Atmospheric carbon mitigation potential of agricultural management in the southwestern USA

Dean A. Martens, William Emmerich, Jean E.T. McLain, Thomas N. Johnsen

Research output: Contribution to journalArticlepeer-review

46 Scopus citations


Agriculture in the southwestern USA is limited by water supply due to high evaporation and limited seasonal precipitation. Where water is available, irrigation allows for production of a variety of agricultural and horticultural crops. This review assesses the impacts of agriculture on greenhouse gas emission and sequestration of atmospheric C in soils of the hot, dry region of the southwestern USA. In Texas, conservation tillage increased soil organic C by 0.28 Mg C ha-1 year-1 compared with more intensive tillage. Conversion of tilled row crops to the conservation reserve program or permanent pastures increased soil organic C by 0.32 ± 0.50 Mg C ha -1 year-1. Soil organic C sequestration was dependent on rotation, previous cropping, and type of conservation tillage employed. Relatively few studies have interfaced management and C cycling to investigate the impacts of grazing management on soil organic C, and therefore, no estimate of C balance was available. Irrigated crop and pasture land in Idaho had soil organic C content 10-40 Mg C ha-1 greater than in dryland, native grassland. Soil salinity must be controlled in cropland as soil organic C content was lower with increasing salinity. Despite 75% of the region's soils being classified as calcic, the potential for sequestration of C as soil carbonate has been only scantly investigated. The region may be a significant sink for atmospheric methane, although in general, trace gas flux from semiarid soils lacks adequate characterization. Agricultural impacts on C cycling will have to be better understood in order for effective C sequestration strategies to emerge.

Original languageEnglish (US)
Pages (from-to)95-119
Number of pages25
JournalSoil and Tillage Research
Issue number1 SPEC. ISS.
StatePublished - Aug 2005


  • Conservation tillage
  • Irrigation
  • Livestock production
  • No-tillage
  • Soil inorganic carbon
  • Soil organic carbon

ASJC Scopus subject areas

  • Agronomy and Crop Science
  • Soil Science
  • Earth-Surface Processes


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