An Extended Octagonal Ring Dynamometer for Measurement of Forces on a Simple Tillage Tool

The analysis, design, construction, evaluation and use of an extended octagonal ring dynamometer for measurement of draught, vertical force and moment on a simple tillage tool are presented. The dynamometer was used to measure tool forces as functions of depth, rake angle and speed, for a wide plane blade.The dynamometer was designed for a maximum draught of 4.4 kN, vertical force of 4.0 kN and moment of 2.2 kN-m. Evaluation and calibration showed linear response (R2 =  0.99 to 1.00) for the relationship between applied load and output voltage and no hysteresis effect within the load range was observed. Actual sensitivity obtained were 0.332 m V/N.V for draught, 0.726m V/N.V for vertical force and 2.5 m V/N-m.V for moment. Maximum cross sensitivity was less than 6%. The dynamometer showed expected response of tool forces as affected by tool depth, rake angle and speed

Predicting Suitable Field Workdays for Soil Tillage in North Central Nigeria

A simulation model was developed to predict suitable field workdays for tillage operations in North Central Nigeria. Predictions were made from a computer model which simulates daily soil moisture in the top 30 cm of soil depth using 6 years of daily meteorological records. The model was tested and validated by comparing its output with the observed workdays during the 1996 farming season on two soil types. Results show that there was good agreement between the observed and predicted values using established tractability criteria

Development of a Computer Program for the Design of Auger Conveyors for Agricultural Products

The screw or auger conveyor is an important conveyor in agricultural and food processing industries. The classical approach to its analysis and design involve the determination of the type and dimensions of the pitch, capacity, screw housing, clearance, length and diameter, shaft diameter, speed of revolution, filling factor, necessary elevation, and power requirements, in addition to the design of the layout. These are done by a combination of calculation and selection from charts. After these, the torque requirement is checked against maximum allowable torque given in charts, which may require the designer to repeat the process in an iterative manner. This can be frustrating where it is done for different products and where it is necessary to consider alternative designs in order to achieve design optimization. A computer program was developed for the above processes to remove the constraints of the classical approach. The program which is iterative and menu driven, accepts relevant input data (material to be conveyed, required capacity, elevations involved, etc) and does the required calculations, selection and optimization. It then gives the user the required dimensions and parameters of the conveyor. Results of evaluation tests show that the program is efficient in the design process and saves time, especially where alternative designs are required to be produced

Conservation and conventional tillage effects on soil properties and soybean production

Four conservation tillage practices and two conventional tillage practices were evaluated for two years to determine their effects on soil properties (moisture content, bulk density, porosity, shear strength, cone index), weed control, germination, growth and yield of soybean (Glycine max (L) Merril). The soil was sandy loam and classified as Typic Haplustalf of Eruwa and Odo Owa series. The conservation tillage practices were: no tillage (NT), chisel ploughing (CHP), use of a cultivator (CU) and disc ploughing once (DP). The conventional tillage practices were disc ploughing followed by harrowing (DPH) and disc ploughing followed by harrowing and ridging (DPHR). The treatments were laid out in a Rand­omized Complete Block Design with three replications. Results show that tillage practices significantly affected soil properties, weed control, germination, growth and yield of soybean. Soil strength and mois­ture content were significantly higher under the conservation tillage practices, whereas porosity was sig­nificantly lower. There was better crop establishment and growth under the conservation tillage practices due to the better moisture conservation under such systems. Weed control was more effective under con­ventional tillage practices. Over the two-year period and compared to NT, the percentage increase in yield with other tillage practices were 9.3% for CHP, 10.1% for CU, 13.7% for DP, 17.9% for DPH and 16.12% for DPHR. In overall performance, when the effect on soil properties and crop performance were considered together, the conservation tillage practices of DP, CHP and CU are recommended for the area, depending on equipment availability. The results are applicable to other regions with the same soil type. Key words: Tillage, conservation tillage, soybean production, conventional tillage. Agro-Science Vol.2(2) 2001: 26-3

Computer Simulation Model Of Available Field Workday For Nsukka Farming Environment

Information on available field workdays (AFW) for agricultural operations in general and tillage operation in particular is required for optimum management and scheduling of operations. This data vary from place to depending on the weather, soil and crop types. Agro meteorological Data and actual AFW for tillage operation were obtained for 10 years (1992-2001) at Nsukka, Nigeria. A simulation model was developed for estimating AFW for tillage operations. The model is based on estimating field soil moisture using a soil moisture budgeting technique. This technique takes into consideration precipitation, drainage, surface runoff and evapotranspiration. The soil moisture estimated is compared with established tractability criteria to decide whether a particular day is a good working day or not. The model was used to predict AFW for tillage operations in Nsukka from 1992 to 2001 planting seasons. Over the ten - year period, the mean AFW observed were 9, 23, 20, 16 for April, May, June and July respectively. Good agreement between predicted values and actual observations was obtained. The overall mean percent deviation of the predicted values compared to observed values was 16.9% thus, the model developed can be used for predicting AFW for tillage for the area. KEY WORDS: Simulation Model, Available Field Workday, Soil Tractability, Soil Moisture Budgeting. Global Journal of Engineering Research Vol.3(1&2) 2004: 1-