[Effect of Biochar-based Fertilizer Application on Soil Enzyme Activity， Fungal Community， and Crop Yield in Winter Wheat-Summer Maize Rotation Farmland].

A study was conducted on the application of biochar-based fertilizer in winter wheat-summer maize rotation farmland in North China， including changes in soil nutrients， enzymes， fungal communities， and crop yield， to provide evaluation basis for the field application of biochar-based fertilizer. In the winter wheat summer maize rotation planting area in northern Henan， four treatments including no fertilization （CK）， high nitrogen application （N1）， optimized nitrogen application （N2）， and biochar-based fertilizer （TF） were set up through field positioning experiments. High-throughput sequencing technology was used to study the changes in soil fungal community composition and its relationship with soil physical and chemical properties， enzyme activity， and crop yield after long-term application of biochar-based fertilizer. The results showed that continuous application of biochar-based fertilizer significantly increased soil organic carbon content by 10.9% and soil total nitrogen content by 8%. The application of biochar-based fertilizer increased soil urease， invertase， and <i>β</i>-glucosidase activity by 31.5%， 13.9%， and 12.6%， respectively. The application of biochar-based fertilizer increased the soil fungal Ace， Shannon， Chao， and Sobs indices， but there was no significant difference among the treatments. The average abundance of the subphylum Ascomycota， Mortierellomycota， unclassified fungi， and Basidiomycota in the soil fungal community was 74.8%， 8.3%， 6.9%， and 6.4%， respectively. The TF treatment increased the relative abundance of Ascomycota by 6.78% and 0.6% compared to in the N1 and N2 treatments， while reducing the relative abundance of Basidiomycota by 30.0% and 8.88%. TF increased the abundance of the Mortierellomycota and Chytridiomycota by 16.3% and 7.0%， respectively， compared to that in N2. At the genus level， the application of biochar-based fertilizer reduced the abundance of <i>Lophotrichus</i> and increased the abundance of <i>Pyrenochaetopsis</i>. The abundance of N2 and TF <i>Fusarium</i> fungi was 35.7% and 14.5% lower than that of N1， respectively. There was a significant negative correlation between soil organic carbon and the Rozellomycota and unclassified fungi. Soil total phosphorus was significantly positively correlated with the Zoopagomycota and negatively correlated with the Rozellomycota. There was a significant negative correlation between soil nitrate-nitrogen and the unclassified fungi. The ascomycetes were significantly positively correlated with soil sucrase， and the Mortierellomycota were significantly positively correlated with soil urease and <i>β</i>-glucosidase. The unclassified fungal phylum exhibited a significant negative correlation with soil urease. Redundancy analysis indicated that soil organic carbon， total nitrogen， and nitrate-nitrogen were the main environmental factors affecting the soil fungal community. The application of biochar-based fertilizer increased wheat and maize yields， with maize yield increasing more. The results of random forest indicated that soil fungal Simpson index and soil urease activity were important for crop yield. In summary， the application of carbon-based fertilizer increased the soil organic carbon and total nitrogen content， soil enzyme activity， and the relative abundance of most dominant fungal phyla in winter wheat and summer maize rotation farmland in North China and had a positive effect on the improvement of crop yield.