Optimization of appropriate boron fertilization application range for two cotton(Gossypium hirsutum L.)varieties in boron‑deficient soilsOA

Background Boron(B)constitutes a critical yield constraint in global cotton production.Although B application plays a vital role in cotton yield,research gaps persist regarding cultivar-specific B requirements,vertical canopy dynamics,and precision management protocols in B-deficient agroecosystems.Results In this study,we investigated the effects of B application rates on yield variation and spatial variation across two varieties at three locations.In Yancheng,applying 2.5 kg·hm^(−2) of boron resulted in yield increases of 14.7%-25.9%,and in Xinghua,applying 2.0 kg·hm^(−2) of boron achieved yield increases of 17.30%-20.58%.The optimal B application rates determined by quadratic function fitting were 1.90-2.36 kg·hm^(−2) of boron for CCRI 425 and 2.05-2.36 kg·hm^(−2) for Siza 3.Vertical canopy analysis revealed that the middle canopy(FB5-8),contributing 48.2%of total yield,responded significantly to B application rates.Conclusions Cultivar-tailored B application within 1.90-2.36 kg·hm^(−2) reconciles yield maximization.The boll number,especially those in the middle canopy,responded significantly to B application rates and was the main factor contributing to differences in yield formation.These findings underscore the necessity of location-and cultivar-specific B management.