What kind of fertilizer should be used to make pear trees sweeter?

Potassium fertilizer is the core for increasing sweetness. Calcium, magnesium, boron and other trace elements help increase sugar content and prevent fruit cracking. The specific measures are as follows: 15 to 20 days after flowering, during the fruit expansion period, apply high-potassium water-soluble fertilizer and humic acid by drenching, and spray 0.2% phosphoric acid dihydrogen potassium and fluid boron on the leaves. Reduce the application of high-nitrogen fertilizers such as urea; 50 days before maturity (the hard core stage), apply low-nitrogen high-potassium potassium sulfate compound fertilizer by root application, combined with fully decomposed manure or rapeseed cake and other organic fertilizers, which can enhance fruit aroma and naturally increase sweetness. Avoid applying potassium chloride. Spray 0.3% phosphoric acid dihydrogen potassium + sugar alcohol calcium + sugar alcohol magnesium once every 10 days, for 2 to 3 consecutive times; during the color change stage, this is the key period for quickly increasing sugar content and eliminating sourness. Only apply high-potassium fertilizers, completely stop nitrogen fertilizers. Apply pure potassium sulfate water-soluble fertilizer by root application, and spray 0.3% phosphoric acid dihydrogen potassium + fruit-specific glucose foliar fertilizer + boron on the leaves once every 7 days, for 2 consecutive times. The base fertilizer should be mainly composed of decomposed organic fertilizers, combined with a small amount of balanced compound fertilizer + superphosphate.