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| Web URL(s): | http://elibrary.asabe.org/azdez.asp?JID=3&AID=4684&CID=t2001&v=44&i=2&T=2&redirType=
Last checked: 10/13/2015
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| Publication Type:
| Report |
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| Author(s): | Ella, V. B.;
Melvin, S. W.;
Kanwar, R. S. |
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| Author Affiliation: | Ella: Associate Professor and Chair, Land and Water Resources Division, Institute of Agricultural Engineering, University of the Philippines, Los Banos, former graduate Research Assistant, Agricultural and Biosystems Engineering Department, Iowa State University, Ames, Iowa; Melvin: ASAE Fellow Engineer, Professor and Head; and Kanwar: ASAE Member Engineer, Professor, Agricultural and Biosystems Engineering Department, Iowa State University, Ames, Iowa |
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| Title: | Spatial analysis of NO3-N concentration in glacial till |
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| Section: | Soil & water
Other records with the "Soil & water" Section
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| Source: | Transactions of the American Society of Agricultural Engineers. Vol. 44, No. 2, March/April 2001, p. 317-327. |
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| Publishing Information: | St. Joseph, MI |
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| # of Pages: | 11 |
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| Keywords: | TIC Keywords: Groundwater; Nitrates; Water quality
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| Abstract/Contents: | "Analysis of the spatial variability of groundwater NO3-N concentration is a logical step for a meaningful groundwater quality assessment, for mapping out areas of environmental concern, and for developing appropriate management schemes in a glacial till aquitard. This study was conducted to characterize the spatial variability of NO3-N concentration in shallow (<6.0 m) and deep (>6.0 m) groundwater in a 12-ha. glacial till aquitard and to estimate NO3-N concentration in unsampled locations. Omnidirectional and directional semivariogram analysis, statistical anisotropy analysis, and model fitting were performed for average and extreme monthly groudwater NO3-N data. Results indicated a weak spatial structure of NO3-N concentration for both shallow and deep well data. However, the best-fitted variogram models generally performed satisfactorily during cross validation, yielding a mean reduced error of -0.01 to -0.074 and reduced variance of 0.6 to 2.18. Untransformed shallow-well NO3-N exhibited a lower range of correlation than deep-well data. Statistical anisotropy was found to coincide with the general groundwater flow directions for the average and maximum observed NO3-N concentrations at the down-gradient areas for shallow wells and at regions close to nitrogen fertilizer application sites for the deep wells. With satisfactory cross-validation performance of the variogram models, the geostatistical results of this study may be used as basis for estimating spatially variable NO3-N loading rates in the glacial till aquitard." |
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| Language: | English |
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| References: | 12 |
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| Note: | Figures
Tables
Graphs |
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| ASA/CSSA/SSSA Citation (Crop Science-Like - may be incomplete):
Ella, V. B., S. W. Melvin, and R. S. Kanwar. 2001. Spatial analysis of NO3-N concentration in glacial till. Trans. Proc. Am. Soc. Agric. Eng. 44(2):p. 317-327. |
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http://elibrary.asabe.org/azdez.asp?JID=3&AID=4684&CID=t2001&v=44&i=2&T=2&redirType=
Last checked: 10/13/2015
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MSU catalog number: S 671 .A452 |
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