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2008—2012年间,对分布于粤中、粤北和粤西的增城、清远和高州三个稻田试验点进行了连续5年的径流养分定点监测试验,研究当地农户常规施肥模式下稻田氮素养分的径流流失特征及其潜在环境风险。径流监测结果表明,三个试验点的稻田径流事件主要发生在早稻季节。增城、清远和高州试验点施肥处理铵态氮浓度分别为0.05~25.05、0.02~19.83 mg·L-1和0.02~55.4 mg·L-1,总氮浓度分别为0.33~36.51、0.46~21.01 mg·L-1和0.49~61.96 mg·L-1。结果显示,施肥明显增加径流水铵态氮和总氮含量,施氮后10 d内径流水铵态氮和总氮浓度均高于地表水Ⅴ类水标准(2.0 mg·L-1),具有一定的环境污染风险;施氮对径流水硝态氮浓度具有一定影响,三个试验点径流水硝态氮浓度均在10 mg·L-1的地表水标准限值内;稻田氮年流失负荷表现出时空差异性大的特点,增城、清远和高州试验点施肥处理总氮年流失负荷分别为24.31~53.68 kg·hm-2、8.71~23.76 kg·hm-2和13.32~88.16 kg·hm-2,相应氮流失系数为1.4%~3.9%、0.1%~5.5%和0.9%~21.6%。不同稻季总氮流失分析显示,53%~86%的总氮流失负荷发生在早稻季,与本地区降雨时间分布有直接关系。
During 2008-2012, five consecutive years of runoff nutrient site-specific monitoring tests were conducted on three paddy field sites in Zengcheng, Qingyuan and Gaozhou in Guangdong, northern Guangdong and western Guangdong to investigate the effect of conventional nitrogen fertilization Runoff loss and its potential environmental risk. The results of runoff monitoring show that the runoff events at the three sites mainly occurred in the early rice season. The concentrations of ammonium nitrogen in fertilization treatments of Zengcheng, Qingyuan and Gaozhou were 0.05-25.05,0.02-19.83 mg · L-1 and 0.02-55.4 mg · L-1, respectively, and the total nitrogen concentrations were 0.33-36.51,0.46-21.01 mg · L-1 and 0.49 ~ 61.96 mg · L-1. The results showed that fertilization significantly increased the contents of ammonium nitrogen and total nitrogen in runoff water. The concentrations of ammonium nitrogen and total nitrogen in runoff water were both higher than those of Grade V water (2.0 mg · L-1) within 10 days after nitrogen application. The nitrate nitrogen concentration in runoff water at three experimental sites is within the standard limit of surface water of 10 mg · L-1. The nitrogen loss load in paddy field The results showed that the total annual nitrogen loss from fertilizer application in Zengcheng, Qingyuan and Gaozhou was 24.31 ~ 53.68 kg · hm -2, 8.71 ~ 23.76 kg · hm -2 and 13.32 ~ 88.16 kg · hm -2 , The corresponding nitrogen loss coefficient of 1.4% to 3.9%, 0.1% to 5.5% and 0.9% to 21.6%. The analysis of total nitrogen loss in different rice season showed that 53% ~ 86% of the total nitrogen loss occurred in the early rice season, which is directly related to the rainfall time distribution in this region.