Agrarian legacy in soil nutrient pools of urbanizing arid lands

Authors

  • DAVID BRUCE LEWIS,

    1. School of Life Sciences, Arizona State University, Tempe, AZ, USA,
    2. Global Institute of Sustainability, Arizona State University, Tempe, AZ, USA,
    Search for more papers by this author
    • 1Present address: Department of Crop and Soil Sciences, The Pennsylvania State University, 116 ASI Building, University Park, PA 16802-3504, USA.

  • JASON P. KAYE,

    1. Department of Crop and Soil Sciences, The Pennsylvania State University, University Park, PA, USA
    Search for more papers by this author
  • CORINNA GRIES,

    1. Global Institute of Sustainability, Arizona State University, Tempe, AZ, USA,
    Search for more papers by this author
  • ANN P. KINZIG,

    1. School of Life Sciences, Arizona State University, Tempe, AZ, USA,
    2. Global Institute of Sustainability, Arizona State University, Tempe, AZ, USA,
    Search for more papers by this author
  • CHARLES L. REDMAN

    1. Global Institute of Sustainability, Arizona State University, Tempe, AZ, USA,
    Search for more papers by this author

David Bruce Lewis, e-mail: dbl11@psu.edu

Abstract

Today's worldwide expansion of dry land cities consumes cultivated and native ecosystems, providing laboratories for investigating imprints of former land use in places where people now live. Around Phoenix, USA, we compared soil nutrient pools in residential yards converted from farms with nutrient pools in yards developed on native desert. Organic matter, carbon (C), nitrogen (N), and soluble ions were >2-fold greater in yards that were previously agrarian than in yards that were not. These pools remain elevated 40 years after land conversion to residential use. Present N accumulation (1.5 g m−2 yr−1) is not affected by prior land use, suggesting that rates of residential fertilizer application and retention are not affected by antecedent soil fertility. Bioavailable, inorganic phosphorus (Pav) is elevated in soil with a recent agrarian past, but this signal disappears after 10–30 years of residential use owing to an accumulation of Pav in never-farmed yards. Our results indicate a ‘direct agrarian legacy,’ wherein agrarian amendment of nutrient pools endures urbanization, more so than an ‘indirect legacy,’ wherein present land management is molded by former land use. Agriculture in dry lands thus sequesters material in soils, and—as we also found higher material contents in residential soils than in contemporary agrarian soils—residential land use simply adds to the agrarian legacy these soils already bear. Intense human use of arid lands may cause increases in material pools in soils, a condition with potential global consequence.

Ancillary