Synergistic Effects of Green Manuring and Nitrogen Fertilization on Soil Fertility and Grain Quality of Basmati Rice

Background: The integration of green manuring and nitrogen fertilization is a sustainable approach to enhance soil fertility and improve crop quality. Specifically, in crops like Basmati rice, these practices are known to influence critical parameters such as protein content and the availability of essential nutrients like nitrogen, phosphorus and potassium. This study aims to evaluate the effects of various green manuring crops and nitrogen application levels on both soil nutrient status and grain quality of Basmati rice. Methods: The experiment was conducted during the 2023 kharif season at the Agricultural Research Farm of Lovely Professional University, Phagwara, Punjab, using a split-plot design. Four main plots were used: M0 (Control, no green manuring), M1 (Sesbania aculeata), M2 (Crotalaria juncea) and M3 (Vigna unguiculata), along with four nitrogen levels as sub-plots: N1 (0 kg ha-1), N2 (15 kg ha-1), N3 (30 kg ha-1) and N4 (45 kg ha-1). Key parameters such as nitrogen, phosphorus and potassium availability in the soil, alongside protein, nitrogen content in the rice grains, were assessed to figure out the impact of these treatments. Result: The application of green manures, particularly in Sesbania aculeata (M1), resulted in significant improvements in both the protein content of Basmati rice grains and the availability of essential nutrients in the soil. The treatments involving Vigna unguiculata (M3) and Crotalaria juncea (M2) also had positive effects, through to a lesser degree. Among the nitrogen levels, the highest protein content and nutrient availability were observed at 45 kg ha-1 nitrogen application followed by 30 kg ha-1 (N3), 15 kg ha-1 (N2), whereas the control treatment with 0 kg ha-1 (N1), with no nutrient input, exhibited the lowest values. These findings underline the critical role of integrating green manuring and nitrogen fertilization to enhance both soil fertility and basmati rice quality.