Sevryughin V.K.

GЕNERAL CHARACTERISTICS OF IRRIGATION TECHNIGUE PROBLEM. NEW APPROACHES AND WAYS OF THEIR SOLVING

In arid climatic conditions of Central Asia, where crop production is impossible without irrigation, agricultural production efficiency depends on level of irrigation reclamation. The latter influences too much upon the whole water consumption system, which predetermines ecological situation in the region.
Rapid development of irrigation reclamation, oriented toward furrow irrigation that replaced during Soviet period the djoyak (zigzag) irrigation way on small well leveled plots has led to inevitability of irrigation having big surface and deep effluents, which grew as irrigation plot got bigger and have reached to 50-60 % of the irrigation rate equal on average to 14000 m3/ha. By 1990 irrigation lands' area year reached 4.2 mln.ha over Uzbekistan alone, throughout the regions on the whole - over 7 mln.ha. Capacity of water off-taking reached 120 km3, approaching to the amount of total water resources, what has brought to ecological disaster adversely affecting the social development of Central Asia peoples.
So, former orientation toward simplified and cheap ways of furrow irrigation now has brought to need in investment of billions to stabilize the situation has been formed. At the present it is absolutely obvious existing technologies of water allocation over irrigated area have to be improved.
Ideally, water allocation technology need to be such under which water is delivered simultaneously to all spots of irrigated field with speed changing according to decrease of moisture absorption speed by the soil. To gain required water allocation only by using appropriate mechanisms in the form of irrigation or sprinkling facilities. Work technology of such machines may provide for intermittent water delivery to short obtuse furrows or delivery by alternating jet, or interrupted sprinkling with regulated frequency of impulses, but, anyway, water delivery speed need to conform to moisture absorption speed by the soil. Otherwise, a flowing off, consequently, and water losses are inevitable. Striving for perfect water allocation technologies must be a guiding line of irrigation reclamation perfection.
Among known and mechanisms manufactured in series, most evenly allocating water over an irrigated field, it should note sprinkling machines. But, high rain intensity and imperfection of former sprinkling technologies didn't allow to widely and efficiently use them in conditions of Central Asia.
Development of irrigation technology with regulation of water delivery speed had not practically been undertaken before the author's investigations, though there is great deal of works on influence determination of individual rain characteristics (intensity, diameter and power of raindrops) upon pre-trickle absorption rates. Among them one should mark out works by: Kostyakov A.N, Petrov E.G., Demidov N.P., Preobrajenskaja N.V., Isaev A.P., Erkhov N.S., Iljin N.I., Abramov A.M., Kervalishvili D.M., Nanitashvili O.S., Sevastyanov V.K., Darimbetov U.D., Ghusejnov G.M., Ghusejn-Zade M.kh., Klepalskiy A.P., Tleukulov A.T., Khuan R.D., Chichasov V.Y., Kolesnik F.I., Moskvichev J.A. and others. So offered scientific conceptions of the author on working out of internal-drainage sprinkling technologies applicable to concrete hydro-reclamation conditions, crops and optimal regimes of their irrigation seem to be very actual.
The author has worked out theoretical basics of internal-drainage technologies of conversion of irrigation water into soil moisture, worked through a practice new methods of experimental studies, and has given strategy of calculation of internal-drainage technologies for certain serial and proposed new sprinkling machines, accounting for moisture dynamics and water consumption of a certain crop during and after irrigation for a concrete crop rotation plot; offered new directions of sprinkling technique improvement with regulated characteristics of torchlight of intermittent rain have been justified by him, and construction elements of the inter-economic irrigation network, suitable for realizing water off-taking astir on local leveled and wavy relieves have been worked out as well.
Tests of sprinkling machines on machine-testing stations (MTS) and in farms were conducted according to the strategy of OST-70.11.1-74 (All-Union standard), and technological schemes of irrigation and parameters of sprinkling technologies were examined taking into consideration recommendations of the former All-Union Research Institute of Mechanization and irrigation Technique and Union's Water Design Institute. Justification methods of effluentless technologies have been developed by the author with provision for known theories on absorption of moisture by soil, proposed by Kostyakov A.N, Budagovskiy A.I., Isaev A.P., Erkhov N.S., Iljin N.I., Tughushi G.E. and others.
Investigations were conducted on a Research Station of Irrigation Technique (RSIT) in the Kalinin district of the Tashkent region, in the state farms "Pakhtaaral" (Kazakhstan), "Severnij majak" of the Sredne-Chirchik district of the Tashkent region, 1A "after Volkov" of the Syrdarya district, "5th anniversary of Uzbekistan" of the Galaba district of Tashkent region. Tests of a sprinkling machine were conducted at the Kyrgyz machine-testing station (Kant-city) and in neighboring to it state farms, as well as in satte farms of Kherson, Nikolaevsk regions, at the South-Ukraine MTS.
Analytical and experimental relations between means disturbing the jet and the jet continuousness' index, as well as relations between the jet's ballistic parameters and rain quality have been determined.
Application of compact and interrupted jets for developing sprinkling machines of new type, which work astir, with periodic water delivery sometimes to one, sometimes to another sides, also working on principle of impulse apparatuses, is suggested.
Calculation methods of irrigation frontal guns have been worked out.
Further ways of improving sprinkling machines on principles having no analogues worldwide and protected by patents are offered.
Experimental relations have been determined, that allow to state that experience of previous investigations on definition drops evaporation did not accounted for influence of fast forming microclimate of the field. So, value of drop evaporation in air virtually less than generally accepted ones.
It has been determined that the method of rain-gauges, applied to define precipitation while sprinkling, including accumulating ones on plant leaves, does not allow for considerable value of evaporation from a water surface accumulated in the rain-gauge.
It has been determined that a difference in precipitation layer of rain-gauges, placed above a plant and by it, does not reflect a layer of precipitation settled on the leaves, since as a result of reflection of rain-drops into the rain-gauge standing by the plant, rain of higher intensity falls.
It has been determined, as a result of rain plume's passing over an irrigated field other microclimate of the field is formed, which gradually, within many days, returns to its initial parameters, influencing upon leaves' transpiration reduction, that entirely stops during plant leaves drying out.
Relationship between non-continuous and continuous sprinkling has been determined through introduction a concept of index of rain intermittence.
As a rain intermittence index reduces its influence's power on a soil is reducing, pre-trickle irrigation rates are rising and penetration depth is increasing too.
A rain intermittence index can be regulated by the way of changing the dash's length or the plume's motion speed, as well as by changing frequency of the jet's disturbance.
Conversion speed of irrigation water into soil moisture on an irrigated tract of lands depends on an area of simultaneous penetration, rain intensity in the plume, diameter of drops, intermittence index, and it can be controlled.
Theoretical basics of internal-drainage conversion of irrigation water into soil moisture taking into account crop irrigation regimes and water consumption at a plot of cotton crop rotation.
It has been defined that artificial rain's plume quality increases if, seasonally, according to an adjusted technology, to exert influence upon the jet by various kind of shoulder blades, transforming the continuous jets into intermittent ones with given index of continuousness.
Analytical dependence has been defined for turbines and sprinklers, determining relation between size of adopted devices and the jet's continuousness index.
Experimental interdependence between the index of a jet's continuousness, its ballistic parameters and rain plume quality has been defined.
Optimal values of continuousness index have been defined, those allow to use non-continuous jets in sprinkling machines working astir.
A new concept (rain non-continuousness index) has been introduced and analytical interdependence between rain intensity in a plume and water delivery intensity.
A technology of internal-drainage conversion of required irrigation rates into soil moisture has been worked out and analytical dependence between irrigation technological parameters (movement speed or plume rotation of rain, irrigation time, pass time or stage of irrigation, pause, precipitation layer, dash length) depending on the rain quality (intensity in the plume, water delivery intensity, diameter of drops) of a certain sprinkling machine taking into account water penetration and evaporation from the design layer of the soil.
Experimental and analytical relations allowing determining a rain's drop evaporation value in the plume accounting for the rain's structure and fast-changing microclimate.
Particular experimental equations have been defined, allowing determining value of sediment layer accumulated on leaves, taking into account development dynamics of cotton leaf's surface.
It has been determined that formulas of SN&P 2.06.03.-85 and OST-70.11.1-74 (Building Standards or Codes and All-Union Standards correspondingly) pertinent to definition of evaporation value when irrigating by sprinkling and losses to evaporation during dropping are not suitable for use, because they are based on strategy of open rain-gauges and give essentially high indications.
Experimental values of absorption parameters have been defined for various soils with an allowance for influence of their moisture, changing according to the horizons, as well as with an allowance for rain quality.
Experimental equations have been taken that allowed determining a decrease dynamics of moisture reserves in the design horizon after sprinkling irrigation.
Calculation strategy for sprinkling technology has been developed taking into account concrete economic conditions, irrigation regimes of concrete crops, and, as a whole, of a cotton crop rotation field; example of calculation with reference to a "Kuban" machine.
Strategy of operating character calculation for irrigation frontal guns has been worked out and directions of their improvement have been offered.
New constructions of sprinkling low-intensive hose machines are proposed.
A supporting bulkhead with water level regulators in tail-water has been developed and a number of constructions of an irrigation network's new elements is offered, those allows severely reducing water losses.
Crop increase and considerable irrigation water saving while irrigating by sprinkling according with the proposed technology have been confirmed by an experiment, possibilities for essential expansion of zone for sprinkling application in Uzbekistan are displayed.
Theoretical and experimental investigations allowed developing series of fundamentally new means controlling jet decomposition, those are protected by certificates of authorship and patents, and, on their base, introducing new irrigation gun of frontal action with periodically disturbed jet into serial manufacture (DFD-80 on figures 1 and 2); developing and introducing strategy of calculation of frontal machines' labor bodies into manufacture of Production Association of the Kherson combine plant; developing and testing an experimental model of the second machine of frontal action with periodic water delivery and higher width, working astir on tool carrier in automatic mode - DFDS-80, fig.3; offering, justifying and giving for development to the design office "AP Rain" (Saint-Petersburg city) a multi-pass hose machine ensuring water delivery to all dots of an irrigated plot, with equal time intervals; offering and substantiating a principally new development direction of sprinkling machines having a rain plume, simultaneously moving along oval and front with water delivery intensity commensurable with crop water consumption speed.

Fig.1 A machine of DFD-80 type, general view.

Fig.2 A DFD-80 machine is working.

Fig.3 An experimental model of automated machine of DFDS-80 type on tool carrier.

Tests of various sprinkling machines in various natural-economic conditions of Uzbekistan allowed working out recommendations on designing an irrigation network for machines working astir on local slope and wavy relieves, constructing experimental-production sites (EPS) for a sprinkling machine "Kuban" with a movable supporting bulkhead in the Sredne-Chirchik, Galaba and Ilichevsk districts of the Tashkent and Syrdarya regions, on an area of over 500 ha.
Theoretically developed technologies of internal-drainage conversion of irrigation water into soil moisture have experimentally been verified at an EPS, and they have confirmed their efficiency when irrigating cotton, thus proving possibility for irrigation water saving and cotton crop capacity increase for not less than 0.3-0.5 t/ha.
Results of the developments have been used by:
- The All-Union Research Institute of Mechanization and Irrigation Technique, Union Water Design Institute, Uzbek State design Institute of Water Economy, design team of Tashkent Region's Department of Water Economy in the form of given them recommendations on irrigation technology by a "Kuban" sprinkling machine. Profit from their introduction amounted to 957 rubles/ha/year;
- The "Production Association of the Kherson combine plant" manufacturing plant, which established serial manufacture of machines of DFD-80 type and got a profit over 5 mln.rubles/year;
- Farms having bought DFD-80 machines and receiving a profit of 1550 rubles/year for each machine;
" The Tashkent Institute of Engineers on Irrigation and Mechanization of Agriculture (TIEIMA), which issued "Methodical manual on sprinkling machine application in Central Asia and calculation of irrigated lands' parameters", prepared by the author, and used it for teaching students;
- The "AP Rain" design office (Saint-Petersburg city), which developed a design documentation for a movable support bulkhead with regulator of water level in tail-water and sprinkling hose machine having rain plume rotating along oval;
- The Institute JGSMI, which approved and accepted for use "Methodical guide on sprinkling technology by machines of frontal action working astir, for conditions of the central part of the Syrdarya river's basin".
Theoretical conceptions of the author underlie of seven thesis works, which were successfully defended by competitors of TIEIMA for degree of candidate of technical sciences (Ph.D.).
Who wants to be acquainted deeper with V.K. Sevryughin's works may see List of lectures prepared for undergraduate students of TIEIMA and contents of problems considered therein.

 

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