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United States Department of Agriculture

Agricultural Research Service

Research Project: USE OF FGD GYPSUM TO IMPROVE THE PRODUCTIVITY AND STABILITY OF HIGHLY ERODIBLE LOESS SOILS

Location: Water Quality and Ecology Research

2011 Annual Report


1a.Objectives (from AD-416)
We propose to evaluate fluidized gas desulfurization (FGD) gypsum influence on surface soil properties that determine soil resistance to erosion losses. The research will help establish proper rates of FGD gypsum to reduce runoff and erosion losses, and improve soil productivity under different tillage systems. We will also provide documentation of water quality improvement associated with FGD gypsum needed to help qualify practices for use as a BMP and water quality credits.


1b.Approach (from AD-416)
The research will be conducted at The University of Tennessee, Research and Education Center, Milan, and in the Department of Biosystems Engineering and Soil Science, Knoxville. The effect of fluidized gas desulfurization (FGD) gypsum on soil properties and cotton yields will be evaluated using both conventional and no-till management systems. FGD gypsum will be applied at rates of 0, 1, 2, 3, and 5 tons per acre to replicated conventional and no-till cotton plots. Cotton yields will be measured at the end of the growing season. Soil samples collected each year will be characterized: for total carbon, nitrogen, and sulfur; pH; extractable aluminum, potassium, and phosphorus; particle size distribution and water dispersible clay. The most appropriate FGD gypsum amendment rate, in terms of yield increases and reduced soil erodibility, will be selected from these data.


3.Progress Report

A cotton experiment was begun in 2009 comparing no-tillage and tilled cotton with five gypsum rates, 0,1, 2, 3 and 5 tons per acre. The experiment is a randomized complete block design with four replications. Initial soil data to a depth of 4 feet in 6 inch increments was taken on each plot prior to gypsum application. Additional soil samples to 8.5 feet were taken on all plots in one replication. These are being processed and analyzed for various chemical constituents. First expanded full leaf samples were taken in early bloom stage for tissue analysis. Plot yields have been taken, and cotton lint quality is being evaluated. The experiment was continued with expanded measurements taken in 2010 including seasonal changes in profile soil water using time domain reflectrometry. Water measurements were taken to 60 cm in 2010 and are now being analyzed. Chemical measurements have included soil pH; citrate-bicarbonate-dithionite (CBD) extractable iron (Fe), aluminum (Al), and manganese (Mn); oxalate extractable Fe, Al, and Mn; cation and anion exchange capacity (CEC and AEC); and exchangeable cations and anions. Collaborative efforts were maintained through routine site visits, email, and telephone communications with collaborators.


Last Modified: 9/1/2014
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