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Development of a tillage reference implement for measuring and comparing tillage draft
Abstract
A tillage reference implement (TRI) concept to predict and compare draft requirements for tillage implements was developed. The reference implement concept was based on implement draft and soil and implement scale factors. The scale factors consist of a soil scale factor, implement scale factor and soil and implement scale factor. The TRI draft with the use of scale factors can predict the implement draft irrespective of soil types and field conditions. The TRI concept was tested using a tandem disk, chisel plow and field cultivator. The predicted implement draft values were in close agreement with the measured values. The TRI was used to determine the force differences in a tillage operation and to predict the tillage induced changes in soil properties. The TRI draft, after the implement operation, was found to be lower than that beside the operation. The relationship of implement draft to soil and implement geometric parameters need to be precisely developed to predict the tillage effect of soil properties. The TRI, tandem disk, chisel plow and field cultivator drafts, vertical forces and torques were significantly affected by the tillage depths and travel speeds. The draft, vertical force and torque models for the implements and TRI were related as a quadratic of tillage depth. A microprocessor based non-contact ultrasonic sensor was used to measure tillage depths. The sensor was tested on concrete, grass, wheat stubble, lightly disked wheat stubble and double disked surfaces. It performed well on concrete and double disked surfaces and the measured values gave coefficient of variation lower than 10% on concrete and double disked surfaces. The precise measurements of tillage depths in the double disked surfaces were used in developing the draft model. To adjust the soil scale factors for variations in soil parameters within a given soil type, a soil cone index was used as a covariate in the draft models. The effects of soil moisture content and bulk density on the cone index values were normalized using covariate analysis technique. The technique allowed treatments comparison at same and across depths. Cone index models for wheat stubble and double disked surfaces were developed based on soil depth, moisture content and bulk density. The model gave a fair estimate and the predicted values of the cone index were found within 8% of the measured values.
Subject Area
Agricultural engineering|Agronomy
Recommended Citation
Yasin, Muhammad, "Development of a tillage reference implement for measuring and comparing tillage draft" (1991). ETD collection for University of Nebraska-Lincoln. AAI9208121.
https://digitalcommons.unl.edu/dissertations/AAI9208121