Decoupling of impact factors reveals the response of cash crops phenology to climate change and adaptive management practice

Abstract

Variations in phenology are regarded as a dynamic bio-indicator of global climate change. Rising incomes and the shift toward a diverse diet have been increasing the cash crop demand. However, the response of cash crop phenology to climate change and adaptive management practice remains largely unknown. In this study, using phenology records from 1991 to 2010, we separate the effects of climatic factors and management on phenological changes in the cash crops of sorghum, peanut, and canola based on the statistical and machine learning models. Our results show: (1) The sowing, emergence, three-leaf, and milk ripening date of sorghum showed a significantly (p < 0.05) advanced trend. The sowing, emergence, and five-leaf for canola likewise exhibited a significantly advanced trend (0.55 to 0.91 days a−1). The phenophases of the peanut were generally delayed (0.12 to 0.86 days a−1). (2) For sorghum, canola, and peanut, there is a delayed effect of increasing sunshine hours on heading/anthesis dates. The sowing date for sorghum and peanut delayed with the increased temperature. The three-leaf and milk ripening date of sorghum were sensitive to the wind speed. (3) Sunshine hours contributed to the extension of the whole growth period for sorghum, peanut, and canola, by 68.1, 60.7, and 40.0 %, respectively. The wind speed and temperature had comparable contributions to the maturity date, the former even dominating the heading date of sorghum. (4) Adaptive management practice partially offsets the effect of climate change and supports the length of the whole growth period for sorghum and peanut. Climate change exerts a positive effect on the vegetative growth period for three crops. Our results identified the main climatic factors regulating cash crop phenology. Wind speed must be incorporated in the process-based model to better account for the phenological variations associated with climate change.