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| DOI： |
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| African Journal of Agricultural Research, 2013, （8）19： 2 272-2 284.Effects of the Planting Structure Adjustment on Water Budget of Field System in Hetao Irrigation Area |
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FU Wenqi, ZHAI Jiaqi, ZHAO Yong, HE Guohua, ZHANG Yue
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State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin,China Institute of Water Resources and Hydropower Research, Beijing 100038, China
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| Abstract: |
| The adjustment of local planting structure is an important measure of agricultural water-saving in an irrigation area. Since 1990 the planting structure in Hetao irrigation area has changed dramatically, the planting area of wheat and other food crops have drastically reduced, while the planting area of sunflower and other cash crops have sharply increased. This great change has brought significant impacts on water cycle system in irrigation area. Based on the processes of water cycle system, the influencing mechanism behind the effects of the planting structure adjustment on the field system and water budget elements in Hetao irrigation area on multiple time scales were analyzed. The change of phreatic evaporation, water consumption of evaporation and other water budget elements from 1990 to 2013 were calculated by using Aver’yanov’s formula, modified Penman formula(1948), and Penman-Monteith formula(1973). The results showed that, ①the water consumption of evaporation and the phreatic evaporation, these two vertical water balance elements were greatly influenced by the changing planting structure, and their flux values reduced remarkably. Furthermore, the influences on irrigation water and infiltration water were weaker. As for horizontal water balance element, the influence on surface displacement was the weakest. ②Whether in high flow, low flow or normal years, phreatic evaporation, water consumption of evaporation, irrigation water and infiltration water decreased at the different degrees, while surface displacement performed differently on different typical years. ③On monthly scale, irrigation water in May and phreatic evaporation in June had strong relationships with the increasing cash crops. ④Both of the total input and output water in field system descended, meanwhile the flux and intensity of water cycle reduced. Water storage was in a negative balance state during 1990—2005. During 2006—2013, water storage was in a positive balance state, nevertheless, the soil moisture was still falling, which resulted from thickness in soil layer. |
| Key words: planting structure; field system; water cycle; water budget; Hetao irrigation area |
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