HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Casey, F. X. M. Articles by Stegman, E. C. Search for Related Content PubMed Articles by Casey, F. X. M. Articles by Stegman, E. C. GeoRef GeoRef Citation Agricola Articles by Casey, F. X. M. Articles by Stegman, E. C. Related Collections Ground Water Quality Best Management Practices Soil Systems

Initiation of Irrigation Effects on Temporal Nitrate Leaching

^a Dep. of Soil Science, North Dakota State University, Fargo, ND 58105
^b Dep. of Agriculture and Biosystems Engineering, North Dakota State University, Fargo, ND 58105
^c USDA-CSREES-Natural Resources and Environment, 1400 Independence Ave., SW- STOP 2210, Washington, DC 20250-2210

View larger version (33K): [in a new window]   Fig. 1. A map of the 2000-ha Oakes Irrigation Test Area (OITA) with an exploded map of the 65-ha center-pivot irrigation Best Management Practices (BMP) research area. The BMP map indicates the type and location of the different instrumentation used to observe subsurface water quality. Light blue areas in OITA map are other irrigated fields.

View larger version (12K): [in a new window]   Fig. 2. A comparison between the Best Management Practices research field and the average of the Oakes Irrigation Test Area for yield and N fertilizer application rates.

View larger version (13K): [in a new window]   Fig. 3. The average N test values in the soil profile to several depths through time.

View larger version (17K): [in a new window]   Fig. 4. Time series data of the average NO3 concentrations observed from the undisturbed-profile lysimeters fitted with Eq. [1]. Nitrate concentrations increase in Phase 1, decrease in Phase 2, and reach and maintain a steady value in Phase 3. Also included are concentrations calculated from the soil N test values from 0 to 1.8 m along with one standard deviation error bars.

View larger version (14K): [in a new window]   Fig. 5. Time series data of the average NO3 concentrations observed from the disturbed-profile lysimeters fit with Eq. [1]. Nitrate concentrations increase in Phase 1, decrease in Phase 2, and reach and maintain a steady value in Phase 3.

View larger version (18K): [in a new window]   Fig. 6. Time series data of the average NO3 concentrations observed from the shallow wells fit with Eq. [1]. Nitrate concentrations increase in Phase 1, decrease in Phase 2, and reach and maintain a steady value in Phase 3. The jagged lines are the 50% confidence limit and the red area indicates a period of time where 50% of the well samples tested above the 10 mg L-1 level.

View larger version (17K): [in a new window]   Fig. 7. Time series data of the average nitrate concentrations observed from the intermediate wells fit with Eq. [1]. Nitrate concentrations increase in Phase 1, decrease in Phase 2, and reach and maintain a steady value in Phase 3. The jagged lines are the 50% confidence limit and the red area indicates a period of time where 50% of the well samples tested above the 10 mg L-1 level.

View larger version (13K): [in a new window]   Fig. 8. Time series data of the average NO3 concentrations observed from shallow groundwater wells from the Albus and Knighton (1998) study and fit with Eq. [1]. Nitrate concentrations increase in Phase 1, decrease in Phase 2, and reach and maintain a steady value in Phase 3.

View larger version (16K): [in a new window]   Fig. 9. Time series data of the average NO3 concentrations observed from the tile drains fit with Eq. [1]. Nitrate concentrations increase in Phase 1, decrease in Phase 2, and reach and maintain a steady value in Phase 3.