multipurpose tree species research for small farms: strategies ... - part

measures to promote the involvement of farmers.
Multipurpose trees can improve production per
unit area and increase the quantity of benefits.
Tangible benefits promote more people's
pprticipation which improves the ecological
environment and consequently restores nutrients
for sustained productivity. The integration of
rapidly growing nitrogcn-fixing trees has the
potential to enhance the rehabilitation process and
increase production.
The Strategy
The first step in the rehabilitation of degraded
land is to identify the constraints and select trees
that fit into the climatic and edaphic parameters,
preferably species which meet with local approval,
This is followed by maintenance which enhances
the successful establishment of seedlings for the
first two to three seasons.
The next step would be to apply soil
amendments to enhance growth, allowing the
plants to utilize radiant energy, moisture and
nutrients; and control pests and diseases to
improve the quality and quantity of produce.
The third consideration to promote and
enhance nutrient cycling for sustained production
is to adopt moisture conservation practices,
slowing runoff to optimize production.
The fourth consideration is the marketability of
the surplus at a reasonable price. The income
from forestry practices should aim to equal or
exceed that from aricultural crops unde.r similar
site conditions, and the farmer must he convinced
of its profitability.
The last consideration is the social milieu and
the involvement of the rest of the community.
Developing cottage industries will increase the
employment potential and help to improve the
economic conditions in rural areas.
Discussion
Observations from studies carried out at the
Central Soil and Water Conservation Research
and Training Institute (SC&WCR&TI), Dehra
Dun, and its research centers located in differing
agroecosystems of the country are discussed.
Plant material
Species recommended for degraded habitats
are presented in Table 1. In general, trees and
grasses with potential for production include
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Acacia nilotica, A. catechu, A. tortilis, Albizia
lebbek, Bauhtiniapuqntrca,B. rariegata, B.
retusa, Bambusa giganteus, Dalbergia sissoo,
Dendrocalamusstriclus,Grewia optiva,
Leucaena spp., Moms alba,Pintsroxbuwghii, P.
carihaea, P.kesiva, and P.pswudostrobusamong
the trees, and Ce'nchnisciharis, C sctigems,
Chrysopogon fuldus, Dichanthium nnulatum,
Eulaliopsisbinata,Panicwln inaiinum and
hybrid napier among the grasses.
Overcoming physical impediments
Constraints such as poor soil texture,
rockiness, and mixtures of boulders and gravel
in the soil provide an unfavorable environment
for young root systems, resulting in poor survival
and growth of the plants. These impediments
should be broken up for best root development.
On degraded sites the plants tend to develop
apical mortality, are short-lived, and
consequently need to be harvested when they
are at their peak ,fgrowth. They are therefore
only suitable for providing fuelwood and small
timbcr.
Drilling 100cm holes for Eucalyptus hybrids
and B. purpurea,thus breaking up the
impediments, showed a high mean annual
increment of 1.32m in height and 0.52cm in dbh
in the Eucalyptus, and a 0.9'0m increase in
height and 1.85cm dbh in Bauhinia as compared
to working the soil to a depth of 50cm.
However, depth of soil tilling did not shew any
response in G.optiva or A. alba.
The growth of Leucuena cv K-8 in degraded
soil was compared with growth in good soil
more than Im in depth. In 45cm holes, the
rowth in height was 4.Im higher with an
increase of 4.5cm dbh in the deep soil. The root
studies on Leucacna, Eucalyptus, Bauhinia,
(rewia and mulberry suggest that the root
systems of Grcwia and mulbcry are confined to
the upper few ccntimetcrs, regardless of the
depth of the hole in which it is planted. Further
studies are in progress, but it suggests that the
root system has a role to play in the depth of soil
that needs to be plowed or dug up, which may
have a direct effect on the cost of establishment.
A spacing of 2x2m for fuel and small timber
on degraded lands is observed to be optimum.
To improve the health and yield of the stand,
the application of interim thinning to provide .in
intermediate yield is suggested. For example, in
the case of the Eucalyptus hybrid, a thinning
applied at the age of 4 years yielded 1.4 t/ha of
fuelwood, and the coppice shoots grew