TheImprovement ofTropical and Subtropical Rangelands

368 IMPROVEMENT OF TROPIOAL AND SUBTROPIOAL RANGELANDS
At preeent, only three St,lo,aratAe, cultivars are commercially available
in Nigeria, and two of them are dangerously IWICeptible to the
fungal diaeue anthracrose, which can wipe out entire stands of the
legume. A wider range of resistant varieties is needed, and ILeA is
carrying out screening trials in order to eelect these.
Seed is prohibitively expensive (USS13.5 per kg) and its quality
is low. Up to 60 percent of a kilo of -eeeds- may in fact consist of
sand. Mixed in with the legume seeds are those of weeds that when
planted may flourish at the expense of the legume. Traditionally,
women who collect seeds are paid by the weight they hand in rather
than the time they spend gathering and winnowing. Buyers will have
to exert tighter quality control if the high eeeding rates (8-10 kg per
hectare) currently needed to start a fodder bank are to be reduced.
During the growing season, animals eat young nutritious gruses
in preference to legumes. In theory, this behavior can be used to
control grUB growth on the fodder bank, allowing the legume to
establish. But in practice the timing of grazing is critical, since
animals do not distinguish graues from legumes until at least four
weeks after the start of the rams. After this, they will graze gruses
only while these are still taller than the legume. Thus, ifthe legume
is to flourish, animal behavior and vegetation growth must both be
closely watched to identify the right moment to take the animals off
the bank.
Once the rams stop and vegetation dries out, fire becomes a
threat. During each of the five years ofILCA's research, entire stands
of legumes have been destroyed as bush fires, started accidentally or
on purpoae, have got out of control.
Predictably, the pastoralists have their own ideas about how
their fodder banks should be used. These ideas came to light during
the extension phue of the reeearch, and ILeA's scientists are now
adapting their component research to take them into account.
Originally, ILeA recommended that the Fulani grue only their
lactating and pregnant caws on the fodder banks, in the hope of increasing
both milk and calf production. But the pastoralists tend to
graze additional animals-often their entire herdlt-aiming to maximize
the welfare of all animals. The scientists are now studying
the effects of these heavy stocking levels on herd performance and
legume regeneration. One encouraging finding is that the heavy
seeding annual S. hamata appears to cope well with both fire and
overgrazing.
Fodder banks still need further refinement and testing, but the