Cover crops may affect diversely boron (B) availability and cotton yield, especially in tropical sandy soils. In turn, B fertilizer rates required by cotton can be dependent on the use of cover crops. This study aimed to evaluate cotton yield, soil-plant B dynamics, and soil fertility as a function of cover crops (fallow, millet, black velvet bean, and millet+ black velvet bean) and B fertilization rates (0, 1, 2, 4, and 6 kg ha⁻¹). The experiment was carried out at the field in two crop seasons (2019/2020 and 2020/2021), in Dracena, São Paulo State, Brazil. Cover crops increased cotton fiber yields by 47% compared to fallow soil (average two crops), as well as improved B cycling and soil fertility. Proper B rates increased cotton fiber yield by 18%. A maximum cotton fiber yield was reached at 4 kg B ha⁻¹ (millet + black velvet bean), 2 kg B ha⁻¹ (black velvet bean) in the 2020/2021 crop season, and 1 kg B ha⁻¹ in the other system. Critical levels of leaf B ranged from 12 to 16 mg kg⁻¹. Maximum B uptakes were 182 and 232 g B ha⁻¹ in the first and second crop seasons, respectively. Boron application and cover crops increased B contents in the soil, but it was below 0.6 mg B dm⁻³ in the topsoil. When associated with B fertilization, cover crops, especially the intercropping between millet and black velvet bean, improved soil fertility, plant nutrition, and cotton fiber yields in the tropical sandy soil.

覆盖作物可能会影响不同的硼（B）可用性和棉花产量，特别是在热带沙质土壤中。反过来，棉花所需的 B 肥用量可能取决于覆盖作物的使用。本研究旨在评估棉花产量、土壤植物 B 动态和土壤肥力与覆盖作物（休耕、小米、黑丝绒豆和小米+黑丝绒豆）和 B 施肥率（0、1、2、4 , 和 6 kg ha ^-1 )。该实验在巴西圣保罗州德拉塞纳的两个作物季节（2019/2020 和 2020/2021）的田间进行。与休耕土壤（平均两种作物）相比，覆盖作物增加了 47% 的棉花纤维产量，并改善了 B 循环和土壤肥力。适当的 B 率可使棉纤维产量增加 18%。在 4 kg B ha 达到最大棉纤维产量^-1（小米 + 黑丝绒豆），2020/2021 作物季节为2 kg B ha ^{-1 （黑丝绒豆），其他系统为 1 kg B ha -1}。叶 B 的临界水平范围为 12 至 16 mg kg ^-1。第一季和第二季的最大 B 吸收量分别为 182 和 232 g B ha ^{-1 。}硼施用和覆盖作物增加了土壤中的 B 含量，但在表层土壤中低于 0.6 mg B dm ^-3。当与 B 施肥相结合时，覆盖作物，特别是小米和黑绒豆之间的间作，提高了热带沙质土壤的土壤肥力、植物营养和棉花纤维产量。