番茄膜下滴灌下土壤水分及硝态氮运移规律试验研究

针对甘肃省石羊河流域农业灌溉水分利用率低，盲目施用氮肥造成环境污染的问题，以大田试验为基础，研究了3种膜下滴灌措施及沟灌对土壤水分和硝态氮运移的影响.研究结果表明，膜下滴灌下土壤水分主要分布于0～60 cm深度，与番茄根系所在层吻合度较高，有利于作物根系对土壤水分的吸收；滴灌条件下土壤中NO3-N含量随时间变化小，沟灌条件下土壤中NO3-N含量随时间变化大；土水势为-30 kPa滴灌措施下0～40 cm深度范围内NO3-N含量高，40 cm以下NO3-N含量低，土水势为-50 kPa、-20 kPa这两种滴灌措施下NO3-N随深度分布规律不明显；土水势为-30 kPa滴灌措施下对作物根系层NO3-N的吸收及防止NO3-N的深层流失效果最好.因此，采用土水势为-30 kPa的膜下滴灌灌溉措施，有利于提高土壤水分及肥料利用效率，可以减小氮肥对环境的污染.

英文摘要:

In view of the situation of the low agricultural irrigation water utilization rate and the problem of environmental pollution caused by blind application of nitrogen fertilizer，a field experiment was conducted to study on the effects of soil water content and nitrate nitrogen transport under three kinds of drip irrigation with plastic film and furrow irrigation in Shiyang River basin of Gansu province.The research results showed that soil water content was mainly distributed in 0-60 cm layer，which was in good agreement with the root layer of tomato under drip irrigation with plastic film.It was beneficial to the absorption of soil water content by tomato roots.The nitrate nitrogen content changed little over time in drip irrigation and the nitrate nitrogen content changed large over time under furrow irrigation.The nitrate nitrogen content was higher in the depth range of 0-40 cm under drip irrigation with the soil water potential of -30 kPa and the nitrate nitrogen content was lower below 40 cm.The distribution of nitrate nitrogen content was not obvious under drip irrigation with the soil water potential of -50 kPa and -20 kPa.The way of absorption of nitrate nitrogen in the crop root layer and preventing the deep loss of nitrate nitrogen were best under drip irrigation with the soil water potential of -30 kPa.Therefore，the irrigation practice of drip irrigation under plastic film with soil water potential of -30kPa can help improve soil water and fertilizer use efficiency，and also can reduce the environmental pollution caused by nitrogen fertilizer.

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