蔬菜地氮磷径流流失量及其规律研究

The amounts of nitrogen and phosphorus losses from a vegetable field via runoff

为研究蔬菜生产过程中氮、磷随地表径流的流失量及流失方式和时间的分布,在常州市蔬菜主产区设立定位监测点,对蔬菜地的水分运动及氮、磷的输入和流失进行研究。结果表明:蔬菜地通过降雨和灌溉输入的氮为21.77 kg·hm^(-2),输入的磷为1.18 kg·hm^(-2)。通过径流水和径流水泥沙流失的氮、磷分别为28.91、3.10 kg·hm^(-2)。除去降雨和灌溉输入的氮、磷,试验期间蔬菜地氮、磷表观净排放量分别为7.15、1.93 kg·hm^(-2)。在氮、磷的流失方式方面,以径流水方式流失的氮、磷占绝对优势,分别占氮、磷总流失量的91.63%、62.63%。在氮、磷的流失时间方面,流失的主要月份是6月和7月,流失的氮、磷量分别占总流失量的72.54%、73.61%,且6月与7月的流失量相当。

To investigate the amounts of nitrogen and phosphorus losses via surface runoff during a vegetable production cycle and the distributions of the loss ways and times,an in-situ monitoring site was established in the main vegetable production area of Changzhou,China.The inputs and outputs of water,nitrogen,and phosphorus in the vegetable field were monitored.The results indicate that the inputs of nitrogen and phosphorus via rainfall and irrigation during the experiment period were 21.77 kg·hm^(-2) and 1.18 kg·hm^(-2),respectively.The outputs of nitrogen and phosphorus via runoff water and runoff sediment were 28.91 kg·hm^(-2) and 3.10 kg·hm^(-2),respectively.Therefore,the net losses of nitrogen and phosphorus from the vegetable field(deduction of nitrogen and phosphorus inputs from the outputs)were 7.15 kg·hm^(-2) and 1.93 kg·hm^(-2),respectively.Regarding the ways of nitrogen and phosphorus outputs,runoff water was predominant.The amounts of nitrogen and phosphorus outputs via runoff water accounted for 91.63%and 62.63%of the total nitrogen and phosphorus outputs,respectively.Nitrogen and phosphorus outputs were predominant during June and July.The amounts of nitrogen and phosphorus outputs in June and July accounted for 72.54%and 73.61%of total nitrogen and phosphorus outputs,respectively,and the output amounts in June were similar to those in July.