根层调控对填闲作物消减设施蔬菜土壤累积硝态氮的影响

Effects of Root Layer Regulation on Reducing Soil Nitrate Accumulation by Catch Crops in Greenhouse Vegetable Production System

【目的】本研究以甜玉米(Zea mays L.)作为填闲作物,探讨根层调控措施对填闲作物消减土壤剖面累积NO3--N的影响。【方法】通过设置休闲、传统种植、土壤调理剂和秸秆还田4个处理,进行田间小区试验。【结果】在本试验条件下,施用土壤调理剂的甜玉米总生物量最大,其吸氮量与秸秆还田处理没有差异,但均明显高于传统种植;填闲季结束后0-100cm土层NO3--N消减量显著高于100-200cm土层,2种根层调理处理0-100cm土层残留NO3--N显著低于传统种植,100-200cm三者之间未表现差异,休闲导致土壤NO3--N高量残留且下移趋势严重;秸秆还田、土壤调理剂处理的30-60cm和60-100cm土层根长密度和根干重显著高于传统种植,根长密度与NO-3-N消减量极显著相关;土壤调理剂和秸秆还田处理在100cm处NO3--N淋失量分别比传统种植减少68.4%和52.6%。【结论】在硝态氮高累积的设施土壤上,填闲作物可以通过土壤调理剂和秸秆还田根层调理措施实现土体NO3--N的快速消减。

【Objective】 In a field plot experiment,three measures including conventional cultivation,root layer regulation agent and straw retention were used to reduce soil nitrate accumulation in catch crop of sweet corn （Zea mays L.）.【Method】 Four treatments of conventional cultivation,soil conditioner ,straw returning to soil and fallow field were designed.【Result】 At the condition of this experiment,the above ground biomass of the treatment of soil conditioner was the highest among the three treatments,and N uptake were not significantly different from that of the treatment of straw returning to soil,but N uptake of the treatments of soil conditioner and straw returning to soil was significantly higher than that of the treatment of conventional cultivation.NO3--N reduction of 0-100 cm soil layer was significantly higher than that of 100-200 cm.The residual NO3--N of 0-100 cm of the two kinds of root layer regulation measures was significantly lower than that of conventional cultivation,but the residual nitrate of 100-200 cm was similar among the three treatments.Fallow led to high residual NO3--N and serious leaching.Root density and root dry weight under the conditions of straw returning to soil and soil conditioner in 30-60 cm and 60-100 cm were higher than that of conventional cultivation,the root length density was very significantly correlated with NO3--N reduction.The NO3--N leakage under the conditions of soil conditioner and straw retention in 100 cm depth was 68.4% and 52.6% less than conventional cultivation respectively.【Conclusion】 In high NO3--N accumulation soil,the soil conditioner and straw returning to soil are effective measures to reduce NO3--N accumulation with catch crops planting.