Date of Award

11-17-2018

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Applied Science

First Advisor

John Bush

Second Advisor

Edmund Buckner

Abstract

The quality and quantity of water in the Mississippi River Basin is of great national importance. As the production of agricultural crops increases in this area, it is very important that monitoring and data analysis plans be implemented aggressively. The National Resources and Conservation Service (NRCS) has developed the Mississippi River Basin Initiative which includes Arkansas as one of 13 states that is participating in this initiative. To date, Arkansas is known as the number one producer of the nation’s rice, bait fish, sport fish, and feeder fish, number two in broiler production, number three in catfish and number six in sweet potato production. Our lab and others are working together to implement conservation practices encouraged by NRCS to promote better water quality and quantity, enhance wildlife habitats, and restore wetlands while sustaining agricultural productivity in Arkansas. Our focus is Edge-of-Field runoff monitoring with ISCO 6712 automatic samplers at several privately owned farm sites (Lonoke & Jefferson counties) to analyze the quality of water in runoff from agricultural fields during rain and irrigation events. The first and second year of cover crop treatment did not show significant difference in concentrations (2016) nor loads (2017) between the control and treatment sites at Bayou Bartholomew Watershed Cousart Bayou-Little Cypress Bayou in Jefferson County. There was a moderate significant difference between total nitrogen and total suspended solids in the first year of cover crop at Bayou Meto watershed at Lonoke County. Nitrate + nitrite showed a moderate difference between control and treatment field plots. With the implementation of cover crops we have seen a decrease in the total sediment, nutrients, and pollutants entering water systems. We also utilized the Agricultural Policy Environmental Extender Model (APEX) to compare field-scale data with model predictions. The predictions from the model showed no correlation between crop yield, total nitrogen, nor total phosphorus. We anticipate that modeling and monitoring will suggest better management practices to improve the water quality and quantity. This project has provided suggestions for best management practices that will help improve agricultural productivity and water quality and quantity by implementing appropriate management practices unique for each farm.

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