科尔沁沙地农田玉米耗水规律研究

首先采用波文比-能量平衡法分析了科尔沁沙地农田玉米(Zeamays L.)不同发育阶段晴天的能量分配特征,在此基础上估算了玉米的蒸散量,并对估算结果和蒸渗仪测定结果进行比较,最后运用作物蒸散量和参考作物蒸散量计算了玉米的作物系数。结果表明:①在玉米的整个生长过程中,能量交换以水分蒸散耗热为主;②根据试验年份的降雨分布情况,该地区的自然降水不能满足玉米对水分需求,玉米各生育阶段水分亏缺比较严重;③科尔沁地区玉米4个生长阶段(苗期、营养期、生殖期、成熟期)的作物系数分别为0.52、0.90、1.13和0.64;④波文比能量平衡法可以较准确的估算玉米农田晴天时的蒸散量。

Water Consumption Law of Maize in Horqin Sandy Land

The Bowen ratio-energy balance method was used to analyze the energy exchange on maize cropland and further to estimate crop evapotranspiration at Horqin Sandy Land. The estimated results had been compared with the data measured by Lysimeter. Crop coefficients for maize calculated from crop evapotranspiration and reference evapotranspiration have been obtained. During growth seasons, latent heat flux occupied large amount of net radiation. The local precipitation of experimental year couldn t satisfy the water need of maize production. The calculated values of crop coefficient for maize at the four crop growth stages (initial, crop development, reproductive and maturity) were 0.52, 0.90, 1.13 and 0.64 respectively. Crop evapotranspiration can be estimated exactly by using Bowen ratio-energy balance method in a fine daytime.