Watershed
design
Title of Research
Project:
Watershed Design Impacts on Water Quality
Principal Investigator: Matt
Helmers (Agricultural
& Biosystems Engineering/ABE)
Co-Principal Investigator(s): Heidi
Asbjornsen (Department
of Natural Resource Ecology & Management/NREM)
Collaborators:
Matt Leibman and Rick
Cruse (Department of Agronomy); Liza
Schulte (NREM); Jean
Opsomer (Department of Statistics); Cindy
Cambardella and Mark Tomer (USDA-ARS-National Soil Tilth Laboratory);
K. Schilling (Iowa Department of Natural Resources Geological Survey
Division).
Objective: To
quantify the influence of different proportions and landscape configurations
of annual (e.g., corn and soybean) and perennial (e.g., prairie, savanna,
agroforestry) plant communities on the storage, cycling, and output
of nutrients, water, and carbon at the field and catchment scale.
Hypothesis:
The strategic integration of perennial plant communities in agricultural
landscapes will disproportionately improve nutrient, carbon and water
fluxes—thereby reducing nutrient loads and movement of precipitation
to surface waters and groundwater—while maintaining high productivity
of the annual crop systems.
Key questions related
to the overall research hypothesis:
1) At what proportion of perennial plant cover within watersheds dominated
by annual crop production do the greatest hydrologic responses occur?
2) What landscape positions within agricultural watersheds would conversion
to perennial plant cover result in the greatest hydrologic response?
3) How do different perennial plant communities vary in their eco-hydrological
functioning and scale up to influence watershed hydrology?
Outcomes:
1) WEPP model nutrient loss component tested and validated
for the twelve watersheds in this study.
2) Eco-hydrological effects of different perennial-annual plant configurations
representing alternative watershed designs assessed for 12 subcatchments
using WEPP.
3) Research design developed for the long-term field experiment to
test hypothesis related to the role of perennial plant cover in ameliorating
agricultural impacts on hydrologic alteration and water quality.
4) One Ph.D. thesis and one M.S. thesis completed on this project,
with associated publications in peer-reviewed journals.
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Title of Research
Project:
Plumbing Agricultural Landscapes for Water Quality Improvement: coexistence
of intensive agriculture and good water quality
Principal Investigator: John
Downing (Department
of Ecology Evolution & Organismal Biology)
Collaborators: Heidi
Asbjornsen (NREM) and Matt
Helmers (ABE)
Objective: Identify
the characteristics of watershed configuration that have the greatest
influence on surface water quality across 132, large, agriculturally-dominated
watersheds.
Outcomes:
1. Empirical identification of watershed components and spatial
configurations that are most conducive to the maintenance of water
quality in Iowa;
2. Identification of watershed limitations to intensive agricultural
production methods for surface water quality maintenance;
3. Identification of watershed design criteria required to maintain
or enhance surface water quality of Iowa lakes and other surface waters
in agriculturally dominated watersheds.
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Agroecological mapping
& Plant data base and risk analysis
Title of Research
Project:
Biogeography of Agricultural Systems
Principal Investigator: Matt
Liebman (Department
of Agronomy)
Co-Principal Investigator: Ray
Arritt (Department
of Agronomy)
Collaborators: Jeremy
Singer and David
James (USDA-ARS-National Soil Tilth Laboratory)
Objective(s): (1)
identify potentially important plant species and genotypes that could
be used as crops or “ecological goods and services providers”
in Iowa and other portions of the Midwestern U.S., and (2) evaluate
how biophysical conditions would affect the productivity of those
plants in the region, including spatial and temporal variation in
relevant soil and climate factors.
Hypothesis:
The development of new crops and new forms of vegetation management
must be based on a comprehensive understanding of the biophysical
environment, particularly with regard to patterns of spatial and temporal
heterogeneity in edaphic and climatic conditions. Such information
is required to assess risks of crop failure due to drought, flooding,
high and low temperature stress, and pests, as well as to assist the
placement of adapted genotypes of new and existing crops across the
landscape.
Key questions related
to research:
1) What potential alternative crop plants are suitably adapted to
significant areas of this region such that both farmer production
and market development can be fostered?
2) What potential alternative plants exist that could better support
ecological services needed in this region, either individually or
in relation with other plant species?
3) What is production stability could be expected of suggested crop/plant
species based on variability in regional climate and environmental
conditions?
Outcomes:
1) Identification of a suite of 10-12 promising alternative crops
representing different functional categories, including species useful
for the production of food, feed, fiber, and fuel, and the protection
of soil and water resources.
2) A literature review of existing efforts
and techniques for characterizing landscapes and land capabilities.
3) Identification and evaluation of existing
spatially referenced data that may be useful for estimating the performance
of alternative crops in Iowa and the Midwestern U.S.
4) Refinement of methods for landscape
characterization and analysis suitable for use with available data.
5) Evaluation of crop-specific opportunities
and limitations for the production of 10-12 potentially important
new crops in Iowa and the Midwestern U.S.
6) Land capability and climatic stability
analyses for individual crops to assess spatial and temporal variability
in their performance.
7) Databases assembled and available
to other researchers interested in new crop development and long-term
environmental monitoring.
