OPTIMUM WORKING CONDITIONS FOR VARIABLE WIDTH PLOUGHS

In this paper, a few assessments of the optimal parametric combinations in the operating regime of agricultural aggregates with ploughs of variable width are made. The starting point was from a classic expression of the tillage draft force required for traction. In order to find optimal points, some problems of constrained extreme have been formulated. Extremes provided by the optimal working width and speed have been found. Such optimal points have existed in the literature, for about half a century. Using these theoretical estimates of the optimal points sought, assessments of the possibilities for their experimental validation were made. Basic conditions for an experimental plan are formulated to highlight such optimal points.

Embodiment design of a soil bin for soil-tool interaction study

The agriculture industry is an important aspect of Indian economy. The changes occurring in global climate and increased frequency of extreme weather conditions pose challenges for agriculture industry. In such unpredictable conditions, achieving required outputs from farming for supporting continuously increasing population necessitates the mechanization of traditional processes. The selection of machinery for such mechanized setup is a key management task. Tractor is one of the farm machines being used in various farm related operations. Thus understanding constraints imposed on selection of a tractor is a primary factor in decision making process. The study has highlighted importance of power requirement for farming operation in tractor selection process. Thus to determine power requirement for farming operation a study of soil-tool interaction is necessary. A soil bin setup is one of the tools for studying the soil-tool interaction. This work presents the conceptual and embodiment design of a soil bin developed to find variation in draft force with respect to variations in the parameters like tillage depth, operation speed and soil moisture level. The tillage depth and operation speed were found to be directly proportional whereas the soil moisture level was found to be inversely proportional to the draft force.

EFFECTS OF DIFFERENT GEOMETRICAL STRUCTURES ON THE SOIL DISTURBANCES AND WORKING RESISTANCES OF VERY NARROW TINES APPLIED ON NATURAL GRASSLAND

Novel tillage tools with high working performance are desired in improving degraded natural grassland tillage system. This paper aimed to find the influence of various geometry structures of very narrow tines on related soil disturbance characteristics and tillage resistances. Four shank-type tillage tines with different cutting head shapes, and the test bench were designed and manufactured. Field experiments under different working depths were conducted. The working depth uniformity, soil over-turning rate, cross-section area of disturbed soil layer, and related forces were obtained, analysed, and compared. Results showed that, the working depth uniformities were above 70%, and soil overturning rates did not exceed 5%. Furrows with V-shaped cross-section were formed. The tine with an arc-shaped cutting edge (AT) obtained a lower draft force value, and the tine with chamfer structure (TTD) presented big differences on the draft force and soil disturbance compared to the tine with blunt cutting edge (TT). Both the draft force and the area of disturbed soil cross section had a good linear relationship with the working depth, and the specific draft force increased with the working depth increasing. Using a very narrow tine with chamfers to split and break the soil layer on the natural grassland without pulling or dragging the roots could be an appropriate tillage method applied for improving degraded natural grassland, but still need further surveys.

Draft measurement of five tyne duck foot plough in clay soil

In the present study, the draft requirement of five tyne duck foot plough was studied on clay soil for different soil moisture content, depth of operation and forward speed of tractor using a specially designed three-point hitch dynamometer. The designed dynamometer was matched with the tractors having category II or III hitch systems. The data acquisition system adopted for the dynamometer had NI WSN-3214 Strain Nodes, NI 9792 WSN real-time Gateway and NI LAB View 2013 software. A data logger program was developed for the three-point hitch dynamometer. The investigation was carried out at that three levels soil moisture content (10-13%, 14-16% and 17-20%), at three different depth of operation (15, 20 and 25 cm) and three levels of the forward speed of tractor (3, 5 and 7 km h-1). The designed dynamometer performed well in all the levels of the experiment. The results showed that draft force required for five tyne duck foot plough was increased (408 kg) with an increase in soil moisture content (17-20%), whereas it was increased (408 kg) with an increase in depth of operation (25 cm) and forward speed of tractor (7 km h-1). The suitable sweep, the forward speed of operation, depth of operation and soil moisture content that influenced the draft force and energy consumption for tillage operation of duck foot type plough were identified and developed duck foot plough was better coverage with better soil operation.

OPTIMIZATION DESIGN OF AN AIR-PRESSURE SUBSOILER TYPE

Through the mechanical analysis of air-pressure subsoiler, it is found that the main factors affecting its tractive resistance are the air pressure injected into the soil, the soil cohesion, the length and width of the shovel surface, the soil disturbance coefficient, and moving speed of the subsoiler. The traditional air-pressure subsoiler was redesigned to solve the problem of large tractive resistance. In the soil trench experiment, the subsoiling shovel’s shape, the air pressure, and the position of air hole were used as test factors, and the ratio of the traction resistance of the shovel to the soil disturbance, namely SDF (Specific Draft Force), was used as the evaluation index. By the response surface test method and analysing the soil disturbance and the tractive resistance, it is determined that rectangular subsoiling shovel with the air hole in the upper part of the shovel is the optimal under the pressure of 1.2 MPa.

RELATIVE ORDERING TESTS FOR DRAFT FORCE MODELS IN SOIL TILLAGE

The article presents results of some test sketches - validation and ordering - of the mathematical models proposed for the physical law rank on soil tillage draft force. The results constitute the continuation and partial completion of a method of testing - validation and ordering - the models proposed and published by researchers in the specialized literature of the last seventy years. The material defines and completes the method (initially only a validation method), up to a method of ordering the models according to their accuracy in relation to the experimental results. The proposed tests are intended to increase the coherence of research in the field of searching for a physical law of soil tillage draft force, assuming that it exists. The method can also be applied in case of other physical laws in research, construction or improvement stage.