Assessment of native nutrient supplying capacity of soil for site specific nutrient management to increase early rice (Oryza sativa L.) productivity in Morang, Nepal

System of Rice Intensification (SRI) was evaluated for the variety Hardinath-1 under nutrient omission treatment (−N, -P, -K, -Zn, -B and +All) through field experiment conducted in randomized complete block design (RCBD) with six treatments and four replications during spring season of 2018 at agriculture field of Sailaja Acharya Memorial Polytechnic, Siswani Jahada, Morang. The highest grain (4.62 t/ha) and straw yields (7.75 t/ha) were obtained from the fully fertilized plot (i. e.+All treatments) which might be due to application of all of the major nutrients in sufficient amount (i. e. 150: 45: 45: 20: 5 N: P: K: Zn: B kg/ha) along with following SRI principles. Omitting the major nutrients showed significantly lesser growth and yield parameters of rice. The P omitted treatment showed significantly higher sterility percentage (23.74) as P had major role on grain filling and development. The nutrients omission treatment also produced significant effect on plant uptake of N, P, K, Zn and B. Significantly higher uptake of N (76.73 kg/ha), P (38.28 kg/ha), K (52.41 kg/ha), Zn (0.086 kg/ha) and B (0.022 kg/ha) was obtained from fully fertilized plot. Based on plant uptake of nutrient on omission plot, native N, P, K, Zn and B supplying capacity of the soil at research plot was found to be 23.51, 25.94, 37.59, 0.075 and 0.019 kg/ha, respectively. The recovery efficiency of applied N, P, K, Zn and B was found to be 35.48, 5.7, 32.93, 0.06 and 0.06%, respectively. Owing to native nutrient supplying capacity of the soil at the research site, N, P, K, Zn and B required to obtain the target yield of 5 t/ha was found 139.5 kg N/ha, 45.22 kg P/ha, 50.8 kg K/ha, 12.1 kg Zn/ha and 2.6 kg B/ha, respectively.