ENVIRONMENTAL SCIENCE : NATURAL RESOURCES 89
(1) Recourse to contour and strip farming,
(2) A network of forest plantations in clumps and rows,
(3) A regular sowing of grass in crop rotations,
(4) The preferential use of organic, rather than inorganic manures,
(5) The use of organic manure as it tends to preserve the quality of soil and also their
humus content.
At present, soil scientists are trying to solve problem of safeguarding soils from exogenous
chemical substances, mineral fertilizers, pesticides, etc. heavy doses of the wrong kind of
inorganic fertilizer have often resulted in creating excessive acidity or alkalinity in the soil.
Besides the indiscriminate use of pesticides and fungicides has caused adverse effects
on soils in addition to their well-known effects on the activities of soil microbes, flora and
fauna. Various kinds of air pollutants and noxious gases also have a harmful effect on soils.
Suggestions
It should be kept in mind that the soil is a living community of micro organisms-algae,
fungi, protozoa and metazoan. It contains many inorganic and organic substances which are
products of weathering and decay of organic matter. Microbes normally oxidize these
substances to inorganic oxides, However, when some organic compounds reach oxygen-defi
ient ground water may remain incompletely oxidized and add to pollution.
At present, so many countries of Africa lying along the south of the Sahara desert are
suffering the severe effects of prolonged drought caused by rain failure or inadequacy. It is
also discovered that the desert is advancing southwards by several kilometers each year.
Local inhabitants plant millet in tiny plots of topsoil fenced in with straw matting to avoid
the sand; they water the wilting shoots by bringing cupfuls of the precious and scarce water,
often from long distance. Despite such frugality, however, the resource could be better
managed.
Two Evil Practices
(1) A practice which leads to resource squandering and wastage, is to set bush fires to
drive out and exterminate desert rats. Such practices are harmful and result in
great impoverishment of the top soil.
(2) Another similar practice is to chop sown the scarce tree wealth for firewood and to
let cattle eat up Acacia branches
It should be, kept in mind that Acacia and other similar plants are very useful since
they help check the advance of desert by the following processes:-
(1) By breaking the winds,
(2) By humus formation,
(3) By binding soil by means of deep penetrating roots,
(4) By trapping the scarce rainwater.
It should be remembered that by controlling excessive destruction of grazing of trees
and planting many more trees or bushes much of the land could be successfully conserved
and reclaimed in due course of time.