[Effect of swine manure application on nitrate leaching in winter wheat field in the Yellow River irrigation area of Ningxia, China].

ABSTRACT

The effect of swine manure application on nitrate nitrogen leaching was investigated in the Yellow River irrigation area of Ningxia. The field experiment was conducted with 3 Treatments Traditional fertilization 225 kg N kg x hm(-2) without swine manure (CK), traditional fertilization with swine manure 4500 kg x hm(-2) (T1) and traditional fertilization with swine manure 9000 kg x hm(-2) (T2). Nitrate nitrogen leaching rates were measured for 30, 60, 90 cm depth soil layers with a resin core absorption method. The results indicated that the nitrate leaching losses of T1 and T2 treatments ranged from 9.33 to 14.04 kg x hm(-2) (pure nitrogen), which accounted for 4.2%-6.2% of applied nitrogen fertilizer. Compared to CK, the nitrate leaching losses of T1 and T2 increased by 2.6% and 2.1% at 30 cm depth, increased by 1.5% and decreased by 1.3% at 60 cm depth, decreased by 8.7% and increased by 4.0% at 90 cm depth, respectively. The difference did not reach statistical significance among CK and T1 and T2 in nitrate leaching loss at 30, 60 and 90 cm depths. However, there was a declining trend of nitrate leaching at deep soil layers of treatments. The key period of nitrate leaching loss was from spring reviving to early filling stage, which had a higher daily leaching loss than the average of the whole growth period, and accounted for 58.7%-75.3% of total leaching loss. Compared with CK, the yields of T1 and T2 increased by 9.3% and 12.5%, respectively.