Progress 03/29/11 to 09/30/11
Outputs
Progress Report Objectives (from AD-416) Enhance carbon sequestration for improved soil quality and erosion control; Quantify the form and release of major nutrients as affected by soil redox potential; and Determine the impacts of conservation tillage on fate of pesticide in soil. Approach (from AD-416) Quantify dissolved organic carbon in runoff samples from subwatersheds in the St. Joseph River; Identify enzymes as soil quality indicators; Monitor effects of changing soil redox potential on nutrient form and release; and Quantify the fate of atrazine, metolachlor and glyphosate under varying temperature and crop residue; Quantify the competition between glyphosate and phosphorus and glyphosate and potassium for possible nutrient decline due to glyphosate usage. Over the last five years, we have sampled 16 experimental watersheds to answer the question of how implemented conservation practices impact on soil quality and carbon sequestration. By the end of the summer, 2011, we will have completed sampling of 11 watersheds. One paper is in press and three other papers are being prepared. We are continuing to monitor changes in soil quality characteristics, carbon sequestration, and productivity in a field experiment designed to determine impacts of corn residue removal on the soil. We are also following changes in soil biochemistry (soil enzyme activity) over time. This summer was the fifth year, and we are conducting a complete soil analysis after harvest (October) to compare to the initial experiments. Accomplishments 01 Carbon on the landscape. The concerns about climate change have increase interest in understanding differences in soil carbon pools and availability. Carbon (C) is not sequestered evenly across the landscape different slope positions. ARS scientists at West Lafayette, IN collecte over two hundred surface soil samples along 20 different transects that followed the shape of the landscape. Soil samples were analyzed for organic carbon (SOC) and the readily available SOC. Overall, the depression areas and the poorly- and very poorly-drained soils, which represented areas with water accumulating for longer time periods, store between 50 to 68% more SOC when compared to the relatively drier areas. Upon incubation, soils from the drier areas emitted about 8.5% of its C carbon dioxide as compared to 5.0% C emitted from soils located in the wetter areas, indicating that proportionally more of the SOC was in more readily available forms in the drier areas. Soils with high and relative less decomposed organic matter represented by the Haplosaprist great gro (organic soils such as bogs, peats, moors or mucks) with high organic matter contents had the highest amount of total SOC, with about 2.5 time the carbon than in the Endo- and Argiaquolls great groups sampled (miner soils that tend to have higher water contents). This indicates that wett arable lands have a greater potential to store C if land is converted to carbon-accruing best management practices. This information will be usef to those modeling soil C stock for global change calculations and to lan managers developing best management systems that will sequester soil carbon.
Impacts
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Publications
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