Effects of vertical rotary subsoiling with plastic mulching on soil water availability and potato yield on a semiarid Loess plateau, China

摘要

Plastic mulching with ridge-furrow planting (PM) increases soil water content, and vertical rotary subsoiling (VRT) changes soil hydraulic properties. However, the effect of the combination of PM and VRT (PMV) on soil water characteristics and crop production has not been investigated previously. A field experiment carried out from 2016 to 2018 using three treatments: VRT for 40 cm depth with PM (PMV); rotary tillage for 15 cm depth with PM (traditional tillage, TT); and rotary tillage for 15 cm depth without PM (CK). The results showed that PMV significantly decreased soil bulk density by 13.3-25.3 % and the soil wilting coefficient by 11.4-23.4 % in the 0-40 cm profile, resulting in significantly increased soil available water storage (SAWS), especially during the dry season (i.e. at the potato squaring stage) of the drought year (2016), when it increased by 12.4 % and 37.1 % during squaring stage compared with TT and CK, respectively. The increased SWAS benefited potato development in that the LAI of PMV increased by 9.7-37.1 % and 24.2-90.4 %, the aboveground biomass increased by 18.2-68.9 % and 64.0-133.4 % compared with TT and CK, respectively. The well-developed potato plants grown under PMV significantly increased evapotranspiration, tuber yield, and water use efficiency (WUE) by 27.5-47.8 %, 11.3-24.0 %, and 12.9-26.7 % compared with TT, and by 61.1-293.7 %, 1.0-27.4 %, and 59.3-207.5 % compared with CK. The highest increases in tuber yield and WUE under PMV were observed during the drought year (2016). These results suggest PMV as a promising method to solve seasonal drought stress and increase potato production in semiarid rain-fed areas mainly covered by loessial soils.