APPLICATION OF A NEW TECHNOLOGY FOR REGULATING THE SALINITY REGIME IN THE SOIL TO RICE CROP ROTATION

Abstract. The article presents a new technology and results of research on reducing the specific salinity in the soil of crop rotation of irrigated lands of the ameliorative engineering system of the Aral Sea region.

Currently, there are more than 251 thousand agricultural lands. Of these, 184 thousand hectares of engineering facilities will be used in 2020. Our goal is not only to improve the soil, but also to put into circulation the remaining 67 thousand hectares. Improving the condition of these lands, improving the yield and quality of agricultural crops and the economic condition of farms. The President of the Republic of Kazakhstan noted that one of the most important tasks in agriculture is to increase the volume of irrigated land to $ 3.0 million. setting itself the task of increasing the hectare, the government clearly I gave you an assignment. In accordance with this instruction, the government approved a plan for the development of irrigated land until 2028.

Today, agriculture is of great importance for the development of the economy of the Kyzylorda region. Since rice is the main crop in this region, its acreage should be stabilized at an area of 80-85 thousand hectares, of which more than 450-500 thousand tons of rice should be produced annually. In recent years, rice has been the only crop in the region that increases its export potential and creates optimal market conditions.

Keywords: salinity, soil, deep tillage, traditional tillage technology, rice.

Introduction.  The accumulation of salts in areas that could potentially be used in agriculture is a worldwide problem, covering 340 million hectares in around the world. During salinization of soils, water-soluble complex sodium and magnesium ions accumulate in their composition. In general, salinization is characterized by the accumulation of excess water-soluble salts in its composition and changes in the cationic-anionic composition of the soil environment. Harmful substances in alkaline soils are nitrated with gypsum, initially treated with sulfuric acid and iron sulfide, and then the resulting fast-dissolving salts are washed with water. This method of reclamation of saline soils is quite common, but its effectiveness directly depends on the possibility of underlying waters. Sometimes rocky waters merge with underground water, increasing their degree and causing the opposite effect. As a result, the risk of secondary salinization of the soil due to rising ground water increases in irrigated areas. Saline soils are typical of arid, desert steppe zones. This is due to the fact that in such regions, due to the heat of the weather, strong winds, the evaporation of water from the Earth's surface occurs very intensively. In this regard, as the soil solution evaporates upward in the soil layers, the salts dissolved in it also rise up and are retained when they hit the soil surface. In a region located in the arid zones, a lot of problems, associated with irrigation and melioration. Irrigated agriculture is the basis of the region's agriculture (Kazakhstan, Uzbekistan, Turkmenistan, Kyrgyzstan, Tajikistan, Azerbaijan)[1,2,13,15]. Moreover, the average annual air temperature in the region has been rising in recent years and the rate of warming is growing.The relative humidity of the air is very low, especially in the summer months, when the amount of evaporation is very high. relative humidity in the range of 54-58% , along with the acceleration of soil dryness, soil salinity also increases [5,6,7]. This factor also affects the land used in agriculture.

Water supplied mainly for sowing should contain a dry residual salt volume of 1.5-2.2 g/l so that the plant can grow independently, and during the period of setting and ripening of the crop, it should not exceed 2.5 g/l. At the same time, you should pay attention to its purity, depending on the content of chlorine and sodium in the water. If the chlorine ion is 0.35 g/l, and the sodium ion is 0.25-0.35 g/L, then the soil can become saline and saline.

The soils of the Aral Sea region belong to the chloride-sulfate form of salinization.There are 251034 hectares of farmland in the Kyzylorda region. The soils of this territory are classified according to salinity in the data for 2019 in the following volume [3,14].

1. unsalted-2840g;

2. lightly salted-123377ga;

3. medium saline-89907 ha;

4. strongly and very strongly saline - 34910 ha.

In 2020, 184.2 thousand hectares of utility networks were used for sowing. The remaining area of agricultural use is removed from circulation due to salinization, land contamination, etc.

In this regard, based on the results of many years of research by scientists of the Institute, several new technologies for regulating the salinity regime of rice soils are being developed. One of them is deep processing of saline soils of rice paddies with a chisel cultivator[1, 2, 4, 8]. When the base continues to plow the ground year after year at the same depth, the soil is compacted by the plow sole, and a layer called the "plow sole"is formed in its lower layer. Since this is a very dense, hard layer, it prevents the movement of plant roots, moisture from the air down. At the same time in the soil the salt is washed away and, without breaking away from the solid layer, rises again to the surface of the soil next year. Therefore, if the solid layer is emptied with a chisel cultivator, the physical properties of the soil are improved, and the emptied layer also contributes to the rapid removal of salt[9, 10, 11, 12].

Materials and methods.The research work was carried out in the field. Meadow-swamp and highly saline soils of arable land belonging to the farm "Er-more" in the rural district of Makpalkol, Zhalagash district, Kyzylorda region, were selected for field experiments. The tested agrotechnical structure is a chizel cultivator PCH-4,5 with deep tillage. Grafted rice variety is the Leader. The seeding rate is 250 c / ha.

Results and discussions.Achieving sustainable development of rice production through the introduction of water-and resource-saving technologies for the cultivation of rice crops and rice crop rotations remains an urgent issue. The main tillage is carried out to a depth of 16-18 cm( ravine), 25-27 cm (ravine, shea), depending on the weeds of the same area. This is a traditional tillage technology.

During the spring sowing campaign, both selected harrows had the same traditional tillage technology, including a chisel cultivator with deep cutting of the soil layer by 45-55 cm, i.e. a new deep tillage technology.

Figure 1.Deep processing chisel cultivator and its treatment of arable soils

Figure 2. Top view of the experimental site

(a – atyz with deep tillage; b-atyz treated using traditional technology)

Timely repairs were carried out in accordance with the growing season of the sprouted rice plant. In addition, phenological and biometric analyses of plants of both names were made, which were always under observation. Taking into account the differences and peculiarities of sown soils in plants and products grown on traditional and deeply treated soils.

Table 1.

Differences of plants of origin by variants

As can be seen from Table 1, the phenological and biometric indicators of rice plants in horses treated with traditional technology showed much lower indicators than rice in horses treated with new technology. Table 2 shows the agrochemical characteristics of the soil state of two fields.

Table 2.

Agrochemical characteristics of soils

If earlier the soil characteristics in both names were the same. The soil type was meadow-marsh, strongly saline. Soil characteristics changed after the summer growing season. The biggest difference is in the dense residue and salinity in the soil. In soils treated with the new technology, humus is stabilized, that is, humus of the soil that reaches a weak type of salinity. And in traditional processing technology, this indicator is reduced.

According to both tables, the salinity content of salty soil decreased on deeply cultivated soil and created conditions for the growth of the sown crop.

Conclusion. The climatic conditions of the Kyzylorda region do not allow you to completely get rid of salt. There is still work to be done to reduce the salt content in the soil. Since since the creation of the first rice crop rotation system in the Aral Sea region, no deep tillage work has been carried out on reclamation and engineering agricultural land, when sowing any crop, the soil of the land was treated with a conventional plow at a uniform depth during the year, the plow was subjected to hardening. Not harmful to the crop sown with emptying of the hard layer conditions for its germination the data obtained in research works showed an increase in production through creation. The main thing is that with this technology, the amount of increased salinity of the soil slows down.