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Askarov Khasanboy, Senior researcher applicant, Institute of Soil science and agrochemistry, E-mail: hasanboy_asqarov@mail.ru Isagaliev Murodjon, head of the chair Soil science department, Fergana state university, E-mail: murodjon-isa@mail.ru Yuldashev Gulyam, of the chair Soil science, Fergana state university, professor E-mail: gulyam48@mail.ru
CHANGE OF PROPERTIES OF SALTED SOILS UNDER INFLUENCE OF DETONATION WAVE AND RINSE
Abstract: Irrigation of irrigated saline soils in Central Fergana on checks after processing by installing a gas-dynamic ripper to a depth of 150 cm, width 4 x 200 mm, a norm of 4 thousand m 3/ha, desalination of soil soils was achieved to the level recommended for agricultural use.
Keywords: salted soils, gas-dynamic ripper, washing, water-soluble salts, non-toxic, toxic salts, salinization, desalination.
Relevance. To form the properties of saline soils, including medium and highly saline soils, the presence of two processes is necessary, the formation of free water-soluble salts in the soil profile and their accumulation. It is known that the main source of salts - it rocks and minerals, which are destroyed during weathering. In this case, salts are formed: chlorides, sulfates, nitrates, nitrites, hydrogen carbonates, carbonates, silicates, phosphates and others. The cationic composition of water-soluble salts is dominated by calcium, magnesium, potassium, and sodium. These salts under the influence of surface irrigation and groundwater in the soil profile migrate until they are removed from the soil-ground strata of the irrigated massif.
Groundwater irrigated lands of Central Fergana (Uzbekistan) mineralized, pressure hoses, which are directly involved in the formation of meadow saline soils above named array. Moreover, these soils are gypsies and poorly permeable, starting from the sub-plow horizon. The destruction of these horizons in order to improve water permeability and soil washing under these conditions is an actual problem.
Methods of conducting the experiment. In the process of carrying out the research, the profile method
of V. Dokuchaev was used, where the soils were studied from the surface to the full depth, successively along the genetic horizons to the parent rock.
A method of soil-regime observations was used in combination with the methodology of field and vegetation experiments [1]. The experiments were carried out in a four-fold repetition in one tier on the territory of the farm of the Kushtepa district.
Field experiments were conducted in 20152017 on irrigated meadow-soils strongly saline soils. The variants of the experiment are as follows:
1. Soil washing without treatment with a gas-dynamic ripper (GDR);
2. one-row cultivation of soils by installation of GDR + washing;
3. two-row soil treatment with GDR installation + washing;
4. three-row cultivation of soils by installation of GDR + washing.
Each variant contains 8 rows of cotton with a length of 100 m. The width between the rows is 90 cm. When cultivating cotton after flushing, the usual agricultural techniques adopted in the farm were used. Processing, i. e. Soil
CHANGE OF PROPERTIES OF SALTED SOILS UNDER INFLUENCE OF DETONATION WAVE AND RINSE
rupture was carried out by installing the GDR by impacting the soil with air shock volleys without mechanical contact with the working organs. The working organs of the GDR are paired pipes, which have a cylindrical turbulizer and a combustion chamber common to each pair of pipes [2]. The opening ends of the pipes are directed towards the treated soils and equipped with silencers.
Soil cultivation was carried out by a hinged aggregate for the T-28 cultivator in the following mode: the distance from the detonation pipe cut to the soil surface is 3050 mm, the width ofthe grip is 200 mm. Therefore, single-row treatment, for example, option 2, means 200 mm of soil treatment, 150 cm deep. Two-row cultivation of soil with a width of400 mm, a depth of 150 cm, etc. up to the fifth option. Soil processing by the specified parameters is made in the middle of the variant from the beginning to the end. After processing and initial lying of the experiment in the fall of 2015, checks were made in each variant separately for the purpose of conducting washing irrigation. Analyzes were carried out according to [3].
Description of the results. Irrigated saline soils when used in agriculture, arable farming exhibit unfavorable properties. These include a slightly alkaline reaction of the soil solution, toxicity of ions and salts, unsatisfactory water-physical characteristics, weak biological activity, transformation of colloids, alkalinity and others. In such conditions, the efficiency of farming decreases, which cause the growth and development of cotton, thus inhibiting the supply of nutrients in them.
As shown, route field and expeditionary research by laying the supporting sections on the investigated areas of the field experiment, a high summer-autumn temperature,
Table 1. - Changes in the
a close level of ground mineralized waters. These provisions determined the development of gley-eluvial and gley processes, combined with saline soils and the formation of saline irrigated meadow soils. Reserves and distribution of salts in the investigated stratum are comparatively uniform and slow growth from top to bottom along the profile is observed. As for the mechanical composition, the content of physical clay along the profile fluctuates in the range of 34.2-60.11%. The density of the soil varies, from 1.24 to 1.43 g/cm 3, on average, is 1.34 g/cm 3-
Maximum hygroscopicity and soil moisture to the bottom increases. Porosity varies from 46 to 52%. The lowest moisture capacity is 25-30% of the weight. The content of humus and nitrogen decreases from top to bottom, and phosphorus is reversed, which is related to the parent rock. But it should be emphasized that the content of total phosphorus in the plow horizon is higher than in the rest, which is due to its annual application to cotton. The distribution of carbonates is uneven, its content in the central part of the profile increases, and the pH of the medium is slightly alkaline.
According to the generally accepted classification, leaching waters are fresh, hydro carbonate-chloride-sul-fate. The norms ofwashing irrigation taking into account the initial salinity of the soils are calculated according to the formula of Volobuyev [4] and submitted in two doses of 2 thousand m 3/ha, totaling 4 thousand m 3/ha. Flushing irrigation was carried out in late December, earlyJanuary. The results are given below. With regard to the quality and quantity of water-soluble salts calculated by Bazilevich [5] before and after washing are shown in the table.
salt composition of soils,%
Section number Depth, cm Amount
Options Na2CO3 Ca (HCO3^ CaSO, 4 MgSO4 Na SO 2 4 NaCl Non-toxic Toxic Total
The initial content of salts is 2015, autumn.
0-32 No 0.106 0.669 0.704 0.469 0.232 0.775 1.405 2.180
32-51 No 0.088 0.776 0.806 0.340 0.249 0.864 1.395 2.259
1, 51-90 No 0.090 0.758 1.118 0.300 0.222 0.848 1.640 2.488
ground 1 90-110 No 0.093 0.806 1.039 0.223 0.183 0.899 1.445 2.344
water, 111-130 No 0.072 0.959 1.043 0.237 0.148 1.031 1.428 2.459
g/l 130-180 Traces 0.106 0.795 1.172 0.294 0.112 0.901 1.583 2.484
180-200 0.001 0.093 0.772 1.193 0.795 0.095 0.865 1.583 2.448
> 200 0.003 0.279 2.315 2.568 2.328 0.289 2.594 5.185 7.779
1 2 3 4 5 6 7 8 9 10 11 12
After carrying out the washing irrigation, 2017, winter.
0-32 No 0.028 0.198 0.123 0.007 0.018 0.226 0.148 0.374
32-51 No 0.028 0.176 0.129 0.008 0.018 0.204 0.153 0.357
4, 51-90 No 0.029 0.169 0.129 0.075 0.020 0.198 0.224 0.422
ground 4 90-110 No 0.030 0.171 0.133 0.073 0.020 0.201 0.226 0.427
water, 111-130 No 0.030 0.173 0.134 0.065 0.036 0.203 0.235 0.438
g/l 130-180 0.009 0.107 0.191 0.153 0.153 0.030 0.298 0.345 0.643
180-200 0.016 0.610 0.507 0.530 0.513 0.107 0.617 1.657 2.274
> 200 0.032 0.180 1.500 1.650 2.020 0.315 1.680 3.017 4.697
Prior to the washing of the soil, the experimental plot was represented by highly saline meadow irrigated soils, where the total amount of salts varies between 2.180-2.489. The distribution is almost uniform, with a maximum in the 51-90 cm layer. In the initial state, the content of Na2SO4 and NaCl, MgSO4 in the soil is relatively high, which is typical for saline soils in Central Fergana, the content of toxic salts ranged from 1.405 to 1.640% in accordance with the uniform distribution of salts there is also their stock.
As a result of soil washing with a rate of 4 thousand m 3/ha in deep horizons, a small increase in the concentration of soda in the range 0.009-0.016% is observed, before washing, it was very low in the form of traces due to its content in groundwater and physicochemical processes that occur during washing in the lower soil layers.
With regard to hydro carbonates, sulphates, chlorides, their content after washing with the norms of 4 thousand m 3/ha there is a significant reduction in their content. As a result, the amount of toxic salts, if prior to washing, ranged in the range of 1.395-1.640%, after washing, 0.148-0.345% became. Similar changes occurred in the content of non-toxic salts and dense residue, that is, the amount of salts.
Before washing salts in an average two-meter layer contained 2.380%, then after washing was 0.443%, that is, the salt content decreased by 5.4 times. As can be seen from the content of the amount of salts, including the toxic discrepancy in desalination of soils between the options after washing large. According to the content of sulfate and chloride salts in the two-meter layer of soil, the change is significant in favor of the fourth variant, where four-lane loosening was carried out to a depth of 150 cm, a width of 200 mm, and a GDR installation.
From the foregoing, it can be concluded that in the chloride-sulfate type of salinization, washing with conventional hydro carbonate-calcium-magnesium waters on the variants treated by the GDR plant resulted in desalination of irrigated highly saline meadow soils to low and medium salinized, sulphate soils, where sulfate salinity permits the content of a dense residue in saline soils in the range of 0.3-0.5%.
The results of the study showed that the fourth option was the most effective option in terms of economics and the removal of water-soluble salts from soil horizons, where four-row soil cultivation was carried out by a gas-dynamic ripper before washing irrigation.
References:
1. Methods of agrochemical, agrophysical and microbiological research in irrigated cotton areas. - T.: - 1963. -425 p. [in Russ].
2. Sulaimonov O. N. Influence of detonation treatment on the properties of irrigated meadow soils and cotton yield. The dissertation author's abstract on competition of a scientific degree of the candidate of agricultural sciences. - T.: - 2005 [in Russ].
3. Arinushkina E. V. Guidelines for the chemical analysis of soils. - M.: - 1964. - 486 p. [in Russ].
4. Volobuyev V. R. Washing saline soils. - Baku: Azerneshr, - 1948. - 147 p. [in Russ].
5. Bazilevich N. I. Experience in the classification of soils in terms of the content of toxic salts and ions. Bulletin Institute of Soil Science named V. V. Dokuchaev. - 1972. - Vol. 4. - P. 36-40 [in Russ].
