藏南河谷农区农业气候条件分析与评价

A GROCLIMATIC ASSEESSMENTS FOR THE VALLEY AREAS IN THE SOUTHERN TIBET

藏南河谷农区是西藏种植业的集中分布区。本文着重分析了区域的光热条件、水分条件和气候灾害的特点及对主要种植作物的影响。

he study area,from 28──30·N and from 86──92·E,is the most important grain─producing region in Tibet. The staple crops are winter wheat , spring wheat and nakedbarley,which are mainly grown in the valley areas at the altitudes from 28oo──44oom above sea level. In this paper,the climatic characteristics and their influences on wheats and naked barley are discussedand analyzed,the main conclusions are as follows:──Light - temperature conditions are favorable for crops and high yields could beexpected with sufficient irrigation and fertilizers.──Rainfall always has low intensity and is in night and in growth period,so itsavailability is high.── Annual evapotranspiration is 991──1183mm,The water requirements of winterwheat ,spring wheat and naked barley are 665──756mm,493 ──520mm and 356 ──403mm respectively. The rainfall can only suppiy 17.6 ──34.2%of the waterrequirement for winter wheat,34.7 ──55.8%for spring、vheat and 37.1 ──57.6% fornaked barley. Irrigations are necessary.── Frequent climatic hazards, particularly low temperature , frost and hailstorm arelimiting factors to crops.