Potassium requirements and effects of K fertilizer application on yield and quality of bananas in Guangxi, China

According to the statistical results of field experiments, banana yield has a strong, positive correlation with the amount of potassium bananas absorb. The correlation coefficient is r=0.915**. The function of yield (y) with absorbed potassium (x) was y=16351.9+1.01x. For banana grown on medium light soils (sandy loam soils), the critical soil K value was 76.8 mg kg-1 of available K. The K supply classes established by statistical analysis were: -1, 76.8-155 mg kg-1 and >155 mg kg-1, corresponding to low, medium and high K supply, respectively. The soil available potassium was lower than 155 mg ⁄ kg in most banana planting regions. After potassium fertilizer was applied, the banana plant yield increased significantly. Banana yield increased 32.38-66.60% when the rate of potassium application was between 477-954 kg ⁄ ha. Application of phosphorus fertilizer also increased the banana yield. It is clear from this study that the application of K fertilizer also markedly increased banana quality.