Accumulation of dry matter in oilseed rape crops in relation to the reflection and absorption of solar radiation by different canopy structures
Leach, J.E.; Milford, G.F.J.; Mullen, L.A.; Scott, T.; Stevenson, H.J.
Aspects of Applied Biology 23: 117-123
ISSN/ISBN: 0265-1491 Accession: 001745616
The proportions of incident total radiation and PAR intercepted, reflected and absorbed at vegetative, flowering and pod growth stages were measured in rape grown at 3 plant densities and given 0, 100 or 250 kg N/ha in spring at Rothamsted in 1987-89. Canopies composed mainly of developing pods intercepted less radiation than vegetative or flowering canopies. The flowering canopy reflected 25% of total and 10-15% of PAR radiation, much more than vegetative or pod canopies. Reflected radiation was affected by N status but not by plant density. The DM:radiation quotient was greater during pod development than during vegetative growth and was very small during flowering due to the large losses in leaf area at this time.