填闲作物替代有机肥对设施土壤氮磷淋洗的影响

Effects of Substitution of Catch Crops for Organic Manure on Nitrogen and Phosphorus Leaching in Greenhouse Soil

为控制设施蔬菜管理体系中有机肥用量、降低设施土壤氮磷负荷、减少设施氮磷面源污染风险,以研究区域农民习惯有机肥用量为对照处理(FP),农民习惯有机肥用量减施50%为有机肥减量处理(FP-M),在有机肥减量处理基础上,利用夏季揭棚休闲季种植饲草玉米(FP-M+C)、饲草高粱(FP-M+S)和草黑豆(FP-M+L),且在下茬蔬菜定植前将其原位还田作为填闲处理,采用原位收集淋洗液的方法,通过3 a田间定位试验,研究填闲作物替代有机肥对设施土壤氮磷淋洗量、有机质含量及其剖面硝态氮、有效磷含量和蔬菜产量的影响。结果表明,与农民习惯有机肥用量处理(FP)相比,有机肥减量(FP-M)及其填闲饲草玉米(FP-M+C)、饲草高粱(FP-M+S)和草黑豆处理(FP-M+L)对蔬菜产量无显著影响,FP-M+C和FP-M+S处理显著提高了0~40 cm土壤有机质含量;与FP处理相比,FP-M、FP-M+C、FP-M+S和FP-M+L处理在设施休闲季总氮淋洗量最高降幅分别为13.9%,59.5%,65.4%和54.5%,在蔬菜生长季最高降幅分别达38.3%,48.5%,39.0%和24.0%;与FP处理相比,FP-M、FP-M+C、FP-M+S和FP-M+L处理在设施休闲季总磷淋洗量最高降幅分别为42.3%,53.9%,45.4%和49.1%,在蔬菜生长季最高降幅达37.7%,33.8%,27.7%和26.3%;与FP处理相比,FP-M、FP-M+C、FP-M+S和FP-M+L处理显著降低了80~200 cm土层硝态氮(NO_(3)^(-)-N)和20~80 cm土层有效磷(Olsen-P)含量。利用设施休闲季种植填闲作物并将其原位还田,不仅能提升0~40 cm土层土壤有机质含量,起到替代有机肥效果,而且可降低土壤氮磷淋洗、减少设施蔬菜氮磷面源污染风险。

In order to control the amount of organic manure in the greenhouse vegetable management system,reduce the load of nitrogen and phosphorus in the greenhouse soil and reduce the risk of non-point source pollution of nitrogen and phosphorus in the greenhouse vegetable,a 3-year field experiment,was conducted,and a total of 5 treatments were set.They were the farmers′traditional amount of organic manure in this study area(FP,i.e.the control treatment),the amount of 50%of farmers′traditional amount of organic manure(FP-M,i.e organic manure reduction treatment),and catch crop planted in the fallow period on the basis of the FP-M treatment with forage maize,forage sorghum and legumes incorporation(FP-M+C,FP-M+S and FP-M+L,respectively).In FP-M+C,FP-M+S and FP-M+L treatment,the straw was returned in situ before vegetable transplanting.The leaching liquor was collected in situ,and nitrogen and phosphorus leaching amount,soil organic matter,NO 3--N,Olsen-P and vegetable yield were measured,to study the effect of substitution of catch crops for organic manure during the fallow period.The results showed that,there was no difference in vegetable yield between FP treatment and FP-M,FP-M+C,FP-M+S and FP-M+L treatment.However,FP-M+C and FP-M+S treatments had significantly higher organic matter content in 0-40 cm soil compare to FP treatment.Compared with FP treatment,the leaching amount of total nitrogen in the FP-M,FP-M+C,FP-M+S and FP-M+L treatment showed a significant decrease in the fallow period,and decreased by as much as 13.9%,59.5%,65.4%and 54.5%,respectively;in the vegetable growing period,and decreased by as much as 38.3%,48.5%,39.0%and 24.0%,respectively.Compared with FP treatment,the leaching amount of total phosphorus in the FP-M,FP-M+C,FP-M+S and FP-M+L treatment showed a significant decrease in the fallow period,and decreased by as much as 42.3%,53.9%,45.4%and 49.1%,respectively;in the vegetable growing period,and decreased by as much as 37.7%,33.8%,27.7%and 26.3%,respectively.The NO _(3)^(-)-N and Olsen-P contents soil profile of the FP-M,FP-M+C,FP-M+S and FP-M+L treatments were significantly decreased compared with FP treatment,in 80-200 cm and 20-80 cm,respectively.Therefore,that reducing 50%of the organic manure by farmers′practice and planting catch crops in the fallow period and returning the straw in situ before vegetable transplanting can increase organic matter content in 0-40 cm soil in the study area.Obviously,the organic manure can be substituted with catch crops.It reduces the risk of nitrogen and phosphorus pollution in greenhouse vegetable while decreasing nitrogen and phosphorus leaching.