Cutting tests of kenaf stems

We developed a new harvesting machine with a rotary impact cutting system for cutting kenaf stems. The design of the machine was based on effective cutting knife angles and cutting speed. In this research, specific cutting force (SCF) and specific cutting energy (SCE) were measured by considering the following factors: knife edge angle (ANE), knife shear angle (SA), knife approach angle (ANA), knife rake angle (ANR), and the cross-sectional area of plant stems. In addition, an experimental impact cutting machine was manufactured and tested in the field. The rotational speed obtained with this machine had the lowest cutting torque. Kenaf stems of the V36 variety were used as the experimental material. An analysis of variance of the SCF and SCE values of the kenaf stems showed that the effects of all the above-mentioned angles (considering a broad range) on SCF and SCE were significant. Moreover, the preferred values of ANE, SA, ANA, and ANR were 25°, 40°, 40°, and 40°, respectively, according to Duncan's multiple range test. Based on the impact cutting test, the rotational cutting speed had a significant effect on the specific cutting torque. Increasing the rotational speed from 308 to 788 rpm decreased the cutting torque by 26.3%. This experimental impact cutting machine had an estimated capacity of 0.07 ha h -1. The average moisture content of cut samples from the lower area of the stems was 70.78% (dry basis)

Design and development of kenaf harvesting machine

Kenaf whole-stem having long bast fibres is more suitable for industries to produce textile and bio-composite panels. Current modified harvesters (sugarcane harvesters, forage harvesters, choppers, reaper binders, mower conditioners, pedestrian harvesters) normally chop the kenaf stems to small segments and/or crash the fibres or unable to cut the thick stems. So, a kenaf harvesting machine is required to cut the thick intact whole-stems having high capacity and satisfactory cutting quality with no damage on the bast fibres. Currently manual whole-stem harvesting which is a labour-intensive, time-consuming, and less profitable process, is being practiced in Malaysia. In this study, a new pull-type four-row whole-stem kenaf harvesting machine with a rotary impact cutting system was designed, developed and evaluated. The machine cutting system design was based on effective cutting knife edge angle (ANE) and cutting rotational speed. In this research, specific cutting force (SCF) and specif cutting energy (SCE) were measured by considering knife edge angle (ANE), shear angle (SA), knife approach angle (ANA), knife rake angle (ANR), and the cross‐sectional area of plant stems. In addition, an experimental impact cutting machine was manufactured and tested in the field. The rotational speed obtained with this machine had the lowest cutting torque. Kenaf stems of the V36 variety were used as the experimental material. An analysis of variance of the SCF and SCE values of the kenaf stems showed that the effects of all the above‐mentioned angles (considering a broad range) on SCF and SCE were significant. Moreover, the preferred values of ANE, SA, ANA, and ANR were 25°, 40°, 40°, and 40°,respectively, according to Duncan's multiple range test (DMRT). Based on the impact cutting test, the rotational cutting speed had a significant effect on the specific cutting torque. Increasing the rotational speed from 308 to 788 rpm decreased the cutting torque by 26.3%. The preferred rotational speed with a minimum cutting torque used in designing the cutting system was 712 rpm. The experimental impact cutting machine had an estimated effective field capacity of 0.56 ha/8 h day. The average moisture content of cut samples from the lower area of the stems was 70.78% (dry basis). The harvesting machine operated best at the field speeds of 3-6 km/h resulted from the cutting quality tests and recommended by DMRT. In preliminary field tests, the average values of the effective filed capacity (EFC), field efficiency (FE), and material capacity (MC) of the machine were found to be 1.68 ha/8 h day, 70.6%, and 114.8 t/8 h day for single-row harvesting (with 75 cm row spacing and about 20 stems/m of row) and 3.37 ha/8 h day, 74%, and 241.9 t/8 h day for 2-row harvesting (with 75 cm row spacing and about 20 stems/m of row), respectively at recommended speeds of 3-6 km/h. The average expected values of EFC, FE, and MC of the machine for 4-row harvesting (with 30 cm row spacing and 10 stems/m of row) were foreseen to be 2.92 ha/8 h day, 77%, and 249 t/8 h day, respectively at recommended speeds of 3-6 km/h in standard field conditions (planted by an accurate planter, proper watering and fertilization, and with no weed or grass). Maximum height, average diameter, average cutting height, and average moisture content of the kenaf stems at the harvesting time were measured as 3.10 m, 21.8 mm,20 cm, and 71.8% (dry basis), respectively. The highest recommended machine effective field capacity evaluated in this study was capable of replacing up to 370 persons per day when harvesting by traditional hand methods. Based on cost analysis results, the total manual harvesting operation cost was 32 times more than the total mechanical harvesting operation cost for harvesting 1,500 hectares of Malaysia kenaf fields for fibre production for one time plantation a year in 2010

Selection of fertilization method and fertilizer application rate on corn yield

A field experiment was carried out on the silty clay soil of Lack-Lack agricultural research field during two years to select the most suitable fertilization method (fertilizer broadcasting, fertilizer pouring in the furrow, fertilizer banding placement in one side and both sides of seedling) and application rate (30, 60 and 90 kg of net nitrogen from source of urea fertilizer/ha) on corn yield and yield components in Hamedan province in Iran. Corn yield components evaluated were plant height, corn height, percentage of corncob, thousand-kernel mass and net yield. A factorial experiment with 12 treatments (four methods x three levels) was replicated three times in 36 test plots. By analysis of variance and comparison of treatment means using DMRT (Duncan's new Multiple Range Test), application methods had no significant effect on plant height, corn height and percentage of corncob, but net yield and thousand-kernel mass were highly influenced. In addition, effect of fertilizer application rate on plant height, corn height, and percentage of corncob was not significant but was highly significant on net yield and thousand-kernel mass. Interactional effects of method x level on plant height, corn height, percentage of corncob and thousand-kernel mass were not significant but their effects on net yield were very significant. In this study, fertilizer banding on one side of seedling with 60 kg of nitrogen/ha applied 10 cm from the seedling at 5 cm soil depth was selected as the most suitable treatment