摘要
为了给农田降雨形成的前期高浓度N、P排水径流拦蓄利用从而减少受纳水体污染提供依据,采用小区实验方法,研究了油菜不同生长期植被覆盖度0、22%、49%、79%和100%时,恒定降雨强度4 mm/h条件下,农田排水的变化特征。结果表明:①随着植被覆盖度增加农田初始排水时间明显延迟,同时排水前期20 min排出的流量也随着植被覆盖度的增加而下降。②随着植被盖度的增加,农田排水中各形态N素浓度逐渐增加。③随着植被覆盖度的增加,农田排水中P的浓度随形态不同呈现不同的变化趋势。可溶性磷DP浓度呈上升趋势;PP和TP的平均浓度随着植被覆盖度的增加呈下降趋势。这说明地面覆盖植被可以有效延长农田排水时间,减少农田排水前期的流量,有效减少农田水肥流失。所以增加植被的覆盖度是减少水肥流失的有效方法之一。地面覆盖植被也可以有效减少农田排水中P素的浓度,但无法减少农田排水中N素的浓度,因此在北亚热带湿润气候区的砂壤土区,通过增加植被覆盖度减少农田排水中氮素浓度是不可行的,只有通过施肥方式的改变来实现。
In order to provide the basis for the high concentration N and P drainage runoff retention and utilization in the early stage of farmland rainfall to reduce the pollution of receiving water body,the change characteristics of farmland drainage under the condition of constant rainfall intensity of 4mm/h are studied under the condition of vegetation coverage of 0,22%,49%,79%and 100%in different growth periods of rape.The results show that:①with the increase in vegetation coverage,the initial drainage time of farmland is obviously delayed,and the discharge in the early 20 minutes of drainage also decreases with the increase in vegetation coverage.②With the increase in vegetation coverage,the concentrations of n elements in farmland drainage gradually increased.③With the increase in vegetation coverage,the concentration of P in farmland drainage showed different trends with different forms.The concentrations of DP and PP decreased with the increase in vegetation coverage.This shows that the ground cover vegetation can effectively extend the drainage time of farmland,reduce the flow in the early stage of farmland drainage,and effectively reduce the loss of farmland water and fertilizer.Therefore,increasing vegetation coverage is one of the effective ways to reduce water and fertilizer loss.Ground cover vegetation can also effectively reduce the concentration of P in farmland drainage,but it cannot reduce the concentration of N in farmland drainage.Therefore,it is not feasible to increase vegetation coverage to reduce the concentration of N in farmland drainage in the sandy loam area in the humid climate area of the north subtropical zone,only through the change of fertilization method.
作者
陈平
熊朕豪
戴晓钰
CHEN Ping;XIONG Zhen-hao;DAI Xiao-yu(College of Hydraulic Science and Engineering, Yangzhou University, Yangzhou 225009, Jiangsu Province, China)
出处
《中国农村水利水电》
北大核心
2020年第12期62-66,共5页
China Rural Water and Hydropower
基金
国家自然基金项目(51279159)。
关键词
植被覆盖度
农田排水
氮素
磷素
水体污染
vegetation coverage
farmland drainage
nitrogen
phosphorus
pollution of water
