Neem, mahua and sesame seed cakes, and tamarind husk powder on improving nitrogen-use efficiency in rice

Purpose: Plant-based by-products are known to improve nitrogen-use efficiency (NUE) while minimizing environmental pollution. Therefore, an experiment was conducted to examine the potential for improving the NUE of the rice variety Bg300 grown in reddish brown earth (RBE) soil (Chromic Luvisols) by incorporating urea with plant-based by-products. Method: A field experiment was laid out as a randomized complete block design with six treatments: the control plot without urea application (C), urea alone (U), urea + neem (UN), urea + mahua (UM), urea + sesame (US), and urea + tamarind (UT). Soil and plant samples were collected at three, five, seven, and nine weeks after broadcasting, that is, at the end of the vegetative growth stage. Results: Rice plants receiving UN had a higher shoot dry weight, shoot N concentration, and shoot N content compared to other treatments (P<0.05). After nine weeks of growth, the NUE of UN and UM was 0.093 and 0.091 g mg⁻¹, respectively, while that of U was 0.078 g mg⁻¹ (P<0.05). Soil N concentration was similar among treatments (P>0.05), except for lower soil N in the control (P<0.05). Conclusion: The use of soil amendments, particularly neem seed cake, shows strong potential for improving the growth and NUE of rice cultivated in RBE soil. Highlights · Seedcakes are by-products of agriculture industry · Those may use to improve fertilizer-use efficiency · Nitrogen use efficiency (NUE) and growth of rice were improved with seedcakes · NUE decreased in the order of neem>mahua>seseme>tamarind