The long-term (25 years) effect of using chemical fertilizers and animal manure on soil phosphorus (P) composition and phosphatase activities was investigated in this study. Results showed that pig manure applications significantly increased soil total P, Olsen P, and phosphatase activities, whereas chemical fertilizers had no significant effects on soil chemical properties and phosphatase activities. Manure applications doubled or tripled the orthophosphate concentrations as compared to chemical fertilizers. Analysis of solution ³¹P nuclear magnetic resonance (NMR) spectroscopy showed that P composition in sodium hydroxide (NaOH)–ethylenediamenetetraacetic acid (EDTA) extracts was dominated by orthophosphate (59–84%), followed by phosphomonoesters (15–40%). More organic P (P_o), especially myo-inositol hexakisphosphate, was observed in soil treated with manure as compared with soil treated with chemical fertilizer.

The breeding of laying hens and broilers in China has increased tremendously. Wet organic fertilizer prepared from hen manure using high-temperature container fermentation preserves high levels of nutrients and a diverse microbial community. We applied low doses of organic fertilizer to peanuts in the black soil area of China’s northeastern region. Based on the calculation of nitrogen content, treatments were set as follows: chemical fertilizer (PCF), organic fertilizer (POF, 4500 kg·ha⁻¹), and replacement of 50% chemical fertilizer with organic fertilizer (PR, 2250 kg·ha⁻¹). Compared to the plots with chemical fertilizers, the use of organic fertilizer and replacing 50% of the chemical fertilizers with organic fertilizer significantly increased peanut yields. Both the organic fertilizer and replacing 50% of the chemical fertilizers with organic fertilizer did not significantly affect the activities of the most tested soil enzymes related to carbon transformation and the absolute abundance of microorganisms. However, they did significantly enhance soil dehydrogenase and α-glucosidase. The community abundance ratio of fungi/bacteria trended downward, leading to soil with a high-fertility bacterial composition. The replacement of 50% chemical fertilizer with organic fertilizer significantly enhanced the species richness and diversity of the bacterial and fungal communities. Organic fertilizer treatment significantly increased the relative abundance of Gemmatimonas and Sphingomonas. The relative abundance of Mycobacterium in the treatment where 50% of the chemical fertilizers were replaced with organic fertilizer was significantly lower than that in the organic fertilizer treatment. PCoA results showed that the low-dose organic fertilizer treatment, replacing 50% of the chemical fertilizers with organic fertilizer, had a significant impact on the composition of soil bacterial communities.

A field experiment was conducted in northeast China to examine the response of nitrogen cycling enzymes, that is, protease, N‐acetyl‐β‐D‐glucosaminidase (NAG), amidase, urease, and peptidase, as well soil organic nitrogen (SON) fractions and their relationships to RT (no maize residue application), NT (no tillage with maize residues placed on the surface), TT (plow maize residues into the soil at 0–35 cm depth in the first year, 0–20 cm in the second year, and 0–15 cm in the third year), and PT (plow maize residues into soil at 0–35 cm depth). The results have shown that NT significantly enhanced the activities of protease and NAG at 0–10 cm soil depth in comparison with other treatments. NT and TT significantly enhanced the activities of protease compared to RT and PT at 10–20 cm soil depth. TT significantly enhanced the activities of NAG in comparison with RT at 10–20 cm soil depth. TT and PT significantly enhanced the activities of NAG and peptidase compared to RT and NT at 20–35 cm soil depth. PT significantly increased the activities of protease in comparison with RT at 20–35 cm soil depth. NT, TT, and PT significantly enhanced the activities of peptidase compared to RT at 10–20 cm soil depth. NT significantly increased the concentration of hydrolyzable in comparison with other treatments at 0–10 cm soil depth. PT significantly enhanced the concentration of hydrolyzable and amino acid N compared to other treatments at 20–35 cm soil depth. Redundancy analysis showed that protease played a crucial role in the cycling of SON under RT and NT, whereas peptidase and NAG played a significant role in the cycling of SON under TT and PT, respectively. This study provided a comprehensive understanding of crop residue return methods for regulating soil N cycling.

The utilization of agricultural waste organic materials through composting technology has gained significant traction in agricultural production as an effective means of crop nutrient management. However, the differences in the impact of organic amendments prepared by traditional composting and vermicomposting on soil properties still deserve further research. Based on field experiments conducted in greenhouse, compared to chemical fertilizer treatments as control, we utilized traditional compost (OF) and vermicompost (VcF) derived from agricultural organic waste edible mushroom bran and cow manure (2:8). Variations in soil physiochemical properties, activities of soil enzymes related C and P cycling, abundances and diversities of bacterial 16S rRNA and fungal ITS gene at total DNA level were analyzed. Both compost treatments enhanced soil organic carbon, soil total phosphorus, and soil available P content significantly and also increased the activities of soil α‐glucosidase, β‐glucosidase, acid phosphomonoesterase, and alkaline phosphomonoesterase significantly. The above results suggested that soil C and P transformations were stimulated effectively by both organic amendments. OF and VcF increased the fungal ITS absolute abundances significantly while diversity indices of soil bacterial community increased significantly under both treatments. Correlation analysis indicated that bacterial community composition was strongly correlated with several soil property indexes while fungal community composition was only significantly correlated with soil total phosphorous content. In conclusion, similar to traditional compost, vermicompost significantly improved soil nutrient cycling (especially C and P aspects). In terms of soil microbes, bacteria and fungi showed different responding mechanism to vermicompost: bacteria adjust microbial structure, while fungi tend to proliferated. In consideration of the advantages of vermicompost in technology and economic cost, it could be applied in the subsequent agricultural production more frequently.