In-Situ Decomposition Dynamics of Cotton Fruiting Structures Under Changing Environmental Conditions

IntroductionG lobally, cotton is the most important natural fiber with economic significance; it plays an important role in boosting the agricultural based economic growth of the country.Its yield is contingent upon environmental factors and agricultural management techniques.In recent years, climate change caused Abstract | Cotton (Gossypium hirsutum L.) sheds a significant portion of its fruiting structures, however the decomposition of these residues and their contribution to soil nutrient cycling remain poorly understood.This study was conducted during 2020 and 2021 across three cotton growing locations of Sindh, Pakistan, namely Cotton Research Station (CRS)-Ghotki, Central Cotton Research Institute (CCRI)-Sakrand, and Sindh Agriculture University (SAU)-Tandojam to evaluate the decomposition dynamics of cotton fruiting structures (squares, flowers, leaves, and mixtures) under changing climate.Residues were placed in mesh bags, buried at 20 cm soil depth, and monitored two-month intervals to assess mass loss, decomposition constant (k), mean residence time (MRT), and nutrient release (C, N, P, K).Decomposition varied significantly by location and season, with faster mass loss under warm, humid conditions.Leaves and flowers decomposed more rapidly than squares due to their lower C:N ratios, while squares and mixed residues showed slower breakdown and longer MRT.Leaves contained the highest nutrient concentrations, whereas higher C:N ratios in squares and flowers limited nutrient turnover.Temperature and rainfall were positively correlated with decomposition rates, while higher humidity prolonged MRT.These findings revealed that cotton fruiting residues were integral to soil organic matter (OM) formation and nutrient cycling.They further emphasized the need to incorporate their in-situ decomposition into soil fertility management strategies to enhance nutrient availability and strengthen system resilience under changing climatic conditions.