Soil strength/penetration resistance of lowland puddled soil is an important parameter for designing farm machinery. This study was aimed to estimate the overall penetration resistance of lowland puddled soils through the assessment of bulk soil parameters. Penetration resistance and bulk soil parameters including moisture content, bulk density, particle density, porosity, texture and organic matter content were measured under real field condition and evaluated to identify the suitable determinants to explain the variation of soil penetration resistance and their relationships. Results revealed that measured penetration resistance by Eijkelkamp hand penetrometer and bulk soil parameters except particle density, notably varied with weed controlling methods, depth of the soil and the time. Penetration resistance showed a significant relationship with bulk density (BD), moisture content (MC) and porosity (

ABSTRACT. This study investigated the effect of reel index and type of combine harvester on header losses when harvesting the long grain paddy variety

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Weeds are the major reason for the significant yield reduction in rice cultivation worldwide. Power weeders have been introduced to rice cultivation as an alternative solution for the controversial herbicide applications. The aim of this study was to appraise the newly designed burial type lowland power cultivator through a comparative performance assessment including cost economics. Five weeding methods using Conoweeder (T 1), Modified "Asakura" wooden clog (T 2), Rotary power weeder (T 3), Newly designed lowland power cultivator (T 4) and manual weeding (T 5 as the control) were evaluated. The T 4 showed a significantly high field capacity of 0.04 ha/h, which is 8 times higher than T 5 , high field efficiency of 88.30% and weeding efficiency of 62.29% which was similar to the performance of T 5. Significantly high performance indexes were observed in T 2 and T 4 (461.65) followed by T 1 and T 3. Plant damage percentage, maximum tiller number and the yield did not show any significant variation (p>0.05) among weed control methods assessed. Further, the T 4 showed a significantly low cost of weeding of 6583 Rs/ha which was 76% of cost reduction of the T 5 , and moderately high break-even point of 0.88 ha/yr suggesting that it is appropriate for the medium and large scale farmers. Moreover, T 4 showed low fuel consumption (0.556 L/h) and power requirement (0.57 kW) representing 48% and 42% respective reductions over the T 3. Further, T 4 showed the significant lowest weed re-growth rate which is essential for sustainable weed control. Based on the above results, newly designed burial type power cultivator could be recommended for medium and large scale paddy farming, since it showed high performance compared to other methods assessed. Machine performance could be further improved by high speed, light weight design with efficient turning mechanism. Besides, it is suggested to conduct detailed ergonomic evaluation in future investigations.

The generation of excessive levels of spicy aroma and the airborne dust in spice grinding mills is one of the main ergonomic problems of the workers and sometimes create social problems due to environmental pollution. Although the fine dust as well as the aromatic chemicals has an economic value, collection of them is fairly a difficult task under small-scale processing plants. A technically and economically feasible low-cost dust filtration system was designed to filter and maintain the concentration of airborne dust level below the recommended level of 10 mg/m 3 for 8-hour exposure time, in a spice grinding plant. The dust filtration system was designed based on a similar principle as in the existing spry tower filter. However, the method does not require very high pressure for fluid atomization as in that system and the unit can be fabricated using locally available materials with a very high lifetime. Dust measurements were carried out using a special cloth bag-collecting device with a fixed airflow rate.Dust removal rates were determined with different concentrations of a foaming shampoo (Lifebuoy shampoo) and a non-foaming detergent ('Rinso' automatic washing machine powder). Results showed that the filtration unit is capable of filtering airborne dust with an efficiency of 91% with the foaming detergent while an efficiency of 78% with the non-foaming detergent. An initial dust load of 108-150mg/m 3 in the air was reduced to 9.6mg/m 3 with the foaming detergent and 32mg/m 3 with the non-foaming detergent or tap water without any detergent. Therefore, the dust filtration system is effective only with the foaming detergent.