Education

Research Description

Soil and Water Enginering

Honors and Awards

• Member of National Academy of Engineering, 1991
• President of American Society of Agricultural and Biological Engineers (ASABE), 2001
• Massey Ferguson Gold Medal Award, Am. Soc. of Agricultural and Biological Engineers, 2009
• Charles A. Black Award, Council Agricultural Science and Tech. (CAST), 2009
• O. Max Gardner Award, University of North Carolina System, 1997
• Alexander Quarles Holladay Medal for Excellence, N. C. State University, 1994
• Distinguished Engineering Alumnus, Purdue University, 1997
• Alexander von Humboldt Foundation Award, 1997
• Member, Engineering Hall of Distinction, University of Kentucky, 1994
• John Deere Gold Medal Award, ASAE,, 1993
• Distinguished University Professor, 1991
• Fellow, American Society of Agricultural Engineers, 1990
• Hancor Soil and Water Engineering Award, ASAE, 1998
• ,

Publications

DRAINMOD modeling framework for simulating controlled drainage effect on lateral seepage from artificially drained fields

Youssef, M. A., Liu, Y., Chescheir, G. M., Skaggs, R. W., & Negm, L. M. (2021), AGRICULTURAL WATER MANAGEMENT, 254. https://doi.org/10.1016/j.agwat.2021.106944

DRAINMOD-P: A MODEL FOR SIMULATING PHOSPHORUS DYNAMICS AND TRANSPORT IN DRAINED AGRICULTURAL LANDS: I. MODEL DEVELOPMENT

Askar, M. H., Youssef, M. A., Vadas, P. A., Hesterberg, D. L., Amoozegar, A., Chescheir, G. M., & Skaggs, R. W. (2021), TRANSACTIONS OF THE ASABE, 64(6), 1835–1847. https://doi.org/10.13031/trans.14509

DRAINMOD-P: A MODEL FOR SIMULATING PHOSPHORUS DYNAMICS AND TRANSPORT IN DRAINED AGRICULTURAL LANDS: II. MODEL TESTING

Askar, M. H., Youssef, M. A., Hesterberg, D. L., King, K. W., Amoozegar, A., Skaggs, R. W., … Ghane, E. (2021), TRANSACTIONS OF THE ASABE, 64(6), 1849–1866. https://doi.org/10.13031/trans.14510

Design drainage rates to optimize crop production for subsurface-drained fields

Ghane, E., Askar, M. H., & Skaggs, R. W. (2021), AGRICULTURAL WATER MANAGEMENT, 257. https://doi.org/10.1016/j.agwat.2021.107045

DRAINMOD Simulation of macropore flow at subsurface drained agricultural fields: Model modification and field testing

Askar, M. H., Youssef, M. A., Chescheir, G. M., Negm, L. M., King, K. W., Hesterberg, D. L., … Skaggs, R. W. (2020), AGRICULTURAL WATER MANAGEMENT, 242. https://doi.org/10.1016/j.agwat.2020.106401

Effects of Drainage for Silviculture on Wetland Hydrology

Skaggs, R. W., Amatya, D. M., & Chescheir, G. M. (2020), WETLANDS, 40(1), 47–64. https://doi.org/10.1007/s13157-019-01202-6

Long-Term Water Table Dynamics of Forested Wetlands: Drivers and their Effects on Wetland Hydrology in The Southeastern Atlantic Coastal Plain

Amatya, D. M., Chescheir, M., Williams, M., Skaggs, W., & Tian, S. (2020), WETLANDS, 40(1), 65–79. https://doi.org/10.1007/s13157-019-01153-y

Method to Assess Climate Change Impacts on Hydrologic Boundaries of Individual Wetlands

Vepraskas, M. J., Skaggs, R. W., & Caldwell, P. (2020), WETLANDS, 40(2), 365–376. https://doi.org/10.1007/s13157-019-01183-6

COMPARISON OF HYDROLOGY OF TWO ATLANTIC COASTAL PLAIN FORESTS

Amatya, D. M., Williams, T. M., Nettles, J. E., Skaggs, R. W., & Trettin, C. C. (2019), TRANSACTIONS OF THE ASABE, 62(6), 1509–1529. https://doi.org/10.13031/trans.13387

DRAINMOD-based tools for quantifying reductions in annual drainage flow and nitrate losses resulting from drainage water management on croplands in eastern North Carolina (vol 166, pg 86, 2016)

Negm, L. M., Youssef, M. A., Chescheir, G. M., & Skaggs, R. W. (2019, December 20), AGRICULTURAL WATER MANAGEMENT, Vol. 226. https://doi.org/10.1016/j.agwat.2019.105811

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Grants

Effects of Silvicultural Practices on Hydrology and Water Quality of Drained Forested Lands

Weyerhaeuser NR Company (subsidiary of Weyerhaeuser)(1/01/14 - 6/30/23)

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Effects of Silvicultural Practices on Hydrology and Water Quality of Drained Forested Lands

Sponsor: Weyerhaeuser NR Company (subsidiary of Weyerhaeuser)

Start Date: 1/01/14

End Date: 6/30/23

Abstract

A long-term forest hydrology and water management study was initiated on three experimental loblolly pine forests in Carteret County, NC in 1988. Data were collected on the research watersheds for 21 years to quantify effects of silvicultural and water management practices on hydrology and drainage water quality. Beginning in 2009 a fourth watershed was added and treatments are being established to study the environmental impacts of growing a biofuel crop (switchgrass) between the rows of pine trees. This project will support collection and analysis of data from the Carteret and Kendricks Creek sites to determine the effects of treatments on hydrology and drainage water quality.

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DRAINMOD Training Materials for USDA-NRCS

US Dept. of Agriculture - Natural Resources Conservation Service (USDA NRCS)(9/01/13 - 12/31/16)

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DRAINMOD Training Materials for USDA-NRCS

Sponsor: US Dept. of Agriculture - Natural Resources Conservation Service (USDA NRCS)

Start Date: 9/01/13

End Date: 12/31/16

Abstract

DRAINMOD is a computer simulation model developed by Dr. Wayne Skaggs and colleagues at the Department of Biological & Agricultural Engineering, North Carolina State University (NCSU), Raleigh, NC. DRAINMOD predicts effects of drainage and associated water management practices on water table depths, soil water regime, crop yields, transport and fate of nitrogen, salinity, drainage effects on adjacent wetlands and hydraulic capacity of systems using wastewater land treatment. DRAINMOD can be used to simulate the performance of drainage water management (DWM) systems. Instructional materials for the application of DRAINMOD have been developed at NCSU and are used in advanced courses on drainage and water management. This contract will provide NRCS access to those materials. It will also develop four additional course modules to cover the application of DRAINMOD for planning and design of drainage systems and DWM, subirrigation, and the use of a short cut method to predict the effect of DWM on annual Nitrogen losses in drainage waters.

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T25 for Determining Lateral Effects of Drains on Wetland Hydrology

US Dept. of Agriculture - Natural Resources Conservation Service (USDA NRCS)(9/01/13 - 12/31/15)

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T25 for Determining Lateral Effects of Drains on Wetland Hydrology

Sponsor: US Dept. of Agriculture - Natural Resources Conservation Service (USDA NRCS)

Start Date: 9/01/13

End Date: 12/31/15

Abstract

A method developed at N.C. State University can be used to determine the lateral effects of drains on wetland hydrology of adjacent lands. Application of the method for a given location/climate requires one-time DRAINMOD analysis to determine T25 values, which are characteristic times required for 25 cm of water table drawdown in threshold wetlands at that location. Work under this proposal would determine T25 values for three states. T25 values would be obtained for 5 locations or climate zones in each state. Values would be obtained for 5 representative soils, 5 drain depths, and 4 surface storages at each location. The T25 values would be inserted in the software that applies the method, such that they could be automatically accessed for given locations.

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Demonstration and evaluation of effective drainage water management for conserving water, increasing crop yields and profits and improving water quality

Environmental Defense Fund(4/01/13 - 10/31/16)

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Demonstration and evaluation of effective drainage water management for conserving water, increasing crop yields and profits and improving water quality

Sponsor: Environmental Defense Fund

Start Date: 4/01/13

End Date: 10/31/16

Abstract

The objectives of this project include: 1. Developing a web-based advisory for drainage water management. 2. Installation of automated drainage water control structures on up to five demonstration sites. 3. Investigating the effects of drainage water management on crop yield, drainage outflow and drainage water quality. 4. Providing guidance to producers who are using the online drainage advisory and/or the automated drainage control structures.

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Automated Water Control Structures for Increased Soybean Yield and Quality

NC Soybean Producers Association, Inc.(4/01/12 - 3/31/15)

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Automated Water Control Structures for Increased Soybean Yield and Quality

Sponsor: NC Soybean Producers Association, Inc.

Start Date: 4/01/12

End Date: 3/31/15

Abstract

The overall goal of the project is To demonstrate and evaluate an economical system to automatically control water levels with flashboard riser systems that will significantly minimize user management while maximizing soybean yields, water conservation, and water quality benefits. Specific objectives are: 1) Develop a functional cost effective automatic water control system that can be retrofitted to existing riser systems designed to enhance soybean yield and improve water quality; 2) Promote plant health and increase soybean quality; 3) Document the yield and water conservation benefits of the practice; 4) Reduce irrigation expenses by managing soil water stresses; 5) Demonstrate the use of the automated water control system to producers; 6) Develop a cost-benefit analysis on the feasibility of the system.

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Effects of Biofuel Planting, Growth, and Harvesting on the Hydrology and Water Quality of Pine Plantations

Weyerhaeuser NR Company (subsidiary of Weyerhaeuser)(4/19/12 - 12/31/15)

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Effects of Biofuel Planting, Growth, and Harvesting on the Hydrology and Water Quality of Pine Plantations

Sponsor: Weyerhaeuser NR Company (subsidiary of Weyerhaeuser)

Start Date: 4/19/12

End Date: 12/31/15

Abstract

The overall objective of this project is to evaluate the environmental effects of large-scale forest bioenergy crop production and utilize these results to optimize cropping systems in a manner that protects the important ecosystem services provided by forests while contributing to the development of a sustainable and economically-viable biomass industry in the southeastern U.S This project consists of plot-scale and watershed-scale experimental studies linked with a modeling effort that will enable us to apply our experimental results broadly across the region. Watershed and plot-scale experiments have been initiated. Matched-watershed studies have been established in North Carolina, Mississippi and Alabama. Each installation includes at least four, small, operational-scale sub-watersheds that are instrumented to provide data on stream discharge, weather, water table and water quality. Biomass treatments that will be applied to the sub-watersheds will represent a spectrum of biofuel management intensities: Typical pine plantation, about 15 years old, Young pine, high value timber regime, Young pine, woody biomass removal, Young pine, interplanted with switchgrass, and Switchgrass only. Additional projects are being conducted to study soil productivity, nutrient and carbon cycling, biodiversity, economics, BMP guidance, and safety.

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Development, Evaluation, and Demonstration of Simple Tools For Nitrogen Credit Trading System Involving Drainage Water Management

US Dept. of Agriculture (USDA)(9/21/12 - 6/30/15)

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Development, Evaluation, and Demonstration of Simple Tools For Nitrogen Credit Trading System Involving Drainage Water Management

Sponsor: US Dept. of Agriculture (USDA)

Start Date: 9/21/12

End Date: 6/30/15

Abstract

The overall goal of this project is to develop, evaluate, and demonstrate the use of a simple tool to quantify the impacts of DWM on the reduction of N losses from subsurface drained cropland. A tool like the one proposed herein would be essential for any water quality credit trading system that involves the use of DWM. The success of this system hinges upon a credible estimate of the nitrogen credit from this non-point source system. Specific objectives include: a) Develop an easy to use and reliable DRAINMOD-based tool to quantify the reduction of annual N mass losses due to the implementation of DWM. This tool can be utilized by the Midwest and Southeast states as part of a water quality credit trading system involving DWM. b) Test the accuracy of the tool by comparing DWM-caused reductions of annual N mass loss estimated by the developed tool to measured and/or DRAINMOD-NII predicted losses for Indiana, Illinois, Minnesota, Iowa, Ohio, and North Carolina. Historic measured data will be used and no additional measurements will be needed for the evaluation of the performance of the tool. c) Develop a website for the tool which includes educational material on DWM, instructional material on how to use the tool, and utilities for preparing the required inputs.

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A Smart Water Management System to Increase Crop Yields and Profits, Conserve Water, and Improve Water Quality for Crop Production Systems on Artificially Drained Lands

US Dept. of Agriculture (USDA)(4/01/12 - 3/31/16)

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A Smart Water Management System to Increase Crop Yields and Profits, Conserve Water, and Improve Water Quality for Crop Production Systems on Artificially Drained Lands

Sponsor: US Dept. of Agriculture (USDA)

Start Date: 4/01/12

End Date: 3/31/16

Abstract

With the emergence of biofuels as one of several alternatives to fossil fuels, land resources, that have been traditionally used for food production, could eventually be used for both food and energy production. To sustainably optimize the use of the limited land resources, ?engineered? crop production systems are critically needed to maximize yields, minimize production costs, conserve land and water resources, and minimize negative environmental impacts. We propose to develop and assess a ?smart? water management system to increase crop yields and profits, conserve water, and improve water quality for crop production systems on artificially drained lands. The system is comprised of : 1) a ?smart? irrigation technique that is automatically triggered based on the soil moisture in the root zone or the water table depth; 2) an automated controlled drainage system that automatically adjust the elevation of the outlet of the drainage system based on water table depth and precipitation. The proposed research will be conducted on two research sites in Eastern North Carolina (currently instrumented). There will be three treatments: conventional (unmanaged) drainage as control, manual (traditional) controlled drainage, and smart water management system (automated controlled drainage combined with smart irrigation). These systems will be monitored to measure hydrologic and climatological data, plant growth and yield data, and nitrogen budget (in plant, soil, and water) data. Farming practices and costs of implementation and maintenance will be documented. The data will be used to assess the performance and feasibility of the system and will also be used to test and further develop the DRAINMOD suite of models (DRAINMOD, DRAINMOD-NII, and DRAINMOD-DSSAT).

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Automated Water Control Structures For Increased Water Use Efficiency on Agricultural Drained Lands

US Dept. of Agriculture (USDA)(9/15/11 - 9/30/14)

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Automated Water Control Structures For Increased Water Use Efficiency on Agricultural Drained Lands

Sponsor: US Dept. of Agriculture (USDA)

Start Date: 9/15/11

End Date: 9/30/14

Abstract

Drained agricultural lands make up about 40% of cropland in North Carolina. Drainage is a necessity on flat poorly drained soils to facilitate seedbed preparation and planting and to minimize plant stress and subsequent yield reduction. However, the drainage intensity required for agriculture production is not the same in all years or all periods of the year. While the primary purpose of drainage system is to reduce wet stresses, the systems can increase drought stresses through over drainage during certain parts of the year. Often drainage systems remove more water than necessary during drier periods, leading to temporary over-drainage (Doty et al., 1986). Problems with drought on drained soils have resulted in a transition from conventional drainage systems to drainage water table management systems (DWM). The latter provides drainage during wet periods and conserves water during dry periods. Recently, NCSU has completed a project to develop a Drainage Water Management online-advisory system through a National CIG grant. Nineteen producers where utilized in the pilot program. The site-specific recommendations for riser management, if correctly followed, predicted an average water conservation effect of 4.75 inches/ac for the producers. This was nearly 10% of the annual rainfall amounts for the area. The water that is conserved in the system can be used by plants during periods of drought which has a direct result on crop yields and water quality. However, a recommendation for management is only useful if it is followed. This means that producers have to place and remove riser boards at the appropriate time of year. A recent survey in 2008 commissioned by the NLEW committee showed that out of 20 producers surveyed randomly in the Neuse River basin that 13 fields had no riser management and the other 7 only had partial management. This has lead to the possibility of reducing the nitrogen credit given to water management control structures for each county in the coastal plain. Since the mid-1980s, over 4000 water control structures affecting about 400,000 acres have been installed in NC (Evans and Skaggs, 2004). Conservative estimates based on results of research indicate that these systems, properly managed, reduced N losses to coastal waters by 4 million pounds annually. If the predicted water conservation from the growers in our pilot program holds across the board this would conserve 30 billion gallons of drainage water per year. Unfortunately, a large majority of CD systems in the North Carolina Coastal Plain are not being properly managed at the present time. In order to address this management issue, we are proposing the transfer and demonstration of similar technology that has been employed in the Mid-west on in-line controlled drainage structures for tile drainage systems, to flashboard risers systems that are here in NC. This project will demonstrate an effective automated method for controlling flashboard riser systems that will significantly reduce producer management. It will have significant water conservation benefits, water quality benefits and may have crop yield impacts. It will also have a significant impact on the mandated reductions for nitrogen in the river basins.

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Optimization of Southeastern Forest Biomass Crop Production: A Watershed Scale Evaluation of the Sustainability and Productivity of Dedicated Energy Crop and Woody Biomass Operations

US Dept. of Energy (DOE)(9/30/10 - 9/30/16)

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Optimization of Southeastern Forest Biomass Crop Production: A Watershed Scale Evaluation of the Sustainability and Productivity of Dedicated Energy Crop and Woody Biomass Operations

Sponsor: US Dept. of Energy (DOE)

Start Date: 9/30/10

End Date: 9/30/16

Abstract

The overall objective of this Project is to evaluate the environmental effects of large-scale forest bioenergy crop production and utilize these results to optimize cropping systems in a manner that protects the important ecosystem services provided by forests while contributing to the development of a sustainable and economically-viable biomass industry in the southeastern U.S.. Specific objectives are to: ? Quantify the hydrology of different energy crop production systems in watershed scale experiments on different landscapes in the southeast US. ? Quantify the nutrient dynamics of energy crop production systems in watershed scale experiments to determine the impact of these systems on water quality. ? Evaluate the impacts of energy crop production on soil structure, fertility, and organic matter content ? Evaluate the ecosystems response to energy crop production systems in terms of flora and fauna population dynamics and habitat quality ? Quantify the production systems in terms of bioenergy crop yield versus the energy and economic costs of production. ? Develop watershed and regional scale models to evaluate the environmental sustainability and productivity of energy crop and woody biomass operations ? Develop and evaluate best management practice guidelines to ensure the environmental sustainability of energy crop production systems. Our research team has established a regional research program to evaluate the environmental consequences of biomass cultivation in forests. We are designing a flexible research program to evaluate a wide range of possible biomass production scenarios that could affect millions of acres in the southeast U.S. This program consists of plot-scale and watershed-scale experimental studies linked with a modeling effort that will enable us to apply our experimental results broadly across the region. Watershed and plot-scale experiments have been initiated. Instrumentation collecting meteorological, hydrological and water quality data has been installed at all study sites. Studies also have been initiated at these sites to define and quantify the environmental effects of biomass production on wildlife habitat, biodiversity, soil properties and productivity, and carbon storage and flux. Support provided by Catchlight Energy and in-kind contributions of time and equipment from the project participants has enabled us to establish these study sites and begin data collection. Our philosophy has been that if we can establish the study sites and provide sufficient funding to support basic data collection and the application of biomass treatments, these sites will attract other funding sources and cooperators to conduct additional studies, ultimately providing a very comprehensive understanding of the environmental effects of dedicated energy crop and woody biomass operations. This detailed information can then be used to modify biomass production protocols to address any identified environmental impacts. The watershed studies form the core of this research platform. Matched-watershed studies have been established in North Carolina, Mississippi and Alabama. Each installation includes at least four, small, operational-scale sub-watersheds that are instrumented to provide data on stream discharge, weather, water table and water quality. Equipment installation is complete, and pre-treatment data are being collected and analyzed. Biomass treatments that will be applied to the sub-watersheds will represent a spectrum of biofuel management intensities: ? Typical pine plantation, about 15 years old ? Young pine, high value timber regime ? Young pine, woody biomass removal ? Young pine, interplanted with switchgrass ? Switchgrass only Two plot-scale studies have been established to intensively examine effects of biomass production on ground water, soil moisture, soil productivity, carbon dynamics, and biodiversity. Data is collected at these plot-scale study sites in a compatible manner with that being collected at the watershed-scale studies, enabling integration of th

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