夏玉米群体水分利用效率影响因素分析

Analysis on affecting factors of group water use efficiency of summer corn

在夏玉米全生育期利用 CO2 分析系统连续测定冠层上方 0 .5m和 2 .0 m高度的瞬时 CO2 浓度差 ,配合波文比装置同步测定总辐射、净辐射、温、湿度等农田小气候特征量 ,并计算了群体水分利用效率。结果表明 ,太阳总辐射、净辐射、CO2 浓度差、空气饱和差等环境因素以不同机制及过程影响群体水分利用效率 ;群体水分利用效率与 0～ 60 cm土层土壤平均相对含水量呈负相关 ,土壤相对含水量在 30 .3%～ 80 %范围内 ,水分利用效率随相对含水量的增加而降低。在生产实际中 ,通过秸秆覆盖、喷灌等措施降低蒸腾驱动势 ,提高水分利用效率 ,利用人工栽培措施促进根系吸收深层土壤水分 ,可在不增加用水的同时提高水分利用效率。

The instantaneous CO 2 flux concentration gradient 0.5 m and 2.0 m higher above the canopy was measured with an infrared CO 2 analysis system during the growing season of summer cron.The field microclimatic factors such as radiation,temperature and moisture were measured simultaneously using the Bowen ration device,and the group water use efficiency was also calculated.The results showed that the group water use efficiency was affected by the factors such as global radiation,CO 2 flux density and air saturation deficit etc.There was negative correlation between group water use efficiency and the relative water content in 0~60 cm soil.When the relative water content was in the area of 30.3%~80%,the water use efficiency decreased with the increase of soil water.The water use efficiency could be raised by means of straw cover and sprinkling irrigation to reduce the driving force of transpiration in agricultural practice,and some measures could be taken to develop the root to absorb the deep soil water and could increase the water use efficiency while the water supply had not increase.