Simple Abundance
In
keeping with the trend of sustainable development, plant growth regulators,
soil conditioners and bio-pesticides are offered as solutions to achieving
sustainability in agriculture
Several
years ago, we were told the story about a countryman who, one morning,
discovered that his farmhouse goose had begun to lay golden eggs.
And of course, we know how the story ends: “… thinking to
get at once all the gold the goose could give, the countryman killed
it and opened it only to find nothing.”
We know the ending, but we missed the point. What’s more ironic
is that, hundreds of years after this fable was written, the one for
whom this fable should mean the most continues to miss the point.
Modern agricultural practitioners seem to ignore the fact that the
earth is a goldmine of renewable resources, not inexhaustible resources.
An analysis of modern farming methods has shown that the unbalanced
use of chemical fertilisers and pesticides has reduced the beneficial
microflora of soils. Further, the inadequate use of organic manure
has reduced the capacity of soils to retain moisture and nutrients,
and to release them on a regular basis. And the near total non-use
of soil conditioner has rendered soils poor in organic carbon, while,
on the other hand, high-frequency flood irrigation has increased soil
salinity.
Sustainable alternatives to each of these problems exist – this
article hopes to provide a practical introduction of some of these.
PLANT GROWTH REGULATORS
Several chemicals have been reported
to improve plant growth. However, their heterogeneity has defied correlation
between structure and function.
Now, it appears that some promote growth by nutrition and others support
growth by protection. These chemicals are known as plant growth regulators
(PGRs).
Among PGRs, widely used are those based on either tricontanol or a
mixture of amino acids. The latter have been found to be convincingly
superior over the former for a number of crops and under widely varying
geo-climatic conditions. They are produced from industrial waste cost-effectively.
PGRs promote minerals absorption, nitrogen metabolism, and chlorophyll
synthesis, and reduce transpiration rates.
SOIL CONDITIONERS
Soil conditioner is a partially
decomposed, valueadded, solid organic product, obtained from biodegradable
waste of agro-industrial origin. Its decomposition is expedited by
dedicated ligninolytic fungi and a consortium of microbes, under humid,
aerobic and warm conditions.The enrichment of soil requires cattle
dung on a large scale. In view of the reduced domestication of cattle
by the farming community, the alternative application of available
dung towards biogas production and for household cooking, the availability
of dung for the fertilisation of the vast acreage of land has been
limited. It has been, therefore, imperative to seek out an alternate
source of organic matter – soil conditioner is found to be the
ideal.
Soil conditioners execute a number of functions. They increase the
porosity of soil, thereby making more oxygen available to the root
system, which, in turn, increases its energy level, and nutrients-absorptive
capacity.
They also provide organic carbon to soil, thereby enhancing its capacity
to ration out the dosage of chemical fertilisers. This, in turn, increases
the efficiency of their use, without causing pollution in underground
aquifers. Its organic carbon renders an excellent colonisation of
nitrogen fixers and phosphate solubilisers in many crops, thereby
increasing the efficiency of the use of chemical fertilisers in conjunction
with drip irrigation which compromises neither the plant’s growth
rate, nor for that matter, its yield.
Soil conditioners improve the water-retention capacity of all types
of soils, especially sandy and loamy soils, thereby improving cohesiveness,
and reducing the frequency of irrigation and the rate of erosion.
This measure improves the soil’s drought tolerance through the
sustained availability of moisture. Soil conditioners further prevent
waterlogging in loamy soils, and promote the sustained release of
moisture to the root system.
This spares the plant from water stress and promotes a sustained growth
rate. The humus content of soil conditioners harbours a number of
beneficial microbes, provides sustained nutrition to the plant, and
controls soil pathogens, presumably due to their siderophore content.
Finally, soil conditioners also facilitate the relocation of plants
from nurseries to farms by absorbing transplantation shock, thereby
ensuring higher survival rates and greater crop density.
BIO-PESTICIDES
The losses incurred
by the agriculturists due to pests are staggering, but rarely comprehended.
While some losses occur while crops are still in farms or greenhouses,
others occur during their storage in grain elevators, storage bins
and granaries. For example, the production of pulses in India during
1996-97 was reported to be 14 million tonnes. At an estimated loss
of 30 per cent, due to pest infestations at various stages, the loss
in pulses comes to 4.2 million tonnes. Assuming the average price
of any pulse to be Rs 23,000 per tonne, the total loss per annum in
pulses alone comes to approximately Rs 9,738 crore plus.
Pesticides are chemicals designed to combat....
contd...
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