An <i>In-Situ</i> Rainwater Collection and Infiltration System to Improve Plant-Available Water and Fine Root Growth for Drought Resistance

Highlights An in-situ rainwater collection and infiltration (RWCI) method is a rainwater catchment utilization technique RWCI is advantageous for increasing sustainable plant-avaibale water to increase drought resistance RWCI significantly increased the amount of water and nutrients in the rhizosphere for uptake by apple tree roots ABSTRACT . A two-year field experiment was undertaken to determine the spatial distribution of plant-available water and roots in soil profiles under two rainfall control systems—an in-situ rainwater collection and infiltration (RWCI) method and a semi-circular basin (SCB)—in apple orchards in the Loess Plateau of China. The results showed that the RWCI treatments with a soil depth of 40 cm (RWCI40), 60 cm (RWCI60), and 80 cm (RWCI80) significantly increased plant-available water in different seasons and depths and increased root growth of apple trees in the experimental soil profile (0–200 cm). At 0–200 cm soil depth, then RWCI treatments had significantly higher (91.86%-110.01%) mean plant-available water storage (PAWS) than the SCB treatment in both study years (2015 and 2016). From 0–120 cm soil depth, the RWCI60 treatment had significantly higher growing season mean PAWS than RWCI40 and RWCI80; however, RWCI80 had the highest from 120–200 cm. From 0–60 cm, the RWCI treatments had 25.84%-36.86% a smaller proportion of root system than the SCB treatment. However, from 60–120 cm, the proportion of root system increased by 131.53% (RWCI40), 157.95% (RWCI60) and 129.98% (RWCI80), relative to SCB. From 0–200 cm, the RWCI treatments had 1.49–1.94 times more root dry weight density than the SCB treatment. The highest concentration of fine roots occurred in the RWCI treatments. Thus, RWCI enabled roots to absorb more water and nutrients from a wider wetted area and improved drought resistance. Keywords: Drought resistance, Fine roots, Loess Plateau, Plant-available water, Spatial distribution.