 1951 to 104 m tons in 2016 [Indiastat, 2017]. of rice cropping system, as it also leads to improved India is currently the second biggest producer of rice soil chemical, physical and biological properties in the world. Concurrently, domestic rice (Thakuria et al., 2009). In organic nutrient consumption has been increasing each year as a management practices, huge quantity of organic result of dietary changes associated with population matter needs to be applied to soil in order to meet growth and economic development, making India a the nutrient requirement of the crop. Non-availability leading global rice consumer. of organic manures in required quantity is the major Rice being an important staple food crop of drawback in adopting the organic farming. However, India, constitutes 36 per cent of total food grain through the adoption of insitu green manuring production of India. Compound annual growth rate of technique the required quantity of biomass can be *Corresponding author E-mail i.d: [email protected] 28  GANAPATHI AND ULLASA generated within the field, which is an efficient seedlings per hill in 24 m2 plot. One spray of econeem management approach for enhancing the productivity, 50000 ppm @ 4ml per L (65 DAT), one spray of cow nutrient use efficiency and to bring sustainability urine and water (1:10) ratio at 35 DAT and two sprays without affecting soil quality. Combined application at 30 DAT & 55 DAT of panchagavya @ 3% were of organic manures and green manures with or given as a measure of pests, disease management without crop residue incorporation is known to and to enhance the plant growth. Representative improve nutrient use efficiency and productivity of surface soil samples (0-15cm depth) were collected rice-based cropping system (Pampolino et al., 2007). before initiating the experiment and after harvest of Hence, there is a need to evaluate the suitable insitu the rice crop using core sampler. The air dried green manuring crops along with suitable nutrient processed soil samples were used for analysis. The management practices to enhance the yield of rice standard methods and procedures suggested by in sustainable manner. Piper (1966) and Jackson (1973) are adopted. Treatment wise soil samples were collected from the MATERIAL AND METHODS rhizosphere of the plants at harvest. The soil samples The field experiments were conducted during collected were placed in a polyethylene bag and 2012 - 2015 Kharif seasons at Organic Farming brought to the laboratory and stored in refrigerator at Research Centre, University of Agricultural and 50 C until used for analysis. Samples were analyzed Horticultural Sciences, Shivamogga, Karnataka (13. for different soil microorganisms viz., total bacteria, 977245 N, 75.578708 E) to study the effect of insitu total fungi and total actinomycetes using standard green manuring on soil fertility, growth and yield of dilution plate count technique and plating on specific rice under organic farming and long term effect of nutrient media. green manuring on soil physical chemical and Uniform cultivation practices were followed biological properties. Soil of the experimental site in all the four years. At each season the plant growth was shallow, well drained, sandy loam in texture, parameters were recorded, soil and microbial near neutral in reaction (pH 6.5) and non-saline soil analysis was carried out. The data obtained from (EC 0.45 dSm-1) and low in organic carbon(4 g kg -1), each season was pooled and statistical analysis of low soil available P2O5 (15 kg ha-1), medium available the data was completed using computer aided K2O (135 kg ha-1), low available N (165 kg ha-1 ), MSTAT. Zn (1.10 ppm), Mn (15.0 ppm), Fe (18.5 ppm) and Cu (1.25 ppm).The experiment was laid out in RESULTS AND DISCUSSION Randomized Complete Block design with three Effect of application of manures on green replications and eight treatments (Table 1). The biomass production quantity of manure applied was on N equivalent basis by considering N content of FYM as 1.02 per cent Pooled data pertaining to green biomass and neem cake as 5.6 per cent as per the treatments. production by green manure crop as influenced by Based on the treatments, dhaincha and other green application of organic manure revealed that among manure crops were sown in each plot eight weeks the treatments, application of 100 kg N equivalent prior to transplanting of main crop. Six weeks old FYM for dhaincha during sowing (T5) has recorded green manure crop was incorporated into the soil by significantly highest green biomass yield (21.55 tons ploughing and allowed to decompose for 15 days. ha-1) as compared to rest of the treatments. However, Three week old rice seedlings were transplanted it was closely followed by mixed green manure crops manually with a spacing of 22.5cm x 10cm @ 3 (16.94 tons ha-1) supplied with 100 kg N equivalent 29  Table 1. Effect of organic nutrient management practices on biomass yield of green manure crops Treat- Green Biomass Yield (t ha-1) Details ment 2012 2013 2014 2015 Pooled T1 Insitu dhaincha(Without Manure) + Supply of recommended FYM at incorporation 6.86 7.88 7.02 7.40 7.29 T2 Insitu mixed green manure(Without manure) + Supply of recommended FYM 5.92 8.05 6.48 6.37 6.45 at incorporation T3 Insitu dhaincha(Without Manure) + Supply of recommended FYM along with 6.56 8.27 7.80 8.68 7.72 50 % additional N through Neem cake at incorporation T4 Insitu mixed green manure(Without manure) + Supply of recommended FYM 6.11 8.13 7.42 8.35 7.32 along with 50 % additional N through Neem cake at incorporation T5 100 % N through FYM at sowing of dhaincha green manure crop + Supply of 20.60 20.93 21.45 23.24 21.55 recommended FYM at incorporation 30 T6 100 % N through FYM at sowing of mixed green manure crop + Supply of 16.26 18.14 18.02 15.34 16.94 recommended FYM at incorporation T7 50 % N through FYM at sowing of dhaincha green manure crop+ 50% 12.29 14.69 14.19 12.24 13.35 recommended N through Neem cake at incorporation T8 50 % N through FYM at sowing of mixed green manure + 50% recommended 11.36 13.44 13.40 10.23 12.11 N through Neem cake at incorporation EFFECT OF INSITU GREEN MANURING ON RICE SEm+ 0.886 1.350 1.120 0.91 0.72 CD@5% 17.73 18.37 16.25 13.77 14.12 Mixed green manure includes: dhaincha + sunhemp + niger + cow pea ; Recommended FYM: 10 t ha-1; 100 per cent N equivalent FYM: 20 t ha-1  Table 2. Effect of organic nutrient management practices on growth and yield parameters of rice (pooled data of four years) Plant No. of Productive No. of Test No. of No. of Treatment height tillers tillers panicles weight filled unfilled (cm) per hill per hill per plant (g) grains/panicle grains/panicle T1 74.3 18.7 17.7 11.0 26.3 146.0 37.3 T2 75.0 20.0 19.0 11.3 27.2 138.0 37.7 T3 78.3 20.3 18.3 12.0 27.8 157.3 27.7 T4 77.0 19.3 18.3 11.7 28.1 156.7 28.0 T5 86.0 25.0 24.0 14.0 30.3 172.7 16.33 T6 84.0 23.3 22.0 13.7 29.0 167.0 18.3 T7 83.3 22.0 21.0 13.0 26.3 161.7 22.7 T8 79.7 20.0 19.7 12.7 29.3 158.3 25.7 SEm+ 0.42 1.72 0.85 0.45 0.56 2.25 1.19 31 CD@5% 1.35 NS 2.32 1.37 1.62 6.83 3.61 T1 Insitu dhaincha (without manure) + Supply of recommended FYM at incorporation GANAPATHI AND ULLASA T2 Insitu mixed green manure(without manure) + Supply of recommended FYM at incorporation T3 Insitu dhiancha (without manure) + Supply of recommended FYM along with 50 % additional N through Neem cake at incorporation T4 Insitu mixed green manure(without manure) + Supply of recommended FYM along with 50 % additional N through Neem cake at incorporation T5 100 % N through FYM at sowing of dhaincha green manure crop + Supply of recommended FYM at incorporation T6 100 % N through FYM at sowing of mixed green manure crop + Supply of recommended FYM at incorporation T7 50 % N through FYM at sowing of dhaincha green manure crop+ 50% recommended N through Neem cake at incorporation T8 50 % N through FYM at sowing of mixed green manure + 50% recommended N through Neem cake at incorporation  EFFECT OF INSITU GREEN MANURING ON RICE FYM. The least biomass yield of green manure crops nutrients being leached out of root zone. The benefits was noticed in treatments which were devoid of basal of green manuring are generally interpreted as its nutrient application (T1, T2, T3& T4). Individual year capacity to produce or provide nitrogen as substitute data also recorded the same trend. Hence, in order for fertilizers. Green manures, particularly the to produce highest biomass of green manure crops legumes have relatively more N, narrow C-N ratio it is essential to apply the basal dose of nutrients in and behave almost like chemical nitrogenous the form of FYM. Similar results were also recorded fertilizers there by enhance the growth and yield of by Ganapathi et al. (2014). succeeding crop (Bhuiyan and Zaman, 1996).Hence, the treatment which produced highest biomass yield Effect of incorporation of green manure crops of dhaincha has provided higher quantity of nutrients and manure application on growth and yield to succeeding rice crop which in turn resulted in parameters of rice higher growth and yield attributes of rice. Data pertaining to plant height of rice pooled Effect of incorporation of green manure crops over years revealed that application of 100 kg N and manure application on yield of rice equivalent FYM for dhaincha crop during sowing along with application of recommended dose of FYM In the experiment, fertilization of preceding for rice (10 t ha-1) during incorporation of dhaincha green manuring crop played an important role in has recorded significantly higher plant height (86.0 realizing the highest growth, yield parameters and cm) as compared to rest of the treatments. This might finally yield of rice. Pooled data pertaining to yield of be due to greater availability and steady release of main crop revealed that significantly highest straw nutrients from the combined organic sources of FYM (80.6 q ha-1) and grain yield (50.49 q ha-1) of rice was and incorporation of green manures, which perhaps recorded with application of 100 kg N equivalent FYM enabled the plants to grow tall. The number of tillers for dhaincha crop during sowing along with hill-1 (25), number of panicles plant-1 (14), test weight application of recommended dose of FYM for rice (30.3 g) and number of filled grains panicle-1 (172.7) (10 t ha-1) during incorporation of dhaincha as were also found significantly higher in the treatment compared to rest of the treatments. However, it was which received 100 kg N equivalent FYM for dhaincha closely followed by the treatment which received 100 crop during sowing along with application of kg N equivalent FYM for mixed green manure crop recommended dose of FYM for rice during during sowing along with application of recommended incorporation of dhaincha crop. The higher growth dose of FYM for rice. The lower growth attributes, and yield parameters realized with application of 100 yield and yield parameters associated with remaining kg N equivalent FYM for dhaincha crop during sowing treatments may be due to non-application of manure along with application of recommended dose of FYM to preceding green manuring crop. Higher yields for rice during incorporation of dhaincha was attributed obtained with application of 100 kg N equivalent FYM to availability of high quantity of nutrients to rice. for dhaincha crop during sowing along with Due to non-supply of basal dose of FYM for preceding application of recommended dose of FYM for rice green manuring crops remaining treatments produced (10 t ha-1) during incorporation of dhaincha could be lower quantity of green biomass which in turn resulted attributed to superior growth parameters associated less nutrients availability to rice crop and finally with the treatment. It could have been due to the reduction in growth and yield of rice. Green manures slow and steady release of N into soil to match the added lot of organic matter to the soil and helped in required absorption pattern of rice and probably, the recycling the nutrients into soil besides preventing adequate supply of nutrients might have promoted 32  GANAPATHI AND ULLASA the grain yield. Dhaincha (Sesbania aculeata L.) upon sowing along with application of recommended dose its incorporation in the soil at succulent stage adds of FYM. Electrical conductivity (EC) also followed 60 kg N ha-1 - 90 kg N ha-1 (Pandey et al., 2008). the same trend. This helps to improve the physical and biochemical The availability of N, P and K also enhanced structure of the soil, prevent leaching losses of due to application of organic manures as compared nutrients, enhancing water holding capacity, to initial status. At the end of four years of preventing weed growth, reducing residual effect of experimentation available soil N varied from 155 to chemicals and also helps in reducing the soil borne 219 kg ha-1. The highest available N (219 kg ha-1) inoculum of phytopathogens (Kumar, 2010). Due to was noticed with application of 100 kg N equivalent all these reasons, treatments which produced highest FYM for dhaincha crop during sowing along with biomass yield of green manure crop has provided application of recommended dose of FYM for rice. optimum condition for production of highest yield of The lowest N content in soil was noticed in T4. The rice crop. Similar results were also reported by highest available P2O5 (205.7 kg ha-1) at the end of Ganapathi et al. (2014). experiment was noticed with application of 100 kg N Effect of long term organic nutrient equivalent FYM for dhaincha crop during sowing management practices on soil fertility along with application of recommended dose of FYM for rice. Potassium content varied significantly due Due to continuous use of bulk quantity of to different manurial treatments. Highest soil available organic manures for four consecutive years the potassium content (326.4 kg ha-1) was noticed with important soil parameters viz., OC, pH, EC and application of 100 kg N equivalent FYM for dhaincha nutrient concentrations varied significantly over the crop during sowing along with application of years. There was a buildup in Organic Carbon content recommended dose of FYM for rice. Significantly over the years, irrespective of the treatments as highest Ca (3.70 C mol kg -1), Mg (1.85 C mol kg -1), compared to initial soil carbon content of 4 g kg-1 Fe (83.37 ppm), Zn (2.22 ppm), Mn (29.46 ppm), Cu soil. Among the treatments, the highest buildup of (1.82 ppm) and S (26.6 ppm) content in soil was OC was recorded with application of 100 kg N also recorded with the application of 100 kg N equivalent FYM for dhaincha crop during sowing equivalent FYM for dhaincha crop during sowing along with application of recommended dose of FYM along with application of recommended dose of FYM for rice. Application of 100 kg N equivalent FYM for for rice as compared to rest of the treatments. Green preceding dhaincha crop resulted in highest biomass manures upon its decomposition not only add to the production (22.6 t ha-1) which upon incorporation into organic matter of the soil but also provides mineral soil along with recommended dose of FYM ultimately nutrients required by the crop plants grown in the enhanced the soil organic carbon content. The field. Decomposition of green manures serve as major regular green manuring results in high organic matter source of energy for the growth of microflora and reserve which enhances both soil chemical and supplies carbon for formation of new cell material to physical properties of soil. Enhanced soil qualities soil-biota which colonizes aprophytically on the of cultivated lands reflected in higher crop yields decomposing litter. During decomposition a series (Egodawatta et al., 2011). Although, variation in pH of biochemical changes takes place which ultimately of soil across the treatments was recorded, the lead to the simplification of various compounds. The variation was negligible as compared to initial level. use of green manure crops reduces soil borne The highest pH (6.74) was noticed with application diseases, suppress the weeds and other pests of 100 kg N equivalent FYM for dhaincha crop during 33  Table 3.Effect of organic nutrient management practices on yield of Rice Yield (q ha-1) 2012 2013 2014 2015 Pooled Treatment Grain Straw Grain Straw Grain Straw Grain Straw Grain Straw T1 26.40 48.56 31.78 53.84 35.10 54.16 36.43 51.93 32.43 52.12 T2 22.70 43.12 32.19 55.80 37.89 58.377 33.33 49.30 31.53 51.65 T3 26.82 47.87 34.14 59.91 42.49 61.91 40.30 58.45 36.06 54.63 T4 23.20 43.25 33.61 59.30 41.57 63.747 38.76 54.26 34.29 55.14 T5 44.0 82.01 48.86 79.30 53.60 80.743 52.56 80.34 50.49 80.60 T6 38.50 79.68 46.69 76.30 51.80 77.867 47.82 71.73 46.20 76.39 T7 36.40 71.40 43.64 69.20 46.18 67.440 44.18 62.47 42.60 67.16 T8 34.50 69.40 41.53 65.35 44.34 64.673 42.63 61.23 40.75 65.63 34 SEm+ 1.97 4.21 2.09 2.04 3.13 6.03 2.50 4.10 4.20 2.30 CD@5% 5.64 12.02 6.35 6.19 9.49 18.29 7.26 12..5 12.40 6.76 T1 Insitu dhaincha (without manure) + Supply of recommended FYM at incorporation T2 Insitu mixed green manure (Without manure) + Supply of recommended FYM at incorporation T3 Insitu dhaincha (without manure) + Supply of recommended FYM along with 50 % additional N through Neem cake at incorporation EFFECT OF INSITU GREEN MANURING ON RICE T4 Insitu mixed green manure(Without manure) + Supply of recommended FYM along with 50 % additional N through Neem cake at incorporation T5 100 % N through FYM at sowing of dhaincha green manure crop + Supply of recommended FYM at incorporation T6 100 % N through FYM at sowing of mixed green manure crop + Supply of recommended FYM at incorporation T7 50 % N through FYM at sowing of dhaincha green manure crop+ 50% recommended N through Neem cake at incorporation T8 50 % N through FYM at sowing of mixed green manure + 50% recommended N through Neem cake at incorporation  Table 4.Effect of organic nutrient management practices on soil chemical properties pH EC N P2O5 K2O OC Ca Mg Fe Zn Mn Cu S Treatment (dS m-1) Kg ha-1 g/kg (Cmol (p+) kg-1) ppm T1 6.62 0.533 172 103 109. 5.8 3.13 1.42 67.44 1.88 7.32 1.52 16.5 T2 6.36 0.640 199 202 175 5.0 3.23 1.55 61.48 2.06 21.08 1.68 15.7 T3 6.57 0.735 185 105 147 5.7 3.13 1.75 63.52 1.51 23.14 1.74 19.4 T4 7.14 0.587 156 105 227 4.5 3.40 1.50 50.49 2.03 14.44 1.64 21.2 T5 6.74 0.595 219 206 326 8.5 3.70 1.85 83.37 2.22 13.41 1.82 26.6 T6 6.26 0.671 207 200 299 7.1 3.60 1.65 80.37 2.34 29.46 1.78 25.3 T7 6.62 0.568 213 100 290 6.7 3.50 1.35 77.47 2.03 26.41 1.73 21.8 T8 6.66 0.633 188 107 207 6.0 3.40 1.45 57.48 1.44 24.48 1.73 20.6 SEm+ 0.17 0.09 12.66 1.30 35.84 0.60 0.29 0.05 12.31 0.11 1.76 0.11 1.08 CD at 5 % NS NS 33.57 3.93 104.34 1.90 0.89 0.15 NS 0.33 5.15 NS 3.12 35 Initial 6.5 0.45 165.0 20.2 135.0 0.40 2.80 1.42 18.5 1.10 15.0 1.25 8.24 T1 Insitu dhaincha (Without Manure) + Supply of recommended FYM at incorporation GANAPATHI AND ULLASA T2 Insitu mixed green manure(Without manure) + Supply of recommended FYM at incorporation T3 Insitu dhaincha (Without Manure) + Supply of recommended FYM along with 50 % additional N through Neem cake at incorporation T4 Insitu mixed green manure(Without manure) + Supply of recommended FYM along with 50 % additional N through Neem cake at incorporation T5 100 % N through FYM at sowing of dhaincha green manure crop + Supply of recommended FYM at incorporation T6 100 % N through FYM at sowing of mixed green manure crop + Supply of recommended FYM at incorporation T7 50 % N through FYM at sowing of dhaincha green manure crop+ 50% recommended N through Neem cake at incorporation T8 50 % N through FYM at sowing of mixed green manure + 50% recommended N through Neem cake at incorporation  Table 5.Effect of organic nutrient management practices on biological properties of soil (after harvest, 2015) Bacteria Fungi Actinomycetes PSM N-fixer Treat- cfu x 105 cfu x 104 cfu x 103 cfu x 103 cfu x 103 ment 30 60 At 30 60 At 30 60 At 30 60 At 30 60 At DAP DAP Harvest DAP DAP Harvest DAP DAP Harvest DAP DAP Harvest DAP DAP Harvest T1 64.3 80.0 61.3 8.0 8.6 7.0 4.3 9.0 5.0 7.0 12.0 7.6 17.0 23.0 14.0 T2 63.0 82.0 61.3 6.6 8.3 6.0 4.0 8.0 4.0 5.0 11.0 7.0 15.0 20.0 11.6 T3 65.6 80.3 62.6 9.0 10.3 9.0 5.6 10.0 7.0 8.7 13.6 8.6 19.0 14.3 15.3 T4 67.3 82.6 64.6 8..3 9.0 8.6 5.0 9.6 6.6 8.0 13.0 8.0 18.3 24.0 15.0 T5 75.6 90.6 70.6 10.6 13.6 10.3 8.6 13.0 8.3 11.3 16.0 10.3 22.0 27.0 17.0 T6 72.3 87.0 68.0 10.3 12.6 10.0 7.0 10.0 8.0 10.0 14.6 9.0 20.3 26.3 16.6 T7 70.6 85.3 65.3 9.6 11.3 9.6 6.6 11.6 7.0 9.6 14.0 8.6 20.0 25.6 16.6 67.0 82.3 65.0 9.0 11.0 9.3 6.0 11.0 7.6 9.0 14.0 8.0 19.6 25.0 16.0 36 T8 SEm+ 0.29 0.370 0.32 0.360 0.268 0.360 0.330 0.256 0.310 0.270 0.375 0.362 0.306 0.289 0.309 CD @ 5 % 0.72 0.925 0.86 0.920 0.800 0.900 0.826 0.630 0.870 0.675 0.937 0.905 0.762 0.850 0.772 Initial 54.00 5.43 5.00 6.80 11.00 T1 Insitu dhaincha (Without Manure) + Supply of recommended FYM at incorporation T2 Insitu mixed green manure(Without manure) + Supply of recommended FYM at incorporation EFFECT OF INSITU GREEN MANURING ON RICE T3 Insitu dhiancha (Without Manure) + Supply of recommended FYM along with 50 % additional N through Neem cake at incorporation T4 Insitu mixed green manure(Without manure) + Supply of recommended FYM along with 50 % additional N through Neem cake at incorporation T5 100 % N through FYM at sowing of dhaincha green manure crop + Supply of recommended FYM at incorporation T6 100 % N through FYM at sowing of mixed green manure crop + Supply of recommended FYM at incorporation T7 50 % N through FYM at sowing of dhaincha green manure crop+ 50% recommended N through Neem cake at incorporation T8 50 % N through FYM at sowing of mixed green manure + 50% recommended N through Neem cake at incorporation  GANAPATHI AND ULLASA getting emphasis because of its sustainable and The application of green manures to soil is environmental friendly nature, thus, helps to promote considered as a good management practice in any organic cultivation (Parajuli, 2011). agricultural production system because it stimulates soil microbial growth and activity, with subsequent Effect of long term organic nutrient mineralization of plant nutrients (Eriksen, 2005), and, management practices on soil microbial therefore, increase soil fertility and quality (Doran et activities al., 1988). From the microbiological point of view, In the investigation treatment which involved green manure and organic manures have two main application of 100 kg N equivalent FYM for preceding positive effects– enhances microbial biomass which dhaincha crop and its incorporation along with converts unavailable nutrients in plant residues to application of recommended dose of FYM for available form and also enhances biodiversity of soil succeeding rice recorded higher population of micro-organisms. These positive effects can be actinomycetes, bacteria and fungi as compared to enhanced by supplying huge biomass of green rest of the treatments (Table 5). There was a gradual manure crop as achieved in treatment T5. Increase increase in the microbial population towards end of in beneficial microbial activity was often related to the growing season as compared to initial microbial increase in organic matter (Sikora and Stott, 1996). status (Table 5). Enhancement of microbial Organic matter is vital as a food source for beneficial population results in effective utilization of the soil microorganisms that are related to disease organic matter supplied through incorporation of green suppression, soil structure, improvement in soil manure crops and FYM. Soil enzymatic activities properties and crop health (Schutter and Dick, 2001). are closely related to microbial activity or biomass The use of green manures in between successive as they catalyse biochemical reactions and nutrient crops helps maintain or increase organic matter in cycling in the soils (Burns, 1982). The population of soils (Pung et al., 2004). Hence, the treatment T3 free living nitrogen fixers also found significantly which added the higher green biomass (21.55 t ha-1) highest in T5 as compared to rest of the treatments to the soil has recorded significantly higher microbial at different growing period of crop viz., 30 days, 60 population. Similar results were recorded by days and at harvesting (Table 5).Another important Ganapathi et al. (2014). functional group of agriculturally important CONCLUSION microorganisms is phosphate solubilizers. Phosphate solubilizing microorganisms are known The study revealed that inorder to achieve to improve P-solubilization, thereby improving crop highest yield in rice in sustainable manner, growth and yield. In the study, abundance of P- application of 100 kg N equivalent FYM to preceding solubilizers are observed in rhizosphere of soils in dhaincha crop at sowing and incorporating the T5 (Table 5). Among different crop growth stages the dhaincha crop 15 days prior to transplanting of the highest microbial population was found at 60 DAS succeeding rice along with recommended dose of as compared to remaining growth stages which can FYM (10 t ha-1) is essential. Supply of 100 kg N be attributed to higher root exudations by the plants equivalent FYM to dhaincha crop has enhanced at this stage. Root exudates includes various organic biomass production of dhaincha crop. Incorporation and inorganic acids and it will attract more beneficial of dhaincha crop 15 days prior to transplanting has soil microflora and results in the higher growth and enhanced the physical, chemical and biological yield of the crops. properties of soil, which inturn resulted in higher yield of rice. 37  EFFECT OF INSITU GREEN MANURING ON RICE ACKNOWLEDGEMENT climate. Tropical Agricultural Research. 22 (2): 172–182. All type of help rendered by the Organic Farming Research Centre, University of Agricultural Eriksen, J. 2005. Gross sulphur mineralization- and Horticultural Sciences, Shivamogga during immobilization turnover in soil amended with course of study to the author is gratefully plant residues. Soil Biology and acknowledged. Biochemistry. 37:2216–2224. 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