Variation of soil moisture and fine roots distribution adopts rainwater collection, infiltration promoting and soil anti-seepage system (RCIP-SA) in hilly apple orchard on the Loess Plateau of China

Abstract

Improving the utilization efficiency of rainwater resources was a key issue for apple orchards in semi-arid areas. The RCIP-SA system combined rainwater collection systems, infiltration promoting tube and soil anti-seepage layer to gather limited rainwater resources into the soil layer where the roots of apple tree were concentrated. To evaluate the effect of the RCIP-SA system on soil moisture change and fine root distribution, a field experiment was completed in a hilly apple orchard on the Loess Plateau of China from 2017 to 2019. The results showed that the soil moisture of the RCIP-SA system was 24.0–43.9% higher than CK in the 0–60 cm soil layer in the rainwater collection ditch, and generated a larger area with higher moisture content near the impermeable layer during the apple tree growth period. The RCIP-SA system also expanded the dense distribution zone of apple tree roots. The dry fine root densities of apple trees in the RCIP-SA system in the 0–200 cm soil layer was 11.7–59.6% and 18.2–30.3% higher than CK under the plastic film (60 cm from the trunk) and edge of the rainwater collection ditch (100 cm from the trunk), respectively. Soil moisture and root distribution of apple trees were significantly different under different impermeable layers, and compacted red clay as the impermeable layer was the best anti-seepage strategy in RCIP-SA systems. The RCIP-SA system brought higher economic benefits; the average yield per tree was recorded for red clay compaction treatment (38.1 kg·tree−1), equating to a production level of 22 800 kg·ha−1, and a difference of 9.6 kg·tree−1 with CK treatment, equating to 5700 kg·ha−1. This strategy should be recommended as an agricultural measurement for apple production on the Loess Plateau of China.