Effects of vertically rotary sub-soiling tillage on water utilization and yield of potato in semiarid area of northwest China.

To examine the effects of vertically rotary sub-soiling tillage (VRT) on stage water consumption, individual and population development, yield, water use efficiency, and economic profit of potato is helpful to find the optimized tillage method which could increase crop drought-resistant, yield, and resource use efficiency. With randomized block design, the field experiment involved in three treatments, 1) vertically rotary sub-soiling tillage for 40 cm depth (VRT), 2) deep loosing tillage for 40 cm (DLT), and 3) rotary tillage for 15 cm (TT). The soil water storage in 0-200 cm soil profile in different growth stages of potato, foliar SPAD value, leaf area index (LAI), plant dry matter content, tuber yield were recorded, and stage water consumption, water use efficiency (WUE), tuber commodity rate, tuber commodity yield, and profit were calculated, to investigate the effects of VRT on production efficiency and economic profit. The results showed that VRT increased water consumption in flowering and tuber expanding stage by 46.7, 35.7 mm in 2016 and 27.2, 47.3 mm in 2017, as compared with DLT and TT. Based on the increased stage water consumption, foliar SPAD value, dry matter content, and LAI increased significantly, suggesting the VRT promoted individual and population development. The higher individual and population biomass resulted in significant increase in tuber yield which increased by 156.8%, 47.8% in 2016 and 24.8%, 41.0% in 2017 respectively, as compared with DLT and TT. Accordingly, WUE increased by 92.3%, 19.2% and 18.9%, 26.6%. The tuber commodity yield and profit significantly increased in VRT treatment, as well as the profit which reached to 12631.9, 11019.1 yuan µ hm^-2 in 2016 and 29498.3, 18245.5 yuan µ hm^-2 in 2017, respectively. VRT promoted potato water consumption in flowering and tuber expanding stages, resulted in significant increases of foliar SPAD value, plant dry matter, and LAI, with positive consequences on the tuber yield, WUE, as well as the tuber commodity yield and economic profit. These indicated that the VRT was helpful to increase potato drought resistance, yield and profit, and thus would be the appropriate tillage method on semi-arid northwest Loess Plateau. [ABSTRACT FROM AUTHOR]