Accurate estimation of crop yield under aeration stress is crucial for field water table management. In this study, the CROPR crop model was improved in two aspects: (i) a new aeration factor, which was related to a drainage index, was proposed and used to represent the condition of soil aeration; and (ii) a multiplicative structure, instead of the original additive structure, was used in the calculation of dry matter accumulation to include the after-effect of aeration stress. Four-year lysimeter experiments on cotton (Gossypium hirsutum L.) growth under aeration stress were conducted from 2008 to 2011 to calibrate and validate both the original and improved CROPR. The results indicated that the improved CROPR performed better than the original CROPR and was suitable for simulating cotton yield under aeration stress. In the calibration, with the improved CROPR, the root-mean-squared error (RMSE) of seed cotton yield was 832.84 kg ha–1 with a normalised value (NRMSE) of 15.87%, whereas with the original CROPR, the RMSE was 973.03 kg ha–1 with an NRMSE of 18.55%. In the validation, with the improved CROPR, the RMSE of seed cotton yield was 686.22 kg ha–1 with an NRMSE of 14.87%; with the original CROPR, the RMSE was 1019.02 kg ha–1 with an NRMSE of 22.08%.

Cotton suffers from alternations of flood and drought in China. A lysimeter trial was conducted to investigate the responses of various cotton yield indices under water-stress treatments including, flood (five-day, eight-day), drought (10-day, 15-day), and five-day flood followed by 10-day drought, during the flowering and boll-forming stage. The results showed that the seed cotton yield was significantly (p < 0.05) reduced under all water-stress treatments, while the harvest index was not affected under any treatment. Significant decreases in dry matter yield, boll number, and boll hull mass were detected under flood treatments but not under drought treatments. The percentage cotton yield losses per day induced by flood and drought were 6.22% and 2.48%, respectively. Under water stress, the associations between seed cotton yield and relevant yield indices were weakened, but yield losses were still strongly related to the decreases in dry matter yield and boll number. Flood followed by drought caused significant reductions in all yield indices except harvest index; however, the reduction was much lower than the additive reductions induced by flood and drought. These results provide bases for scheduling irrigation and drainage under climate change.

In the middle reach of the Yangtze River Plain, cotton (Gossypium hirsutum. L) can experience aeration stress at multiple growth stages, often accompanied by high temperature. These two stresses can negatively affect growth and yield. This study aimed to investigate the responses of cotton at different growth stages to aeration stress, particularly under high temperature. Two field experiments examining cotton responses to aeration stress were conducted over 8 yr, and structural equation modeling was performed to reveal the relationships among aeration stress, high temperature, and the growth and yield of cotton at four growth stages. The interannual variability in the yield‐reducing effect of aeration stress was closely associated with high temperature. Aeration stress and high temperature both interactively (in Experiment 1) and independently (in Experiment 2) reduced seed cotton yield. The interaction between these two stresses was observed only in Experiment 1, in which the impact of aeration stress was relatively slight. In Experiment 1, the growth stage most sensitive to aeration stress changed with high temperature. In both experiments, under high temperature, the sensitivity of seed cotton yield to aeration stress was threefold higher at the flowering and boll‐filling stage than at the other stages. In conclusion, the responses of cotton to aeration stress depend on the time at which aeration stress occurs and the additional impact, if any, of high temperature.

Waterlogging severely restricts cotton (Gossypium hirsutum L.) production worldwide. To assess the impacts of waterlogging on cotton yield, a series of field experiments with multi-form waterlogging were conducted during four cotton growth stages in Hubei Province, China from 2003 to 2011. Moreover, regional waterlogging events were characterized by the sum of excess rainstorm amount index (SER) and the sum of excess standardized precipitation and evapotranspiration index (SESPEI); accordingly, the spatiotemporal variations in waterlogging in Hubei Province during 1961-2019 were analyzed. The results showed that the 1980s was the most waterlogging-prone decade and northeastern Hubei was the most waterlogging-prone region for Hubei. The impact of surface waterlogging on cotton was greater than that of subsurface waterlogging, and the impact of their combined stress was lower than the additive effects of individual stresses. The most waterlogging-sensitive cotton growth stage was the flowering and boll-forming stage, whereas the most waterlogging-proneness growth stage was the budding stage. A normalized waterlogging index integrating both waterlogging sensitivity and proneness indicated that the budding and the flowering and boll-forming stages were the periods when cotton suffered the greatest waterlogging impacts. Both the SESPEI and SER were significantly (p < .05) and negatively related to the detrended cotton yield, and the former was found more efficient in describing the negative effects of waterlogging. In conclusion, different forms of waterlogging should be accounted for in-field drainage schedules, and extra attention should be paid during the budding and the flowering and boll-forming stages of cotton, especially for northeastern Hubei.