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A knowledge-based system for agricultural tillage equipment selection and management is presented. There are ten tillage systems suitable for corn and soybean production in Ontario. These systems manipulate the soil by different amounts resulting in varying levels of soil degradation, crop yields, and weed problems. Many factors, such as soil characteristics, climate, farm economics, and environmental impact make the selection of the most appropriate tillage practice a difficult task. Except for mouldboard plough, few farmers have experience operating and managing these tillage systems. Knowledge and information obtained from three experts is incorporated into the knowledge-based computer program to aid farmers in the selection and management of tillage systems. Selection criteria included in the program are environmental impact, management difficulty, economic return, and energy output/input ratio.

A software using the Finite Element Method for machine-soil system was developed with the following features: (1) an iterative increment algorithm for solving dynamic problems with material non-linearity; (2) five strategies for reducing program running time; (3) strategies to utilize the computer memory resources under DOS environment; (4) a complete macro-command system; and (5) an advanced element-library managing structure.

The relationship between the soil parameters measured during soil testing using the bevameter system and horizontal forces acting on a simple tillage tool were investigated. Field experiments were conducted on untilled, compacted soil and on recently tilled soil. On both soils, five sites were randomly chosen where bevameter and draft measurements were performed. The parameters measured were modulus of soil deformation, wet and dry bulk density, soil moisture content, tool operating depth, tool operating speed and horizontal draft. A statistical analysis of data indicated that a mathematical model for predicting draft should include operating depth, dry bulk density and modulus of deformation.

Field tests in sandy loam and clay soils were conducted with simple vertical tillage tools up to a speed of 18 ms-1 (65 km h-1) to determine the influence of soil types on the high-speed performance of tillage tools and the detailed relationship between draft and speed. A non-linear, dynamic finite element method (FEM) was used to simulate the variation in tool draft witii cutting speed. The prospects of high-speed tillage were discussed on tie basis of these experimental and analytical results.

Understanding the Relationships between plants and soil is important in the development of methods of crop production. Although physical properties of soil conducive to plant growth can be recognized by experienced observers, many of these properties have not been defined satisfactorily in mathematical or physical terms. A method of measuring penetration resistance and energy exerted by a mechanical seedling (a steel probe simulating a seedling) as it moved upward through the soil surface under different levels of surface compaction and soil moisture was examined. Mechanical seedlings with 2.06, 3.19 and 4.65 mm tip diameters were tested at soil moisture levels of 13, 17, and 20%. The penetration rate of the mechanical seedling while moving through the soil was held constant at 10 mm/min. Results showed that the emergence energy increased directly with soil surface compaction pressure, initial soil moisture content, and mechanical seedling diameters.

In order to use computer to carry out quick, accurate and economic design of product shape and colour, a package of AUTOLISP programs was developed which can be run under AUTOCAD main environment. Due to the limitation of AUTOCAD 11.0 and 12.0 in 3-D design of complex curved surface, the 3-D design functions were enhanced in the following aspects: (1) 3-D line JOIN and BREAK commands were developed to join and break 3-D polylines. SPIRAL command was designed to create 3-D cone or cylindrical spiral line. In addition, EFTURN and MEFTURN commands were developed to change the vertex sequence of polyline totally or midway. (2) 3-D elements and characters Existing subroutines were revised to directly generate Box, Cone, Pyramid, Dome or Dish, Torus, Sphere and Wedge ready for solid modeling. Furthermore, CONVEX, HOLE and TUBE commands were developed to generate different kinds of convex, hole and tube respectively.