Maize‐potato rotation maintains soil water balance and improves productivity

Abstract

AbstractContinuous maize cropping dries soils, while continuous potato cropping results in a soil moisture surplus, but decreases land productivity. To determine whether soil water balance and economic returns could be manipulated through maize‐potato rotation. The effects of 1) continuous maize cropping (M), 2) continuous potato cropping (P) and 3) maize‐potato rotation (R) on the variation in soil water content, water consumption, biomass and yield, economic benefits, and water economic yield were investigated. The depth of soil water consumption reached the maximum in 2016 (a dry year), at 260 cm, 200 cm, and 200 cm in M, P, and R, respectively. Compared with soil water storage in the 0–280 cm before planting in 2013, those after six years of cultivation were decreased by 186.31 mm in M, increased by 42.20 mm in P, and increased by 11.29 mm in R. R increased the post‐flowering/total depletion% by 16.81–44.65%, the post‐flowering/total biomass percentage by 10.83–24.83%, and water use efficiency of grain/tubers by 15.52–23.39% in 2016–2018, compared with M. Compared with M, R and P increased the total benefit by 55.44% and 41.62%, decreased ET by 10.69% and 17.93%, and increased EWUE by 74.02% and 72.52%, respectively. However, tuber yield and the water use efficiency of tubers in P decreased by 31.19% and 16.78%, respectively, from 2014–2017. Treatment R maintained the soil water balance, alleviated the over‐consumption of deep soil water caused by continuous maize cropping, and reduced the decline in soil productivity caused by continuous potato cropping.