稻田田面水氮磷素动态特征研究

为了合理运筹施肥，防控农业面源污染，通过独立排灌系统的田间试验，设计了6个不同氮肥水平，研究了施肥后水稻田田面水氮素和磷素的动态变化特征。结果表明，施肥后田面水中的总氮(TN)、NH4+-N和NO3--N浓度随着施肥量的增加而增加，随着时间的推移三者的浓度呈现上升后下降的趋势，7天后趋于稳定；施入基肥后，NH4+-N浓度在第2天达到峰值后迅速下降，第3天即下降到峰值的25.69%~36.80%；NO3--N浓度远远低于NH4+-N浓度，3个施肥时期峰值分别为8.87 mg/L、1.91 mg/L和1.50 mg/L，且出现在施肥后第3~5天。田面水NH4+-N/TN随着施氮量的增加而增加，且在施肥后第2~3天达到峰值后下降。不同施氮量，相同施磷量处理条件下，田面水中TP浓度随着施氮量增加而增加；施肥后第1天，田面水中TP浓度达到峰值3次施肥后TP浓度峰值逐渐降低。

Study on the Variations of Nitrogen and Phosphorus in Surface Water Body of Paddy Field

In order to look for the best fertilization management for controlling N and P loss availably, a field experiment based on independent irrigation system was conducted to study the dynamic characteristics of nitrogen and phosphorus in surface water of paddy field, which applied with six different levels of nitrogen fertilizer. The results showed that the high amounts of fertilizer will enhance the concentration of total nitrogen (TN), ammonium nitrogen (NH4+-N) and nitrate nitrogen (NO3--N) in the surface water. The content of TN, NH4+-N and NO3--N increased at the beginning and then decreased as the time past, finally approached a relatively stable level after a week; NH4+-N in the surface water reached the peak on the following day after fertilizer application, and rapidly decreased to 25.69%-36.80% of the maximum on the third day. The concentration of NO3--N in surface water was lower than that of NH4+-N, and the peak value which appeared during the 3th day to 5th day was 8.87 mg/L, 1.91 mg/L and 1.50 mg/L, respectively. NH4+-N/TN was increased with the amount of nitrogen fertilizer and peaked 2-3 days after fertilizer applied. With the same level of P fertilization, the concentration of TP was increased with the amount of N fertilization. The concentration of TP peaked on the first day after fertilized and decreased afterwards after three times of fertilization.