Research Results - (PDF, 101 mb) - USAID

had more than twice the silica levels as new
growth from the control plants; in the case of the
most severe clipping treatment the increase was
more than threefold. The treatment effect on
wax content was also significant, but less pronounced.
On average, defoliation increased wax
content of young shoots by 32%. These results
suggest that alfa grass has an adaptive chemical
reaction to defoliation which reduces palatability
of the regrowth and protects the species
against grazing. This conclusion complements
that of Mouttaqui working at Plaine de l'Aarid,
as reported last year, who found that rate of
regrowth after defoliation was slower than
growth rate of leaves on non-defoliated shoots,
also suggesting a low tolerance for grazing.
Table 2. Effect of clipping alfa grass at different
levels on wax and silica content of the
regrowth, and on various nutritional parameters
measured on the regrowth. Data are
combined across all four sampling times and
both sites, and expressed as percent dry matter,
Clipping Treatment
10 mm
base of above
shoot ligule ligule control
silica 1.74a 1.47b 1.14c 0.49d
wax 1.42a 1.51b 1.65b 1.16c
CP 15.71a 7.54b 6.84c 6.42d
ash 4.78a 3.80b 3.32c 2.75d
NDF 73.85a 77.68b 78.28b 80.72c
ADF 45.58a 48.44b 47.91bc 47.53c
ADL 5.59a 7.55b 7.57b 7.67b
Means followed by the same letter in a row are
not significantly different (p