Spatial Distribution of Soil Moisture and Fine Roots of Apple Trees under Water Storage Pit Irrigation

Abstract

AbstractThis study was conducted to determine the spatial distribution of soil moisture and fine roots (white, diameter <2 mm) growth under water storage pit (WSP) irrigation of apple trees in an experimental apple orchard. Three irrigation treatments have been used since 2009—WSP60 (water storage pit irrigation, pit depth 60 cm), WSP40 (water storage pit irrigation, pit depth 40 cm), and CK (border irrigation)—in controlled trials. In the considered soil profile of a 0–2 m depth, the soil moisture was mostly distributed in the middle-deep soil layer (40–150 cm) of the rhizosphere of apple trees, yet this was lower at a depth of 0–40 cm under WSP (WSP60 or WSP40) irrigation. For CK, the soil moisture was mainly concentrated within a depth of 0–60 cm of the rhizosphere of apple trees. Compared with CK, the fine root length density (FRLD) in the surface soil (0–40 cm) was reduced by 7.52–7.56% under WSP (WSP60 and WSP40) irrigation, whereas in the middle-deep soil layer (40–110 cm), it increased by 10.32–1...