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Hydrologic impacts of mechanical shearing of Ashe juniper in Coryell County, Texas

Several studies have been conducted to research the effectiveness of
brush removal on hydrologic properties such as increased water yields and water
quality. The Leon River Restoration Project (LRRP) is a large scale brush
management program aimed at assessing the impacts of the mechanical
removal of Ashe juniper (Juniperus ashei) on the quantity and quality of water, as
well as wildlife habitat and livestock forage production.
The objectives of this particular study are to assess the short and long
term impacts of mechanical rangeland management techniques on runoff water
yield and sediment loss from rainfall simulator plots. Two ecological sites were
used to conduct rainfall simulation in 3 stages. Rainfall simulations were
completed on Redland and Low Stony Hill sites in June 2003 prior to treatment,
July 2003 after Ashe juniper was sheared from treated areas of both sites and 11
months after treatment in June 2004.
Infiltration rates on both the Redland and Low Stony Hill sites increased
after juniper was removed except for the treated brush plots on the Redland site,
which experienced a 33% decrease. During the third simulation, infiltration rates decreased on all plots. Grass and litter biomass, as well as bare ground were
influential on both sites. Percent bare ground affected infiltration rates the most
on the Redland site where bare ground on the treated brush site was 23% in July
2003 and 42% in June 2004. The grass plots on the Low Stony Hill site had the
greatest percentages of bare ground during the second simulation.
Very few significant differences were apparent with sediment production
on the Low Stony Hill site; however, the treated brush plots on the Redland site
did experience a significant increase in soil loss following treatment. Sediment
production increased from 24.6 kg/ha to 1,730 kg/ha in one month on the treated
brush site. All other plots on the Redland site decreased in sediment discharge.
Sediment production also had minor increases on the grass plots and treated
brush of the Low Stony Hill. Once again, standing crop and bare ground seemed
to have the greatest influence on sediment production.

Identiferoai:union.ndltd.org:tamu.edu/oai:repository.tamu.edu:1969.1/4381
Date30 October 2006
CreatorsGreer, Courtney Hale
ContributorsKnight, Robert W.
PublisherTexas A&M University
Source SetsTexas A and M University
Languageen_US
Detected LanguageEnglish
TypeBook, Thesis, Electronic Thesis, text
Format672362 bytes, electronic, application/pdf, born digital

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