Shifts and recovery of soil microbial communities in a 40-year field trial under mineral fertilization

• Published in: Pedobiologia 2019-11, Vol.77, p.150575, Article 150575
• Main Authors: Čuhel, Jiří, Malý, Stanislav, Královec, Josef
• Format: Article
• Language: English
• Subjects: Extracellular enzymes; Long-term field experiment; Microbial community composition; Mineral fertilization; Resilience; T-RFLP
• ISSN: 0031-4056; 1873-1511
• DOI: 10.1016/j.pedobi.2019.150575

•We examined the impact of 40-y mineral fertilization on soil microbial communities.•Fertilization affected the functioning and composition of microbial communities.•Enzyme activities were accompanied by changes in microbial community composition.•Soil bacteria are more resilient to mineral fertilization disturbances than fungi. Inorganic fertilizers have been reported to have effects on both microbial activities and soil microbial community structure. However, the published results are often contradictory. To overcome short-term fluctuations in microbial parameters it is necessary to study their changes over the long term. We investigated the impact of a 40-y inorganic fertilization of a grassland field on selected soil microbial enzymatic activities and on the composition of bacterial and fungal communities, assessed by terminal restriction fragment length polymorphism (T-RFLP). The following fertilizer treatments were compared: C (control, no fertilization), PK (phosphorus and potassium) fertilizer, 80N (lower nitrogen plus PK fertilizer) and 160 N (higher nitrogen plus PK fertilizer). The field trial also included a NF treatment where fertilization with high nitrogen doses was terminated after 20 y, and the subsequent 20 y were under a non-fertilization regime. Except for arylsulfatase, addition of PK was not sufficient intervention to influence enzyme activities. On the contrary, we observed a significant increase in cellobiosidase, phosphomonoesterase, and β-glucosidase activity in soils fertilized with N, although there was no difference in the enzyme activities between the 80N and 160N treatments. The activities of these enzymes in soils under NF treatment returned to the values of the control soils. Decreased activity of arylsulfatase was detected in treatments with fertilization compared to the control treatment. The shifts in the enzyme activities were accompanied by changes in the composition of whole bacterial and fungal communities, which was also affected by the long-term fertilization. Community composition in fertilized soils clearly differed from the control soils. Contrary to bacteria, 20 y following the cessation of fertilization in the NF treatment was not enough time for complete recovery of the fungal community to that observed in the control treatment. Our findings suggested that soil bacteria are more resilient to chemical fertilization disturbances than fungi.