桃树茎直径微变化与土壤水势及气象因子的关系

Micro-variation in peach stem diameter and its relationship with soil water potential and meteorological factors

通过对充分供水和逐步干旱处理的盆栽"仕女红"桃树茎直径微变化动态的观测,分析了茎直径日最大收缩量(MDS)、日增长量(DI)和日最大值恢复时间(RT)对水分状况和气象因子的响应,并对适宜灌溉控制指标进行了探讨。结果表明:随土壤水势降低,桃树茎直径MDS和RT呈增大趋势,DI呈下降趋势并由正值变为负值;气象因子对桃树茎直径变化影响显著,太阳辐射(Rn)和空气相对湿度(RH)对MDS影响最强烈,连续降雨对DI和RT影响显著。DI受土壤水势影响产生变化的趋势明显并受气象因子影响较小,是最理想的灌溉控制指标,可将DI=0作为灌溉控制临界值;MDS受气象因子影响强烈,变异性较大,且需要充分灌溉条件下的MDS作为参考,RT与土壤水势的相关性不高,因此均不适合单独作为灌溉控制指标。

In well-irrigated and gradual-drought pot experiments, micro-variations in ＂Shinvhong＂ peach stem diameter were continuously monitored. Responses in maximum dally stem shrinkage （MDS）, stem increase （DO, and stem diameter recovering time （RT） to soil water potential and meteorological factors were then analyzed and a suitable irrigation index established. The results show that when soil water potential decreases, RT and MDS increase while DI rapidly drops below zero. Meteorological factors have a notable impact on peach stem diameter. Factors including radiation and air relative humidity have the strongest impact on stem diameter. In fact continuous rainfall significantly affects DI and RT. DI is the most ideal irrigation indicator as it is very much influenced by soil water potential and less affected by meteorological factors. DI value of zero is probably the best irrigation threshold. MDS is strongly affected by meteorological factors and requires reference MDS under well-irrigated conditions. RT on the other hand is not significantly related with soil water potential. Therefore neither of these variables is suitable as irrigation index.