灌溉对孕穗期冬小麦农田温度的影响

Effects of irrigation on winter wheat field temperature at booting stage

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。

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.