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Title: Switchgrass growth and pine-switchgrass interactions in established intercropping systems

Intercropping switchgrass (Panicum virgatum L.) with loblolly pine (Pinus taeda L.) has been proposed for producing bioenergy feedstock in the southeastern United States. This study investigated switchgrass growth and pine–switchgrass interactions at two established experimental fields (7-year-old Lenoir site and 5-year-old Carteret site) located on the coastal plain of eastern United States. Position effects (edge and center of switchgrass alley in intercropping plots) and treatment effects (intercropping vs. grass-only) on above ground switchgrass growth were evaluated. Interspecific interactions with respect to capturing resources (light, soil water, and nitrogen) were investigated by measuring photosynthetically active radiation (PAR) above grass canopy, soil moisture, and soil mineral nitrogen contents. Switchgrass growth was significantly (P = 0.001) affected by treatments in Lenoir and by position (P < 0.0001) in both study sites. Relative to the center, PAR above grass canopy at edge in both sites was about 48% less during the growing season. Soil water content during the growing season at the edge of grass alley was significantly (P = 0.0001) lower by 23% than at the center in Lenoir, while no significant (P = 0.42) difference was observed in Carteret, in spite of more grass growth at center at both sites. Soil mineralmore » nitrogen content at the center of intercropping plots in Lenoir (no fertilization during 2015) was significantly (P < 0.07) lower than at the edge during the peak of growing season (June, July, and August), but not during early and late parts of growing season (May, September, and November). Position effects on soil water and mineral nitrogen were less evident under conditions with higher external inputs (rainfall and fertilization) and lower plant uptake during nongrowing seasons. Here, results from this study contributed to a better understanding of above- and belowground pine–switchgrass interactions which is necessary to properly manage this new cultivation system for bioenergy production in the southeastern United States.« less
Authors:
 [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [2] ;  [1]
  1. North Carolina State Univ., Raleigh, NC (United States)
  2. Weyerhaeuser Company, Columbus, MS (United States)
Publication Date:
Grant/Contract Number:
EE0004395; 2011-67009-20089
Type:
Published Article
Journal Name:
Global Change Biology. Bioenergy
Additional Journal Information:
Journal Volume: 9; Journal Issue: 5; Journal ID: ISSN 1757-1693
Publisher:
Wiley
Research Org:
North Carolina State Univ., Raleigh, NC (United States)
Sponsoring Org:
USDOE
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES; 60 APPLIED LIFE SCIENCES; 09 BIOMASS FUELS; agroforestry; competition; grass growth; interspecific interactions; loblolly pine; switchgrass
OSTI Identifier:
1266400
Alternate Identifier(s):
OSTI ID: 1271466; OSTI ID: 1393499