填闲作物消减蔬菜生产棚室土壤硝态氮潜力研究

为了明确填闲作物对棚室蔬菜土壤NO₃^--N的消减潜力, 揭示不同填闲作物消减土壤剖面累积NO₃^--N的特征, 并为探索阻控棚室蔬菜土壤氮素淋溶损失机制及预防地下水污染提供理论依据, 本研究以华北平原传统的棚室蔬菜轮作体系作为研究对象, 在蔬菜休闲期采用种植深根型填闲作物甜玉米、甜玉米+牛膝间作和白菊花的田间原位修复技术。结果表明:甜玉米和甜玉米+牛膝处理的总含氮量和吸氮量较高, 分别为20.11、19.62 t·hm^-2和240.34、287.56 kg·hm^-2, 显著高于白菊花的5.81 t·hm^-2和57.13 kg·hm^-2;根长密度和根干重均随土壤剖面深度的加深而降低, 其中白菊花处理的根长密度与根干重在0~30 cm土层显著高于其他处理, 30 cm土层以下的根干重在各处理间无差异, 根长密度在数值上表现为间作甜玉米> 甜玉米> 白菊花> 间作牛膝;甜玉米对土壤剖面0~200 cm土层的消减量高达907.87 kg·hm^-2, 显著高于白菊花的891.16 kg·hm^-2和甜玉米+牛膝间作的879.93 kg·hm^-2。因此, 在蔬菜作物轮作的间歇期, 种植填闲作物能有效地降低硝态氮在土壤中的累积, 控制土壤剖面硝态氮向下淋溶。

The Potential Research of Catch Crop in Decrease Soil Nitrate Under Greenhouse Vegetable Production

In order to clarify the impact of catch crops on greenhouse vegetable soil nitrate, explore the mechanism of barrier and controll soil nitrogen leaching losses in greenhouse, and provide a theoretical basis for control nitrogen leaching and prevention of groundwater pollution, this study selected the traditional greenhouse vegetable rotation system in North China plain as research subjects, using field situ remediation technologies on deep-root planting catch crops in the vegetable fallow period by sweet corn, Achyranthes bidentata and white Chrysanthemum. The results showed that: nitrogen content and nitrogen uptake of sweet corn and sweet corn with Achyranthes bidentata intercropping were the highest, respectively 20.11 t·hm^-2, 19.62 t·hm^-2 and 240.34 kg·hm^-2, 287.56 kg·hm^-2, significantly higher than white Chrysanthemum. The density of root length and root dry weight decreased with soil depth in the profiles, root length density was demonstrated in order as: intercropping sweet corn> sweet corn> white Chrysanthemum> intercropping Achyranthes bidentata blume. The reduction of NO₃^--N of sweet corn reached 907.87 kg·hm^-2 in soil profile 0~200 cm, significantly higher than sweet corn and hyssop intercropping and white Chrysanthemums. In the interim period of vegetable crop rotation, planting catch crops could effectively reduce nitrate accumulation in the soil, control the soil profile nitrate leaching down.