Sevryughin
V.K.
Morozov A.N.
THERE ARE RESOURCES ! BUT WHY IS
THERE WATER SHRTAGE ON FIELLDS OF UZBEKISTAN ?
(The article is preparing to publication in a "Economical herald
of Uzbekistan" journal)
Two last, far from the years of lowest-water,
proved to be ones of quite scarce for agricultural water consumers
of the Republic. However, according to the analysis made by the Central
Asian Research Institute of Irrigation (SANIIRI) [1], water resources
in the Republic by no means are exhausted. So, water resources of
the Syrdarya and Amudarya rivers total 100-120 km3, meanwhile need
of the Republic of Uzbekistan is 88-89 km3. Out of 19.7 km3 of groundwater's
resources only 2.5-3.5 km3 is used, and totally in the Republic 52-56
km3 is used now.
In accordance with the analysis made by the Institute of Water Design
these figures are somewhat different. So water capacity delivered
to field is estimated as 63 km3, and water capacity exported out of
the field (losses to discharge and filtration) is 36 km3. That is
efficiency of the irrigation system is 0.43. If to make an allowance
for capacity of water reused (8.4 km3), field efficiency will be 0.56.
Anyway that is close to the figure, being given by the SANIIRI (efficiency
is 0.6). Discrepancy of water balances has always existed, though.
So, estimation of the efficiency within 0.4-0.6 can be considered
as reliable. And this means that under existing furrow irrigation
technique 50 % of water is used inefficiently. Moreover, this water
(about 30 km3) not just runs through field provoking erosion and washing
away fruitful layer, but also it carries out to water sources hundred
thousands of ton of injurious salts, herbicides and pesticides. At
the same time, most part of salts being carried out comes from horizons
situated lower vegetation layer of soil. This is furthered by wasteful
irrigation rates of vegetation and winter leaching irrigation. That
is why statement of some specialists that series of intensive leaching
in winter period are good under the irrigation technology, which exists
in practice at present, is disputable enough [1]. One should remember
that under existing technique of irrigation by furrows and leaching
by flooding, both irrigation and leaching promote to groundwater rise,
along with those relict salts rise upward, causing lands salinity,
what results in removing them from agricultural use. And this is confirmed
by the whole historical experience, when owing to too high irrigation
and water application rates fast groundwater rise occurred and following
salinization of lands.
Thus, one should search for new water reserves, so that to expend
them for groundwater raising. It is necessary to proceed to progressive
irrigation ways, having made a good showing worldwide and sufficiently
well approved, including in Uzbekistan [2]. These are sprinkling and
irrigating machines and in some cases drip irrigation. And though
manual furrow irrigation is still widely enough used, but it is used
in general in under-developed countries. In such countries as USA,
Ukraine, Russia only mechanized irrigation is used.
USA's experience is a model in this respect, where manual irrigation
was substituted firstly for irrigation applying pipes, next the pipes
were placed on wheels, and they got a stub of multiplace use. Then
they put the wheels athwart to the pipe and raised the latter over
plants and made a far-reaching frontal irrigation machine. Then they
replaced water outlets by sprinkling nozzles and constructed up-to-date
far-reaching sprinkling machines. Further, to increase evenness of
water allocation and reduce losses to evaporation, the nozzles by
means of hoses have been drawn near to the land and equipped with
diaphragms automatically regulating discharge. In the result they
took machines ensuring highest irrigation evenness, operating in automatic
mode, controlled from satellites and irrigating big tracts of land
by an adjusted program in accordance with optimal irrigation regimes.
Thus, owing to construction of systems having closed irrigation network
and high-grade irrigation technique, efficiency of irrigation systems
has approached to theoretically possible that - one.
At once, one should note that application of the most perfect irrigation
technique has allowed saving to 50 % of irrigation water, increasing
crop capacity for not less than 30 %, and practically solving associated
problems of irrigated agriculture, need for strengthened drainage
and export of huge capacities of return waters related. And these
are not advertising conjectures of such firms as "Walmount"
(USA), "Bayer", "Leinghlikh" (Germany), "Iritrak"
(France), but these are real facts.
On the background of paid water use, which have been introduced in
the mentioned countries, efficiency of application of that expensive
equipment tells immediately, and the one is recompensed for 2-5 years.
Similar sprinkling equipment, but less expensive, manufactured in
neighboring overseas countries (Russia, Ukraine) would allow to self-benefit
it in Uzbekistan for shortest terms. At the present, in Ukraine sprinkling
machine of frontal irrigation DFD-80 is manufactured, scientific studies
of that were performed in the SANIIRI. This machine is one of the
cheapest and most mobile ones, what makes it accessible for farmers,
but by rain quality and technological capabilities virtually it does
not concede to machine DDA-100MA, which, even nowadays, by its technical-economical
indications surpasses all known sprinkling machines.
Sprinkling machine DFD-80 can operate on irrigation of high-stalk
crops, gardens and vineyards, as well as crops of cotton-corn complex.
This machine now is passing through production tests in the "Baykozan"
farm of the Parkent district of the Tashkent region. Manufacture of
it in series would allow in shortest terms reforming irrigated lands,
requiring in the first place for sprinkling use. Lands with high water-permeability
(sands, pebbles, clay sands, light loamy soils) are among them. There
are over 1 mln.ha (308.5 thous.ha are heavily water-permeable and
743.8 thous.ha are of higher water-permeability) of such lands in
Uzbekistan. These are the most disadvantage lands, from standpoint
of furrow irrigation. Sprinkling them will let essentially reduce
wasteful water losses to deep discharges.
Another types of sprinkling equipment are manufactured in Ukraine,
which could be applied in the conditions of Uzbekistan. These are
far-reaching "Dnepr" machine, ones of MDSh-30/275, MDSh-25/100
types. One should not forget that the last ones can operate on badly
leveled fields and under certain revision they can be supplied in
the form of irrigation machines. The same can be said of machines
of kind of "Valley" (USA), which at present are operating
in the " 5th anniversary of Uzbekistan" farm of the Galaba
district of Tashkent region. But conditions of its maintenance do
not allow reveal merits of machines of similar class, requiring for
large areas and corresponding sizes of irrigated plots, occupied with
single crop. Use of sprinkling is possible practically on all lands
of Uzbekistan, including salted ones, where their application can
twice reduce water consumption to leaching. In all cases introduction
of sprinkling or irrigating machines will allow finding additional
water resources, receiving of those under up-to-date practice of ubiquitous
manual furrow irrigation is impossible.
Policy of gradual abandoning non-mechanized furrow irrigation and
transfer to progressive irrigation ways has allowed to the Republic
of Uzbekistan decreasing down to 20 km3 of irrigation water losses.
Inefficiently expended to surface and deep discharges. Even using
sprinkling only on soil of high water-permeability could allow saving
5-10 km3, heighten the coefficient of irrigation evenness of irrigated
land from 0.3 up to 0.9 and hereunder to increase crop capacity for
25-30 %. Profitability of irrigated hectare would rise for 300-500
US dollars, and annual gross income would increase for 0.3-0.5 billion
US dollars. This amount of money would be quite enough to purchase
or produce the most modern sprinkling equipment and its maintenance,
and water saved up can be used for development of new agricultural
production.
Thus, application of perfect irrigation ways can become the only right
and perspective way out of the situation established in water economy.
Literature.
1. Ikramov R.I. There are reserves. Economical herald of Uzbekistan.
# 12, 2001y.
2. Sevryughin V.K., Morozov A.N. Estimate of irrigation efficiency
under various irrigation technique. Economical herald of Uzbekistan.
# 9, 2001y., pp. 26-29.
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