Agriculture Reference
In-Depth Information
soil. Care should, therefore, be exercised while drawing conclusions about growth
of plants in a plantation.
The growth rate of a plant depends upon the type of soil, not only in terms of its
fertility and depth, but also other properties such as drainage, texture, pH value, and
presence or absence of root-associative fungi. Certain plants will not respond well in
any but a limited class of soils with high nutrient availability, whereas certain others
will thrive even in the poorest soils. In case of limited depth of soils, plants may at
first put on an encouraging growth but as soon as the roots strike the pan or the rock,
they stop growing, or even die. Similarly, response of certain species to climatic
conditions is very characteristic. Xerophytic plants, for example, grow only during
a part of the year and remain dormant in the summer season. Such plants cannot be
expected to make the same progress as those that grow throughout the year, though
seasonal growth profile is present in all species to some extent.
The age and health of plants at the time of outplanting is a vital factor deter-
mining growth of the plants. If plants are overage they probably suffer from coiled
roots and will not make progress in the field. If they are too tender, they will have
underdeveloped root systems and will therefore grow slow with a longer seedling
establishment period. The factors defining the intrinsic growth rate of a plant have
already expressed themselves in the nursery. Whether genetically superior quality
of plant material (i.e. seeds and cuttings) has been used will depend upon nursery
work. Also, if the quality of potting mix was poor and all the nutrients in the ball of
earth were exhausted at the time of planting, this will lead to slow post-outplanting
growth.
6.13
Tending the Rootstock
Naturally occurring rootstock in a plantation area is an important asset that can be
regenerated with relative ease and economy. Most of the rootstock would be of
endemic species and therefore better suited to the climate and the site. These species
would perhaps also be more acceptable and useful to the local communities. Density
of such rootstock may vary from site to site. It is a good practice to survey such
rootstock carefully, enumerate plants specieswise and conditionwise in categories
that will require different treatments, and to draw up a tending plan. In certain cases, it
will be enough just to tend the rootstock in order to fully afforest the area, dispensing
altogether with the need for artificial planting. Fencing of the areas along with the
basic S&WC works is all that is needed for afforesting such areas (these are better
described as regenerative closures rather than plantations). However, such areas may
not be common, given the widespread land and vegetation degradation occurring in
arid and semiarid tropics. Most sites will have some scanty rootstock the tending of
which must be supplemented by artificial planting.
The plants that have become scandent (e.g. in response to continuous grazing)
should be cut back to stimulate fresh growth of shoots. In the cut-back operation,
the residual stem is cut obliquely with a sharp implement, and all old growth is
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