半干旱区雨养春小麦蒸腾效率的计算与应用

Calculation and application of transpiration efficiency of rainfed spring wheat in semi-arid area

与作物叶片水平的蒸腾效率研究相比,由于群体蒸腾量难以直接测量,作物产量水平的蒸腾效率往往不被重视。本研究根据文献中所给出的产量水平的小麦蒸腾效率与自由水面蒸发量之间的关系,依据文献数据、田间试验观测资料以及桶栽试验观测资料,建立黄土高原西端半干旱区雨养春小麦产量与耗水量之间的关系,并计算获得了该区1987-2011年春小麦蒸腾效率,从而模拟了该区春小麦水分利用效率的变化。结果表明,半干旱区雨养春小麦耗水量与产量呈极显著的线性关系(P<0.01),不受不同年份气候条件、供水变化以及作物品种的影响。春小麦蒸腾效率平均为16.301 kg/(hm^(2)·mm),土壤水分蒸发量平均为156 mm。而依据自由水面蒸发量推算每年的春小麦蒸腾效率,所获得的蒸散量与实测产量关系符合该地区文献记录的耗水量与产量关系,论证了蒸腾效率在不同地区相同作物中的保守性特点。同时依据桶栽试验观测所得的胞间二氧化碳浓度与大气二氧化碳浓度比值与生育期平均空气饱和差之间的关系,修订已有的研究公式,能够模拟所研究地区的春小麦水分利用效率。本研究结果可为半干旱区雨养春小麦产量的提高及水资源的高效利用提供可借鉴的依据。

Compared with the study of transpiration efficiency at crop leaf level,the transpiration efficiency at crop yield level is often neglected because the population transpiration is difficult to measure directly.In this study,according to the relationship between wheat transpiration efficiency and free water surface evaporation at the yield level given in the literature,the relationship between spring wheat yield and water consumption in the semi-arid area of the western end of the Loess Plateau was established based on the literature data,field experiment observation data and barrel planting experiment observation data.The transpiration efficiency of spring wheat in this area from 1987 to 2011 was calculated,and the change of water use efficiency of spring wheat in this area was simulated.The results showed that there was a significant linear relationship between water consumption and yield of rainfed spring wheat in semi-arid area(P<0.01),which was not affected by climatic conditions,water supply status and wheat varieties.The average transpiration efficiency of spring wheat was 16.301 kg/(hm^(2)·mm),and the average soil water evaporation was 156 mm.The annual transpiration efficiency of spring wheat was calculated based on the free water surface evaporation.The relationship between evapotranspiration and measured yield was consistent with the relationship between water consumption and yield recorded in the literature,indicating that the transpiration efficiency was conservative in the same crop in different regions.At the same time,according to the relationship between the ratio of intercellular carbon dioxide concentration to atmospheric carbon dioxide concentration and the average vapor pressure deficit during the growth period,the existing research formula was revised to simulate the water use efficiency of spring wheat in the study area.The results of this study can provide a reference for the improvement of spring wheat yield and the efficient utilization of water resources in semi-arid rainfed areas.