分根交替灌溉对土壤水分分布和桃树根茎液流动态的影响

采用管式-时域反射仪(Tube-Time Domain Reflectometry, Tube-TDR)和热脉冲技术，研究了分根交替灌溉对土壤水分分布和桃树根茎液流动态的影响。研究结果表明，根区两侧同时灌溉(Both Partial Irrigation，BPI)时土壤水分向深层运动而远离根系层，不能被根系有效地吸收利用，而半边固定灌溉(Fixed Partial Irrigation，FPI)和两边交替灌溉(Alternate Partial Irrigation,API)时减少了水分向深层运动，有利于根系有效地吸收。干湿交替和部分根干燥能促进根系补偿效应的发挥，使根系具有更强的吸水能力，但是又由于FPI干燥部分的根系长期处于干旱之中，使根系老化而造成复水后不能恢复其吸水能力。树干液流与ET0呈线性相关，并且其回归方程的系数在BPI、API和FPI处理中依次呈递减的趋势，这说明了在同样的大气潜在蒸发能力条件下，采用不同的根区湿润方式时，桃树蒸腾液流对大气潜在蒸发能力的响应程度存在着明显的差异。根液流与ET0成非线性相关，其相关程度低于树干液流与ET0的相关程度，说明了树干液流比根液流与大气潜在蒸发能力之间的关系更为密切。API和FPI的平均产量与BPI的相比有所降低，但是其灌溉水量相对减少，说明了API和FPI能明显提高灌溉水利用效率。

Effects of root-divided alternative irrigation on soil moisture distribution and root-trunk sap flow dynamics of peach trees

Soil moisture distribution, root-trunk sap flow dynamics and yields of peach trees under the condition of different root zone wetting patterns were investigated by means of Tube-TDR (Time Domain Reflectometry) and heat pulse technology. The results show that soil moisture moves deeply apart from root zone and cannot be up-taken high efficiently by root system in Both Partial Irrigation (BPI). But in Fixed Partial Irrigation (FPI) and Alternative Partial Irrigation (API) the movement of soil moisture is relatively slow which is in favor of efficient up-take of the root. The alternation of dry and wet promotes the compensative effect of the root and elevates the uptake capability. The trunk sap flow for different types of irrigation correlates linearly with ET0 and the coefficients in regressive equations are various. It means that the response of trunk sap flow in peach trees to atmospheric potential evaporation is various for different irrigation. Furthermore, the root sap flow nonlinearly correlates with ET0 and the degree of correlation is low. It hints that the trunk sap flow is correlated with atmospheric potential evaporation more closely than root sap fow. The average yield of API and FPI is lower than that of BPI, but the amount of water use for API and FPI is less than that of BPI. It shows API and FPI can enhance the efficiency of irrigation water use.