摘要
西藏高原平均海拔在４０００米以上，气温偏低，年变化和年际间变率较小，降水量地区、年内分布不均，年际间变率较小，降水强度小；干旱和相对较低的温度使农业气象灾害相对较轻；日照百分率和直接辐射比率高，对补偿气温低有较大作用．分析了农作物主要生育时期所需适宜下限温度及所能抵抗的低温霜冻指标；不同作物品种所需＞０℃积温值及该值随海拔升高有所减少的变化情况，明确了决定作物分布界限的基本温度条件是春季日平均气温回升到０℃到秋季日最低气温出现－２℃间＞０℃积温应在９４０℃以上，最好在１１００℃以上。并用各类作物不同品种所需积温去衡量广大河谷农区和高寒农区的热量资源，表明是足够的，部分地区还有不同程度的剩余，可分别供复种早熟油菜、豌豆或豆科饲料绿肥用。
The average elevation of Tibetan Plateau is over 4000 metres.The temperature is lower and the temperature doesn't vary too much with different seasons or years in the highland.Usually,there is no heavy rain and rainfall varies from one region to another,but total amount of rain water is basically balanced in different years. Damaged to agriculture due to climate calamities are not serious as the lower rain intensity and lower temperature link with drought.Higher percentage of sunshine and higher rate of solar irradiation play an important role in compensating the lower temperature. Lower limit temperature for crop suitably growing at main growth stages,indices of crop against frost injury,values of accumulated temperature above 0℃ needed for various crops and the values declining with elevation going up etc.were analized.It is verified that the basic conditions for determining crop distribution boundary are that:the temperature must be above O℃ in spring,the minimum temperature in autumn cannot be below-2 ￣O℃and accumulated temperature around the year must be over 940 ℃.Solar energy in valley and highland regions is enough to satisfy various crops,even in some regions the heat quantity is surplus,where early rape,Pea,beans or leguminous plants used as green manure or forage,could be intercroped or multiplanted.
出处
《西南农业学报》
CSCD
1995年第3期100-106,共7页
Southwest China Journal of Agricultural Sciences
