Vertical rotary sub‐soiling affects soil moisture characteristics and potato water utilization

Abstract

AbstractVertical rotary sub‐soiling (VRT) has potential to increase potato (Solanum tuberosum L.) yields in semiarid rainfed area. However, despite the importance of this food crop, little research had been done on this topic. We describe results from a field experiment carried out during 2016–2017 in a semiarid area (104°36′E, 35°35′N), where potato crop was grown in a field with three tillage treatments: (a) vertical rotary sub‐soiling to a depth of 40 cm (VRT), (b) sub‐soiling to a depth of 40 cm (SS), and (c) traditional rotary tillage to a depth of 15 cm (TT as control). The results showed that the VRT decreased soil bulk density by 0.8–22.2 and 13.3–25.3% compared with SS and TT, respectively, leading to increased porosity (by 12.5–14.8 and 12.3–23.7%) and saturation water content (by 23.7–33.2 and 25.6–59.0%), together with reduced water content at wilting point (by 12.5–23.4 and 11.4–23.4%). This was equivalent to 23.7–33.2 and 25.2–59.0% increase in soil maximum available water (SMAW) of the soil profile down to 40‐cm depth compared with SS and TT, respectively. The increased SMAW resulted in increased tuber yield by 156.8 and 47.8%, corresponding increases in water use efficiency by 92.3 and 19.2% in 2016 compared with SS and TT, respectively. The similar results were observed in 2017. Our results demonstrate that VRT was an effective technology to further increase water use efficiency and crop yield on top of plastic film mulching in semiarid rainfed area.