Increased soil organic matter after 28 years of nitrogen fertilization only with plastic film mulching is controlled by maize root biomass

Nitrogen (N) fertilization and plastic film mulching (PFM) are two widely applied management practices for crop production. Both of them impact soil organic matter individually, but their interactive effects as well as the underlying mechanisms are unknown. Soils from a 28-year field experiment with maize monoculture under three levels of N fertilization (0, 135, and 270 kg N ha−1 yr−1) and with or without PFM were analyzed for soil organic C (SOC) content, total soil nitrogen (N), root biomass, enzyme activities, and SOC mineralization rates. After 28 years, N fertilization increased root biomass and consequently, SOC by 26% (averaged across the two fertilizer application rates) and total soil N by 25%. These increases, however, were only in soil with PFM, as PFM reduced N leaching and loss, as a result of a diurnal internal water cycle under the mulch. The SOC mineralization was slower with N fertilization, regardless of the PFM treatment. This trend was attributed to the 43% decrease of β-glucosidase activity (C cycle enzyme) and 51% drop of leucine aminopeptidase (N cycle) with N fertilization, as a result of a strong decrease in soil pH. In conclusion, root biomass acting as the main source of soil C, resulted in an increase of soil organic matter after 28 year of N fertilization only with PFM. © 2021 Elsevier B.V.

Ding F.1 , Ji D.1 , Yan K.1, 2 , Dijkstra F.A.3 , Bao X.4 , Li S. 1 , Kuzyakov Y. 5, 6, 7 , Wang J. 1
Elsevier B.V.
  • 1 College of Land and Environment, Shenyang Agricultural University, Shenyang, 110866, China
  • 2 Institute of Soil and Water Resources and Environmental Science, Zhejiang University, Hangzhou, 310058, China
  • 3 Sydney Institute of Agriculture, School of Life and Environmental Sciences, The University of Sydney, Eveleigh, NSW 2015, Australia
  • 4 Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, 110016, China
  • 5 Department of Soil Science of Temperate Ecosystems, Department of Agricultural Soil Science, University of Gottingen, Göttingen, 37077, Germany
  • 6 Laboratory of Conservation and Dynamic of Volcanic Soils, Department of Chemical Sciences and Natural Resources, Universidad de La Frontera, Temuco, Chile
  • 7 Agro-Technological Institute, RUDN University, Tyumen State University, 117198 Moscow, Tyumen, 625003, Russian Federation
Ключевые слова
Carbon input; Carbon sequestration; Long-term experiment; Nitrogen addition; Nitrogen induced acidification; Soil organic carbon
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