Potential wind and water erodibility of four land-use systems in south-eastern Montana, U.S.A.

Abstract

As part of an assessment of a 1930s federal government land purchase/management program, a study was undertaken to compare the potential wind and water erodibility (as determined by soil properties) of reseeded cropland (purchased, retired and reseeded to crested wheatgrass) with abandoned cropland, cropland and native range land-use systems on series of Haploboroll, Camborthid and Argiboroll soil great groups in south-eastern Montana. The percentage of non-wind erodible (>0.84 mm diameter) aggregates (sampled in spring) of the surface 30 mm was greatest in cropland (85.0%), with lower values in abandoned and reseeded cropland, and native range (66.3, 66.1 and 61.4%, respectively). Permanent vegetation on the non-cropland systems probably prevented significant wind erosion. The universal soil loss equation (USLE) soil erodibility factor, K, was higher (and thus more erodible) in cropland (0.33) and lower in the other systems (0.26, 0.25 and 0.26 for native range, abandoned and reseeded cropland, respectively). Lower organic matter and platier soil structure were primarily responsible for the higher cropland K value. Comparison of reseeded cropland and cropland suggests reseeded cropland was more wind erodible but less water erodible (based only on a one-time soil sampling). Similarly managed (except for reseeding) abandoned cropland and reseeded cropland were not different in any property measured suggesting no present-day effect of seeding on erosion susceptibility. The federal purchase, retirement and revegetation of these lands almost certainly reduced erosion as compared with continually cropped land, although reseeding the lands did not affect potential wind/water erodibility as compared with naturally revegetated (abandoned) cropland.