Soil Organic Carbon Maintenance in Corn (Zea mays L.) and Soybean (Glycine max L.) as Influenced by Elevation Zone
Landscape processes may impact the amount of carbon (C) required to maintain soil organic C levels. The objective of this study determined the influence of elevation zones on soil organic C maintenance and C-budgets. Research conducted between 1995 and 2003 in a 160 ac (65 ha) east-central South Dakota field measured spatial and temporal biomass [corn (Zea mays) and soybean (Glycine max)] production and changes in soil organic C and ^sup 13^C isotopic discrimination (Δ). Results from this study showed that: 1) data collected through precision farming practices (yield and grid soil samples analyzed for soil organic C) can be used to determine soil organic C maintenance requirements; 2) the corn - soybean rotation may not return enough biomass-C to maintain soil organic C levels at all landscape positions; 3) calculated maintenance rates were dependent on the approach used to estimate below ground biomass; 4) footslope areas had higher maintenance rates than summit/shoulder areas; and 5) 1.84 percent and 1.21 percent soil organic C measure in 1995 (SOC^sub 95^) were mineralized annually in elevation zones less than 527.3 and greater than 527.3 m, respectively. To maintain soil organic C levels, areas where mineralization is high (footslopes) will require higher biomass-C additions than areas where soil organic C mineralization is low (shoulders). The potential benefits of increasing biomass-C additions to footslope areas at the expense of summit/shoulder areas must be balanced against the potential effects on erosion.
Journal of Soil and Water Conservation
Clay, David E.; Carlson, Gregg; Clay, Sharon; Chang, J.; and Malo, D. D., "Soil Organic Carbon Maintenance in Corn (Zea mays L.) and Soybean (Glycine max L.) as Influenced by Elevation Zone" (2005). Agronomy, Horticulture and Plant Science Faculty Publications. 159.