Skip Links

USGS - science for a changing world

Scientific Investigations Report 2012–5203

National Water-Quality Assessment Program

Changes in Water Budgets and Sediment Yields from a Hypothetical Agricultural Field as a Function of Landscape and Management Characteristics—A Unit Field Modeling Approach

By Jason L. Roth and Paul D. Capel

Thumbnail of and link to report PDF (2.3 MB)Abstract

Crop agriculture occupies 13 percent of the conterminous United States. Agricultural management practices, such as crop and tillage types, affect the hydrologic flow paths through the landscape. Some agricultural practices, such as drainage and irrigation, create entirely new hydrologic flow paths upon the landscapes where they are implemented. These hydrologic changes can affect the magnitude and partitioning of water budgets and sediment erosion. Given the wide degree of variability amongst agricultural settings, changes in the magnitudes of hydrologic flow paths and sediment erosion induced by agricultural management practices commonly are difficult to characterize, quantify, and compare using only field observations.

The Water Erosion Prediction Project (WEPP) model was used to simulate two landscape characteristics (slope and soil texture) and three agricultural management practices (land cover/crop type, tillage type, and selected agricultural land management practices) to evaluate their effects on the water budgets of and sediment yield from agricultural lands. An array of sixty-eight 60-year simulations were run, each representing a distinct natural or agricultural scenario with various slopes, soil textures, crop or land cover types, tillage types, and select agricultural management practices on an isolated 16.2-hectare field. Simulations were made to represent two common agricultural climate regimes: arid with sprinkler irrigation and humid. These climate regimes were constructed with actual climate and irrigation data. The results of these simulations demonstrate the magnitudes of potential changes in water budgets and sediment yields from lands as a result of landscape characteristics and agricultural practices adopted on them. These simulations showed that variations in landscape characteristics, such as slope and soil type, had appreciable effects on water budgets and sediment yields. As slopes increased, sediment yields increased in both the arid and humid environments. However, runoff did not increase with slope in the arid environment as was observed in the humid environment. In both environments, clayey soils exhibited the greatest amount of runoff and sediment yields while sandy soils had greater recharge and lessor runoff and sediment yield. Scenarios simulating the effects of the timing and type of tillage practice showed that no-till, conservation, and contouring tillages reduced sediment yields and, with the exception of no-till, runoff in both environments. Changes in land cover and crop type simulated the changes between the evapotransporative potential and surface roughness imparted by specific vegetations. Substantial differences in water budgets and sediment yields were observed between most agricultural crops and the natural covers selected for each environment: scrub and prairie grass for the arid environment and forest and prairie grass for the humid environment. Finally, a group of simulations was performed to model selected agricultural management practices. Among the selected practices subsurface drainage and strip cropping exhibited the largest shifts in water budgets and sediment yields. The practice of crop rotation (corn/soybean) and cover cropping (corn/rye) were predicted to increase sediment yields from a field planted as conventional corn.

First posted October 15, 2012

For additional information contact:

Chief, National Water-Quality Assessment
U.S. Geological Survey
413 National Center
12201 Sunrise Valley Drive
Reston, Virginia, 20192
http://water.usgs.gov/nawqa/

Part or all of this report is presented in Portable Document Format (PDF); the latest version of Adobe Reader or similar software is required to view it. Download the latest version of Adobe Reader, free of charge.


Suggested citation:

Roth, J.L., and Capel, P.D., 2012, Changes in water budgets and sediment yields from a hypothetical agricultural field as a function of landscape and management characteristics—A unit field modeling approach: U.S. Geological Survey Scientific Investigations Report 2012-5203, 42 p.



Contents

Foreword

Abstract

Introduction

Study Methods

Changes in Water Budgets and Sediment Yields as a Function of Landscape and Management Characteristics

Summary and Conclusions

Acknowledgments

References Cited

Appendix 1. Summary of Water Erosion Prediction Project Model Simulations

Appendix 2. Water Erosion Prediction Project Model Installation Files and Instructions

Appendix 3. Climate and Irrigation Data Used in Simulations

Appendix 4. Annualized Summaries of Water Budget Components for Simulations


Accessibility FOIA Privacy Policies and Notices

Take Pride in America logo USA.gov logo U.S. Department of the Interior | U.S. Geological Survey
URL: http://pubs.usgs.gov/sir/2012/5203/
Page Contact Information: GS Pubs Web Contact
Page Last Modified: Thursday, January 10, 2013, 08:01:23 PM