Abstract:

The single-cropping region in northern China is the major potato-producing areas and a typical semiarid dryland agricultural location in China. Recently, due to the intensification of climate change, annual precipitation in this area has decreased, and the frequency and intensity of drought have increased significantly, which has greatly affected the growth and production of local potatoes. Therefore, to explore the effects of various degrees of drought stress on the growth and yield of potato in the single-cropping region in northern China, this study was conducted on the basis of years of potato growth and meteorological data to verify the Agricultural Production Systems Simulator (APSIM-Potato) model and evaluate the applicability of the APSIM-Potato model in Wuchuan County, Inner Mongolia, China. The validated model was used to analyze the response of potato leaf area index (LAI), above-ground biomass, and yield to drought scenarios at different developmental stages. (1) The results show that the APSIM-Potato model is superior simulating potatoes growth and yield formation in Wuchuan over time. The root mean square error of the calculated and measured values at each development stage was within 3 days; the normalized root mean square error of the calculated and measured values of LAI, above-ground biomass and yield was less than 20%, and the coefficient of determination (R²) and consistency index (D index) were both greater than 0.85. It could be demonstrated that the calculation accuracy of the model was relatively high, and the APSIM-Potato model had applicability in the study region. (2) With the increase of drought stress time and intensity, the LAI, above-ground biomass, and yield would decrease. When calculating drought at a single developmental stage, the LAI, above-ground biomass, and yield were the most responsive to water stress in the branch-flowering stage. Compared with CK, the LAI, above-ground biomass, and yield of potato were respectively reduced by 3%-33%, 17%-35%, and 2%-25%; When calculating drought during continuous development, the LAI, above-ground biomass, and yield were the most responsive to water stress during the whole growth period. Compared with CK, the LAI, above-ground biomass and yield were reduced by 10%-57%, 29%-69%, and 55%-75%, and the time for its LAI and above-ground biomass to reach the maximum value also increased by 10-17 d and 13-18 d. The recent study results had laid a theoretical foundation for analyzing the applicability of the APSIM-Potato model in the single-cropping region in northern China and for in-depth study of the impact of drought on potato in the single-cropping region in northern China under the background of climate warming.

Key words: potato, APSIM-Potato model, applicability evaluation, drought simulation, leaf area index (LAI), biomass, yield