The survey of customary farm practices for improving the cropping system in Guyan Prefecture of Ningxia Autonomous Region, which is located at the western part of the Loess Plateau in China, was carried out. This work has been conducted as a part of the research project on the “Fundamental study of the establishment of grasses and crops on the Loess Plateau in China” sponsored by the Ministry of Education, Science and Culture, Japan. In this paper, we described the farm practices of flax, millet and pea, of which there were consisted crop rotation. We have already reported in our previous paper about wheat, which is one of the rotation crops.
1) Flax is an important oil crop in this area. however, farmers have made little effort to improve its cultvation because increasing the yields of food crops like wheat has been considered more important. In the cultivation of flax, farmers plowed their fields three times in autumn, this was the same as in the case of wheat cultivation, but generally they did not apply any organic fertilizer at that time. In spring, after finishing stirring tillage for weeding, farmers sowed the seeds with the same seeder as that for wheat sowing. During the growing season, farmers weeded only once with a hoe. For the harvest system, farmers pulled out the plants, bound them, and then shocked them in the fields. After drying plants, farmers piled them up and then threshed them whth a stone-made roller. The labor requirements for the flax cultivation was 43.5-50.5hr/10a, which was the lowest value among all the rotation crops. The reason for the low labor hours was that farmers did not have to carry and spread any organic fertilizer for this crop.
2) Proso millet and foxtail millet have been cultvated in this area for many years. In recent years, however, the planted areas of those crops have been gradually decreasing because of an increase in wheat production. The method of land preparation in autumn for proso millet was the same for flax. In spring, farmers sowed the seeds with a seeder 10 to 15 days after spreaping organic fertilizer and plowing. In the process of crop rearing, farmers gave trampling with a roller to the young plants and weeded by hand. The harvest system for proso millet was almost similar to that of wheat. However, the plants were not piled up because the proso millet would not dry easily. The labor requirements for proso millet cultvation was 51.5-58.5hr/10a, whch was smaller than that for wheat cultivation.
3) Pea is mainly cultivated for keeping soil fertility high. Farmers cropped with pea in the fields after having harvested millet in late-September. Because the suitable period for autumn land preparation for pea was very short, farmers could plow the fields only once. In following spring, farmers plowed the fields, sowed the seeds by hand, spread organic fertilizer, and covered the seeds with turned soil of the next furrow, as a series of farm practice. During the growing geason, farmers weeded only once. The harvest system of pea was very similar to that of wheat. The labor requirements for pea cultivation was 49.0-59.8hr/10a, which was nearly equal to that for proso millet.

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All of farm fatal-injured accidents in 4 years during 1983 to 1990 occurred in Hokkaido were surveyed by interview. The results of survey is divided two report, named part 2 and 3. The details of tractor over turn accidents on the field, catch-in to machine, run over by vehicle, pinch in to machine, fall down from high position and traffic troubles were described in this report.
1) The fatal-injured accidents with tractor in farm field were classified under the tumble down from field, over turn in the field and slip down at the field entrance slop. And the main reasons of accidents were described.
2) The correlational chart of reasons about tractor accidents in the field showed that the most of critical condition of farm area cannot improve, and if the person who has weak point to operate farm machines alive, no man can change to him. So the operator must control the machine with fully cautions to the critical condition every time.
3) The main reasons of catch in accidents to machine, run over accidents by vehicle and pinch in accidents to machine were clarified.
4) The real situations that the fatal-injured accidents brings critical conditions to his family and his farm were described.

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In a potato harvester, the tuber damage is mainly caused by the primary web. In this reseach, the relations of web speed, ratio of web speed to forward speed and tuber size to tuber damage were investigated. The speed monitor was developed to measure and display wed speed, forward speed and speed ratio. The tuber damages were evaluated by DAMAGE POINT and DAMAGE INDEX that had been defined by the extent of wounds and bruises.
The results obtained were as follows:
(1) The tuber damage became severer as web speed or its speed ratio was greater. This fact shows that soil on web acts as a cushioning stuff. Covering structure, by rubbers or soft materials released the soil from cushioning duty. However, as bruising occured by small shock which did not make wound, the web speed should be less than 1m/s with the forward speed of less than 0.5m/s.
(2) The grade and number of damages on one tuber tended to become greater, as tuber size became greater.
(3) The wounds were distributed evenly on all part of tuber. On the contrary, 70-80% of the bruises were located on the top and bottom part of tuber. Therefor, potato harvester should be designed on the basis of no occurence of bruising on top/bottom part of tuber.

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In this study, the farming systems of‘N Farming Association’in Noda, Chiba prefecture were simulated by using actual data, and the possibility of reducing production cost and expanding the farm scale were estimahed.
The results were as follows:
1) It is possible to expand the managing area from 7.0ha to 15.4ha in soybean plot, from 24.3ha to 50.0ha in wheat plot and from 13.0ha to 28.5ha in barley plot under the same scale of machinery system. By means of this expansion, it is possible to reduce the production cost from 38, 835/10a to 36, 137/10a in soybean plot, from 32, 163/10a to 27, 336/10a in wheat plot and from 29, 325/10a to 24, 587/10a in barely plot.
2) The labor cost considerably influenced the production cost. The influence was especially larger in the soybean in which the labor cost was larger.
3) If a grain combine and a grain dryer are introduced to the farming association, it is possible to reduce the labor time and labour cost without increasing the production cost.
4) The earnings of the farming association increased by the reduction of labor cost accompanied with the expansion of management area.

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Utilizing the experimental results reported before, the bulblet harvester of the Chinese yam has been fabricated and demonstrated to ascertain its field performance. Its design concept includes simplicity for structure, size reduction for power transmission unit and lower cost. This laboratory experiments unveiled several findings as mentioned below.
1) The efficiency of harvest was greatly affected by the moisture content of dune sand exhibiting sharp decrease from 2% d.b. or so and unable to harvest at more than 2.8% d.b.. What is more, with the increase of peripheral speed under the limited range of 0.11 to 0.22m/s, the harvesting efficiency decreases and accelerates this tendency further when setting the working depth greater, i. e. from 2 to 5cm.
2) The percentage of dune sand passed through bucket is affected heavily by the moisture content of dune sand as well as the harvesting efficiency.
3) The moisture content of dune sand surface strata is desirable to keep less than 2% d.b. in terms of the stable operation unless forced oscillation of bucket type harvester is provided.
As a part of the subsequent studies following bucket type harvesting mechanism, the prototype being applicable in the form of attachment unit of a power tiller was designed and fabricated. Designing philosophy includes that the machine should be provided with simpler mechanism, less portion to be driven and reasonable cost.
The practicability of this machine was testified at the growing field of Chinese yam through performance test. Harvesting efficiency is heavily influenced by the undulating field surface, the amount of dead leaves and the moisture content of dune sand. Weather permitting, almost 90% of harvesting efficiency may be obtained under flat field and drier dune sand conditions as well.

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In this paper, in order to construct cropping pattern, livestock and agricultural machinery model in the mechanized farming model system and to obtain the data for optimum design of the model system, survey of farmings for four regions of Hamasaka, Koyama, Houjou and Kyuhin sand dunes in the Tottori province was conducted. The survey results were summarized as follows.
1) From statistic materials and the survey of agriculture on current farming system, the data such as agriculture labor, area of cultivated land, crops planted and livestock, cropping pattern, farm household economy, working days of agriculture, ownership of agricultural machinery for optimization and construction of the mechanized farming model systems about three different farm households in sand dune field could be obtained.
2) Population that mainly engaged in farming is 2.5 persons per one household in the survey region, which is more than 1.5 persons of the national average. The total number of population that mainly engaged in farming is 319 persons. The number of persons above 56 and under 20 years old among the 319 persons surveyed are 197 and 6, respectively. Therefore, the survey region also shows the problem of lack of inheritors as well as advanced age of farmers.
3) Agricultural incomes per one household of full-time farming house, house mainly engaged infarming and house mainly engaged in other activities are ¥4, 452, 550, ¥3, 237, 554 and ¥ 2, 091, 657, respectively. The income of full-time farming house is consequently more than the two other farming houses. However, the total income of farm household per household of full-time farming house has the least of the three kinds of farming household, and the income is equal to half of that of the household mainly engaged in farming.
4) The power of agricultural machinery per one household of full-time farming household is 53.8 PS, and a popularization of wheel tractor and power sprayer is higher than that of national average. Especially, the spread of wheel tractor is to be attributed to the sand dune field which is inclined, and to that simultaneously with marketing of Baker's garlic harvester there is the introduction of 4WD-tractor.
5) As the cultivation of special product such as Baker's garlic, Chinese yam, and Welsh onion is mainly dependent upon man power in sand dune field, there is the necessity for the development of exclusive farm machineries such as planter, harvester and processing machinery after harvesting.

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