Potassium application to the cover crop prior to cotton planting as a fertilization strategy in sandy soils

This study investigated the efficacy of applying potassium (K) to ruzigrass (*Urochloa ruziziensis*) cover crop before cotton planting in sandy soil. The hypothesis was that this approach could effectively cycle K, ensuring sufficient cotton nutrition, yield, and quality without the need for split K application. Field experiments compared different K management strategies, including applying K to ruzigrass, to cotton after grass, without grass, or split application (conventional method). No yield differences were found among K-fertilized treatments. However, 0 K resulted in low cotton yields, which increased by 16% with prior ruzigrass growth. Short fiber content was reduced with increased K availability, and ruzigrass increased micronaire similarly to 116 kg ha⁻¹ K application without the grass. Fiber maturity improved with K applied to the grass or split application. The study concludes that ruzigrass allows early K fertilization, and potential K rate reductions due to improved efficiency.

Fábio Rafael Echer, Vinicius José Souza Peres, Ciro Antonio Rosolem