In changing climatic conditions, the deep continuous loosening of soils can be the most effective alternative measure for expensive reconstruction of existing reclamation systems, and, at the same time, an effective adaptive means for the accumulation of free-soil moisture. The accumulation efficiency depends on the structure of the loosened soil. The value of the proportionality coefficient of the Bond comminution hypothesis was experimentally established, which makes it possible to determine the energy saturation of technical means for loosening a certain soil mass. It has been established that the required capacity of technical means for deep loosening is approximately 2 times less for sandy soil than for loamy soil. So, with a total working width of 2 m, a working speed of 2 m / s for deep loosening (by 0.75 m) and 4 m / s for the basic tillage (by 0.25 m), it is necessary to have the power of 170- 240 kW of technical equipment for sandy soil and 390-440 for loamy soil
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In changeable climatic conditions, the deep continuous loosening of mineral soil developed by us can be the most effective alternative measure for expensive reconstruction of existing reclamation systems, and, at the same time, an effective adaptive means for the accumulation of free-soil moisture (Iglesias, Garrote, 2015; Kovalenko etc., 2019; Mazhayskiy etc., 2020).
Deep loosening of ameliorated lands is carried out by special tools to a depth of 0.6...0.8 m or more to ensure water drainage through loosened soil to closed collectors (drains). They are used on heavy mineral soil, as well as on light loam and sandy loam soil with the presence of dense, poorly permeable to water layers in the subsoil horizons (at a depth of 0.3...0.4 m and deeper). Loosening of drained soil to a depth of 0.6...0.8 m against a background of closed drainage improves their water-physical properties and increases the yield of cultivated crops. The influence of the depth of cultivation on the work of drainage is manifested in an increase in drainage runoff and a decrease in surface runoff. The depth of cultivation has the greatest influence in the first year after it is carried out, in the future its influence decreases.
The depth of loosening depends on the depth and strength of poorly permeable soil horizons. It should be 0.2…0.3 m less than the minimum depth of drainage, i.e., 0.6…0.7 m. When loosening to a depth of 0.6…0.7 m, chemical analyses of the soil in the loosening zone are performed. If harmful compounds are detected, it is recommended to reduce the depth of loosening.
On soils with water-resistant layers and moderate waterlogging, located on poorly drained plains and levelled watersheds, the depth of loosening can be 0.5…0.6 m.
Loosening drained soils to a depth of 0.6…0.7 m on the background of closed drainage improves their water and physical properties and increases the yield of cultivated crops.
It was found that increasing the depth of loosening from 0.4 to 0.6 m, as a rule, does not affect the density and overall porosity of the arable soil layer. In the soil layer of 0.25…0.4 m, the density may decrease and the porosity may increase (about 5% in the first year and 2…3% in three years). A more significant effect occurs in the layer of 0.4…0.6 m, in which the density decreases to 10%, and the total duty cycle increases by 15…20%.
Depth of loosening affects the work of drainage. This is manifested in some increase in drainage and decrease in surface runoff. The depth of loosening has the greatest influence in the first year after its carrying out, further influence of loosening decreases. Improving the water and physical properties of the soil and increasing the effect of drainage with increasing depth of loosening has a positive effect on the yield of crops grown on drained lands.
The efficiency of deep loosening is influenced by the design of the working body. The use of tools with passive working bodies requires a lot of traction, and one of the criteria for justifying the depth of loosening is also the choice of the type of tractor-tractor and ripper.
Loosening intervals (distance between the working bodies of the leavening agent) depend on the water-physical properties of the soil and the design of the working bodies of the leavening agent. On soils with a filtration coefficient of less than 0.1 m/day, the distance between the working bodies should be 0.6…0.8 m. It can be increased to 1…1.2 m by reducing the density of the subsoil horizon and the presence of permeable layers.
For this purpose, a number of researchers are developing and evaluating the effectiveness of the working bodies of subsoilers in the destruction of compacted soil layers. At the same time, such works on various types and shapes of subsoilers are presented in terms of thrust and requirements for the energy of destruction of the soil massif, reduction of compaction and ease of operation. However, one of the important points that stands out in this case is the degree of soil destruction or the quality of loosening. Traditional rack-mount subsoilers are very unimportant in this case. In addition, it is highlighted that the development of subsoilers may be preferable to traditional means due to a decrease in the overall demand for specific engine power (Odey, Manuwa, Seth, 2018).
To reduce traction and reduce the use of power for increased soil crushing, some works suggest the use of vibratory (oscillatory) or rotary subsoilers (Celik, Raper, 2012; Li, Zhang, Zhang, Osman, 2012; Odey, Manuwa, 2016).