High quality and efficient fertilization management technology of Shatian pomelo

1. Fertilization management of young trees after planting, fertilizer should be applied in time according to the growth of seedlings, but only thin bio-organic fertilizer can be applied to prevent damage to new roots. after that, the amount of topdressing can be gradually increased twice a month. 2. Fertilization management of fruiting trees 1. Re-application of fruit-picking fertilizer: before and after the Beginning of Winter to Lesser Snow (November), combined with soil improvement and hole expansion, fruit-picking fertilizer was re-applied to restore tree potential as soon as possible, promote flower bud differentiation and accumulate nutrients for fruit in the second year. When expanding the hole, each plant applies 15 jin of bio-organic fertilizer, 0.5 jin of phosphate fertilizer and an appropriate amount of nitrogen fertilizer. According to the actual growth of the tree, 0.5% potassium dihydrogen phosphate can be used as external topdressing fertilizer and 0.2% boric acid can be sprayed once to facilitate flower bud differentiation. 2. Strong shoot fertilizer: apply quick-acting fertilizer once from February to March, applying 0.5 jin of urea and 1 jin of phosphate fertilizer per plant. After spring shoot germination, 0.5% potassium dihydrogen phosphate and 0.3% urea can be used for extra-root topdressing (spraying) to promote the development of robust branches and flowers. 0.3% urea and 0.5% potassium dihydrogen phosphate can be used for external topdressing in early and middle March, respectively. 3. Stable fruit fertilizer: fertilizer can be applied according to the growth of the tree from April to May. Compound fertilizer is applied to each plant by 1.5 jin. After the middle of April, 0.5% potassium dihydrogen phosphate is applied outside the root. After flowering, 0.5% magnesium sulfate and 300ppm are sprayed once after flowering. 4. Strong fruit fertilizer: the fruit expands rapidly from July to August, and the fertilizer should be mainly organic fertilizer and available fertilizer. Each plant was fertilized with bio-organic fertilizer 2m / kg, compound fertilizer 0.6 / kg, and urea with half a jin per plant. According to the tree potential, the amount of fruit should be increased as appropriate. When fertilizing, the method of open trench is generally used, with the crown dripping line as the midpoint, the ditch length is 0.5 meters, the depth and width are 0.15 meters, and there are 10 ditches per plant, and the soil is covered after fertilization, and the position should be changed every time.