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Title: Eleven years of crop diversification alters decomposition dynamics of litter mixtures incubated with soil

Agricultural crop rotations have been shown to increase soil carbon (C), nitrogen (N), and microbial biomass. The mechanisms behind these increases remain unclear, but may be linked to the diversity of crop residue inputs to soil organic matter (SOM). Here, we used a residue mixture incubation to examine how variation in long-term diversity of plant communities in agroecosystems influences decomposition of residue mixtures, thus providing a comparison of the effects of plant diversification on decomposition in the long term (via crop rotation) and short term (via residue mixtures). Three crop residue mixtures, ranging in diversity from two to four species, were incubated for 360 d with soils from five crop rotations, ranging from monoculture corn (mC) to a complex five-crop rotation. In response, we measured fundamental soil pools and processes underlying C and N cycling. These included soil respiration, inorganic N, microbial biomass, and extracellular enzymes. We hypothesized that soils with more diverse cropping histories would show greater synergistic mixture effects than mC. For most variables (except extracellular enzymes), crop rotation history, or the long-term history of plant diversity in the field, had a stronger effect on soil processes than mixture composition. In contrast to our hypothesis, the mC soilmore » had nearly three and seven times greater synergistic mixture effects for respiration and microbial biomass N, respectively, compared with soils from crop rotations. This was due to the low response of the mC soils to poor quality residues (corn and wheat), likely resulting from a lack of available C and nutrients to cometabolize these residues. These results indicate that diversifying crop rotations in agricultural systems alter the decomposition dynamics of new residue inputs, which may be linked to the benefits of increasing crop rotation diversity on soil nutrient cycling, SOM dynamics, and yields.« less
 [1] ;  [2] ;  [3] ;  [4]
  1. Univ. of New Hampshire, Durham, NH (United States). Dept. of Natural Resources and the Environment; Iowa State Univ., Ames, IA (United States). Dept. of Agronomy
  2. Univ. of New Hampshire, Durham, NH (United States). Dept. of Natural Resources and the Environment
  3. Univ. of New Hampshire, Durham, NH (United States). Dept. of Natural Resources and the Environment; Michigan State Univ., East Lansing, MI (United States). Dept. of Plant, Soil and Microbial Sciences
  4. Univ. of Toledo, OH (United States). Dept. of Environmental Sciences
Publication Date:
Grant/Contract Number:
FC02-07ER64494; AC05-76RL01830; 2014-67019-21716; DEB 1027253; ACO5-76RL01830
Published Article
Journal Name:
Additional Journal Information:
Journal Volume: 7; Journal Issue: 8; Journal ID: ISSN 2150-8925
Ecological Society of America
Research Org:
Univ. of Wisconsin, Madison (United States); Pacific Northwest National Lab., Richland, WA (United States)
Sponsoring Org:
USDOE Office of Energy Efficiency and Renewable Energy (EERE); USDA; National Science Foundation (NSF)
Country of Publication:
United States
59 BASIC BIOLOGICAL SCIENCES; 54 ENVIRONMENTAL SCIENCES; biodiversity; crop rotation; decomposition; extracellular enzyme activity; litter mixture; microbial biomass; mixture effect; nitrogen mineralization; plant biodiversity; respiration; soil fertility
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1315840; OSTI ID: 1376236