摘要
以沂蒙山区典型的坡耕地为例,通过2种雨强(40 mm.h-1和70 mm.h-1)下的野外原位模拟降雨试验,分析了横坡与顺坡垄作地表径流溶解态无机氮Inorganic-N(NO 3--N、NH 4+-N)以及溶解态磷(DP)的输出特征,并利用Inorganic-N/DP、NO 3--N/DP和NH 4+-N/DP等3种氮磷比对2种耕作方式径流的富营养化风险进行比较.结果表明,与传统顺坡垄作相比,相同雨强下,横坡垄作径流中DP浓度增加,而不同形态Inorganic-N浓度的变化不一致;横坡垄作可有效地控制径流并减少径流Inorganic-N和DP的输出率;雨强增大时,横坡较顺坡垄作控制径流的效果增强,其径流Inorganic-N和DP的输出量也大幅度减少,其中,40 mm.h-1雨强下可分别减少43%与5%,70 mm.h-1雨强下分别为68%与55%.较高的Inorganic-N/DP和NO 3--N/DP率表明,2种耕作方式下的径流均存在一定程度的富营养化风险,且风险水平在降雨过程中呈增加趋势,但横坡较顺坡垄作不仅能够明显地延缓这一增加趋势,而且可降低径流的富营养化风险水平,从而相应减轻坡耕地径流对于受纳水体富营养化过程的影响.
Field in-situ rainfall simulation tests with two rainfall intensities（40 mm·h^-1 and 70 mm·h^-1）,which were conducted at typical sloping cropland in Yimeng mountainous area,were designed to analyze the output characteristics of dissolved inorganic nitrogen,Inorganic-N（NO 3--N,NH 4＋-N） and dissolved phosphorus（DP） in runoff water,as well as to compare the eutrophication risk in this water by calculating three ratios of Inorganic-N/DP,NO 3--N/DP,and NH 4＋-N/DP,respectively,in cross ridge and longitudinal ridge tillage methods.Results showed that,under the same rainfall intensity,the DP level in runoff water was higher in cross ridge than longitudinal ridge,while the change of different Inorganic-N level between the two tillage methods were not consistent.Cross ridge could effectively reduce runoff and the output rate of Inorganic-N and DP when compared to the longitudinal ridge tillage,which would be more outstanding with the increases of rainfall intensities.The losses of Inorganic-N and DP in runoff water were 43% and 5% less,respectively,in cross ridge than longitudinal ridge at the 40 mm·h^-1 rainfall intensity,and were 68% and 55%,respectively,at 70 mm·h^-1.The higher Inorganic-N/DP and NO 3--N/DP ratios suggest that runoff water from either cross ridge or longitudinal ridge tillage have a certain eutrophication risk,which present an increasing trend during the precipitation-runoff process.Compared with longitudinal ridge,cross ridge can not only hinder the increasing trend of eutrophication risk,but also can significantly lower it,and thus effectively reduce the effect of sloping cropland runoff on the eutrophication processes of receiving waters.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2011年第2期428-436,共9页
Environmental Science
基金
教育部新世纪优秀人才支持计划项目(NCET-08-0877)
山东省中青年科学家奖励基金项目(2007BS08025)
山东省自然科学基金项目(Y2008E23)
关键词
横坡垄作
顺坡垄作
径流
氮磷输出
富营养化风险
cross ridge
longitudinal ridge
runoff water
output of nitrogen and phosphorus
eutrophication risk
