砂姜黑土区保护性耕作对GSPAC水文过程及农业用水效率的影响研究

To improve agricultural water use efficiency (AWUE) is the key to realize water-saving for agriculture, also it is a powerful way to solve water shortage and food security problems, and achieve ecological rehablitation and regional sustainable development. In Huaibei plain, an important agricultural region in China, crops often are suffered from staggered drought and waterlogging because the temporal and spatial distribution of precipitation does not match with crop water requirement. More serious are the drought and waterlogging because of poor structure, heavy texture and low organic matter content of Shajiang black soil. conservation tillage can improve soil water retention, increase precipetation infilltration, the use of crop on groundwater and the soil fertility. In view of irrigation water shortage, shallow watertable,lack of studying water transfer laws in SPAC considering water relations between root-zone and sub soil layer in physical mechanisms, as well as lack of theoretical system to study effect of conservation tillage on AWUE in the shallow watertable region of China.Therefore, based on eco-hydrological experiment,taking Huaibei plain, Anhui as the study region,Wudogou experimental foundation as the experimental place, hydrological process of groundwater-soil-plant-atmosphere continuum(GSPAC) of crop ecosystem under different cultivation mode will be studied; model in estimating the impact of conservation tillage mode on AWUE will be constructed; the controlling factor of AWUE in space heterogeneity will be analyzed; the optimized tillage mode to further improve AWUE will be revealed; and the theory of effect of conservation tillage on AWUE in Shajiang black soil in shallow water table regions will be established.

提高农业用水效率，是实现农业节水的关键，是解决水资源短缺及粮食安全问题并实现区域可持续发展的有力途径。做为中国重要旱作农业区的淮北平原由于降水时空分布不均，与作物需水不相匹配，更由于砂姜黑土结构性较差、质地粘重及有机质含量低的特点，作物常受到阶段性旱涝的威胁。保护性耕作可以大大改善砂姜黑土的保水性和透水性，增加其肥力。以安徽淮北平原为研究区，以五道沟水文试验站为试验场所，以平原区生态水文过程实验为基础，研究不同保护性耕作模式下砂姜黑土作物生态系统地下水-土壤-植物-大气连续统(GSPAC) 水文过程，特别是地下水浅埋深区的水文过程；构建保护性耕作模式对砂姜黑土区农业用水效率影响的量化模型；分析砂姜黑土区农业用水效率空间差异性的决定性因子；揭示提高农业用水效率的优化对策；构建地下水浅埋深区砂姜黑土保护性耕作对农业用水效率影响研究的理论体系。

为了提高淮北平原砂姜黑土区作物地农业用水效率，解决水资源短缺及粮食安全问题并实现区域可持续发展。以安徽淮北平原为研究区，以五道沟水文试验站为试验场所，通过12种保护性耕作模式下的蒸渗仪及样田三年对照试验，研究砂姜黑土区作物生态系统地下水-土壤-植物-大气连续统(GSPAC) 水文过程。揭示淮北平原农业用水效率的时空差异性及其灌溉对策。结果发现:夏玉米地土壤水分的突变是由降雨的突变所引起的；冬小麦播种期至出苗期、拔节期至灌浆期未来要注意适当减少灌溉次数和数量；出苗期至拔节期、灌浆期至成熟期适当增加浇水灌溉次数和数量；构建了保护性耕作下农业用水效率计量模型中的关键参数（根系分布、作物系数）的计量模型；研究区地下水埋深浅，地下水补给量（潜水蒸发量）是作物生长的一个重要水源，在灌溉需水量计算中是不可忽视的；深松、秸秆还田及亏缺灌溉组成的保护性耕作模式显著地提高了淮北平原砂姜黑土区的农业用水效率。