| Pak. J. Bot., 41(2): 511-517, 2009. | Back to Contents | ||||
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Updated: 09-07-09 | ||||
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SEASONAL VARIATION IN NUTRITIVE VALUE OF CHRYSOPOGON AUCHERI (BOISS) STAPF., AND CYMBOPOGON JWARANCUSA (JONES) SCHULT., IN HIGHLAND BALOCHISTAN, PAKISTAN
GUL BANO1, MUHAMMAD ISLAM2, SARFRAZ AHMAD2, SOHAIL ASLAM2 AND SHAISTA KOUKAB2
Abstract:
Chrysopogon aucheri
(Boiss) Stapf., and Cymbopogon jwarancusa (Jones) Schult., are
the dominated perennial range grasses in highland Balochistan. Seasonal
concentration dynamics of nitrogen (N), phosphorus (P), magnesium (Mg)
and calcium (Ca) in Chrysopogon aucheri and Cymbopogon
jwarancusa were determined at a protected site. The concentration of
nitrogen in spring ranged from 12.4 to 13 mg g-1,
early summer 15.4-17.26 mg g-1 and late summer 6.7 to 10.7 mg
g-1, respectively during 2001 and 2002 seasons. In 2001, the
concentration of P in spring and early summer was (1.1-3.4 mg g-1)
and least in late summer (0.26-0.81 mg g-1) while in 2002 the
concentration of P in spring and early summer was significantly higher
(1.28-3.35 mg g-1) and least in late summer (0.38-1.01 mg g-1).
In both grass species, there was a similar response of concentrations of
K, Mg and Na and the concentration of these elements were higher during
spring and then dropped and remained static for the remainder of the
year while the concentration of Ca was lower in early spring and
significantly (p<0.05) increased with the passage of time during the
season. In both grasses the N: P ratio was below < 14 suggesting
N-limitation during March and July and showed more than >16 during drier
months of August and September. Overall, both the grasses are low in N,
P and other nutrients except Na and Ca. These findings suggest that
heavy but short-term grazing of very long protected grasslands after
substantial rainfall may be one strategy to increase palatability and
animal nutrition. Results of this study also indicate the need for
direct and high quality mineral supplementation for grazing stock.
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