Evaluating fertilizer value of shedded material from cotton under changing environment

Abstract

Climate change induced environmental stresses have increasedthe shedding of fruiting structures in cotton, resulting in yield losses and altering the return of reproductive biomass to the soil. Although these shedded fruiting structures contain nutrients that may contribute to internal nutrient cycling, their fertilizer value has not been quantified, and current fertilizer recommendations do not account for this potential nutrient contribution. This knowledge gap constrains the development of efficient and climate resilient nutrient management strategies for cotton production. The objective of this study was to quantify the fertilizer value of shed cotton fruiting structures and assess their contribution to nutrient availability, crop productivity, and fertilizer optimization under changing environmental conditions. Field experiments were conducted at three locations (Sakrand, Tandojam, and Ghotki) using a factorial arrangement of fruiting-structure management (retained vs. removed) and six fertilizer levels (0, 20%, 40%, 60%, 80%, and 100% of the recommended fertilizer dose). Yield, yield components, chlorophyll content, quality traits, and nutrient concentration were evaluated. The three-way interaction among location, fruiting structure management, and fertilizer level was non-significant; however, individual effects of fertilizer level and fruiting structure management were significant across locations. Seed cotton yield, yield components, and chlorophyll content increased significantly with increasing fertilizer rates, irrespective of fruiting structure treatment. The highest yields were recorded at 100% RDF, followed by 80%, 60%, 40%, and 20% RDF compared with the unfertilized control, with The greatest response observed at Sakrand, followed by Ghotki and Tandojam. Most fiber quality parameters were significantly influenced by fertilizer levels, regardless of location and fruiting structure shedding. The quantity of shed fruiting structures was highest at Ghotki, followed by Sakrand and Tandojam. Nutrient concentration varied significantly across fertilizer levels under changing environmental conditions. Overall, results indicated that shed fruiting structures contributed up to 9% of cotton yield through nutrient recycling. These findings demonstrate that cotton fruiting structure shedding represents a measurable internal nutrient source and should be considered in fertilizer planning to improve nutrient use efficiency and climate resilience in cotton growing regions