灌溉对孕穗期冬小麦农田温度的影响

灌溉是抵御和减轻冬小麦晚霜冻危害的有效措施之一。针对黄淮地区2010年4月的一次强降温过程,通过郑州农业气象观测站的灌溉防霜试验,对比分析了冬小麦孕穗期田间空气温度和土壤温度特征。结果表明:在外界环境温度下降时,灌溉可以提高田间最低气温0.1～0.6℃,增温效应主要集中在地上5cm处,灌溉可减少气温≤0℃的持续时间1～2h;对土壤温度的影响随着深度而存在差异,0cm土壤温度以增加为主,5～20cm土壤以降温效应为主;灌溉减小了气温和0～5cm土壤温度的变异系数和平均相对变率,而增大了10～20cm土壤温度的变异系数和相对变率;灌溉引起的温度差异只在15和20cm土壤处比较显著,其余各层温度差异并不明显。

Effects of irrigation on winter wheat field temperature at booting stage

Irrigation is one of the effective measures to resist and alleviate the impact of late frost disaster on winter wheat.Aiming at the strong cold weather process occurred in Huang-Huai Area of Central China in April 2010,and through a field experiment with irrigation to prevent frost in Zhengzhou agro-meteorological observation station,this paper analyzed the characteristics of air-and soil temperature in winter wheat field at booting stage.The results showed that when the environmental temperature dropped,irrigation could increase the minimum air temperature by 0.1-0.6 ℃,compared with no irrigation.The effect of irrigation in increasing air temperature was mainly concentrated in the 5 cm zone above soil surface.In addition,irrigation could shorten the duration of air temperate ≤ 0 ℃ by 1-2 h.The soil temperature under irrigation varied with soil depth,being higher at 0 cm depth but lower at 5-20 cm depth,as compared with no irrigation.Irrigation decreased the coefficient of variance and relative variability of air temperature and 0-5 cm soil temperature,but increased the two indices of 10-20 cm soil temperature.The differences of soil temperature caused by irrigation were distinct at 15 and 20 cm soil depths,but not obvious at other soil depths.