Responses of field evapotranspiration to the changes of cropping pattern and groundwater depth in large irrigation district of Yellow River basin
Responses of field evapotranspiration to the changes of cropping pattern and groundwater depth in large irrigation district of Yellow River basin
复制标题
黄河流域大灌区田间蒸散量对耕作方式和地下水埋深变化的响应
DOI：
10.1016/j.agwat.2017.03.028
复制
发表时间：
2017
影响因子：
6.7
通讯作者：
Huang Lingxu
中科院分区：
文献类型：
--
作者：
Bai Liangliang;Cai Jiabing;Liu Yu;Chen He;Zhang Baozhong;Huang Lingxu
为解决黄河水资源日益减少的问题，1999年起在华北河套灌区实施了节水控水改造工程。通过该项目，预计在过去15年中，当地的水文循环将受到影响或改变。以河套灌区第二大分区解放闸灌区为研究对象，探讨了该灌区农业用水量、水量分配、种植方式与地下水位变化的关系。基于2000 - 2015年Landsat和MODIS数据，采用SEBS（Surface Energy Balance System）模型和ESTARFM（Enhanced Spatial and Temporal Adaptive Reflectance Fusion Model）算法，分时段计算农田蒸散量（ET）。结果表明，随着时间的推移，种植模式发生了很大的变化，地下水位逐年下降。农业蒸散发总量相对稳定，年均消耗量为8.9 × 108 m3。农业蒸散量的时间变化对种植方式的调整不敏感。不同作物4 - 10月蒸散量差异不显著，但各作物生长季蒸散量差异明显。农业蒸散量的空间分布与地下水埋深呈显著负相关，尽管15年来农业种植结构发生了很大的调整，但其空间分布并没有发生变化。节水工程运行期间，地下水埋深由1.76 m下降到2.33 m，减少了土壤蒸发，对土壤盐渍化起到了积极作用。净灌溉水利用率由0.59提高到0.66。这些效果表明，实施节水改造项目对水管理和环境产生了积极影响。然而，随着参考蒸散量的逐渐增加，实际作物系数Kc略有下降，这表明净灌溉水可用性持续减少和地下水位下降可能会导致干旱胁迫。
To solve the problems of decreasing water resources from the Yellow River, the renovation project of water-saving and controlling water distribution was implemented in the Hetao Irrigation District of North China since 1999. The local hydrological cycle is expected to be influenced or changed during the past fifteen years through the project. Jiefangzha Irrigation Region, the second large partition of the Hetao Irrigation District, was selected as the typical area to explore the relationship between agricultural water consumption, water distribution, cropping pattern and changing groundwater level. In this paper, the SEBS (Surface Energy Balance System) model and the ESTARFM (Enhanced Spatial and Temporal Adaptive Reflectance Fusion Model) algorithm were applied to produce daily field-scale evapotranspiration (ET) based on Landsat and MODIS data from 2000 to 2015 at intervals. The results indicate that the cropping pattern had changed greatly, while the water table descended through the years. The total agriculture ET stayed relatively stable, with the average annual consumption of 8.9 × 108m3. The temporal variation of agriculture ET was not obviously sensitive to the adjustment of cropping pattern. There was no significant difference in April–October ET for different crops, in spite of the clear distinction of ET in each crop-specific growing season. The spatial distribution of agricultural ET did not change in spite of the great adjustment of cropping pattern during fifteen years, which has a close inverse correlation with the groundwater depth. Groundwater depth descended from 1.76 m to 2.33 m during the operation period of the water-saving project, which might reduce the soil evaporation and have a positive effect on soil salinization effectively. Meanwhile, the net irrigation water use efficiency was improved from 0.59 to 0.66. These effects indicate the positive impact of the implemented water-saving renovation project on water management and environment. However, the actual crop coefficientKc,adecreased slightly with the gradually increasing reference evapotranspiration, indicating possible drought stress as an effect of the continuing reduction of the availability of net irrigation water and declining groundwater table.