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SOIL QUALITY RECOVERY IN PREVIOUSLY FARMED FIELDS SEEDED TO PERENNIAL WARM SEASON NATIVE GRASS
Mehaffey, M. H., K. Kindscher, AND V. Smith. SOIL QUALITY RECOVERY IN PREVIOUSLY FARMED FIELDS SEEDED TO PERENNIAL WARM SEASON NATIVE GRASS. Presented at Ecological Society of America Annual Meeting, Spokane, WA, August 19, 1999.
A study of twelve Conservation Reserve Program sites in northeastern Kansas was conducted to determine native grass species and selected soil textures influence on soil quality recovery.
Plant productivity, plant carbon and nitrogen concentrations, total soil nitrogen and carbon, and soil pH were used to assess recovery. The variables of concern were initial seeding time (1987 to 1990 = older sites and 199 1 to 1 994= younger sites) and soil texture (silt loam vs. silty clay loam). Soil quality changes taking place in the study sites revolved around increases and decreases in the relative biomass of a limited number of species, namely the seeded perennial grasses and annuals already present in the soil seed bank. Biomass increases were greater for shoots than roots resulting in lower root to shoot ratios in older sites. Above ground biomass averaged C:N ratios of I 00 - Soil samples indicated little improvement in carbon, both younger and older sites averaged around 185 g m-'. Soil pH was only slightly lower in the older sites (5.7 vs 5.8). Soil C:N ratio was greater in the older sites, however, the increase was the result of lower total soil nitrogen (10.5 vs. 13.5 g m-' ), rather than an increase in carbon storage. Overall, little soil quality improvements are being generated during the IO year contract period of the Conservation
Reserve Program. If recovery and retention of more soil resources is to be an attainable goal, new implementation and management procedures need to be considered for species composition and soil texture selection criteria.
The primary objectives of this research are to:
Develop methodologies so that landscape indicator values generated from different sensors on different dates (but in the same areas) are comparable; differences in metric values result from landscape changes and not differences in the sensors;
Quantify relationships between landscape metrics generated from wall-to-wall spatial data and (1) specific parameters related to water resource conditions in different environmental settings across the US, including but not limited to nutrients, sediment, and benthic communities, and (2) multi-species habitat suitability;
Develop and validate multivariate models based on quantification studies;
Develop GIS/model assessment protocols and tools to characterize risk of nutrient and sediment TMDL exceedence;
Complete an initial draft (potentially web based) of a national landscape condition assessment.
This research directly supports long-term goals established in ORDs multiyear plans related to GPRA Goal 2 (Water) and GPRA Goal 4 (Healthy Communities and Ecosystems), although funding for this task comes from Goal 4. Relative to the GRPA Goal 2 multiyear plan, this research is intended to "provide tools to assess and diagnose impairment in aquatic systems and the sources of associated stressors." Relative to the Goal 4 Multiyear Plan this research is intended to (1) provide states and tribes with an ability to assess the condition of waterbodies in a scientifically defensible and representative way, while allowing for aggregation and assessment of trends at multiple scales, (2) assist Federal, State and Local managers in diagnosing the probable cause and forecasting future conditions in a scientifically defensible manner to protect and restore ecosystems, and (3) provide Federal, State and Local managers with a scientifically defensible way to assess current and future ecological conditions, and probable causes of impairments, and a way to evaluate alternative future management scenarios.
Record Details:Record Type: DOCUMENT (PRESENTATION/ABSTRACT)
Organization:U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF RESEARCH AND DEVELOPMENT
NATIONAL EXPOSURE RESEARCH LAB
ENVIRONMENTAL SCIENCES DIVISION
LANDSCAPE ECOLOGY BRANCH