Canopy, microenvironment, and nitrogen effects on summer recovery of tall fescue

Stand losses in temperate grasses after summer defoliation of tall canopies inspired an investigation of microenvironmental and plant responses in tall fescue. Microenvironment and regrowth of tall fescue in response to mowing managements and nitrogen rates in spring that created different canopy structures was studied. In early spring, 50 and 160 kg/ha of N were applied. Mowing managements were: clipping at 4 or 8 cm biweekly, monthly, and in late June. In late June all 6 treatments were mowed to prescribed stubble heights with a seventh unmowed check. Canopy light regimes, leaf area index, and regrowth of tillers were monitored along with soil, fair, and shoot temperatures in stubbles after the June harvest. Mowing more frequently in spring decreased canopy yields of the June harvest, but increased leaf area (LAI) of stubbles as compared to spring-accumulated canopies. High nitrogen decreased specific leaf weights (SLW) in stubble leaves and increased LAI except in spring-accumulated canopies. Increased LAI decreased light penetration and canopy temperatures. Temperatures were highest in harvested spring-accumulated stubbles with a shift of 4-10 C between unharvested and harvested stands while radiation penetration into the stubble increased from 5 to 75% of total. Some large stand losses occurred in lodged portions of harvested Spring-accumulated plots. Generally, regrowth yields were not affected by prior clipping managements. Concentration of TNC was uniformly high with all treatments.

Name thesis:degree_name

Ph. D.

Level thesis:degree_level

doctoral

Discipline thesis:degree_discipline

Agronomy

Department dc:contributor.department

Agronomy

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

1977

Author dc:creator

• Stringer, William C.

Chairs dc:contributor.committeechair

• Blaser, Roy E.
• Wolf, Dale D.

Committee members dc:contributor.committeemember

• Fontenot, Joseph P.
• Hutcheson, Thomas B. Jr.
• Orcutt, David M.

• grasses

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en

Dc Identifier Other

etd-11292012-040244

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/40367