Browsing by Author "Blake, George R."
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Item Eighteenth Annual Report Water Resources Research Center(Water Resources Research Center, University of Minnesota, 1982-10) Blake, George R.; Espointour, ElizabethItem Fifteenth Annual Report Water Resources Research Center(Water Resources Research Center, University of Minnesota, 1979-10) Blake, George R.; Espointour, ElizabethDuring fiscal year 1979 the Water Resources Research Center sponsored 12 research projects emphasizing quality of both surface and ground waters,public health aspects of groundwater pollution, irrigation, drainage, a trophic classification of lakes and social factors in resource development decisions. Twenty-four project-related reports were published by the Water Resources Research Center in 1979-80, including six bulletins. Each of two of the bulletins were sent to about 300 people. The other four were distributed by the Principal Investigator to about 250 people. In addition the Center answered about 500 requests for bulletins published in past years. The budget for the Water Resources Research Center was $320,922 derived from the University of Minnesota, the University of Minnesota Graduate School and the Office of Water Research and Technology of the U.S. Department of Interior. About 33 students were employed on water-related projects funded by the Center.Item Midseason Soil Water Recharge for Corn in the Northwestern Corn Belt(Water Resources Research Center, University of Minnesota, 1983-03) Blake, George R.; Johnson, Bradley S.; Nelson, Wallace W.Incomplete soil water recharge between growing seasons and insufficient growing-season precipitation limit plant growth in southwestern Minnesota. Field experiments were conducted from 1979-81 on a Nicollet clay loam soil (Aquic Hapludoll) to determine the effects of midseason soil water recharge on corn (Zea mays L.) production. Six treatments consisting of timing and amount variables of supplemental water addition were studied. "Daily precipitation and air- temperatures were measured. Soil water contents and potentials were measured with a neutron probe and tensiometers, respectively. Progressive developmnent of soil water deficiencies occurred during the three-year study. Following a wet year in 1979, a shallow-receding water table was present during the 1980 growing season. Extensive soil water depletion to 90 cm occurred in both 1980 and 81, the water table could not be detected within 200 cm of the soil surface in 1981. Despite these diverse conditions, positive and significant grain yield responses to the addition of supplemental water were observed in each year of the study. Grain yield resulting from the midseason application of 7.6 cm of water exceeded grain yield with natural precipitation by 1808, 2130, and IB47 kg/ha tn 1979, 80, and 81, respectively. Grain production was enhanced as effectively by single-midseason applications of 7.6 cm of water as by "optimum irrigation" (application of 3.8 cm at 50 percent depletion of plant-available water to a soil depth of 90 cm). In the presence of a receding water table (1980), 90 percent of the grain yield variability and 92 percent of the variability in total dry matter-production (TMDP) was accounted for by the amount of supplemental water added and early-season water table depth. Response to the addition of supplemental water diminished with decreasing early-season water table depth.Item Seventeenth Annual Report Water Resources Research Center(Water Resources Research Center, University of Minnesota, 1981-12) Blake, George R.; Espointour, ElizabethItem Sixteenth Annual Report Water Resources Research Center(Water Resources Research Center, University of Minnesota, 1980-10) Blake, George R.; Espointour, ElizabethDuring fiscal year 1980 the Water Resources Research Center sponsored ten projects funded through programs of the U.S. Department of Interior, Office of Water Research and Technology and two funded through grants from the Upper Mississippi River Basin Commission. These research projects dealt with the following topics: 1) Water conservation through reuse of agricultural drainage waters and through prediction of irrigation scheduling by use of climatic data; 2) Wetlands as related to county drainage ditches and to agricultural runoff;3) Water quality for towns in rural areas, methods for measuring aquatic organics, removal of heavy metals by zeolites, and propagation of hydrocarbon spills to shallow aquifers;4) Groundwater recharge rates as related to rainfall, predicting recharge rates in surficial aquifers; 5) Economics of water use for irrigation; 6) Flood prevention through hydrologic simulation of critical watersheds; and 7) Septage disposal on land by defining loading rates. Research sponsored by the Upper Mississippi River Basin Commission consisted of a Summary Resource Description of the Upper Mississippi River System and an Evaluation of the Impacts of Navigation and Associated Operation and Maintenance Procedures on Recreation, Cultural Resources and Potential Wilderness Areas of the River System. Two project-related bulletins were published by the Water Resources Research Center in 1979-1980. Bulletins are sent to a mailing list of about 300 people initially. The Center answers around 500 requests each year for copies of bulletins published both this year and past years. The Center also publishes and distributes four Newsletters each year. Through Water Research Centers projects, two professors, three research associates and about 28 students, mostly graduate students, were given part-time employment. A seminar series was sponsored on the University’s Twin City Campus. The Center’s budget was $395,736 derived from the University of Minnesota, the University Graduate School, the Office of Water Research and Technology of the U.S. Department of Interior and grants from the Upper Mississippi River Basin Commission.