Growth analysis and grain yield of rice (Oryza sativa L.) varieties under green manure based integrated nutrient management

Field experiments were conducted at Bhubaneswar, Odisha during kharif seasons of 2018 and 2019 to study the growth behavior of rice varieties under nutrient management practices. Six treatment combinations comprising of three nutrient management (100% Soil Test Based Nitrogen Recommendation (STBNR), 75% STBNR + in situ green manuring (dhaincha) and 50% STBNR + in situ green manuring of dhaincha) and two rice varieties (Manaswinee of 125d duration and Hasanta of 145d duration) were tried in randomized complete block design (RCBD) with four replications. The results showed that crop growth rate (CGR) was significantly influenced by both nutrient management practices and varieties. Pooled over the years, application of 75% STBNR + green manuring of dhaincha exhibited the maximum CGR of 11.33 and 20.80 g/m2/day during 30-60 and 60-90 DAT, respectively and which were superior to 100% STBNR and 50% STBNR + green manuring of dhaincha. Similarly, rice cv. ‘Hasanta’ recorded CGR of 10.98 and 20.42 g/m2/day during 30-60 and 60-90 DAT, respectively, which were higher over cv. ‘Manaswinee’. The maximum relative growth rate (RGR) of 23.77 mg/g/day was registered with 50% STBNR + green manuring of dhaincha, being at par with 75% STBNR + green manuring of dhaincha during 60-90 DAT. Application of 75% STBNR + green manuring of dhaincha recorded the maximum Net assimilation rate (NAR) of 3.41 and 4.26 g/m2 leaf area/day during 30-60 and 60-90 DAT, respectively. Both cultivars were equally effective for RGR and NAR. The treatment trend for physiological indices led to higher grain yield under 75% STBNR + green manuring of dhaincha among nutrient management practices and cv. ‘Hasanta’ between rice varieties. Grain yield and the three physiological indices were positively correlated, but the correlation coefficient values were significant for CGR and NAR.