雄安新区上游农业种植结构及需水时空演变

Trend of agricultural plantation and irrigation requirements in the upper reaches of Xiong'an New Area

  • 摘要: 本文利用作物模型模拟小麦、玉米灌溉需水量,结合蒸发皿法估算蔬菜、果树等其他作物需水量,回溯雄安新区上游1986-2015年农业种植结构及农业需水的时空演变趋势,摸清不同作物的需水量比例及时间变化,并推算了消除降水年际波动的1970-2015年农作物灌溉需水量,探讨单纯人类活动下的农业需水量变化趋势。结果表明,1986-2015年,研究区作物播种总面积总体呈上升趋势,耕地面积多年平均84.9万hm2,有效灌溉面积平均71.3万hm2,占总耕地面积的84%。其中小麦播种面积稍有下降,玉米、蔬菜播种面积显著增加,果树种植比例在山区增加、平原区减少。研究区多年平均灌溉需水量22.52×108 m3,小麦、玉米、蔬菜、果树和其他作物分别占灌溉需水总量的58.6%、12.6%、5.8%、16.3%和6.7%,受播种面积增加影响,1970-2015年,蔬菜和果树需水显著上升。从空间上来看,灌溉需水总量在上游山区上升显著,而在平原区表现为下降;排除降水的年际波动后,研究区作物需水自1970年以来一直呈上升趋势,进入20世纪80年代中期,虽然整体上升减缓,但随农业播种总面积增加和蔬菜、水果需水增加影响,需水量整体呈缓慢上升趋势。因此,控制上游农业用水,种植低耗水作物、减少耗水作物的种植面积,是恢复雄安新区清水产流的关键。

     

    Abstract: The agriculture is a major consumer of water. Since Xiong'an New Area is facing serious water shortage and groundwater declining, it is necessary to optimize the scale of upstream agriculture water use. By using crop models for simulating the irrigation requirements of wheat and maize, and taking the Pan-evaporation coefficient (Kp) approach to estimate the irrigation requirement of other crops, such as vegetables and fruit trees, our study reconstructed the spatial and temporal trend of agriculture plantation and irrigation requirement in the upper reaches of Xiong'an New Area from 1970. The proportion of irrigation requirements and time-dependent changes of different crops formed a clear trend. The results showed that the total planting area generally increased. There was no significant change in the area of cultivated land and the effective irrigated area. The average cultivated area for many years was 849 000 hm2, while the effective irrigated area averaged 713 000 hm2, accounting for 84% of the total cultivated land area. The planting area of wheat decreased slightly, the planting areas of maize and vegetables increased significantly, and the planting proportion of fruit trees increased in the mountain area and decreased in the plain area. The annual average irrigation requirement was 22.52×108 m3, of which wheat, maize, vegetables, fruit trees, and other crops accounted for 58.6%, 12.6%, 5.8%, 16.3%, and 6.7% of the total irrigation requirement, respectively. The irrigation requirement of vegetables and fruit trees increased significantly, and was affected by the increase in planting area. Spatially, the total irrigation requirement increased significantly in the mountain area but decreased in the plain area. After elimination of the influence of annual precipitation fluctuation, the irrigation requirement showed a sharply increasing trend from 1970 to 2015, but slowed down in the mid-1980s. Owing to the increase of planting area and irrigation requirements of vegetables and fruit trees, the irrigation requirement showed a slow increasing tendency overall. Therefore, controlling the agricultural water use in the upper mountainous reaches of Xiong'an New Area, planting of low-water-consuming crops and reducing the planting area of water-consuming crops are keys to restoring water production for Xiong'an New Area. Finally, the sustainable utilization of regional water resources should be based on local natural conditions and the layout of agricultural production should be arranged in accordance with the spatial and temporal distribution of water resources to seek a coordinated development for the water-ecology-social economy of Xiong'an New Area.

     

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