【摘要】 分析了通辽市近４５ 年降水、潜在蒸散及农田水分盈亏的变化，结果表明：年降水量在周期变化中具有减小的趋势，年降水量的稳定性增加，潜在蒸散波动上升。本世纪６０ 年代以来，春旱有所缓减，秋旱有所加剧更多还原

【Abstract】 The change of precipitation, potential evapotranspiration and profit and loss of soil moisture in Tongliao city for the last forty-five years were analysed. The results show that: the trend of yearly precipitation has decreased, at the same time its fluxuation has also lessened; evapotranspiration, on the other hand has been increasing in a wave pattern; since the 1960s, spring drought has lightened in somewhat while autumn drought has become more serious.更多还原