Development and testing of a Prosopis africana pod thresher

Prosopis africana is an under utilized tree crop with immense medicinal and industrial values. Manual threshing of the pods to extract the seeds is uneconomical, time consuming, associated with drudgery and low output capacity. A motorized Prosopis africana pod thresher was designed, fabricated and assessed for performance. The main components of the thresher include hopper, threshing unit, cleaning fan and the frame. The best threshing performance index of 92.55 % which comprises of 98.03 % threshing efficiency, 94.45 % cleaning efficiency, 2.36 % seed loss and 1.59 % mechanical damage index was obtained. A combination of 1200 rpm cylinder speed, 1200 rpm fan speed, 30 kg/h feed rate and 16 % wb moisture content of the pods is recommended for optimum results. The thresher has a capacity of 70 kg/h. The performance of this thresher has indicated the possibility of exploiting the full industrial potential of Prosopis africana pods and seeds

Performance and economic comparisons of manual and mechanised fertiliser applications for mature oil palm

The problem of labour shortage in addition to environmental hazard due to improper fertiliser application method calls for efficient and effective method of fertiliser application. This study compares the productivity of workers, human energy expenditure and operational cost between manual and mechanised method of fertiliser application operation for matured oil palm in Malaysia. Results indicate that workers' productivity increased by 3.74 times with mechanised method compared to the manual method based on the measured field capacities of 4.64 ha per hour and 1.24 ha per hour for the mechanised and manual methods, respectively. In addition, mechanised fertiliser application was 4.53 times less labour intensive than manual application based on the measured human energy expenditure of 2.03 kcal per min and 9.19 kcal per min for mechanised and manual methods, respectively However, the estimated total cost for the mechanised method is 1.6 times more than the manual method which amounted to an additional cost of RM4.18 per hectare based on the estimated total cost of RM11.10 per hectare and RM6.92 per hectare for mechanised and manual methods, respectively. The high estimated total cost of the mechanised method is due to the low annual usage of the tractor considered in the economic analysis for this study

Physical and mechanical properties of Jathropa curcas L. fruits from different planting densities

Jatropha curcas L. is a versatile and rugged crop with enormous unexploited potentials. In order to efficiently take advantage of its full potentials, its physical and mechanical properties need to be well understood. Laboratory tests were conducted to investigate the properties of Jatropha curcas L. fruits obtained from trees of three planting densities namely 10880, 5446 and 3630 plants acre-1. The properties included detachment force, rupture force, deformation at rupture point, deformation ratio at rupture point, hardness, energy used for rupture at both vertical and horizontal loading positions. Other properties studied were 1000 unit mass, dimensions, sphericity, bulk density, solid density, porosity, coefficient of static friction on plywood, steel and stainless steel. The solid density value of 0.97 g cm-3 was obtained which implies that the fruit could float in water for easy cleaning and separation from foreign materials. It was observed that the fruit had the least coefficient of static friction on stainless steel (0.44). The average values obtained for the detachment force and rupture force at vertical orientation were 16.62 N and 57.17 N, respectively. No clear cut trend was observed in the physical and mechanical properties with respect to planting density. However, the mechanical properties were significantly different with respect to the orientation of the fruits. Both the physical and mechanical properties are essential for the design and development of harvesting and processing machines for Jatropha curcas L. fruit

Effect of adding palm oil mill decanter cake slurry with regular turning operation on the composting process and quality of compost from oil palm empty fruit bunches

Formation of compost from oil palm empty fruit bunches (EFB) and decanter cake slurry by adding palm oil mill effluent (POME) with regular turning operation was investigated. The experiment was conducted in a commercial composting plant under the normal production process. The addition of decanter cake slurry has hastened the composting process of the EFB. The C/N ratio after 51 days for the mature compost with the decanter cake slurry was 18.65 while that of the matured compost without the decanter cake slurry remained high at 28.96. The compost formed from the addition of decanter cake to EFB and POME had 46.4% nitrogen, 17.9% phosphorus, 17.7% potassium and 23.1% calcium more than that without decanter cake. The use of compost produced from EFB, POME and decanter cake slurry could solve more environmental problems and enhance economic benefits in the oil palm industry

Calibration and accuracy determination of a microwave type sensor for measuring grain flow

Impact type grain flow sensor for crop yield monitoring is known to have problem of some thrown grain by the elevator conveyor in a combine not hitting the sensing impact plate. New technology of microwave solid flow sensor was used to solve the problem of impact-type sensor. A calibration stand with its instrumentation systems to stimulate the actual operation of the clean grain auger in a rice combine had been designed and constructed in this study for the purpose of conducting the calibration and evaluation study of the sensor. Two different solid flow sensor orientations and three different solid flow sensor extrusions were investigated in order to find the best positioning of the sensor on the chute for the measurement. Results from the conducted tests indicates that the best sensor positioning is on totally flat ground at 180o orientation and 8 cm extrusion of the chute cross section (R2=0.9400). Then, the solid flow sensor was tested at seven chute pitch angle positions (i.e-4.5o, -3.0o, -1.5o, 0o, +1.5o, + 3.0o, and +4.5 o), seven chute roll angle positions (i.e-4.5o,-3.0o, -1.5 o, 0o, +1.5o, +3.0 o, and +4.5o). Finally, accuracy tests undertaken to compare the real time measurements against the average flow measurements. ANOVA test shows that both pitch angle and roll angle positions have significant effects on the measurement accuracy of the sensor. The measurement errors increased with increasing roll angles and increasing pitch angle. Conclusively, this conducted laboratory study was able to quantify the measurement accuracy of the SWR Solid Flow sensor for real-time measurement of grain flow under a simulated laboratory rice combine test set-up

Effects of operational variables on rotary valve metering system for a variable rate technology fertilizer applicator for oil palm

In the Malaysian oil palm plantation, fertilizer application was observed to be done manually or mechanically at uniform rate without due consideration to nutrient variability. The available constant rate mechanical fertilizer spreaders on oil palm plantation were found to be susceptible to excessive fertilizer application. On the other hand, Variable Rate Technology (VRT) could be used to forestall the hazards of excessive fertilizer application. However, full knowledge of the operational variables of the metering system of a VRT applicator has become inevitable for proper utilization of this technology. A rotary valve metering system test rig was designed and constructed for the purpose of studying the characteristics of the system. A linear regression equation was developed to relate the discharge rate of the metering system to the screw conveyor speed, rotary valve speed, fertilizer bulk density and repose angle. The coefficient of determination (R2) of the regression equation was 98.65%. The screw conveyor speed, the rotary valve speed and type of fertilizer were found to have statistically significant effect on the discharge rate of the system. It was observed that the discharge rate of the system decreased with increase in rotary valve speed. The outcome of this study will enhance the use of rotary valve in the VRT fertilizer applicator for oil palm

A novel variable rate pneumatic fertilizer applicator

The canopy prevents the use of global positioning system based fertilizer applicators in oil palm plantations. Hence, a radio frequency identification triggered variable rate pneumatic fertilizer system was developed for this application. A real-time embedded system was used as the core controller, LabVIEW software was used to program and coordinate the operations of the embedded system and the host computer. A speed measuring unit was used to provide feedback to the system. A field test was conducted to examine the response time. The sensors were calibrated in the laboratory and the measurement linearity had regression coefficients close to 1. Two to three seconds were required for the device to respond to changes in application rate. It is expected that this approach will become an alternative in plantations where the canopy hinders proper application of global positioning systems

Development of variable rate technology granular fertilizer applicator for oil palm plantations

Currently, in the Malaysian oil palm plantation, fertilizer is applied manually or mechanically at a uniform rate without due consideration to nutrient variability. Excessive application of this fertilizer leads to contamination of ground water by increasing its mineral contents to value that is above the world health organization (WHO) limit for safe drinking water. On the other hand, a variable rate technology (VRT) fertilizer applicator promotes Green Engineering practice by encouraging reduction in excessive fertilizer application, land degradation, pollution through leaching and volatilization among others. It could also increase crop yield and profit. Unfortunately, GPS-based VRT fertilizer application could not be successfully implemented in the oil palm plantation due to tree canopy cover that hinders GPS signal reception. A novel radio frequency identification (RFID) based VRT fertilizer applicator for band application of granular fertilizer on oil palm plantation was designed, developed and evaluated. The VRT fertilizer applicator has a 1.20 ton capacity hopper, two 1.88 kg/s capacity rotary valves, two 3.33 kW @ 2850 rpm centrifugal blowers and a 5.46 kg/s @ 30 rpm screw conveyor. The VRT fertilizer applicator was mounted on a 51 kW @ 2600rpm four wheel drive (4WD), four wheel steer (4WS) universal prime mover specially designed for oil palm plantation terrain. In addition, a graphical user interface written in Visual C++ 6.0 was developed to provide a digital chart for the selection of a configuration of the VRT fertilizer applicator during field operation. Extensive laboratory calibrations were conducted on the individual sensors and machine components that make up the VRT system of the VRT fertilizer applicator. The calibrated sensors were used in the calibration of the screw conveyor, rotary valves and centrifugal blowers of the machine system. LabVIEW 2011 program was used in collecting data and saving it in real time in the computer hard disc. Factorial analysis was used to study the effects of the screw conveyor speed, rotary valve speed and the centrifugal blower speed and their interactions on the discharge rate of fertilizer. Mathematical expressions relating the fertilizer discharge rate to the screw conveyor speed, rotary valves speed, centrifugal blower speed and fertilizer bulk density and repose angle was developed using multiple linear regression analysis. The results of the test were used in programming the graphical user interface in Visual C++ 6.0. Furthermore, field tests were conducted in order to determine the response time of the VRT system, the field performance and the fertilizer distribution uniformity of the VRT fertilizer applicator. An application table which contained the geo-position of each tree; the corresponding RFID code and the amount of fertilizer to be applied on each tree was developed and stored in the database of the computer system on the VRT fertilizer applicator. The RFID reader on the VRT fertilizer applicator detected the RFID code of each tree, sent the code to the LabVIEW 2011 program which related the information to the database and triggered the control system to discharge the right amount of fertilizer to the required palm tree. An evaluation test was conducted to validate the previously developed mathematical expression for fertilizer discharge rate. The application assembly of the VRT applicator has 99.28 % and 99.09 % accuracy on the right side and left side respectively of discharging the set application rate. It took 2 to 3 seconds for the VRT applicator to respond to changes in application rate depending on the magnitude of the change. The distribution uniformity test resulted in coefficient of variation (CV) range of between 6.51 % and 10.94 % which were within the acceptable percentage range specified by ASABE standards. Furthermore, the VRT fertilizer applicator has a field capacity of 7.22 ha/h and 7.71 ha/h with field efficiencies of 0.54 and 0.52 at the travelling speed of 4.43 km/h and 4.92 km/h,respectively. At field speed of 4.92 km/h the field capacity and field efficiency of the VRT fertilizer applicator were 1.67 times and 1.49 times respectively higher than those of the (uniform rate) UR fertilizer applicator at 6 km/h. It is expected that the use of RFID technology will serve as alternative for tree crops where tree canopy has hindered proper application of GPSbased precision agriculture practices

Variable rate technology fertilizer applicator for oil palm plantation

Currently, in the Malaysian oil palm plantation, fertilizer is applied manually or mechanically at uniform rate without due consideration to nutrient variability. Excessive application of this fertilizer contaminates ground water and raises its mineral contents above WHO limit for safe drinking water. However, Variable Rate Technology (VRT) fertilizer applicator promotes reduction in excessive fertilizer application, land degradation and pollution through leaching and volitization. A VRT fertilizer applicator for band application of granular fertilizer on tree crop was designed, developed and tested. Using RFID reader and LabVIEW computer program, the VRT fertilizer applicator detects the RFID code of the tag on each tree, relates the information to the database and triggers the control system to discharge the right amount of fertilizer to the required tree. The distribution uniformity test resulted in Coefficient of Variation (CV) range between 6.51 and 10.94 %. The VRT applicator has a field capacity of 7.22 ha/h and 7.71 ha/h with field efficiencies of 0.54 and 0.52 at the travelling speed of 4.43 km/h and 4.92 km/h, respectively. It is expected that the use of RFID technology will serve as alternative for tree crops where tree canopy has hindered proper application of GPS-based precision agriculture practices