RU2850079C1 - Method for improving heavily salinised soils - Google Patents

Abstract

FIELD: agriculture.

SUBSTANCE: invention relates to land reclamation and can be used in the development of heavy saline soils for various agricultural crops. The land reclamation method includes laying permanent and cutting temporary drains and slits and subsequent washing of the soil by supplying water to its surface, while against the background of continuous deep loosening of the field, tractors of class 5 (e.g., K-700) parallel to the drains, along the tractor track, to a depth of 75-80 cm, 10 cm wide slits are cut at intervals of 2 m, which approximately corresponds to the width of the track. The slits are cut by removing soil to the surface, then cutting the soil layer in half and placing it at the edges of the slits, forming ridges that help maintain the water layer in the inter-slit strips. The slits are simultaneously filled to the level of the ridges with a porous filler that has high water permeability and moisture retention capacity. Sand is used as a porous filler. After that, a trencher is used to cut temporary drains to a depth of more than 80 cm perpendicular to the slits. Upon completion of this work, the embanked inter-row strips are flooded and the water level is maintained until the soil is saturated to the depth of the slits. After the soil is saturated, excess water with dissolved salts is drained through the slits to temporary drains, from where it flows into deep permanent drains. In the second stage, the entire complex of reclamation works is repeated in the same sequence as the arable layer dries out, but the slits are cut in the middle of the inter-slit strips parallel to the previous ones, i.e. with a 1 m offset. Next, the site is levelled so that the soil from the ridges and the sand between them is distributed evenly in the inter-slot strips. After levelling, the site is ploughed with the soil layer turned at an angle to the direction of the slits so that the porous material from the upper part of the slits is evenly mixed with the soil, improving its water-physical properties, including filtration capacity, and sown with the planned agricultural crop.

EFFECT: extension of the service life of the drainage network, improvement of water-physical properties, preservation of the natural structure of the soil walls of the slits, increase in water permeability, desalination of soil on heavily salinated lands.

1 cl, 2 dwg

Description

The proposed invention relates to the field of agriculture, in particular to land reclamation, and can be used in the development of heavy saline soils for various agricultural crops.

A known method for desalinating irrigated lands (analogous to this method) involves flushing the soil with increased irrigation rates through a slit-mole drainage mesh. This method involves cutting slits 70-75 cm deep at 1-meter intervals parallel to deep permanent drains, and perpendicular to their direction at a depth of 75-80 cm—mole drains spaced 1 meter apart.[1]

However, with this method of soil desalination, the cracks and mole drains crumble and become clogged with soil after the first heavy waterings. The soil's original density is restored, and water permeability is not improved. The soil is not structurally improved, and subsequent leaching is ineffective. This necessitates repeated and annual re-installation of the labor-intensive and expensive crack and mole drainage network.

A method of land reclamation (prototype) is also known, in which a slit grid is cut in stages over a period of 4 years, 70 cm deep and at intervals of 0.5 m, while simultaneously filling them with porous material.[2]

The disadvantages of this method include the fact that, when flooding at elevated rates, after the soil has been saturated and consumed by plants, excess water, with dissolved salts, inevitably flows from the arable horizon into the cracks, then to temporary collector drains, from where it flows into deep permanent drains, because the plow sole and the compacted walls of the cracks during cutting, as well as the dense soil of the lower horizons, poorly absorb water. Consequently, the displacement of salts from these horizons may not occur, and only the arable soil layer is subject to leaching. (Fig. 1)

The aim of the invention is to improve the water-physical properties of the soil, increase water permeability, desalinize the soil throughout the entire root zone profile on heavily saline soils, preserve the natural structure of the soil walls of the cracks, and extend the service life of the drainage network.

Fig. 1 shows a diagram of the flushing process for the land reclamation method adopted as a prototype, and Fig. 2 shows a diagram of the flushing process for the proposed method.

1 - soil layer, plowed with layer turnover; 2 - cracks with porous filler; 3 - soil layer, processed with a deep ripper; 4 - water layer in inter-crack strips; 5 - rollers.

The stated goal is achieved by the fact that the complex of reclamation works is carried out in two stages during the non-growing season.

During the first stage, continuous deep loosening of the field is carried out against a background of systematic deep drainage. Next, Class 5 tractors (e.g., K-700) cut 10-cm-wide slits 2 parallel to the drains along the tractor track to a depth of at least 75-80 cm at intervals of 2 m (which roughly corresponds to the track width). The slits are created by extracting soil to the surface, then cutting the soil layer in half and placing it along the edges of the slits, forming ridges 5, which help maintain a water layer in the inter-slit strips 4. The slits are simultaneously filled to the ridge crests with a porous filler (e.g., coarse sand or fine expanded clay) with high water permeability and water retention capacity. A ditch digger then cuts temporary collector drains to a depth of over 80 cm perpendicular to the slits.

Once these works are completed, the embanked strips between the slits are flooded and maintained under a layer of water until the soil is saturated to the depth of the slits. Once the soil is saturated, excess water, along with dissolved salts, is diverted through the slits to temporary collection drains, from where it flows into deep permanent drains.

At the second stage, the entire complex of reclamation works is repeated in the same sequence as the arable layer dries out, but the cracks are cut in the middle of the inter-crack strips parallel to the previous ones, i.e., with an offset of 1 m.

Next, the area is planned in such a way that the soil from the rollers and the sand between them are distributed evenly in the inter-slit strips.

After planning, the area is plowed with the layer turned at an angle to the direction of the slit cutting so that the porous material from the upper part of the slits is evenly mixed with the soil, improving its water-physical properties, including filtration capacity, and is sown with the planned agricultural crop.

Thus, a shallow, stable drainage from cracks with porous filler and an interval of 1 m is formed in the subsoil horizon, which allows for the subsequent annual leaching of saline heavy soils due to increased irrigation rates for cultivated crops.

The implementation of this method of land reclamation makes it possible to solve two problems simultaneously: accelerated desalination of irrigated lands from the very first year of development and improvement of the soil structure.

Literature

1. Mirzoev E. M.-R. Description of the invention to the USSR Author's Certificate No. 709758. Method for desalinization of irrigated lands. Bulletin No. 2, 1980.

2. Abdulgalimov M.M., Teymurov S.A. Description of the invention to patent No. 2792673 RU "Method of land reclamation", Bulletin No. 9, 2023.

Claims (1)

A method of land reclamation that includes laying permanent and cutting temporary drains and slits and subsequent washing of the soil by supplying water to its surface, characterized in that, against the background of continuous deep loosening of the field, parallel to the drains, along the track of the tractor, to a depth of 75-80 cm, slits 10 cm wide are cut at intervals of 2 m, while the slits are cut by extracting soil to the surface with subsequent cutting of the soil layer in half and forming from it rollers along the edges of the slits with simultaneous filling them up to the mark of the crests of the rollers with a porous filler, which is used as sand, then temporary drains are cut with a ditch digger to a depth of more than 80 cm perpendicular to the slits, after which the banked inter-slit strips are flooded and the soil is washed to the depth of cutting the slits, and at the next stage after drying the soil, cutting slits with the extraction of soil and the formation of rollers along their edges is carried out in the middle of the inter-slit strips parallel to the previous ones, the soil is washed again, after which the rollers with filler between them are leveled and plowed with the layer turning at an angle to the direction of cutting the slots.