Abstract

Soil aggregates are the key functional units of soil ecosystems which are essential to biogeochemical cycling and plant growth. However, it remains unclear how fertilization regimes influence soil aggregation, associated resources, and microbial distribution among aggregates, as well as the potential subsequent impacts for other abiotic and biotic processes. For this, a long-term maize cropping field experiment was conducted in the subtropical region of China under four fertilization treatments: no fertilizer, chemical fertilization, organic fertilization, and chemical plus organic fertilization. Additionally, we classified soil aggregates into large macro aggregates (>2 mm), small macro-aggregates (0.25-2 mm), and micro-aggregates (<0.25 mm) and compared soil nutrients, enzyme activities, and microbial communities of each aggregate fraction and bulk soil as well as crop productivity and plant carbon (C), nitrogen (N), and phosphorus (P). Results showed that long-term organic fertilization (1) increased soil C, N, and P contents within macro-aggregates, while increased bacterial and fungal biomass within all three aggregate size fractions, (2) increased N-acquiring enzyme activity, C:P, and N:P enzyme ratios but decreased phosphatase activity and C:N enzyme ratio regardless of aggregate fractions, and (3) promoted crop productivity but decreased plant C:N, C:P, and N:P ratios compared with chemical fertilization. Additionally, the fungi:bacteria ratio and phosphatase activity decreased, but the gram-positive to gram-negative bacterial ratio, C-acquiring enzyme activity, C:N and C:P enzyme ratios increased with decreasing aggregate size. The partial least squares models confirmed that macro-aggregates had strong effects on crop performance while micro-aggregates was the main determinant of microbial community. Taken together, long-term organic fertilization promotes soil functioning and crop productivity via increasing the proportion of soil macro-aggregates.

Keywords

Soil aggregates; Fertilization regimes; Microbial community; Nutrient stoichiometry; Soil functioning; Agriculture sustainability

Published in

Soil Biology and Biochemistry
2022, Volume: 165, article number: 108533
Publisher: PERGAMON-ELSEVIER SCIENCE LTD

SLU Authors

• Tian, Shanyi

  • Department of Forest Ecology and Management, Swedish University of Agricultural Sciences
    
  • Jiangsu Collaborat Innovat Ctr Solid Organ Waste
  • Nanjing Agricultural University

• Kardol, Paul

  • Department of Forest Ecology and Management, Swedish University of Agricultural Sciences
    

Sustainable Development Goals

SDG2 Zero hunger


UKÄ Subject classification

Soil Science


Publication Identifiers

DOI: https://doi.org/10.1016/j.soilbio.2021.108533

Permanent link to this page (URI)

https://res.slu.se/id/publ/116855