Impact of climate change and crop management on cotton phenology based on statistical analysis in the main-cotton-planting areas of China

Abstract

Phenology is one of the prominent indicators for studying the impact of climate change on crop production. Based on cotton phenology and meteorological data from 79 agricultural weather stations in China between 1981 and 2017, the Pearson correlation, multi-variate linear regression and path analysis are applied to investigate the spatial and temporal changes of cotton phenological indices and climate variables (precipitation (Pre), sunshine duration (Sun), average (Tave), minimum (Tmin) and maximum temperatures (Tmax), influence degrees of Pre, Sun, and Tave on phenology, and isolated effects of climate change and crop management on cotton phenology. The results showed that: (1) Emergence (Eme), squaring (Squ), flowering (Flo), and boll opening (Bol) dates of cotton advanced by 0.026–0.351 days year−1, respectively. The cotton sowing (Sow) and maturity (Mat) dates were delayed by 0.170 and 0.337 days year−1. The average phenological stages from Sow-Eme, Squ-Flo, and Flo-Bol were shortened about 0.19–0.30 days year−1, Eme-Squ, Bol-Mat and the Sow-Mat were delayed by 0.11, 0.77, and 0.082 days year−1, respectively. (2) Pre had a positive effect on most of the lengths phenological stages of cotton except during Bol-Mat. The effect of Sun on the length of the various phenological stages of cotton was the opposite of that of Pre. Tave, Tmin, and Tmax on the general negative effects on the length of the cotton phenological stages. (3) Pre, Sun, and Tave had different influence degrees on the cotton phenological stages because of different regional climate characteristics. (4) The impact of climate change on cotton phenology was weaker than crop management or combined effects of climate change and crop management. Under the combined impacts, and isolated impact of crop management, the lengths of the stages from Sow-Eme and Squ-Flo were shortened while other phenological stages were extended. The isolated impact of climate change shortened the lengths of stages from Sow-Eme, Eme-Squ, and Flo-Bol, extended Squ-Flo, Bol-Mat, and Sow-Mat, implying that the longer-duration cotton varieties in a changing climate might be a better choice for planting. This could be a viable strategy for adapting to climate change. In addition, the study found that Seed cotton yield (Scy) decreased with the delay of Sow, Eme, Squ, Flo and Bol dates, increased with the increase of the lengths of Sow-Eme, Flo-Bol, Bol-Mat and Sow-Mat. And the change trend of Scy affected by climate change was less than that affected by crop management or combined effects.