Abstract:

To understand the effect of bio-organic fertilizer on growth and soil microbial functional diversity, one-year-old ‘Yanfu No.8’ apple seedlings were used as materials in pot experiment, and four treatments were set up, namely: chicken manure CK [35 g/(kg·soil)], bio-organic fertilizer T1 [23.3 g/(kg·soil)], T2 [35 g/(kg·soil)] and T3 [70 g/(kg·soil)]. The results showed that bio-organic fertilizer could promote the growth of apple seedlings. Among the treatments, the plant height and root length under 23.3 g/(kg·soil) treatment significantly increased by 14.24% and 24.02% compared with those under CK, while the difference between 23.3 g/(kg·soil) treatment and other treatments was significant. Bio-organic fertilizer could enhance the resistance of apple seedlings and promote nutrient absorption. Leaf proline content, chlorophyll SPAD value and potassium content significantly increased by 38.46%, 15.45% and 27.33%, while the MDA content was decreased significantly under 23.3 g/(kg·soil) treatment. The soil microbial Shannon's index H', richness index S, McIntosh index U, and soil microbial utilization of carbohydrates and amines in the treatment of 70 g/(kg·soil) were the highest, increased by 0.91%, 7.60%, 4.14%, 6.33%, and 18.92% compared with those of CK. respectively, while the difference between 70 g/(kg·soil) and 23.3 g/(kg·soil) treatments was not significant. In the principal component analysis, the 23.3 g/(kg·soil) bio-organic fertilizer treatment had the highest score. Therefore, bio-organic fertilizer can improve the growth, stress resistance and nutrient absorption of apple seedlings, and soil microbial functional diversity and utilization intensity of carbon source, and 23.3 g/(kg·soil) treatment is the best.

Key words: bio-organic fertilizer, apple seedling, physiological characteristics, functional diversity of soil microbial communities