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Study region: The China-Pakistan Economic Corridor (CPEC) is a critical hub of the ''Belt and Road'' initiative, making it particularly vulnerable to drought effects driven by climate change and human activities. Study focus: This study evaluates the Standardized Precipitation Evapotranspiration Index (SPEI) and the Soil Moisture Deficit Index (SMDI) at 0–10 cm and 10–40 cm depths using monthly grid data for meteorological and soil moisture from 1981 to 2021. The Run Theory, principal component analysis, and other methodologies were employed to analyze drought evolution and its driving factors. New hydrological insights for the region: The longer the timescale, the stronger the correlation between SPEI and SMDI. ''Dryness-dryness,'' indicating prolonged low moisture, and ''dryness-wetness,'' marking transitions to wetter conditions, were recorded during 1998–2003 and 2016–2021, respectively. Spatial trend analysis revealed significant declines in SPEI during summer and winter, while SMDI showed an upward trend in the northeast and southwest regions of CPEC. As indicated by the SPEI, SMDI0–10, and SMDI10–40, extreme drought events occurred with respective counts of 10, 8, and 6. These significant drought events primarily affected Sindh, Punjab, and Gilgit-Baltistan. The study identifies strong correlations (r > 0.7) between drought indices and climate factors, with atmosphere status exerting the more significant impact on drought in CPEC. These insights are invaluable for formulating effective drought monitoring and early warning systems within the CPEC region.

Verticillium wilt is one of the most crucial diseases caused by Verticillium dahliae that threatens the cotton industry. Statistical results showed that the return of cotton plants infected with V. dahliae to the field might be an essential cause of the continuous aggravation of cotton Verticillium wilt. The correlation among the cotton plants infected with V. dahliae returning to the field, the occurrence of Verticillium wilt, and the number of microsclerotia in rhizosphere soil need further investigation. A potted experiment was carried out to explore the effects of the direct return of cotton plants infected with Verticillium dahliae to the field on the subsequent growth and Verticillium wilt occurrence in cotton. As a risk response plan, we investigated the feasibility of returning dung-sand (i.e., insect excreta) to the field, the dung-sand was from the larvae of Protaetia brevitarsis (Coleoptera: Cetoniidea) that were fed with the V. dahliae–infected cotton plants. The results demonstrated that the return of the entire cotton plants to the field presented a promotional effect on the growth and development of cotton, whereas the return of a single root stubble or cotton stalks had an inhibitive effect. The return of cotton stalks and root stubble infected with V. dahliae increased the risk and degree of Verticillium wilt occurrence. The disease index of Verticillium wilt occurrence in cotton was positively correlated with the number of microsclerotia in the rhizosphere soil. The disease index increased by 20.00%, and the number of soil microsclerotia increased by 8.37 fold in the treatment of returning root stubble infected with V. dahliae to the field. No Verticillium wilt microsclerotia were detected in the feed prepared from cotton stalks and root stubble fermented for more than 5 days or in the transformed dung-sand. There was no risk of inoculation with Verticillium wilt microsclerotia when the dung-sand was returned to the field. The indirect return of cotton plants infected with V. dahliae to the field by microorganism–insect systems is worthy of further exploration plan of the green prevention and control for Verticillium wilt and the sustainable development of the cotton industry.