Effects of Foliar Potassium Supplementation on Yield and Nutrient Uptake of Plant Sugarcane

Sugarcane, a globally significant economic crop, depends on potassium (K) for critical processes such as photosynthesis and sugar translocation. This study explored the impacts of various foliar K supplements, including 2.5% w/v KCl, KNO3, K2SO4, and K2SiO3, alongside diluted molasses and vinasse (5 x dilution). The field experiment was conducted on sugarcane grown in soil with sufficient soil K levels, applying foliar solutions at 120 days at 2667 L/ha. The results indicated that combining soil chemical fertilizers with foliar K2SiO3 and KNO3 resulted in the highest yields of 155.19 and 154.81 tons/ha, respectively, significantly outperforming the foliar water combined with soil chemical fertilizers (132.81 tons/ha) and the control (no basal fertilizer with foliar water, at 130.67 tons/ha, P <= 0.05). This enhancement is expected to result from the improvement in chlorophyll content and photosynthesis, enabled by timely K and nutrient acquisition, bypassing root transport. However, no significant differences were noted among the foliar K forms. Foliar K application also affected nutrient concentrations and uptake, with molasses showing the highest nutrient absorption in stalks: N (322 kg/ha), K (215 kg/ha), S (80.9 kg/ha), and Si (23.2 kg/ha) (P <= 0.05). These findings provide valuable insights and recommendations for utilizing foliar application of K2SiO3 and KNO3 to improve plant sugarcane yield, as well as employing molasses foliar application to enhance nutrient uptake in sugarcane cultivated in soils with adequate K.