Soil Productivity of Four Land Use Systems in Southeastern Montana
1988
McConnell, S. G. | Quinn, M.-L.
Present and potential productivity of formerly cultivated land in southeastern Montana purchased by the federal government in the 1930s was unknown. Therefore, a study was undertaken to compare the productivity of this purchased, retired, and reseeded cropland with other land use systems. Biomass production and soil chemical properties of selected federal tracts (reseeded cropland) were compared to abandoned cropland, continually cultivated land (cropland), and native range on series of Argiboroll, Camborthid, and Haploboroll soil great groups. Above-ground biomass from cropland was approximately 400% greater than for the other three systems. Native range had approximately 700% more below-ground biomass than cropland, abandoned and reseeded cropland having intermediate amounts. Greenhouse growth of spring wheat (Triticum aestivum L. CV. Newana) on intact soil cores from native range was greater (0.92 g core⁻¹) than the average of the past or presently cultivated systems (0.61 g core⁻¹). Surface soil (0 to 0.25 m) organic C, total N, and mineralizable N values for native range were greater (14.1 g C kg⁻¹, 1.3 g N kg⁻¹, and 41.4 mg N kg⁻¹, respectively) than the average of the past or presently cultivated systems (10.8 g C kg⁻¹, 1.1 g N kg⁻¹, and 23.2 mg N kg⁻¹, respectively), indicating a decline in soil productivity with cultivation. Significant correlations of greenhouse biomass with organic C (r = 0.56), total N (r = 0.58), and mineralizable N (r = 0.45) indicate that organic matter loss affects soil productivity. When compared to cropland, cultivated land purchased and retired by the federal government (reseeded cropland) maintained or improved its long-term soil productivity. In the properties measured, though, similarly managed reseeded cropland and abandoned cropland displayed no differences.
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