RU2261953C1 - Soil desalinization method - Google Patents

Abstract

FIELD: agriculture, in particular, desalinization of saline soil of agricultural lands.

SUBSTANCE: method involves cutting slits on plot to be desalinized; feeding rinse water onto strips between slits; removing salt from slit surfaces and spilling soil therein, with slits being cut to depth exceeding depth of season soil wetting with precipitation; providing cavities on strips between slits; closing cavities with shields of hydrophobic water-impermeable material, said shields being equipped with perforations extending along their central axes and float members; fastening shield edges in upper part of slits; providing soil desalinization facilitated by precipitation. Upon precipitation, rain water flows over walls of cavities to infiltrate through perforations and fill cavities bottom part, with the result that salt is washed into depth of soil to be desalinized. Moisture will be preferably moved by capillary force and due to evaporation of moisture from slit wall surfaces toward slit walls, accompanied by accumulation thereon of salts. Washing process may be accomplished during one or several seasons depending upon precipitation intensity and salt concentration. After completing of desalinization processes, shields are removed, salts are buried by spilling soil into slits, and soil on desalinized plot is mellowed to depth of season soil wetting. Burying of salts at the level below depth of season soil wetting and destruction of capillaries by deep mellowing of desalinized soil layer protect it from secondary salinization.

EFFECT: increased fertility of agricultural areas on unirrigated agricultural lands in the absence of potable water sources without the necessity of constructing expensive water feeding systems.

4 dwg

Description

The present invention relates to the field of agriculture and can be used for the salinization of salted agricultural land.

There is a method of desalinization of the soil, implemented using the reclamation system for washing heavy saline lands (Aut. St. USSR No. 1358848, IPC E 02 13/00, BI No. 46, 1987)

This method of desalination of the soil includes laying deep closed drainage, cutting supply elements, slots and additional trenches located on quid strips parallel to drains, then feeding the supply elements, cracks and additional trenches of washing water and draining it together with dissolved salts into deep drainage. Wash water flows from the drain to the water inlet. As the latter, specially selected depressions are used, where lakes of mineralized water are formed, or rivers in which the flow of drainage water causes an increase in the salt content. This method allows you to remove salts from the soil with high efficiency, increasing its fertility in this way. The quality of soil desalination depends on the amount of fresh water supplied to the wash network. The average leaching rate varies from 20 to 60 thousand m ³ per hectare.

The disadvantages of this method are the large capital investments in the construction of closed drainage and cutting of an open washing network, the large expenditures of fresh water for washing, significant areas of land allotment for lakes — accumulators, salinization of adjacent lands, or an increase in the salinity of water in the water intake rivers.

The closest to the proposed is a method of desalination of the soil, including the supply of water to the washed area, cutting slots on it, supplying water to the inter-slit strips and subsequent removal of salts from the walls of the cracks (Aut. St. USSR No. 1428297, IPC E 02 B 13/00, BI No. 37, 1988).

This method allows for desalination of the soil without the construction of deep closed drainage, to reduce the consumption of fresh water for flushing and to eliminate the drainage of saline water into water inlets.

The disadvantage of this method is the need to supply fresh water to the brine site. At the same time, there is a large number of non-irrigated saline agricultural lands, where low yields are obtained due to the negative influence of salts. In particular, this concerns pastures, where seasonal precipitation produces salt movement to a certain depth and creates favorable conditions for the growth of forage crops. However, with the onset of the dry season, salts are pulled to the surface and inhibit plants, dramatically reducing their productivity.

The task of the invention is to increase the fertility of agricultural dry lands by carrying out desalinization of the soil without supplying fresh water, using moisture from seasonal precipitation.

The solution to this problem is achieved by the fact that in the method of desalination of the soil, including cutting cracks in the desalinated area, supplying washing water to the inter-slot strips, removing salts from the surface of the cracks and filling the latter, the cracks are cut to a depth exceeding the depth of seasonal soil wetting by sediments on the inter-slot strips hollows are formed, which are covered with screens of a hydrophobic waterproof material with perforations and float elements placed along their central axis, the edges of the screens are fixed in the upper part and cracks, with the help of precipitation, the soil is desalinated, after which the screens are removed, the salts are buried, filling the cracks, and the soil is loosened to the depth of its seasonal wetting by precipitation.

The economic and environmental significance of this invention is based on the fact that on the globe in the arid and subarid zones there are millions of hectares of saline low-fertile lands, where there are not enough fresh water reserves for washing, at the same time, a significant amount of rainfall occurs in the autumn-spring period.

The invention is illustrated by drawings, where figure 1 shows a General view of the salinized area; figure 2 is a section along aa before desalination; figure 3 is a section along aa during resettlement; figure 4, a section along aa after desalination.

The proposed method of soil desalinization is implemented in the following sequence.

At the end of summer, gaps 2 are cut in the desalted area 1, while gaps 3 are formed on the inter-slit strips, which are covered with screens 4, equipped with culvert perforations 5 in the middle part and float elements 6. The edges of the screens 4 are fixed in the upper part of the cracks 2. In case of precipitation rainwater, flowing down the walls of the troughs, seeps through the perforation 5, fills the bottom of the troughs 3, washing the salts into the depth of the washed soil layer. Moreover, under the action of capillary forces and evaporation of moisture from the surface of the walls of the cracks 2, the movement of moisture will occur mainly in the direction of the walls of the cracks with the accumulation of salts on their surface. In case of precipitation with an intensity higher than the absorption capacity of the soil, as well as with prolonged precipitation, rainwater, seeping through the perforation, will fill the hollow, forming a moisture reserve in it to the level of the crests of the hollow. In this case, the float elements 6 will float above level 7, and most of the water will drain along the outer surface of the screen 4 and wash off the salt from the walls of the slots 2 to the bottom, forming a focus of accumulation 8. When filling the slots with water, salts will be washed out of the focus 8 to a greater depth . Part of the water, seeping through the perforation, will drain into the cracks 2 through the crests of the troughs, ensuring their washing. After the cessation of precipitation, the water supply from the trough 3 will be gradually filtered through the inter-slit layer of the soil, washing it with the accumulation of salts on the surface of the walls of the cracks. At the next precipitation, the flushing cycle will be repeated. At negative temperatures, precipitation will accumulate on the surface of the screen in the form of snow, and as it melts, moisture will seep through the perforation 5 and the soil will be washed in the inter-gap spaces according to the scheme described above. The washing process, depending on the intensity of precipitation and the concentration of salts, can be completed within one or several seasons. After the washing is completed, screens 4 are assembled and slots are filled up with salts buried in zone 8, the troughs 3 are leveled and the saline soil is loosened to the depth of seasonal soaking with precipitation. The formation of zones 8 deeper than the seasonal soil wetting and the destruction of capillaries with deep loosening of layer 9 provides protection of the brine layer from the risk of secondary salinization.

Thus, the application of the proposed method of leaching saline soils can increase the fertility of agricultural land in rainfed lands in the absence of fresh water sources and without the construction of expensive water supply systems.

Claims (1)

A method of desalinizing the soil, including cutting cracks in the desalinated area, supplying washing water to the inter-slot strips, removing salts from the surface of the cracks and filling the latter, characterized in that the cracks are cut to a depth exceeding the depth of the seasonal soaking of the soil with sediments, and troughs are formed on the inter-gap strips, which covered with screens of a hydrophobic waterproof material with perforations and float elements placed along their central axis, the edges of the screens are fixed in the upper part of the slots, using the cages produce desalination of the soil, after which the screens are removed, the salts are buried, filling the cracks, and in the salty area, the soil is loosened to the depth of its seasonal soaking with precipitation.

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