RESEARCH ON THE EFFECT OF P2O5 AND CaCO3 DOSAGE ON THE GROWTH AND YIELD OF RICE ON ACID SULFATE SOILS IN CAM PHUOC DONG COMMUNE, CAM RANH CITY, KHANH HOA PROVINCE

Abstract

Acid sulfate soils adversely affect soil chemistry and reduce rice yield. Therefore, in rice production on acid sulfate soils, it is necessary to have improvement measures to change soil chemistry to help increase rice yield. This study was conducted to evaluate the effects of P₂O₅ and CaCO₃ doses on rice growth and yield on acid sulfate soils in Cam Phuoc Dong commune, Cam Ranh city, Khanh Hoa province. The experiment was arranged in a completely randomized block design with 8 treatments and 3 replications. The results showed that different doses of P₂O₅ and CaCO₃ tested for rice production (Dai Thom 8) on acid sulfate soil in Cam Phuoc Dong commune, Cam Ranh city, Khanh Hoa province did not affect the growth period, plant height, effective number of flowers/m² and weight of 1,000 grains. However, it greatly affects the ability of rice roots to develop, increasing root length increased from 2.1 - 4.9 cm compared to control 1 and from 1.3 - 4.1 cm compared to control 2) helps plants absorb nutrients better, and the yield is higher than the control. The formula of (Base fertilizer (110 kg N + 80 kg K₂O + 1.5 tons organic microbial fertilizer)/ha) + 110 kg P₂O₅/ha + 1,000 kg CaCO₃) from sea snails/ha achieves the highest yield of 9.2 tons/ha, the total profit (29,790,000 VND) increased compared to control 1 (18,840,000 VND) and control 2 (18,055,000 VND) > 50% and profit margin reached 56%.