Forage evapotranspiration and photosynthetically active radiation interception in proximity to deciduous trees

Charles M. Feldhake

Agricultural Water Management, 2009, vol. 96, issue 7, pages 1170-1174

Abstract: Practically all of the extensive body of research on evapotranspiration (ET) in agricultural systems has been done for open fields. There is a lack of information on how the microclimate variability within silvopasture systems affects water requirements of forages. Small 26 cm diameter, 23 cm deep lysimeters planted with either orchardgrass (Dactylis glomerata L.) or tall fescue (Schedonorus phoenix (Scop.) Holub) were placed in the ground along the north and south edge of two 15 m wide x 50 m deep notches cleared into a mature second growth hardwood forest. One notch opened to pasture on the east receiving more early day solar radiation and one to pasture on the west receiving more wind and late day solar radiation. There was no significant difference in ET between orchardgrass and tall fescue. North edges, receiving more direct beam radiation, had significantly higher ET (39%) than south edges which received a higher percentage of diffuse radiation. The west notch had significantly higher ET (11%) than the east notch. At the sunniest sites, advection provided 20% of the energy used for ET while at the shadiest sites it provided more than half (56%) with the rest provided by incident solar radiation. Dates where photosynthetically active radiation (PAR) was restricted by clouds resulted in decreased ET relative to PAR compared to more sunny days. However, sites where PAR was restricted by tree shade had higher ET relative to PAR than more open sites. These results indicate tree modification of microclimate does not decrease forage ET to the extent that PAR is decreased.

Keywords: Advection; Cloudiness; Forest; edge; Orchardgrass; Silvopasture; Tall; fescue (search for similar items in EconPapers)
Date: 2009

Downloads: (external link)
http://www.sciencedirect.com/science/article/B6T3X ... cf3f41d9f857e0e233cd
Full text for ScienceDirect subscribers only

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: http://EconPapers.repec.org/RePEc:eee:agiwat:v:96:y:2009:i:7:p:1170-1174

Access Statistics for this article

Agricultural Water Management is edited by B.E. Clothier, W. Dierickx, J. Oster and D. Wichelns

More articles in Agricultural Water Management from Elsevier
Series data maintained by Heidi Boesdal ().