地下穴灌对苹果冠下土壤水分分布及叶片水分利用效率的影响

Effect of Cavity Irrigation Underground on the Distribution of Soil Water Under the Canopy and Leaf Water Use Efficiency of Apple

【目的】探讨地下穴灌技术对苹果树冠下土壤水分分布和叶片水分利用率的影响,明确地下穴灌方法的作用特点。【方法】以8年生苹果树为试材,通过穴贮肥水和地面集中灌溉的比较,研究地下穴灌处理果树冠下土壤水分时空分布,分析苹果叶片光合性能和水分利用效率。【结果】采用地面集中灌溉处理,果树冠下土壤含水量在灌溉后第3天快速下降,土壤水分主要集中于10—30 cm土层,水分分布区呈"盘子状"。采用地下穴灌土壤含水量在灌溉7 d后迅速下降,土壤水分主要集中在40—60 cm土层。地下穴灌使土壤含水量在较长时间内维持最高水平,土壤水分"上少下多",分布区如正立的"葫芦状";采用穴贮肥水灌溉处理后,土壤水分主要分布在10—60 cm土层,分布区如"圆筒形"。采用地下穴灌的果树叶片叶绿素含量、光合速率及水分利用率在3种灌溉方式中均最高。【结论】地下穴灌将土壤水分稳定在根系集中分布层,提高了光合速率和叶片水分利用率。

[ Objective ] The aim of this investigation was to elucidate the distribution of soil water under the canopy and leaf water use efficiency of apple by the cavity irrigation underground. [ Method ] Eight-year-old apple trees were used as materials in the experiment. The spatial and temporal distribution of soil water under canopy of trees and photosynthetic rate and water use efficiency of leaves were analyzed by comparing the cavity irrigation underground with storing water and fertilizer in the hollow and normal surface irrigation. [ Result ] The results showed that the soil water under canopy of trees rapidly declined after 3 days and it mainly concentrated in the range of 10-30 cm by the normal surface irrigation, and the area of water distribution presented a ＇plate shape＇. The soil water rapidly declined after 7 days and it mainly concentrated in the 40-60 cm by the cavity irrigation underground. The soil water content had been maintained the highest level for a long time by cavity irrigation underground, and the area of water distribution that upside was less than the following liked ＇gourd shape＇. The water was mainly distributed in the 10-60 cm deep soil zone similar to a ＇cylinder shape＇ by the storing water and fertilizer in the hollow. Leaf chlorophyll content, photosynthetic rate and water use efficiency by cavity irrigation underground were the highest among the three irrigation models. [Conclusion] The soil water kept in the concentrated area of root and both photosynthetic rate and water use efficiency of apple leaf were improved by cavity irrigation underground.