伊犁河谷天然草地土壤水库-小水窖联合集雨技术与应用

Due to factors such as overgrazing and climate change, Xinjiang is facing serious grassland degradation and soil water loss problems. Grassland restoration as well as soil and water conservation could be reached simultaneously by using rainwater harvesting to adjust and reuse surface runoff. Currently, rainwater harvesting researches in natural grassland are still less, while studies of this technology in Xinjiang are rare. This project will take the rain-rich Piliqing river watershed of Ili Valley as the study area, and use two experiment approaches, i.e., natural rainfall observation and field simulated rainfall. Through analyzing characteristics of hillslope runoff generation under different underlying surface conditions, we plan to determine whether improving infiltration (rainwater harvesting by soil water reservoir) or collecting surface runoff (rainwater harvesting by small water cellar) should be preferentially used for hillslopes with various site conditions. This study will compare the ecological benefits of three soil water reservoir enlarging measurements, including sawdust coverage, level trench, and harrowing. The effects of long-term supplemental irrigation with harvested water by small water cellar on grassland restoration and improvement of soil properties will be monitored. In order to check the suitability of rainwater harvesting in the study area, the best joint rainwater harvesting technology using soil water reservoir and small water cellar should be selected and demonstrated at hillslope scale. We hope to obtain creative results in research fields such as high-efficient utilization of rainwater resource in drylands, soil and water loss control, and grassland degradation prevention. Therefore, this project could promote the upgrading and development of rainwater harvesting agriculture, grass-based animal husbandry, as well as soil and water conservation industry.

超载过牧、气候变化等原因导致新疆面临严重的草地退化与水土流失问题。使用集雨技术，通过调控及再利用地表径流，有望同时实现草地恢复与水土保持。目前，有关天然草地集雨技术的研究较少，在新疆该技术的研究也相对薄弱。本研究以降雨丰沛的伊犁河谷匹里青河流域为研究区，采用自然降雨观测和野外人工模拟降雨两种实验手段，通过分析不同下垫面条件坡面产流的特点，研究各草被立地条件的坡面在集雨时，适合采用增加入渗(土壤水库集雨)还是适合采用收集地表径流(小水窖集雨)。本研究将比较木屑覆盖、水平沟以及松耙三种土壤水库扩蓄增容措施的生态效益；监测小水窖长期集雨补灌对草被恢复和改善土壤性质的影响；筛选适宜的土壤水库-小水窖联合集雨技术，并在坡面尺度示范，以验证该技术在研究区的适用性。本研究预期在干旱区雨水资源高效利用、水土流失阻控、草地退化防治等方面取得创新性成果，推动我国集雨农业、草牧业和水土保持产业的升级发展。

超载过牧、气候变化等原因导致新疆面临严重的草地退化与水土流失问题。使用集雨技术，通过调控及再利用地表径流，有望同时实现草地恢复与水土保持。目前，有关天然草地集雨技术的研究较少，在新疆该技术的研究也相对薄弱。.本项目主要研究内容有：(1)探讨地形、土壤与草被之间的耦合关系；研究下垫面因素对降雨特征(雨强、降雨量)与径流量关系的影响。(2)以不干扰的草地为对照，比较枯草覆盖、水平沟、增渗孔等三种草地管理措施对减流减沙、土壤储水量和草地恢复的影响。(3)研究小水窖集雨补灌及草地管理对草被恢复和土壤性质的影响。(4)筛选适宜的土壤水库-小水窖联合集雨技术，并在坡面尺度示范，以验证该技术在研究区的适用性。.取得的重要结果有：(1)坡度、有效土层厚度、年均降雨量、砾石覆盖度是影响草地覆盖度的主要因素。(2)伊犁河谷降雨量>4.0mm且最大30min雨强>3.6mm/h时，可引发侵蚀；水土流失主要由短历时、高强度的偶然性暴雨导致；枯草覆盖在棕红土草地减流效果最好，水平沟在灰钙土草地减流效果最好。(3)水平沟能在雨后最大化提高土壤含水量，枯草覆盖能延滞雨后土壤含水量的下降。三种坡面措施均能显著促进草被恢复生长，其中枯草覆盖效果最好。(4)水平沟处理显著提高了土壤总孔隙度、田间持水量、及最大持水量，而枯草覆盖的效果不明显。(5)塑料布和坡面的产流阈值分别是0.1mm和6.0mm，每375m2的集雨坡面需要1m3的储水窖容积。库鲁斯台河流域40%的面积有较高的径流利用潜力。谷坊+植物措施适用于侵蚀沟集雨。.本项目揭示了土体构型(厚度、砾石含量)、坡度与草地退化之间的关系，发现伊犁河谷夏季短时强降雨是引发水土流失的重要条件。水平沟等坡面人为管理措施不仅能减流抑沙、调控土壤水分，还可以改善土壤孔隙及持水性能，进而有利于草被恢复。坡面塑料布集雨及沟道谷坊集雨也能促进植被恢复。本研究提出的草地集雨设计方案对牧草地管理及水土流失防治有借鉴意义，有望缓解洪水灾害、草地退化等生态问题。