低纬度高原区农业灌溉需水规律研究

Research on Low Latitude Plateau Irrigation District Agriculture Irrigation Water Rule

低纬度高原灌区同时具有低纬度和高海拔地区的双重气候特性,倒春寒、8月低温、春夏连旱等灾害天气的危害对农业灌溉提出了多重要求。以云南省为例,系统地进行了各种纬度、海拔、气候、种植条件下水稻灌溉需水定额的分析方法探索研究,从面上证明了提出的方法可以推广运用到其它气象资料缺乏地区的灌溉定额分析计算。研究表明,低纬度高原灌区的水稻灌溉定额随纬度的变化规律杂乱,但与海拔的关系呈现出以1400m附近为节点的分岔现象,根本原因是干热河谷及多云天气的作用结果;水稻灌溉定额在年际间的变化主要受降水的影响,年内需水高峰期出现于移栽-返青期,而不是抽穗-灌浆的水分敏感期。

Low latitude plateau areas have both the characters of low latitude and high altitude. There are several kinds of disastrous weather such as Coldness in the late Spring, low temperature in August, and Drought between Spring and Summer. Irrigation and Drainage in these districts must meet the needs. Currently national water resources comprehensive planning demands a series of irrigation water data from 1956 to 2000. This also needs high reliability and precision of climate and agriculture data. Because of observing item and recording time limit, it is very difficult to get those yearly computing or experiment result. Based on YunNan Provincial plateau, the author explore the method of computing paddy irrigation water under vary kinds of latitude, altitude, climate, and planting modes. The result of total 39 types in the province proved the method is correct, and can spread to other district that is short of basic climate data. The research also discovered that the rule between low latitude plateau paddy irrigation water and latitude is disordered, there is a fork at altitude 1400 meters because of dry-heat basin and cloudy affect to paddy irrigation water need, the changes over the years is mainly influenced by precipitation, and the fastigium of paddy irrigation in a year is not the period of tassel and grouting, but at the transplant time.