Title page for ETD etd-11292012-040244


Type of Document Dissertation
Author Stringer, William C.
URN etd-11292012-040244
Title Canopy, microenvironment, and nitrogen effects on summer recovery of tall fescue.
Degree PhD
Department Agronomy
Advisory Committee
Advisor Name Title
Blaser, Roy E. Committee Co-Chair
Wolf, Dale D. Committee Co-Chair
Fontenot, Joseph P. Committee Member
Hutcheson, Thomas B. Jr. Committee Member
Orcutt, David M. Committee Member
Keywords
  • grasses
Date of Defense 1977-07-05
Availability restricted
Abstract

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—accumu1ated canopies. High nitrogen decreased specific leaf weights (SLW) in stubble leaves and increased LAI except in springaccumulated canopies. Increased LAI decreased light penetration and canopy temperatures. Temperatures were highest in harvested springaccumulated 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.

Files
  Filename       Size       Approximate Download Time (Hours:Minutes:Seconds) 
 
 28.8 Modem   56K Modem   ISDN (64 Kb)   ISDN (128 Kb)   Higher-speed Access 
[VT] LD5655.V856_1977.S755.pdf 3.50 Mb 00:16:11 00:08:19 00:07:16 00:03:38 00:00:18
[BTD] next to an author's name indicates that all files or directories associated with their ETD are accessible from the Virginia Tech campus network only.

Browse All Available ETDs by ( Author | Department )

dla home
etds imagebase journals news ereserve special collections
virgnia tech home contact dla university libraries

If you have questions or technical problems, please Contact DLA.