Document Type : Research Article
Authors
1
Department of Agricultural Machinery and Mechanization Engineering, Faculty of Agricultural Engineering and Rural Development, Agricultural Sciences and Natural Resources University of Khuzestan, Mollasani, Iran
2
Agricultural Mechanization and Industries Development Center, Ministry of Agricultural Jihad, Tehran, Iran
Abstract
Introduction
Soil compaction causes a decrease in water and air penetration into the soil, impairs root development, and consequently leads to a substantial decline in crop yield. The most rapid countermeasure is subsoiling. Subsoiler devices and the subsoiling operation are recognised among the most energy-consuming and heaviest soil tillage operations. Tillage tool vibration effectively reduces traction force, resulting in increased soil fracturing and mixing, which decreases soil adhesion. The objective of this research is to determine the optimal vibration frequency for an electrical oscillating subsoiler. This will lead to a modification of the conventional subsoiling process and the application of these research findings in routine agricultural subsoiling operations, particularly in the lands managed by the Khuzestan Sugarcane Development Company. Improving this operation can significantly reduce soil losses, energy consumption, and associated costs, given the vast annual volume and area involved.
Material and Methods
This research is a developmental and applied type. It contains the installation of an electric oscillation system, followed by the execution of treatments utilising the independent variables of the study, which consist of the vibration frequency of the subsoiler blade at five levels (0, 20, 30, 40, and 50 Hz) and soil moisture content at two levels, dry (5.5–5.8%) and moist (15–19%). The vibration generation system installed on the subsoiler consisted of two electrical circuits: one for supplying electrical energy from the tractor’s battery, and another for adjusting the vibration acceleration. This alteration was achieved by modifying the rotational speed of the vibrator motor, which, in turn, changed the frequency. The highest frequency of 50 Hz and the absence of vibrations could be achieved using the F300-2R2G-2 model of a programmable inverter drive, which supportsn both manual and automatic control. The five frequency levels, ranging from 0 to 50 Hz, were generated by the driver from within the tractor cabin, in accordance with the experimental design. The required electrical energy was also continuously supplied without fluctuations or interruption. The experiments were conducted in a pre-divided and prepared field, with three replications, utilising the experimental design of split-plots in the form of completely randomised blocks. Data obtained from the tests, including traction force, working width, working depth, and the cross-sectional area of the tilled soil, were compiled and statistically analysed using Excel and SAS software.
Results and Discussion
The results indicated that at high moisture levels, the working depth increased, while the working width and the effectiveness of the vibratory subsoiler decreased. Vibration levels at the 0.01 significance level had a significant impact on performance indicators, including working width, working depth, the cross-sectional area of tilled soil, and specific traction force. Under conditions of minimum moisture and maximum vibration, the highest effectiveness was achieved, meaning that the width, working depth, and disturbed soil area increased, while the specific traction force decreased. The maximum traction force occurred at the lowest frequency and under dry soil conditions. Therefore, in subsoiling operations, selecting a time when the soil is within the suitable moisture range and utilising higher frequencies of vibration leads to a larger area of disturbed and fractured soil. Additionally, a reduction in the required specific traction force further enhances the efficiency of the vibratory subsoiler.
Conclusion
The electric vibration system offers an innovative solution for vibration management and control by the operator. It offers a wider range for achieving optimal vibration in soils of varying textures, thereby maximising the efficiency of the tractor-tiller system. The application of variable-rate vibration enables electrification and is independent of the PTO.
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