Effects of different types and rates of potassium fertilizer on yield and quality of cauliflower

In order to develop rational potassium(K) fertilization and increase K use efficiency,field experiments were conducted on soils with different fertility levels to study the effects of different rate of potassium sulfate and potassium chloride on cauliflower yield and quality.The results showed that K fertilization increased cauliflower yield significantly as compared with control.Cauliflower yield was less responsive to potassium chloride than to potassium sulfate,which was influenced by soil Cl content and K rates.The K nutrient use efficiency(NEU) decreased with K rates.Potassium sulfate had higher NEU than potassium chloride.Applying K fertilizers increased Vc content of cauliflowers,but high K rate could have negative effect on Vc content.The actual effects of K fertilization on Vc were affected by soil K levels.Significant differences were detected between different types of K fertilizers,with potassium sulfate having better effects on Vc than potassium chloride at medium and high fertilization rates.K fertilization decreased total amino acid(AA) content,although AA content of cauliflower treated with potassium chloride was higher than that treated with potassium sulfate,especially glutamic acid and alanine.K increased nutrient uptake of cauliflower,with potassium chloride being favorable to the uptake of K,translocation of N,Ca and Mg while hindering the translocation of K from stalks to florets of cauliflower.The differences of yield and quality between types of K fertilizer were highly related to the companying Cl of K fertilizer and soil Cl content.In soils with high Cl,potassium sulfate was better for cauliflower.