不同用量猪粪对红壤花生坡地水土流失和磷素流失的影响

通过田间径流微区定位试验,以中亚热带3种典型母质(花岗岩、红砂岩、红黏土)发育红壤花生坡地为研究对象,以当地常规化肥用量处理为对照,连续3年研究了在常规化肥用量减半条件下配施6个不同用量腐熟猪粪(猪粪含有0,0.5,1,2,4,8倍的对照处理磷用量)对红壤花生坡地水土流失和磷素流失的影响,以期为典型红壤地区合理施用猪粪提供科学依据。结果表明:化肥减半配施猪粪处理能有效降低红壤坡地的产流产沙,但随着猪粪用量的增加,径流水和泥沙磷含量均呈线性增加,环境风险增大。径流量和泥沙量均为花岗岩红壤红砂岩红壤红黏土红壤。配施3 500kg/(hm~2·a)猪粪,花岗岩红壤的径流量减少了28.0%、泥沙量减少了6.3%,红砂岩红壤的径流量减少了23.2%、泥沙量减少了37.1%;而配施7 000kg/(hm~2·a)猪粪,红黏土红壤的径流量减少了40.7%,泥沙量减少了12.8%。当花岗岩红壤、红砂岩红壤、红黏土红壤的猪粪用量分别达到14 000,28 000,28 000kg/(hm~2·a)时,径流水总磷平均含量超过地表水环境质量标准V类限值。径流水总磷含量为花岗岩红壤红黏土红壤红砂岩红壤,而泥沙总磷含量则为红黏土红壤花岗岩红壤红砂岩红壤。在减半化肥用量条件下花岗岩红壤和红砂岩红壤配施与常规化肥处理等磷量P含量40kg/(hm~2·a)]的猪粪、红黏土红壤配施2倍常规化肥处理磷含量P含量80kg/(hm~2·a)]的猪粪,可有效减少水土流失,且3年内不会增加磷素流失风险。

Effects of Different Amounts of Pig Manure on Water and Soil Erosion and Phosphorus Loss of Peanut-grown Sloping Lands in Red Soils

In order to provide scientific basis for rational application of pig manure as an organic fertilizer in typical red soil sloping lands,a field runoff micro location test in peanut-grown red soils that developed from three typical parent materials (granite,red sandstone and red clay) was conducted for three consecutive years to monitor the effects of different pig manure amounts on water and soil loss and phosphorus loss in red soils in mid-subtropical region of China.The treatments included six application rates of pig manure (phosphorus content was 0,0.5,1,2,4 and 8 times that of the control) that combined with half amount of local conventional chemical fertilizers,and the application of conventional chemical fertilizers alone was taken as the control.The results showed that runoff and sediment were obviously reduced by the application of pig manure,but the phosphorus content in runoff and sediment increased linearly with the increasing of pig manure application rate,and this suggested a growing environmental risk.Runoff and sediment volume of the three red soils listed in the order of granite ＞ red sandstone ＞ red clay.When the pig manure application rate was 3 500 kg/(hm2 · a),runoff and sediment reduced by 28.0％ and 6.3％,respectively,in the red soil developed from granite,and the above two parameters reduced by 23.2％ and 37.1％,respectively,in the red soil developed from red sandstone.When the pig manure application rate was 7 000 kg/(hm2 · a),runoff and sediment reduced by 40.7％ and 12.8％ respectively in the red soil developed from red clay.When the pig manure application rates were 14 000,28 000 and 28 000 kg/(hm2 · a) for red soils from granite,red sandstone and red clay,respectively,the average total phosphorus content in runoff exceeded the standard value of Environmental Quality Standards for Surface Water of Class V.Total phosphorus content in runoff of the three kinds of red soil listed in the order of granite ＞ red clay ＞ red sandstone,and total phosphorus content in sediment of the three red soils listed in the order of red clay ＞ granite ＞ red sandstone.Under the condition of halving the conventional amount of chemical fertilizer,applying pig manure at the rate of 40 kg P/(hm2 · a) for soils developed from granite and red sandstone,and at the rate of 80 kg P/(hm2 · a) for the soil developed from red clay,could effectively reduce water and soil loss without increasing the risk of phosphorus loss over 3 years.