Background: To determine the effectiveness of controlled slow-dissolving NPK fertilizers with NPK 19-16-18 to improve soil nutrients on rice (Oryza sativa L.).
Methods: The field experiment was on saline-affected acid sulfate soil in Hau Giang province, Viet Nam, in the Winter-Spring rice crop 2018-2019. The experiment consisted of 2 treatments, corresponding to 2 formulas and 2 types of fertilizers, including new generation fertilizer application with the formula 50N-40P2 05 -30K20 kg/ha; and conventional fertilizers of 126N-88 P205-23K20. Each formula with 3 replications and each repetition is 1,000 m2
Result: The NPK-CFR fertilizers and urea humate help improve proper soil nutrients and total micro-organisms. In which; (i) when compared to the farmer’s control field, the rice growth and yield were comparable and did not differ significantly (5.68 tons/ha in the farmer’s control field and 5.85 tons/ha in the experimental field). (ii) However, when compared to the farmer’s field, the amount of fertilizer in the experimental field is reduced by more than 50%. Besides, the economic efficiency of NPK-CFR and Urea humate is higher than in farmers’ fields, from 1 to 8.6%. The total profit is higher than farmers' fields. The NPK-CFR fertilizers and urea humate can be used to replace traditional fertilizers.