Improvement of technology and technical means for antierosion tillage in Uzbekistan

Topicality and demand of the theme of dissertation. As a result of acceleration of wind and water erosion, soil productivity all over the world is dramatically reducing. Its restoration is a very hard and long-term global environmental problem. At present, at the period of agriculture intensification around «the world nearly two billion hectares of land area became unfit for agriculture. About 31% of soil is subjected to water, and 34% - to wind erosion. Each year, more than 60 billion tons of topsoil is washed out into seas and oceans»1.
Systematic plowing of soil and the change in the system of agriculture, especially on slopes, leads to an increase of the part of areas subjected to erosion. The problem of water erosion and soil moisture deficit is particularly acute on dry farming slope lands. In our republic, soils, suitable for dry farming, come to 2 million 130 thousand hectares, including 756,82 thousand hectares of plowed up soil, «10.1% of land is subjected to water erosion, 76.6% - to wind erosion and 7.5% - to water and wind erosion»3.
According to analysis of scientific research and practical work in our country, machines used on land areas subjected to erosion for subsurface and moldboard tillage, do not provide quality tillage at required level: power consumption is high, and productivity is low.
In this connection, the studies, aimed at improving the system of tillage, reduction of energy consumption, improvement of accumulation and retention of moisture, which protect soil from wind and water erosion, development of technologies and technical means which enhance the fertility, arc very acute and important ones.
This dissertation work is devoted to performing such tasks as improving of soil fertility, increase of crop yield, high-quality processing of plants, protection from wind and water erosion, providing with resource-saving technologies and technical means defined by the Decree of the President of the Republic of Uzbekistan No UP-3932 “On measures on radical improvement of the system of land reclamation" dated 29 October, 2007 and the Resolution of the President of the Republic of Uzbekistan No PP-1958 "On measures for further improvement of irrigated lands and water resources management for the period 2013-2017".
Purpose of research. Development of mechanical and technological bases of processing of eroded soils and creation on this basis of new techniques that protect soil from wind and water erosion, reduction of energy consumption for processing, improvement of accumulation and retention of soil moisture, increase in unit productivity.
Scientific novelty of dissertational study consists in development of:
Technology of processing of eroded soils, principal schemes and design of two-tier ripper and a plow for crested-stepped plowing;
Mechanical and mathematical models of turnover of a layer combined with lateral shift and without lateral shift of its center of gravity;
Mechanical and mathematical models of the effect on soil of working elements of two-tier ripper and directing plate of a plow;
Analytical dependences, allowing us to determine rational parameters of working elements of developed instruments;
Analytical dependences, allowing us to analyze the stability of operation of developed instruments;
Regularities of changes of quality and energy performance of two-tier ripper and a plow for crested-stepped plowing, depending on parameters of their working elements and motion velocity;
GENERAL CONCLUSIONS
Data analysis has shown that the problem of preservation of fertility and soil moisture-content, elimination of wind and water erosion during primary tillage is not solved yet. As a result, existing machines for primary tillage in the process of operation impair physical, mechanical and technological properties of soil, increase the sensitivity of tilled soil to wind and water erosion, decrease soil fertility and crop yields. Structural, technological and kinematic parameters of machines arc selected for one mode of primary tillage only - full and deep overturning of the layer, which is one of the main causes of increased power consumption and material intensity of the process of plowing
Soil protection from wind and water erosion, improvement of the quality of tillage, reduction of energy and material intensity of agro-method due to development and implementation of differentiated system of tillage; technological and technical provision of this processing present an actual scientific problems.
Worked out mechanical-mathematical and computational experimental models, reflecting the relationship of quantitative and qualitative indicators of soil saving tillage systems, energy and materials consumption of this agro-method with rational parameters of two-tier ripper-plow and a plow for crested-stepped plowing, soil response on their working elements compose scientific foundations of the problem and allow to solve practical problems of the latter.
As a result of the study, the following scientific research results have been obtained.
1. On the basis of analysis of the mechanics of tillage process the problem of development of scientific bases for improved differentiated systems of tillage has been formulated; this system, studying the causes and ways to reduce wind and water erosion during primary tillage, is implemented in the form of alternating of technologies of crested-stepped and subsurface two-tier processing of soil (on the slopes) with their scientific and technical provision.
2. On the basis of studies of the types of working elements, interacting location, modes of operation and stability of ripper motion with upper and lower working bodies it was stated that the most rational design scheme of two-tier ripper with inclined props is a plow scheme with alternating upper and lower working elements with the lower bending of the prop; qualitative soil loosening with the least energy consumption is provided at longitudinal and transverse distances between working elements 50-60 cm and 35-40 cm, respectively; width and length of the landsidc arc 7cm and 16 cm, respectively.
3. Regularities of the change in soil resistance to the shift of working element with inclined prop have been stated, depending on its structural parameters, operating modes and soil properties. Rational values of parameters of working element arc within the following limits: the sharpening angle of the cutter is 16-20°, sharpening angle of the prop - 18-22°, the height from inclined working part of lower working element up to bearing surface of the chisel is 25 cm, of the upper working element - 15 cm, chisel width - 6,0-7,0 cm, angle of chisel lifting is 20-25°, the angle of inclination of the prop in transverse-vertical plane - 45°, maximum angle of installation of loosening plate to the surface of the prop is 25°, length and width of the plate - 12-15 cm and 9-12 cm, respectively.
4. An effective way of crested-stepped plowing of slopes is an alternation of partial turnover of a layer with complete turnover within its furrows at 180° in combination with belt subsurface tillage. To form a water-retaining crest partial overturn of the layer should be realized as follows: turnover of a layer from 0 to (л/2+y) without lateral shift of the center of gravity; further complete turnover of the layer with transverse shift of its center of gravity.
5. Worked out model of technological process of crested-stepped plowing with simultaneous subsurface belt loosening and research of interacting location of bases and subsoilers, bases and guiding plate, operation modes and stability of motion of a plow have shown that rational structural scheme of a plow for crested-stepped plowing is a stepped schemes with alternating of equal in sizes bases with short and long directing plates and subsoil plows set behind even bases. When longitudinal distance between the bases is 50 cm, required quality partial turnover of a layer with the least energy consumption is provided at the following parameters of directing plate of odd bases: length of directing plate - 75 cm, width of directing plate - 25 cm, height of stabilizing plate -15 cm, minimal distance from plowshare point to stabilizing plate -25 cm.
6. Physical-mechanical and technological properties of soils prone to erosion, allow us to set the reasons of wind and water erosion and identify the ways to prevent them.
Based on research results a number of technical solutions on technological and layout schemes, instruments structure, their working elements have been developed and recommended for implementation; these solution arc protected by patents of the Republic of Uzbekistan for the invention:
- Means and apparatus for implementation of technologies of subsurface tillage (№FAP 00701, №FAP 00656, №FAP 00669, №FAP 00787, №FAP 00850);
- Means and apparatus for implementation of technologies of crested-stepped plowing (№FAP 00719, №FAP 00863);
- Means and apparatus for implementation of combined soil-saving tillage (№FAP 00672, №FAP 00657, №IAP04832, №FAP 00864).
7. One of perspective ways of soil preservation from wind and water erosion is a development and building of combined machines, capable to produce simultaneously subsurface and subsurface and moldboard tillage, belt subsurface tillage, fertilization, soil preparation for sowing in a single pass of the unit.
8. Technological processes of tier loosening of soil and crested-steppcd plowing, two-tier ripper and a plow for crested-steppcd plowing have been validated.
Results of studies have been accepted by "BMKB-Agromash" and used in development of initial requirements to structure of two-tier ripper and a plow for crested-steppcd plowing.
9. Results of field trial tests of worked out instruments have shown that they excel serial machines in all characteristics, prevent soils from wind and water erosion, improve the quality of tillage, reduce energy and fuel consumption, increase productivity of units.
Economic effect of application of research results consists of the following components:
- application of two-tier ripper with inclined props reduces labor costs by 18,75%, fuel consumption - by 19,12%, labor productivity increases by 18,96%;
- application of a plow for crested-steppcd plowing reduces labor costs by 14,4%, fuel consumption - by 14,25%, labor productivity increases by 14,28%.
Annual economic effect of two-tier plow-ripper implementation is 7,17 million soums and a plow for crested-steppcd plowing - 5,35 million soums (in prices of 2014).
Thus, on the basis of theoretical generalization and implementation of new scientific concepts stated in the dissertation a major problem of development of bases of the theory of differentiated and soil-saving tillage system has been solved; it has an important economic significance.