Soil particulate organic matter increases under perennial bioenergy crop agriculture

I. B. Kantola, M. D. Masters, E. H. DeLucia

Research output: Contribution to journalArticlepeer-review

Abstract

Annual row crop agriculture contributes to carbon (C) losses from Midwest soils, while the establishment of perennial crops for food and fuel has the potential to increase soil C stocks. Perennial grasses eliminate the need for tillage and increase belowground biomass, both critical to the accumulation and conservation of soil organic matter and to soil C sequestration. The effect of C4 perennial grasses on particulate organic matter carbon (POM-C), consisting primarily of partially decomposed plant material, was evaluated in Illinois, where native switchgrass (Panicum virgatum L.) and a sterile hybrid of the Asian grass Miscanthus (Miscanthus x giganteus) were planted as bioenergy feedstocks at the University of Illinois Energy Farm in 2008. Six years after establishment of perennial crops, POM-C was compared with a maize-maize-soybean (Zea mays L., Glycine max L.) rotation typical of the area and a 28-species restored prairie. POM-C concentrations increased for all crops between 31 and 71% over 6 years, with the greatest increases in prairie and M. x giganteus soils. POM-C concentrations were highest at the 0–10 cm depth. Isotopic analyses showed 23–44% of POM-C was new C4 material under perennial bioenergy crops after 6 years. As soil organic matter is primarily plant-derived, increases in POM-C reflect increased organic matter inputs or decreases in the rate of decomposition from the cessation of tillage. Increases in POM-C under annual row crops may result from the incorporation of aboveground organic matter by tillage, while POM-C increases in untilled perennial crops mirror increases in belowground biomass. As soil aggregation protects POM-C from microbial degradation, untilled soils under long-term perennial crop production increase the residence time for soil C.

Original languageEnglish (US)
Pages (from-to)184-191
Number of pages8
JournalSoil Biology and Biochemistry
Volume113
DOIs
StatePublished - Oct 2017

Keywords

  • Biomass crops
  • C sequestration
  • Particulate organic matter
  • Perennial crops
  • Soil organic carbon

ASJC Scopus subject areas

  • Microbiology
  • Soil Science

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