This report describes the results of investigation and analysis by “Subjective Symptoms of Fatigue” to forestry tractor operators, the vibration on the seat of forestry tractor, the position of controls, the frequencies of control operations and operator's head movement. The level of forestry tractor operators' work intensity were allowable, their average complaint rates at “after work” being 11.9%, from the analysis of 167 responses of “Subjective Symptoms of Fatigue” to 31 tractor operators. They had much complaints of pain in some parts of the body. Judging from high complaint rates at “before work”, it can be said that operator always feels fatigue in the shoulder and low back.
They operate tractors about 5.7 hours in a day, By means of 1/3 octave band frequency analysis of the vibration on the seat of 8 tractors in 3 directions, the vibration on tractors' seat were alowable, these vibration levels being below the “Fatigue-Decreased Proficiency Boundary” according to the ISO-proposal.
Comparing the position of the levers and pedals of 12 kinds of tractors with JIS A 8450-proposal, it found that 9% of levers as the distance from hand to levers and 24% of controls as the direction from Seat Reference Point to control are arranged at unsuitable positions. The percentage of operating time by hand or foot in yarding cycle is 40%, and the state of operating the steering lever, the clutch pedal and the brake pedal appear mostly. The most operating time in links between hand or foot and each controls in yarding cycle appears in the case of operating brake pedal and winch lever, being operator's twisted body posture. Furthermore, operator's head movement was analyzed from the center of phots obtained by eye camera in 3 tractors. In “Driving without load”, the operator “A” of the wheel type tractor often faces the right-rear to direct attention to rear wheel. In “Cable skiddng”, 2 operators “B, C” of crawler type tractor face just to the rear, looking at the winch, but the “A” operator faces to the right-rear, as it stops in the bending position of the back part. As the results of operator's head movement and operating time of tractor in a day, there were much frequencies of operator's twisted body posture in operating tractor, “A” operator being 30.7%, “B” 14.6%, “C” 14.7%.
Considering the above results, it can be said that one of the factors causing operator fatigue would be the actuation of the wrong arrangement of controls in operator's twisted body posture.

View full abstract

Contamination of barley grain by mixing of volunteer wheat grain is now causing a serious problem in barley production under the alternating cropping system between barley and wheat. We chosed 8 upland fields of 7 farmers, whose growing area was rather large, and 7 upland fields converted from paddy fields by 4 farmers. We investigated the growth of volunteer wheat plants in those fields and discussed how harmhul volunteer wheat was to the production of barley in Ibaraki Prefecture.
The fields were investigated regarding cropped barley and wheat alternately so as to prevent a yield decrease caused by continuous cropping or the yellow mosaic disease.
In the fields where barley was planted after harvesting wheat, the contamination of barley grain by mixing of volunteer wheat grain occurred in the upland fields, regardless of summer cropping.
The volunteer wheat plants grew on both the inter-row spaces and ridges in the barley fields, so it was difficult to control volunteer wheat plants using cultivators.
The benefit of barley production decreased by 14-57% due to the contamination of barley grain by mixing of volunteer wheat grain. The alternate cropping system between barley and wheat has been of interest to the farmers in the areas infected with yellow mosaic. However, the best way to control volunteer wheat plants is still being sought.

View full abstract

The objectives of this experiment are to clarify the relation between the growth of volunteer wheat plants and the cultivation methods under an alternating cropping system between barley and wheat.
In the fields where left in fallow or planted with buckwheat during the summer following the wheat harvest using a head-feeding combine, a great number of volunteer wheat plants had grown in the barley fields. This was observed, also, in the fields where upland rice or peanut were planted in the inter-row spaces between the wheat rows. The fields which were left in fallow or planted with buckwheat during the summer following the wheat harvest using a conventional combine harvester showed few volunteer wheat. Almost no volunteer wheat plants grew in fields which were plow-tilled followed rotary-tilling and where left in fallow after flooding the fields during the summer.
As a result of pot test, flooding the wheat grain for 5-7 days was effective in controlling volunteer wheat plants.

View full abstract

This study was undertaken to clarify the effects of rice transplanting date on the heading time and the harvest time, by using 3- or 4-day seedling of cv. Sasanishiki for 3 years (1989-1991).
Transplanting dates, from late April to middle May, caused some variation of heading time and could spread the period of desirable harvest time. And the highest yield produced from the 3- or 4-day seedling at each transplanting date was about equal to or higher than the average yield in the same area. We, therefore, have judged that transplanting the 3- or 4-day seedling in this period will be possible from practical point of view.
Based on these results, we suggest a pattern of transplanting working system using the 4-day rice-seedling. Treating the work from seeding to transplanting as 1 unit, a farmer will be able to manage 12 units in 30 days from April 20th. That means he can cultivate paddy rice of more than 12ha under his present farming facilities.

View full abstract

We established a new system of fertilizing-seeding and subsequent management of carrot cultivation, which is labor-saving, low cost and adaptable to large scale field farming management in Hokkaido.
The results obtained are as follows:
1. The system developed can be used for three processes; 1) fertilizing-seeding, 2) weeding, and 3) split dressing and molding on carrot cultivation. With this system, traditional 8 processes (total operation time: 181.1h/ha) was decreased to 3 processes (7.4h/ha). Fertilizing and seeding carrot was done by the newly developed trial machine.
2. The trial machine for fertilizing and seeding is adaptable to 4-row cultivation with the row width of 65cm and the tractor which power is 60 PS or more is required for pulling this machine. By using this machine, traditional 4-process management is decreased to one process and the seeding performance is 3-4ha per day. The belt-type device which intrarow spacing is 5cm (2 rows at 10cm in width) was the most adequate as a seed metering device. By using this device with control plate of fertilizing band, fertilizer can be applied zonally. The 95% of fertilizers could be applied to the soil within 20cm in width, 15-20cm in depth. Therefore, remarkable fertilizer saving can be expected, compared to the traditional system.
3. The same machines which are commonly used in main crop farm are available to spraying of agricultural chemicals and split dressing and molding.
4. The level of growth and yield of carrot in the new system is equal to or more than the level of traditional system.

View full abstract

An experimental shooter-type planter to be applied for the planting of taro-seeds was developed, with the examination of planting position of the device, performed. The results obtained are as follows.
1) The proper planting rate of the individual seed (Variety: Akamedaikichi) was 92-82% under the planting speed of 0.17-0.37m/s, respectively. The planting rate at the diagonal position was 4-14% under the planting speed of 0.17-0.37m/s, respectively.
2) Judging from the operation load for an assistant operator, the proper planting speed was under 0.37m/s.
3) The proper planting rate of the individual seed (Variety: Ishikawawasemaru) was 95-88% under the planting speed of 0.17-0.37m/s. The planting rate at the diagonal position was 2-5% under the planting speed of 0.17-0.37m/s, respectively.
4) The planting space and the planting depth were 300±58mm 120±25mm in case of the two varieties, respectively.
5) The planting rates of the two varieties were obtained as 91% (Akamedaikichi) and 93% (Ishikawawasemaru) under the proper planting speed of 0.27m/s. The working efficiency was 1.16h/10a, which was about 5 times higher as compared with the customary operation. The practical usage of this machine was well recognized.

View full abstract

Analitic investigation of 258 modern novels published from middle of Meiji era (about 1900) to Showa 20 (1945) revealed some characteristics of farm work and rural life, especially those of workload and main factors of them as follows:
1) The descriptions of actual farm work were found on about 30% of investigated novels. Most of work were carried on without any implements or machines, being exposed to natural climate.
2) Environment and intensity of work were very hard beyond the manual limit of effort. Those often caused various health harzard.
3) Additionally inappropriate work organization and human relations in rural societies also loaded both mentaly and physically.
4) A few examples of accidents and health effects were found. Analysis revealed too heavy workload and excessive fatigue also have close relations to these harzard.

View full abstract