Soil chemical properties during succession from abandoned cropland to native range

Abstract

Succession from abandoned cropland to native range provides the opportunity to study soil transformation in progress from a known date. The purpose of this study was to assess soil transformations under abandoned cropland reverting back to native range in the Brown and Black Chernozemic soil zones of southern Alberta, Canada. Total extractable organic acids and phenols were generally greater in abandoned cropland soils than In adjacent native range soils. Ammonium N increased with succession but nitrate N decreased. Percent identifiable N of hydrolyzable N decreased with time of recovery. Aliphatic carboxylic acids increased quantitatively with succession in the Black soils and decreased in the Brown Chemozemic soils. A change in quality of soil organic matter towards a more complex and stable form occurred with time. Regression analyses of the Brown Chemozemic soils abandoned in 1925, 1927, 1950, and 1975 are interpreted to show that response to years of the chemical characteristics studied was essentially linear. In order to form the type of organic matter that occurs in undisturbed Black and Brown Chernozemic soils, recovery of abandoned cropland may take at least 150 years in the former and 75 years in the latter under moderate grazing.