采用田间试验方法,研究了太湖地区旱地氮磷向水体排放的年负荷。结果表明,太湖流域典型旱地氮磷向水体迁移的年负荷分别为12.66,4.05 kg/hm2,分别约占年施肥量的5.6%和4.1%。示范区内旱地氮磷向水体迁移的年总量为3.86 t和1.24 t。NO3-—N和PN是氮流失的主要形式,应重点控制NO3-—N和PN的流失;而PP是磷流失的主要形式,占总磷的76%,是控制的重点。氮磷向水体迁移具有明显的季节特征,夏季和秋季为氮磷高负荷季节,6—11月占全年氮磷输出总量的83.4%和79.8%。在当前的非点源污染治理中,应采取有力措施控制农田养分流失。
The released nit rogen and phosphorus by surface runoff from uplands in the Taihu Lake catchment were investigated in a case study. Results showed that each year , about 12.66 kg/hm2 of nit rogen and 4.05 kg/ hm2 of phosphorus from the uplands in the catchment were discharged into water body , accounting for 5.6% and 4.1% of annual fertilization , respectively. About 3.86 t of total nitrogen and 1.24 t of total phosphorus f rom the uplands in the demonst ration area were discharged into water body per year. Nit rate —N and PN were the main component part of N loss , which indicates that controlling Nit rate —N and PN loss is the key to controlling non-point pollu-tion. PP was the main component part of phosphorus loss , accounting for 76 % of total phosphorus. Nitrogen and phosphorus loss were obviously characterized by seasonal variation. Summer and autumn were the high load sea- sons , in which nit rogen and phosphorus loss fromJune to November accounted for 83.35 % and 79.79 %of total loads , respectively.We should pay great attention to controlling nutrient loss during farming for non-point pollution control.