Production and physiological responses of Italian ryegrass and white clover grown in mono cultures and mixed stands.
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Date
1993
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Abstract
The aim of this study was to test the hypothesis that ryegrass
and clover, when grown under optimal conditions in mixed stands,
interact in response to available light energy. with other
resources non-limiting, pasture yield is determined by the
efficiency with which solar radiation is intercepted by canopies
and converted into dry matter.
The clover-ryegrass interaction under varying light regimes, as
experienced in the canopies of these pastures, was studied by
investigating the growth and production of ryegrass and clover
in relation to light harvesting abilities and photosynthetic
utilization of intercepted light.
Pasture canopy structure and growth were studied under a four-weekly
clipping treatment. The interception of photon flux
density (PFD) in the pasture canopy was monitored diurnally and
seasonally in mixed and mono cultures. Light use efficiency (C02
fixed/ unit absorbed PFD) as well as photochemical efficiency of
photosystem II (Fv/Fm) were studied by monitoring CO2 assimilation
rates and chlorophyll fluorescence respectively.
The results obtained from this study indicated that interaction
did occur between ryegrass and clover, cultivated in mixed
pastures. The mixture was capable of more efficient light
interception than the mono cultures, which resulted in higher
productivity. Light interception abilities, as manifested in
canopy architecture, and not physiological utilization of light
energy, were found to govern the interaction between the two
pasture components.
Description
Thesis (M.Sc.)-University of Natal, Durban, 1993.
Keywords
Light--Physiological effect., Plants--Effect of light on., Theses--Botany.