横坡垄作和秸秆覆盖对红壤坡耕地氮磷流失的影响

Effects of cross slope ridge cultivation and straw mulching on nitrogen and phosphorus loss in red soil slope farmland

为研究南方红壤坡耕地油菜-玉米轮作模式氮磷养分地表径流损失对不同耕作方式的响应机制,本文采用田间定位试验的方法,研究坡耕地顺坡垄作(CK)、横坡垄作(T1)、横坡垄作+秸秆覆盖(T2)、顺坡垄作+秸秆覆盖(T3)4个处理模式连续2 a对坡耕地氮磷养分地表径流损失的影响。结果表明:不同处理地表径流总量与氮磷流失总量均呈现出CK>T3>T1>T2,横坡垄作和秸秆覆盖处理均能有效降低坡耕地地表径流量和径流液中氮磷养分含量,其中T2处理对控制地表径流及氮磷损失的效果最好,较其他处理分别降低地表径流量、氮和磷流失总量24.46%~74.90%、39.60%~86.37%和36.84%~79.66%;坡耕地氮素流失以硝态氮为主,不同处理下径流液中全氮浓度与硝态氮浓度呈显著正相关关系。横坡垄作+秸秆覆盖对减少坡耕地土壤氮、磷素损失效果最好,观测期内横坡垄作+秸秆覆盖处理土壤全氮和全磷含量分别增加了19.42%和21.98%。研究表明,在南方红壤坡耕地上推广横坡垄作+秸秆覆盖的保护性耕作措施有利于降低氮磷径流损失风险、提高红壤坡耕地可持续生产能力。

To study the response mechanism of surface runoff loss of nitrogen(N)and phosphorus(P)nutrients during rapeseed and maize rotation using different tillage methods in red sloping farmland located in southern China,the field positioning test was used to examine the effects of slope ridge cultivation(CK),cross slope ridge cultivation(T1),cross slope ridge cultivation+straw mulching(T2),and along slope ridge cultivation+straw mulching(T3)on the surface runoff loss of N and P for two consecutive years.The total surface runoff of N and P with different treatments decreased in the order of CK>T3>T1>T2.T2 could effectively reduce the surface runoff of sloping farmland and N and P levels in the runoff.T2 had the best effect on controlling surface runoff and N and P.Compared with other treatments,the total loss of N and P in T2 decreased by 24.46%~74.90%,39.60%~86.37%and 36.84%~79.66%,respectively.The N loss of slope farmland was mainly nitrate nitrogen(NO_(3)^(-)-N).Total N concentration and NO_(3)^(-)-N concentrations in different treatments had a significant positive correlation.T2 had the best effects on diminishing the loss of soil N and P.During the observation period,total contents of soil N and P increased by 19.42% and 21.98% respectively. Therefore, promoting conservation tillage measures of T2 reduces the risk of N and P runoff loss and improves the sustainable production capacity on red soil slope farmland in southern China.