nitrogen and soil water were studied in loblolly pine (Pinus taeda L.) seedlings grown in monoculture and in competition with sweetgum (Liquidambar styraciflua L.) or crab grass (Digitaria spp.). Rhizotron cells were maintained at high soil water availability (approximately −0.1 MPa) or subjected to three dry-down cycles to low soil water availability (approximately −1.0 MPa), over two growing ...