Growth, biomass production and
photosynthesis of Cenchrus
ciliaris L. under
Acacia tortilis (Forssk.) Hayne based silvopastoral
systems in semi arid tropics
A.K. Mishra, H.S.
Tiwari and R.K. Bhatt*
Indian
Grassland and Fodder Research Institute, Jhansi - 284 003, India
(Received: September 07, 2009; Revised
received: February
10, 2010; Re-revised received: March 12, 2010; Accepted: April 20, 2010)
Abstract: The growth, biomass production and
photosynthesis of Cenchrus ciliaris
was studied under the canopies of 17 yr old Acacia
tortilis trees in semi arid tropical environment. On
an average the full grown canopy of A. tortilis at
the spacing of 4x4 m allowed 55% of total Photosynthetically
Active Radiation (PAR) which in turn increased Relative Humidity (RH) and
reduced under canopy temperature to -1.75oC over the open
air temperature. C. ciliaris attained higher height
under the shade of A. tortilis. The tiller production
and leaf area index decreased marginally under the shade of tree canopies as
compared to the open grown grasses. C. ciliaris
accumulated higher chlorophyll a and b under the shade of tree canopies
indicating its shade adaptation potential. The assimilatory functions such as
rate of photosynthesis, transpiration, stomatal
conductance, photosynthetic water use efficiency (PN/TR) and carboxylation efficiency (PN/CINT) decreased under the tree
canopies due to low availability of PAR. The total biomass production in term
of fresh and dry weight decreased under the tree canopies. On average of 2 yr
C. ciliaris had produced 12.78 t ha-1
green and 3.72 t ha-1 dry biomass under the tree
canopies of A. tortilis. The dry matter yield
reduced to 38% under the tree canopies over the open grown grasses. The A. tortilis + C. ciliaris maintained
higher soil moisture, organic carbon content and available N P K for
sustainable biomass production for the longer period. The higher accumulation
of crude protein, starch, sugar and nitrogen in leaves and stem of C. ciliaris indicates that this grass species also maintained
its quality under A. tortilis based silvopastoral system. The photosynthesis and dry matter
accumulation are closely associated with available PAR indicating that for
sustainable production of this grass species in the silvopasture
systems for longer period about 55% or more PAR is
required.
Key words: Acacia tortilis, Biomass, Cenchrus ciliaris, Chlorophyll,
Nutrient, PAR, Photosynthesis, Silvopasture system
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