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针对河西地区农田水资源短缺和水分利用效率较低的问题,利用人工控制灌水的方法研究了春小麦的蒸散量阶段变化特征和日变化特征、蒸散量的影响因子及蒸散量与产量的关系,旨在为该地区小麦水分利用率的提高提供理论依据。结果表明,春小麦阶段蒸散量高峰值集中于灌浆期,占全生育期的41.3%~68.6%,其次为拔节期到抽穗期。不同生育阶段蒸散量的日变化为一单峰曲线,一天中16:00时达最大值,2:00时至6:00时为最低值。回归分析表明,太阳辐射、气温、相对湿度、灌溉定额和土壤含水量是影响蒸散量的主要因子。拔节期至抽穗期蒸散量对产量的影响较大,并与穗粒数和千粒重有很大的相关性。通过用Jensen模型分析生育期不同阶段缺水与产量的敏感程度,以拔节期~抽穗期的敏感指数最大,为0.4238,说明此时期为春小麦需水的临界期。
In view of the shortage of water resources and the low water use efficiency of farmland in Hexi Corridor, the characteristics of evapotranspiration and its diurnal variation characteristics, the relationship between evapotranspiration and evapotranspiration and yield were studied by artificial controlled irrigation. Provide a theoretical basis for improving the water use efficiency of wheat in the area. The results showed that the peak value of evapotranspiration in spring wheat was concentrated in the filling stage, accounting for 41.3% -68.6% of the total growth period, followed by the jointing stage and the heading stage. The diurnal variation of evapotranspiration at different stages of growth was a single peak curve, reaching the maximum at 16:00 in the day and the lowest at 2:00 to 6:00. Regression analysis shows that solar radiation, air temperature, relative humidity, irrigation quota and soil water content are the main factors affecting evapotranspiration. The effect of evapotranspiration at jointing stage to heading stage on yield was significant, and had a significant correlation with grain number per spike and 1000-grain weight. By using Jensen model to analyze the sensitivity of water deficit and yield during different growth stages, the sensitivity index at jointing stage to heading stage is the largest, which is 0.4238, indicating that the critical period of spring wheat water requirement is at this stage.