Seasonal differences in clear-sky nighttime forage temperature in proximity to deciduous trees

Paper presented at the 11th North American Agroforesty Conference, which was held May 31-June 3, 2009 in Columbia, Missouri.In Gold, M.A. and M.M. Hall, eds. Agroforestry Comes of Age: Putting Science into Practice. Proceedings, 11th North American Agroforestry Conference, Columbia, Mo., May 31-June 3, 2009.Considerable research has been done on daytime forage shading by silvopasture trees since solar radiation is required for photosynthesis. However, trees also impact nighttime temperature on clear nights when trees also effectively shade forages from cold skies. Appalachia has a temperate climate and deciduous-tree silvopasture nighttime temperature patterns will differ between spring before tree leaves emerge and summer when trees are in full canopy. Longwave radiation sensors, which simulate forage (surface) temperature, were installed in triplicate at four locations differing in obstruction to open sky by trees. An open pasture site (O) had 90 [percent] exposure to open sky during summer. A site within an adjacent closed-canopy second growth mixed hardwood forest (F), with only small canopy gaps, had 10 [percent] exposure to open sky. Two intermediate sites within a 15 X 50m gap cleared into the forest had 20 and 40 [percent] exposure to open sky respectively (G2 and G4). Air temperature was recorded at 2m at all sites. Temperatures were measured every 10s and hourly averages recorded from 1-Feb.-2008 through 10-July-2008. Summer differences between surface and air temperature in response to radiation cooling during clear night hours were -6.7, -2.9, -1.5, and -0.7oC for sites O, G4, G2, and F respectively. Respective late winter and early spring temperature differences were -6.3, -6.4,-5.7 and -4.3oC. There was a threefold difference between longwave radiation forage cooling at O compared to F in summer compared to early spring. Also, summer surface-air temperature differentials increased linearly as sky exposure increased. During tree leafless periods, temperature differentials were constant down to 40 [percent] sky exposure but decreased exponential approaching 10 [percent] sky exposure. During periods with full cloud cover there were no site temperature differences between air and surface during either season. These results suggest different forage management strategies in response to different forage nighttime temperatures may be warranted.C.M. Feldhake ; USDA-ARS, Appalachian Farming Systems Research Center, 1224 Airport Rd., Beaver, WV, 25813.Includes bibliographical references

Establishment and production from thinned mature deciduous-forest silvopastures in Appalachia

Paper presented at the 11th North American Agroforesty Conference, which was held May 31-June 3, 2009 in Columbia, Missouri.In Gold, M.A. and M.M. Hall, eds. Agroforestry Comes of Age: Putting Science into Practice. Proceedings, 11th North American Agroforestry Conference, Columbia, Mo., May 31-June 3, 2009.Past research has not adequately addressed effective management and utilization of silvopastures developed from the ubiquitous mature woodlots which comprise 40-50% of small Appalachian farm acreage. While some grazing in woodlots is common, a set of guidelines for optimal utilization of these areas is not. We thinned a white oak dominated mature second growth forested area establishing two 0.5 ha, eight-paddock, orchardgrass-perennial ryegrass-white clover silvopasture replications for comparison with two nearby open pasture replications. After thinning trees, silvopastures were limed, fertilized and seeded. Sheep were fed hay and corn scattered across the area to facilitate removal of residual understory and incorporation of applied materials into surface soil. We measured soil moisture in the top 15 cm using TDR and photosynthetically active radiation (PAR) using a system of 16, 1 m line Quantum Sensors during the subsequent growing seasons of 2004, 2005, and 2006. Paddocks were rotationally grazed by sheep with two 1 m2 herbage mass samples taken prior to animal grazing. There was no significant difference in soil moisture between silvopastures and open pastures however, there was adequate rainfall to prevent drought all three years. The two silvopasture replications had residual tree stands of 14.1 and 15.6 m2 ha-1 diameter breast height allowing 42 and 51 [percent] of total daily incident PAR compared to measurements in the open field. Total forage mass yield from open pasture for 2004, 2005 and 2006 was 9.9, 10.5 and 10.2 t ha-1 respectively and for silvopasture 8.5, 6.7 and 6.7 t ha-1. Silvopastures received 47 [percent] of open pasture incident PAR yet yielded an average of 72 [percent] as much herbage mass as the open pastures. The silvopasture soils were managed for forage production only a few years unlike the open pastures which received roughly a century of better management. Soil limitations may have contributed to decreased forage yield in silvopastures in addition to reduced PAR.C.M. Feldhake, J.P.S. Neel and D.P. Belesky ; USDA-ARS Appalachian Farming Systems Research Center 1224 Airport Road, Beaver, WV.Includes bibliographical references

Fall 1983

Canada Geese Control (page 3) Coloring the Course (5) Irrigation\u27s Role for Turf and Landscape (7) Perennial Ryegrass Update (12) Crabgrass - A Common Troublesome Weed in Turfgrass (15) Thatch and Its Control (18