International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

The agricultural machines become more and more complex and complicated systems aimed to produce cheaper and plenty of agricultural products. The modern farmers uses computer technology and equipment not only for monitoring and analysis of the financial results from his activity, but also for expert assessment of yields, state of soil, crops, animals, machinery, product parameters, climatic conditions. Being acquainted with the principles of operation, structure, parameters and modes of adjustment and work with such electronic systems is becoming an obligatory part of the training of agricultural production experts.

The main physical soil properties are considered highly important for soil fertility. Measuring only 4 indicators taken from the soil samples and by using physical equations can determine valuable results for the soil physical properties. To facilitate the analysis a develop software could help.

Cover crops (green manure) brings not only immediate advantages like slowing erosion, suppressing weed growth, improving soil structure, increasing nutrients and water content and hindering some pests but also long term ones like decreasing erоsion, air pollution, investment in mineral fertilizers and herbicides and increasing microbiological activity. The paper gives examples of good practices both for whole and row-crop grains. It also suggest a useful crop rotation for a period of five years.

The paper researches the influence of two tillage systems – conventional tillage and strip tillage on soil nutrients content, soil acidity and microbiological activity over a reseаrch period of four year – from 2014 to 2017 included. The test are carried out on the same fields in Northeastern Bulgaria. Soil nutrient testing can help determine the necessary amount of fertilizers to be used on a specific field.

The main physical soil properties are considered highly important for soil fertility. Measuring soil moisture, in-depth soil hardness and soil density can help in choosing an appropriate soil tillage method. The paper shows a practical handbook, which can be used with addition to soil moisture meter and a hardness meter to reach these conclusions. The selection of the tillage method is done by using a paper disk, provided in the handbook, showing good tillage practices.

There are significant benefits to be gained from reduced and no-tillage in connection to soil protection policies but the unique requrements of such practices create the need for seed drills capable of matching these requirements. It is necessary to reach a quantative representation of the effectiveness of different brands of seed drills in order to chose a suitable drill for the task. The seed drill’s efficiency can be judged after the biological and economic risks of its usage have been evaluated. This paper shows a method which uses the technical data of the seed drill and reaches a cumulative grade to evatuate the biological risk and also an existing software which compares and evaluates the economic risk for a chosen seed drill compared to Cross Slot seed drill. Combining the two types of risk evaluation lets us chose the best type of seed drill for seeding in reduced tillage.

The paper discusses the gradual transition from conventional tillage through reduced tillage to no-tillage while creating favourable conditions for increase of organic matter. The paper suggests crop and tillage method rotation for a period of five years in order to facilitate this transition. It also reviews tests of soil physical properties which can help farmers determine how their soils are changing and what effect the change of tillage method has on them.

The degradation of soils is due to a combination of factors. One of them is the annual deep plowing. In this way the soil is left exposed to the vagaries of nature for a few months. Precipitation presented by the rain drops and their energy, destroys the soil structure and activates anthropogenic erosion processes. With intensive tillage, involving reversing of the plow layer, a number of processes are initiated, leading to oxidizing and burning of organic matter and, hence, to its continuous decrease. The extensive use of large quantities of mineral fertilizers and the additional commercialization of crop rotation also have a negative effect in the form of soil degradation. With the purpose of reducing the number of passages of tractor units on the field surface, a new type of tillage is proposed, without reversal of the plow layer, but with retaining a large part of the plant residue on the surface instead.

The Importance of the Problem "Stability of Soil Aggregates" The assessment of soil quality indicators and their interpretation should be considered as a process in which all soil resources are assessed in terms of soil functions and the changes that would occur in these functions as a result of Natural or specific stresses and / or certain human activity. The process of formation of soil aggregates or organominerals complexes from primary particles and humic and other bounding substances, is called aggregation. It is the first step in the development of soil structure. Humified organic matter, with its long polymer chains and electric charge balanced by polyvalent cations, is a very effective cementing agents. Structural stability is the ability of a soil to retain its arrangements of solids and void space when external forces area applied. External forces can be natural or anthropogenic. The aggregate stability depends on the bonding agents involved in cementing the particles together

Organic polymers used for seed coating have been reviewed aiming to protect the seeds placed into the soil under unfavorable for them conditions. Organic materials could be important hydrophobic agent in both high moisture and low temperature which could protect seeds from early germination. At the same time polymer film couldn’t be a obstacle for seed germination in favorable environment. Study of the polymers is important issue for the agricultural science and practice. In present work effect of soil temperature and moisture over germination of seed covered by organic polymer have been studied. It has been found that seeds coated with thin layer of organic polymer stead in dormancy under 8⁰ C independently of soil moisture. The polymer doesn’t effect on seeds germination ability as well.

Prospective energy technology devises for controlled traffic farming is the wide span tractor (vehicles). Their driving can be built behind the kinematic or force principle of the turn. At the kinematic turn, the schemes are applied by turning the steered wheels (front, rear or both front and rear) relative to the car’s frame. The widest distribution in wide span tractor (vehicles) was obtained by turning schemes with all steerable wheels. The theoretical foundations of the dynamics of the parallel-span parallel motion tractor (vehicles) in the horizontal plane are presented in the article under the kinematic method of its control (by turning the wheels). Theoretical research is based on the basic principles of theoretical mechanics, tractor theory, statistical dynamics and the theory of automatic control of linear dynamical systems when they reproduce statistically random control and disturbing input effects. The amplitude and phase frequency characteristics are based on the analysis of the evaluation of the degree of influence of the circuit and parameters of the investigated wide span tractor (vehicles) on its controllability and stability of motion. The physical object of the theortical studies was the prototype of the wide span tractor (vehicles) of the new design. Mathematical models of the wide span tractor (vehicles) movement are represented in the differential and operator form of recording. On the basis of mathematical models, the calculated amplitude and phase-frequency characteristics of the dynamic control system development are plotted, represented by the average rotation angle of the front wheels of the wide span tractor (vehicles). The constructed mathematical models, amplitude and phase-frequency characteristics allow estimating the effect of the control parameter of the wide span tractor (vehicles), as well as its design and other parameters on the controllability and stability of motion.

Modern technologies of harvesting sugar beet tops provide solid preliminary cutting and collecting its harvest at the increased altitude and subsequent additional root crops heads cleaning from tops residues on a root. This last operation also defines quality of root crops of beet before their digging up. Objective of this research is improvement quality of root crops heads cleaning from tops remains, by development of interaction theory of flexible cleaning blade with a spherical surface of root crop head. In the theoretical study were used methods of modeling, higher mathematics and theoretical mechanics, as well as programming and carrying out numerical calculations on the PC. As a result of the conducted theoretical research the interaction theory of flexible cleaning blade with a root crop head surface in the course of its cleaning from tops remains is developed. On the basis of the received differential equations of blade movement which is pivotally mounted on the drive shaft with a horizontal axis of rotation, new mathematical dependences which justify basic parameters of this technology process are given.