Study on the Best Mode for Burying Fermentation of Fruit Tree Branches

Objective  In order to reduce the labor consumption of picking up, transporting, crushing, composting and fertilizing of branches in the process of branch fertilizer, a time-saving and labor-saving branch fertilizer technology under the background of rural labor shortage was explored.

Method  Deep ditches with width of 30-35 cm and depth of 35- 40 cm were opened in the operation line by using ditching machine, the branches, fallen leaves and withered grasses were filled in the ditches, and then the microbial agent, urea and soil conditioner were added to cover the soil for backfilling(the backfilling depth was 8-10 cm). The effects of the mode of burying fermentation on the decomposition rate of branches, the incidence of rotten disease and ring rot disease of fruit trees, the CO₂ concentration of orchard, the soil temperature and the moisture content were studied.

Result  (1) The decomposition rate of buried and fermented branches showed a trend of decrease-increase-decrease with time passing. According to the proportion of 75 kg/hm² nutrient microbial agent, 50 kg/hm² urea and 20 kg/hm² soil conditioner per hectare, it was found that the annual decomposition rate of treatment 2 was the highest, reaching 40.1%.(2)The incidence of rotten disease and ring rot disease of fruit trees in treatment group was lower than that in CK. The incidences of rotten disease and ring rot disease of fruit trees of treatment 2 were lowest, which were 0 and 15.2% respectively.(3)The concentration of CO₂ in the treatment group was significantly higher than that in CK, and the concentration of CO₂ of treatment 2 was highest, reaching 550 μmol/mol.(4)Among different treatments, the soil temperature was higher than the surface temperature in cold climate, and lower than the surface temperature in hot climate, especially in treatment 2; and the soil moisture content of treatment group was higher than that of CK.

Conclusion  Microbial agent, urea and soil conditioner have the synergistic effect of accelerating the decomposition of branches and increasing the concentration of CO₂ in near-atmosphere layer. The branch burying fermentation technology can reduce the incidence of rotten disease and ring rot disease of fruit trees. Branch burying fermentation can buffer soil temperature and conserve water. Treatment 2 is the best way of branch burying fermentation.