This document summarizes a study on using cover crops to improve water quality and reduce soil compaction in coastal plain soils. The project established demonstration sites to evaluate the impacts of cover crops on soil moisture, water infiltration and runoff. Sensors were installed to automatically monitor soil moisture, and flumes were set up to measure surface water runoff. Preliminary results found that rye cover crops helped maintain soil moisture for cash crops and reduced water runoff compared to areas without cover crops. The project aims to demonstrate these benefits to farmers and develop tools for monitoring soil moisture with Internet of Things technology.

1. Utilizing Cover Crops to Improve
Water Quality and Reduce Soil
Compaction in Coastal Plain Region
Michael Marshall and Jose Payero
Clemson University

2. Introduction
 Coastal plain
soils in the
southeast US
have a
compaction layer
(E) that forms
between the
sandy loam (A)
and sandy clay
loam (Bt)
horizons

3. Introduction (cont)
 Coastal plain soils also have low
water holding capacity
 Typically ~0.1 inch water /inch of soil
 Low organic matter (<1.0%)
 Nutrient losses can result from deep
percolation of water from the root
zone.

4. Introduction (cont)
 Use of cover crops is
increasingly popular
sustainable farming
practice.
 Cover crop residues
improve water
infiltration and storage.
 Cover crop also
improve soil physical
and help retain
nutrients.

5. CIG Project Objectives
 Establish cover crop demonstration sites
in South Carolina and Georgia.
 Evaluate the impacts of cover crops on
water infiltration, holding capacity, and
quality.
 Implement training programs for county
agents, growers, consultants on benefits
of cover crops and water storage and
quality.
 Develop a IoT (Internet-of-Things)
system for collecting soil moisture and
water run-off from test sites.

6. CIG Project Methods
 Grower field sites were divided into two
sections (cover and no-cover).
 Rye was planted in the cover section
after crop harvest in the fall
(~November).
 Cover crops were terminated using
herbicides in the spring of the following
year.
 The cash crop (cotton or soybean) was
planted 21 days after termination.
 Watermark soil moisture sensors
installed at 4 depths (6,12,18, and 24

7. CIG Project Methods (cont)
Soil Moisture Monitoring Equipment:

8. CIG Project Methods (cont)
 An Environmental Quality Monitoring
site was established at Edisto REC in
2018.
 A six-acre field was subdivided into six
one-acre sections (~100 by 500 ft).
 Each section was bermed to prevent
water from entering from a neighbor
section.
 At each outlet, a H-flume system was
installed to measure and capture a
portion of the run-off from each

9. CIG Project Methods (cont)
Water Runoff Site (Water Quality
Monitoring):

10. CIG Project Methods (cont)
 The eTape device
was installed in the
H-flume to measure
water depth during
run-off events in
each flume.
 eTape was
connected via IoT to
transmit data to the
internet for
monitoring.

11. CIG Project Methods (cont)
 A rye crop was
seeded in the fall in
3 of the 6 sections.
 Cover crops were
terminated using
herbicides in the
spring of the
following year.
 The cash crop
(cotton or soybean)
was planted 21
days after
termination.

12. Field View of H-Flumes

13. CIG Project Methods (cont)
Water Runoff Site (Water Quantity and
Quality Monitoring):
Coordinator End NodeWireless Sensor Network

14. Water Quality Monitoring Site
EREC
Weather Station near Flume Field

15. ThingView App
Data from weather station shown in cell phone using the
ThingView app.

16. Soil Moisture Monitoring

17. CIG Project Results
Demonstration Site Soil Moisture System
Monitoring 2018

18. Soil Moisture Monitoring System
Grower Field - 2019

19. Flume Runoff Site Results

20. Water Quality Monitoring Site
EREC - 2019
Terminated Rye Cover with Cotton Conventional Tillage with Cotton

21. CIG Project Results
Water Runoff Demonstration Site:

22. CIG Project Results
Water Runoff Demonstration Site:

23. CIG Project Summary
 Grower demonstration sites were established
with a summer crops at each site in South
Carolina/Georgia.
 Automated soil moisture sensors were
installed at the grower field sites in the cover
and no-cover areas of the field at 6
demonstration sites in 2018 and 2019.
 Soil moisture data was collected from
grower’s fields and transmitted and stored
Cloud using IoT technology (ThingView).
 A weather station was constructed and
installed at the water quality monitoring site at
Edisto Research and Education Center.

24. CIG Project Impacts
 Demonstrated that biomass from winter cover
crops can help capture and maintain soil
moisture in the following cash crop to
growers in South Carolina and Georgia.
 Developed the tools and methods for growers
to monitor soil moisture from automated
sensors using an app on their phone.
 Established an IoT-based H-flume water
quantity and quality system for collecting run-
off from the field.
 Demonstrated these results to growers at
several field days and county meetings in
2018 and 2019

25. Funding Acknowledgements
 USDA-NRCS CIG Grant Program
 South Carolina Cotton Board