| Structure adjust ment of regional water resources based on ecological water require ment of vegetation ——A case study in Jinghe Watershed |
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| DOI：10.7606/j.issn.1000-7601.2007.01.09 |
| Key Words: Jinghe Watershed structures of vegetation ecological water requirement utilization structure of water resource countermeasures |
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| Abstract: |
| Jinghe river is one of the ten major rivers of the Yellow River,and a main stream in the losse plateau.It consists of 31 administrative counties in Ningxia Hui Autonomous Region,Gansu and Shaanxi Province. Now Jinghe Watershed is confronting with the restriction and threat because of water resource scarcity and environments exacerbation.Vegetation consists of forest, grass and crops. Water requirement structure of vegetation partly reflexes water use structure,and structure of ecological and economy benefit.After studying the quota of every kind of vegetation,with quota-area method,we analyzed vegetation ecological water requirement,vegetation ecological water requirement structure and vegetation ecological water requirement per unit.Our study conclusions are as follows: the suitable ecological water requirement of the forests in Jinghe watershed is 341 773.23×104 m3, the ecological water requirement of the grass is 569 705.99×104 m3,and the ecological water requirement of the crops is 740 543.20×104 m3. The wheat,maize,corns and vegetables in Jinghe watershed require more water than any other crop.The crop ecological water requirement is nearly half of total vegetation ecological water requirement,however,the ecological benefit of crops is far less than that of forest and grass.This calculation is under the hypothesis that water requirement quotas of most vegetation in one County are equal to that in another County.The 31 counties have different vegetation structures,which results in large difference in vegetation water requirements per hectare and in crop water requirements per hectare at county level.The highest of vegetation water requirements per hectare,5 339 m3/hm2,is in Jingyang County; the lowest,2 082 m3/hm2, is in Huan County;the average is 3 081 m3/hm2. The highest of,5 682 m3/hm2, is in Jing-yang County;the lowest,4 022 m3/hm2,is in Ding-bian county;the average is 4 583 m3/hm2.Based on these calculation and analysis,the countermeasures suggested for high-efficiency use of water and land resources are: to adjust vegetation structure and crops structure to realize water resource optimal allocation,especially to increase grass through grain for green;to develop water-saving agriculture;to perfect water integrated management mechanism to balance man and nature at watershed system level;further to resolve relative scientific problems. |
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