Grasslands Research Station, Marondera, Zimbabwe
Silverleaf desmodium (Desmodium uncinatum) was seeded into Hyparrhenia grassland on a sandy clay soil using disced strips which covered 0, 1/3, 2/3 and the whole area. After the Silverleaf desmodium had established, the plots were used for carrying weaner beef steers, at two stocking rates, through the dry season over a period of five years.
Reinforcement with Silverleaf desmodium increased herbage yields at
pregrazing samplings and resulted in marked botanical changes, with
taller-growing Hyparrhenia spp. displacing H. filipendula
and Sporobolus pyramidalis. Lodging and death of these Hyparrhenia
spp. then led to invasion by broad-leafed weeds. Steers in all treatments
lost liveweight over the dry season but this loss was reduced on average
by 15 kg head–1 by reinforcement with Silverleaf desmodium.
During the period of liveweight loss, stocking rate had little effect
but in the two years in which the steers remained in the trial after
the plants had started shooting there was a marked effect of stocking
rate during the period of liveweight gain. Liveweight changes were found
to be related to faecal nitrogen percentages and to the initial yields
It is concluded that herbaceous trailing legumes, such as Silverleaf
desmodium, are not well-suited to a regime of use during the dry season
only, especially in areas subject to frost, and attention is now being
directed towards the use of browse trees for this purpose.