Presentation on theme: "The Water Cycle: Impacts of Annual/Perennial Bioenergy Crops Eleanor Burkett - Extension Educator, University of Minnesota Roberta Dow, PhD - Extension."— Presentation transcript:
The Water Cycle: Impacts of Annual/Perennial Bioenergy Crops Eleanor Burkett - Extension Educator, University of Minnesota Roberta Dow, PhD - Extension Educator, Michigan State University
Course outline Overview of the water and water cycle Demands for water Water quantity & bio mass production Water quality & bio mass production Other considerations Evaporation Runoff
Earths Water Budget OCEANS ATMOSPHERE LAND 97.5% 2.4% <. 001% No new water !
Water Quantity Julie Doll Crop water needs are determined by considering crop, soil type and region as well as climatic conditions CLIMATIC CONDITION CROP WATER NEEDS LOWHIGH SunlightCloudySunny HumidityLowHigh TemperatureLowHigh WindCalmwindy
Evaporation Considerations Air pressure Temperature of the air Temperature of the water at the air-water or air-soil surface Air humidity Area of the air-water surface (larger area, greater evaporation) Depth of water affects water currents moving heat and the ability to keep the surface temperature at evaporation level Airflow at the water or soil/air surface Shallow water table and bare soil for soil-water evaporation
Evaporation Influences Plant canopy over soil – impacts soil temperature Mulch or leaf litter –impacts water temperature, and air flow Amount of water in soilimpacts temperature Soil texture http://techalive.mtu.edu/meec/module01/images/Evaporation.jpg
Infiltration & Runoff Influences Slope Slope Soil typepermeability Soil typepermeability Impermeable surfaces in developed areas Impermeable surfaces in developed areas Soil surface coverPlants and mulch or other organic matter on surface Soil surface coverPlants and mulch or other organic matter on surface Soil moisture channels –Worm holes, animal burrows, root channels all increase infiltration Soil moisture channels –Worm holes, animal burrows, root channels all increase infiltration Cultivation & management techniques such as contour farming, terracing, grassed filter strips, etc. Cultivation & management techniques such as contour farming, terracing, grassed filter strips, etc. http://upload.wikimedia.org/wikipedia/commons/9/95/Runoff_of_soil_%26_fertilizer.jpg
Crop selection related to the water cycle Seasonal differences: frozen vs. non-frozen Soil coverNRCS Runoff Control Numbers for various covers Bare vs covered Forested vs annual Grasses vs annual
Infiltration Considerations Plant precipitation interception differences Row crop vs grass or woodland Annual vs perennial Soil infiltration differences Clay, loam, sand, gravel Rooting depth Deeper rooted plants provide deeper root channels when they die.
Transpiration Influences Plant type Size of stomatal opening Light Plant density Wind speed Temperature Humidity Soil moisture Season & region http://en.wikipedia.org/wiki/File:Tomato_leaf_stomate_1-color.jpg
Northwest 40 % of ave. annual precipitation EvapotranspirationEvapotranspiration. Southwest 100 % of ave. annual precipitation Northeast 40 % of ave. annual precipitation http://geochange.er.usgs.gov/sw/changes/natural/et/
Water Movement The lower 5 miles of atmosphere moves approximately 40,000 billion gallons of water vapor over the contiguous United States each day. Around 10 % of this moisture precipitates.
Biomass Production, Potential Ethanol Production & Needed Land Area Feedstock Biomass (Tons/ acre) Ethanol (gal/acre) Million acres needed for 35 billion gallons of ethanol % 2006 harvested U.S. cropland Corn grain 1 4.545612.624.4 Corn stover 2 3.330019.137.2 Corn total7.87567.614.8 Switchgrass4.642113.626.5 Miscanthus13.211984.89.3
The Hydrologic Cycle and Biofuel Crop Considerations Water usage for biofuel crop production Biofuel crop versus other land use Crop impacts on water needs by other organisms Crop impacts on runoff and infiltration Methods to decrease the water use impacts of biofuel crop production will promote their agricultural sustainability
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