桃树树干液流和冠层温度对不同灌溉水量的响应

The response of stem sap flow velocity and canopy temperature of peach tree to different irrigation water quantities

【目的】通过对不同灌水量下桃树主要需水信号,如液流速率、冠层温度和冠层温度-气温差的测定,分析不同水分亏缺灌溉桃树主要需水信号的变化规律,为果树的精量控制灌溉提供理论依据。【方法】以在移动式遮雨棚下生长的4年生桃树为试验材料,设置某时段桃树的实际需水量（ETc）的100%（I1）、75%（I2）、50%（I3）和25%（I4）4个灌水量处理,3次重复,研究不同灌水量处理下桃树液流速率、冠层温度和冠层温度-气温差的变化规律。【结果】不同灌水量处理之间桃树液流速率日变化和连日变化存在明显差异,高灌水量处理桃树液流速率大,低灌水量处理液流速率相对较小,在正常生长状态下液流速率日变化动态为多峰曲线,且阴天的液流速率明显小于晴天。桃树液流速率随大气相对湿度的变化呈现昼夜的周期性,相对湿度下降,液流速率上升。桃树生育期内冠层温度和冠层温度-气温差均存在明显的日变化,低灌水量处理的冠层温度和冠层温度-气温差高于高灌水量处理,且差异明显。冠层温度-气温差与0~100 cm土壤含水量具有较好的负相关关系。【结论】液流速率、冠层温度和冠层温度-气温差可以较合理地反映土壤水分的变化状况和作物水分的亏缺程度,是诊断作物缺水状况的重要指标。

【Objective】 Through the measurement of the variations of main water signals of peach tree such as sap flow velocity,canopy temperature,discrepancy between canopy and air temperature under different irrigation water treatments,the change rule of peach＇s main water signals under different water deficit irrigations was analyzed,in order to provide theoretical basis for fruit tree＇s precise control irrigation.【Method】 With 4-year-old peach tree grown under a mobile rainproof canopy as test material,four different irrigation treatments 100% ETc（I1）,75%ETc（I2）,50%ETc（I3） and 25%ETc（I4） and three reiterations established to realize the change rule of main water signals of peach tree such as sap flow velocity,canopy temperature and discrepancy between canopy and air temperature under different irrigation treatments.【Result】 The sap flow velocity of peach tree presents obvious daily variation and day-to-day change during different irrigations and the performance is that with high water irrigation treatment the sap flow velocity is high and with low irrigation water treatment the sap flow velocity is relatively low,the daily change of sap flow velocity presents multi-peak curve characteristic under normal growth condition,moreover,it is obvious that the sap flow velocity is lower in overcast than in sunny day.Besides,with the variation of relative humidity of atmosphere,the sap flow velocity shows the day and night＇s periodicity,the relative humidity drops,the sap flow velocity rises;otherwise,the relative humidity rises,the sap flow velocity starts to drop.Both the canopy temperature and the discrepancy between canopy and air temperature of peach tree have obvious diurnal variation in growth period,the canopy temperature and the discrepancy between canopy and air temperature with low irrigation treatment are higher than with high irrigation treatment,moreover,the difference is presented obviously.The discrepancy between canopy and air temperature and 0-100 cm soil moisture content have good negative correlation.【Conclusion】 Sap flow velocity,canopy temperature and discrepancy between canopy and air temperature not only can reflect changes of soil moisture and crop water deficit content reasonably but also are important indexes in diagnosing crop water shortage status.