滇东北雨养旱作条件下提高玉米对降水的利用率研究

A STUDY ON THE UTILIZATION RATE OF RAINFALL OF MAIZE UNDER RAINFED CONDITION IN NORTHEAST YUNNAN PLATEAU

在年降雨量９００～１０００ｍｍ的半湿润易旱地区的滇东北高原红壤土上，降水分布不均是阻碍该区玉米生产发展的主要气象因子，伏旱对玉米产量的影响最为严重。玉米生产对降水资源的利用不充分，还有较大的生产潜力可挖。选育和推广高产抗旱的玉米良种是提高玉米降水利用率的基本保证，在最佳节令播种是提高玉米降水利用率的关键措施。施肥能促进作物根系发达，提高作物吸收和运转水份的能力，从而提高降水利用率。补充灌溉能满足作物各个生育阶段对水份的需求，是提高降水利用率的必要手段。

On the red soil of the Northeast Yunnan Plateau where the annual rainfall is between 900～1000mm, the unbalance of rainfall distribution is the major climate restrictive factor which results in seasonal drought and hinders the development and production of maize in the area. The late summer drought is the most severe one of all which affects the maize production.The utilization of the rainfall resources in maize production is not adequate and thus leaves much room to be further exploited. Adopting high yield maize varieties with drought tolerance is a basic guarantee for improving the utilization rate of rainfall. Sowing at the optimal season is the crucial measure. Applying fertilizer helps the roots of the crop well-developed,and which in turn improves its absorbing and transporting ability. Therefore, the utilization rate of rainfall is enhanced. The additional irrigation may satisfy the crop'S demand for water at its different developmental stages,and that is also an essential step for raising the utilization rate of rainfall.