果树根部加压注水灌溉对土壤特性及水势分布的影响

The Influence of Forcing Injection Irrigation in Root on Soil Characteristics and Soil Water Potential

采用根部加压注水灌溉,研究土壤水势分布特征及土壤三相变化规律。结果表明,影响土壤水势分布的因素主要为压力和流量。低压下,水分主要以垂直运移为主,离开孔处越近,土壤水势越大;高压下,水分出流速率在出口处较大,垂直方向及水平方向上水分运移均较明显,离开孔处越远,土壤水势越大;流量的增加促进了水分在垂直方向运移。低压下,土壤受水分冲刷影响较小,固相比例变化不大,浅层土壤液相增加,气相降低;灌水量增加,开孔处土壤受水分冲刷影响升高,固相降低,液相和气相增加;高压下,灌水量对土壤结构造成一定影响,开孔处土壤固相降低,深层土壤固相增加,灌水量越大,该现象越明显。

The distribution characteristics of soil water potential and the change of three phases of soil werestudied under forcing injection irrigation in root. The results showed that： pressure and flow were themain factors influencing soil water potential distribution. Under low pressure, soil water moved mainly invertical direction, and the closer to the hole, the larger soil water potential; Under high pressure, discharge rate was higher at the exit, moisture migrations in vertical direction and horizontal direction wereboth obvious, and the closer to the hole, the smaller soil water potential; The increase of the flow promoted soil moisture migration in vertical direction. Under irrigation with low pressure, water erosion had little impact on soil, the ratio of soil solid phase changed hardly, the ratio of soil liquid phase increased andthe ratio of soil gas phase decreased in the shallow soil; Soil water erosion was aggravated near the hole,the ratio of soil solid phrase became smaller, and the ratios of soil liquid phase and gas phase became largerwith the increase of irrigation water amount. Under irrigation with higher pressure, irrigation water amount had a certain influence on soil structure, the ratio of soil solid phrase decreased near the hole and itincreased in deep soil, which was more obvious with the increase of irrigation water amount.