Thirty four years of nitrogen fertilization decreases fungal diversity and alters fungal community composition in black soil in northeast China

Abstract Black soil is one of the main soil typesin northeast China, and plays an important role in Chinese crop production. However, nitrogen inputs over 50 years have led to reduced black soil fertility. It is unclear how N affects the fungal community in this soil type, so a long-term fertilizerexperiment was begun in 1980 and we applied 454 pyrosequencingand quantitative PCR to targeted fungal ITS genes. There were five treatments: control (no fertilizer), N 1 (low nitrogen fertilizer), N 2 (high nitrogen fertilizer), N 1 P 1 (low nitrogen plus low phosphorus fertilizers) and N 2 P 2 (high nitrogen plus high phosphorus fertilizers). Soil nutrient concentrations (Total N, Avail N, NO 3 − , NH 4 + , etc.) and ITS gene copy numbers increased, whereas soil pHand fungal diversitydecreased in all the fertilizedtreatments. Relationships between soil parameters and fungal communities were evaluated. Dothideomycetes, Eurotiomycetes, Leotiomycetes, Sordariomycetes, and Agaricomyceteswere the most abundant classes in all soils. Principal coordinates analysis showed that the fungal communities in the control and lower- fertilizertreatments clustered closely and were separated from communities where more concentrated fertilizerswere used. Fungal diversityand ITS gene copy number were dependent on soil pH. Our findings suggested that long-term nitrogen and phosphorous fertilizerregimes reduced fungal biodiversity and changed community composition. The influence of the more concentrated fertilizertreatments was greater than the lower concentrations.