Technical Key Points for Applying Biogas Fertilizer to Apple Trees

In addition to being rich in the major elements nitrogen, phosphorus and potassium, biogas fertilizer also contains trace elements such as boron, copper, iron, manganese, calcium and zinc that play an important role in fruit tree growth, as well as large amounts of organic matter, various amino acids and vitamins. In addition, applying biogas fertilizer can significantly improve the soil, ensure a good microecological environment needed for fruit tree growth, help enhance their frost and drought resistance, and reduce pests and diseases. Under normal circumstances, cultivating fruit trees with biogas fertilizer can save about 150 yuan in investment per 1/15 hectare and increase yield by 12%-28%. The specific methods for cultivating fruit trees with biogas fertilizer are introduced as follows:

1. Apply sprouting fertilizer before flowering

The fertilization time is from early February to late March (depending on the flowering period of different fruit trees and different varieties), and the amount applied accounts for 25% of the annual fertilization amount. Apply about 25 kg of biogas residue or 50 kg of biogas slurry per tree, plus 0.3 kg of borax, and cover with soil promptly (if biogas fertilizer is insufficient, supplement with nitrogen, phosphorus and potassium fertilizers). At the same time, use biogas slurry filtered through double-layer gauze to spray the tree canopy, spraying about once every 10 days.

2. Apply sufficient fruit-setting fertilizer during the flowering period

The flowering of fruit trees and the growth of fruit after flowering each year both require relatively more nutrients, and the amount of fertilizer applied at this time accounts for 50% of the annual fertilization amount. Apply about 50 kg of biogas residue or 100 kg of biogas slurry per tree, plus 0.5 kg of potassium dihydrogen phosphate (if the tree vigor is weak and biogas fertilizer is insufficient, chemical fertilizers must be used to supplement). At the same time, spray biogas slurry on the leaf surfaces of the tree canopy, spraying once every 10 days for better results.

3. Heavily apply the post-harvest “recovery fertilizer”

The “recovery fertilizer” should be applied after the fruit trees are harvested, generally before the end of October, and the amount used accounts for 25% of the annual fertilization amount. Apply 25 kg of biogas residue or 50 kg of biogas fertilizer per tree (this may be appropriately increased or decreased according to the fruit quantity of that year and the size of the tree canopy), and borax may also be mixed with biogas residue at the usual rate and applied.

4. Precautions

When spraying biogas slurry on fruit tree leaf surfaces, biogas slurry from the discharge chamber of a biogas digester that has been producing gas normally for more than 3 months must be used, and it must be clarified, filtered and left to stand for 2-3 days; leaf surface spraying should be carried out on a windless sunny or cloudy day, and it is best to choose early morning or evening when humidity is relatively high, and it must not be sprayed on rainy days or at noon on sunny days when the temperature is relatively high; determine the fertilization amount and operating techniques according to the growth vigor of the fruit trees, applying heavily to those with poor growth, lightly to those with good growth, heavily to old and declining trees, lightly to young and vigorous trees, heavily to those bearing many fruits, and lightly to those bearing few fruits; biogas slurry may be broadcast on the roots or applied deeply in trenches, while biogas residue should be applied deeply in trenches.