The study aimed to evaluate the absorbility of N-NH4+ and TP in surface water and underground water on intensive paddy rice fields. An experiment site was set up in a paddy rice field where farmers could cultivate the same plants. The surface water mixed from three points on the study site, and underground water mixed from ten PVC tubes which put deep into the soil layer were collected 6 times through the paddy growth period. The results showed that in surface water, the concentration of N-NH4+ ranged from 1.114 mg/L to 4.215 mg/L, and TP ranged from 1.141 mg/L to 4.894 mg/L. N-NH4+ and TP varied with the fertilization cycle, increasing at the beginning of fertilization and then gradually decreasing. The concentration of N-NH4+ and TP in surface water is influenced by rainfall and evaporation. In underground water, N-NH4+ concentrations were ranged from 0.335 mg/L to 0.969 mg/L, and TP were ranged from 0.627 mg/L to 1.519 mg/L. The concentration of N-NH4+ and TP in underground water also varied with the fertilizer cycle but is more stable than in surface water, as permeability is influenced by several factors. The results show that paddy rice does not absorb all the fertilizer supplied, but some of the protein and phosphorus has been lost through surface water and penetrated into underground water which lowers the efficient of fertilizer process.
Tạp chí khoa học Trường Đại học Cần Thơ
Lầu 4, Nhà Điều Hành, Khu II, đường 3/2, P. Xuân Khánh, Q. Ninh Kiều, TP. Cần Thơ
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