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United States Department of Agriculture

Agricultural Research Service

Research Project: Cig Gypsum Curtain Project

Location: Pasture Systems & Watershed Management Research

2012 Annual Report


1a.Objectives (from AD-416):
1. Implement and demonstrate the effectiveness of gypsum curtains for reducing soluble P on farms in Somerset County, Maryland. (a) Demonstrate effectiveness at a sub-watershed scale. (b) Demonstrate effectiveness across different soil types in the region. (c) Evaluate potential adverse environmental impacts.

2. Work in concert with NRCS personnel and other entities to develop standards for this practice.


1b.Approach (from AD-416):
Stream and ditch monitoring in the study area will be intensified in order to further establish a base line for assessing the effectiveness of this practice. Following six or more months of monitoring, gypsum curtains will be installed, and stream and ditch monitoring methods will be used to measure changes in groundwater, ditch and stream chemistry following filtration.


3.Progress Report:

Soil samples were collected from all fields on all farms and submitted for soil test analyses. The results were shared with the land owners. Approximately 7,000 additional tons of FGD gypsum was delivered to the collaborator’s farms from Exelon Corporation-Constellation Energy (ECCE) for curtain installation. A sideshooter was purchased from Mensch Manufacturing for use in delivering gypsum to the trench. It was modified to place the gypsum in the trench from a greater distance to alleviate occasional caving of the trench wall. Curtain installation was contracted with a local business and installation was completed on two of the four farms that are participating in this project. This amounted to the installation of approximately 31,000 feet of gypsum curtains. An innovative sample collector device was designed to collect water samples before and after water gypsum curtain treatment from agronomic fields without disrupting normal tillage operations and was installed at multiple locations to determine the efficiency of soluble phosphorus (P) from groundwater passing through the curtains. Water samples from ditches are being collected periodically by automated samplers for testing in our water quality lab. Water samples are being filtered and analyzed for P, mercury, arsenic, pH and other parameters as applicable.

A graduate student was hired to conduct the major portion of the land application and infiltration enhancement component of this project under the leadership of Co-PI Gary Felton, University of Maryland (UMD). Agronomic fields for infiltration experiments have been selected. Gypsum applications at 2, 4 and 6 tons per acre were applied at the beginning of the 2012 growing season. Initial infiltration measurements have been conducted. We hosted a Field Day activity for a cadre of local farmers, extension specialists, ECCE representatives, USDA-Natural Resource Conservation Service Personnel, UMES and UMD scientists, graduate and undergraduate students, USDA-Agricultural Research Service scientists, and a USDA-ARS liaison person station on loan to UMES. The attendance was approximately 30 individuals. Methods for measuring infiltration and preliminary results were presented, and gypsum curtain installation and monitoring techniques were demonstrated. The event was well received and was reported in the Delmarva Farmer. As a result of this publicity, we have been invited to give a talk to a group of farmers about our work with gypsum as part of the Delaware Ag Week Poultry Program in January of 2013.


Last Modified: 8/21/2014
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