摘要
摘要:设施菜地因大水大肥管理方式导致的氮素淋失已成为当前关注焦点。探寻氮素淋失阻控技术需要首先探明土壤中NO₃^--N的运移和淋失过程, 找到淋失阻控的关键点, 从而实现蔬菜栽培高产量低环境成本。本研究以京郊设施菜地黄瓜-番茄轮作系统为研究对象, 通过田间试验获取土壤温度、湿度、NO₃^--N含量等数据, 对反硝化-分解(DNDC)模型进行参数校验, 并以农民常规种植模式为基线情景, 设置改变土壤基础性质、灌溉量、施氮量等不同情景, 运用DNDC模型对设施菜地系统土壤氮素运移及淋溶损失进行定量评价。结果表明:经验证后的DNDC模型能够较好地模拟蔬菜产量、5 cm土壤温度和0~20 cm土壤孔隙含水率变化以及NO₃^--N的迁移过程, 是模拟和评价氮素运移和损失的有效工具。模拟不同情景表明, 设施菜地0~60 cm土壤NO₃^--N累积主要受灌溉水量和氮肥施入量的影响, 此外土壤pH和土壤有机碳的变化也是影响NO₃^--N运移的重要因子。节水节肥是设施菜地氮素淋失减量的最有效方法, 相比常规措施, 同时减少20%灌溉量和20%施氮量可明显降低59.04%的NO₃^--N淋失量。同时, 在节水节肥的基础上改变灌溉方式并提高20%土壤有机碳含量, 在保证蔬菜产量的前提下, 能够进一步降低69.04%的NO₃^--N淋失量。可见, DNDC模型为设施菜地NO₃^--N淋失评价和阻控提供了一个较好的解决方案。在当前重点关注减氮节水等管理措施的同时, 提高土壤本身的质量, 不失为一种更有效的减少设施菜地氮素淋失的途径。
关键词:设施菜地/
氮淋失/
水氮控制/
土壤有机碳/
DNDC模型
Abstract:Nitrogen (N) leaching is caused by the mismanagement of water and fertilizer in greenhouse vegetable fields. Understanding N movement and leaching process is important for achieving high crop yields at low environmental costs. A field experiment was conducted for a greenhouse cucumber–tomato rotation system in the suburbs of Beijing, China. The DeNitrification-DeComposition (DNDC) model was used to quantitatively evaluate the soil N transport and leaching loss in the facility vegetable field after considering factors obtained from field experiments, such as soil temperature, humidity, and nitrate nitrogen (NO₃^--N) content. Conventional practices were selected as the baseline scenario, and the modeled scenarios, such as changes in soil properties, irrigation, and N application, were set according to the baseline. The results showed that the DNDC model can better simulate the vegetable yield, 5 cm soil temperature, 0–20 cm soil water-filled pore space, and NO₃^--N migration process, indicating that it is an effective tool for simulating and evaluating N transport and leaching in vegetable field soil. The modeling scenarios showed that the accumulation of NO₃^--N in the 0–60 cm soil was primarily affected by the irrigation amount and N application; soil pH and organic carbon were also important factors affecting NO₃^--N migration. Increasing irrigation amount significantly accelerated the downward movement of NO₃^--N, and increasing N application promoted the accumulation of NO₃^--N at the surface and a depth of 20 cm. Increasing soil pH lessened NO₃^--N surface accumulation; and to a certain extent, increasing soil organic carbon delayed the downward movement of NO₃^--N.Controlling water and fertilizer was the most effective method for mitigating N leaching. Compared with conventional measures, reducing irrigation and N application simultaneously by 20% significantly reduced NO₃^--N leaching by 59.04%. Changing irrigation method and increasing soil organic carbon content by 20% (to save water and fertilizer) further reduced NO₃^--N leaching by 69.04%. The DNDC model is a useful method for evaluating and controlling NO₃^--N leaching in vegetable fields. Changing management practices, such as N and water amounts as the soil quality improves, may be an effective way to reduce N leaching in vegetable fields.
Key words:Facility vegetable field/
Nitrogen leaching/
Water and nitrogen control/
Soil organic carbon/
DNDC model



PDF全文下载地址:

http://www.ecoagri.ac.cn/article/exportPdf?id=c9dc6815-789b-41da-96ec-058e76821144