Asian Journal of Soil Science and Plant Nutrition

An experiment was planned and conducted at Instructional Farm (IF), Odisha University of Agriculture & Technology (OUAT), Bhubaneswar in the years 2022 and 2023 during the Kharif seasons to study the effect of the cumulative addition of nine varieties of nutrients on the yield and protein contents of two varieties of rice namely Gayatri and Vandana. The applied fly ash (FA) was alkaline in nature whereas the soil was acidic. The grain yield of the Kharif crop in 2022 (Gayatri) varied from the lowest of 31.56 qha^-1 to the highest of 37.21 qha^-1. It varied from the lowest of 38.66 qha^-1 to the highest of 43.82 qha^-1 in 2023. The crude protein content varied from the lowest of 7.97% to the highest of 9.16% in 2022 but it varied from the lowest of 7.31% to the highest of 8.39% in 2023. The non-protein nitrogen (NPN) content varied from the lowest of 7.97% to the highest of 9.16% in 2022 but it varied from the lowest of 7.31% to the highest of 8.39% in 2023. The true protein content varied from the lowest of 6.90% to the highest of 7.97% in 2022 but it varied from the lowest of 6.12% to the highest of 7.50% in 2023. It was observed that the grain yield, crude protein, non-protein nitrogen (NPN) and true protein content decreased by the application of FA over control (only NPK fertilizer). The crude protein content decreased in all the treatments in 2023 over its 2022 counterpart whereas NPN increased by the cumulative addition of nutrients. This resulted in higher values of true protein content in the grains in the year 2023. Grain yield increased in all the treatments in 2023 over the previous year resulting in higher yield of true protein content. Hence more amount of protein rich grains per hectare can be obtained by the cumulative addition of nutrients in spite of varietal difference of the grains.