| Effects of rainfall fluctuation on water consumption and water use efficiency of winter wheat in the loess tableland |
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| DOI：10.7606/j.issn.1000-7601.2017.04.13 |
| Key Words: soil water rainfall fluctuation water use efficiency winter wheat water consumption |
| Author Name | Affiliation | | NI Pan-pan | Institute of Soil and Water Conservation, Chinese Academy of Sciences, Yangling , Shaanxi 712100, China
University of Chinese Academy of Sciences, Beijing 100049, China | | ZHU Yuan-jun | Institute of Soil and Water Conservation, Chinese Academy of Sciences, Yangling , Shaanxi 712100, China
State Key Laboratory of Soil Erosion and Dryland Farming of the Loess Plateau, Northwest Sci-Tech University of Agriculture and Forestry, Yangling, Shaanxi 712100, China | | GONG Tie-xiong | Institute of Soil and Water Conservation, Chinese Academy of Sciences, Yangling , Shaanxi 712100, China
University of Chinese Academy of Sciences, Beijing 100049, China |
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| Abstract: |
| A real-time rainfall control technique consisting of artificial rainfall-shields and gravitational trickle irrigation system was used to investigate the effects of normal rainfall (CK), rainfall reduction 1/3 (R-1/3), and rainfall increase1/3 (R+1/3)) on 0～4 m soil water storage, winter wheat water consumption and WUE in the loess tableland. The results indicated that:(1) Rainfall fluctuation modified water utilization of winter wheat and soil water supply. With the reducing of rainfall, winter wheat used more soil water, resulting in the decrease of deep soil water content during growth and fallow periods, which was hardly restored by rainfall during fallow period. With the increase of rainfall, deep soil water content decreased during growth period but could be restored even higher than initial soil water content after harvest due to the supply of rainfall in fallow period. (2) Winter wheat used soil water that transformed from current rainfall event firstly and then used early soil water. For evapotranspiration(ET) of the period from overwintering to mature period, winter wheat of R-1/3 used more soil water from 0 to 2 m. Precipitation(P) and ΔW0~2 m each accounted for about 40% of the ET. The ratio which P accounted for in ET of R+1/3 was about 1 times more than ΔW0~2 m. However, in the treatment of CK, The proportion which P accounted for in ET was about 15% more than ΔW0~2 m. Under the condition of rainfall decrease, the proportion of soil water transformed from current rainfall event to winter wheat water consumption decreased and the proportion of 0～2 m early soil water increased. Opposite result was obtained with rainfall decreasing. (3) Campared with CK, the winter wheat WUEbio (on biomass level) decreased by 1.3% in the treatment of R-1/3, and its WUEgrain (on grain level) increased, because the decline on grain level(7.1%) was less than the degree of water drops(14.2%). The winter wheat biomass decreased by 5.3% and grain yield increased by 4.5% in the treatment of R+1/3 when it was harvested, but its WUEbio and WUEgrain decreased because of 11.4% increase in soil water consumption. Generally, rainfall fluctuation had effects on soil water use, soil water supply, winter wheat water consumption composition and the balance between biomass and grain of winter wheat, which affected the winter wheat WUE finally. |
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