Production costs of rice in Japan are very expensive comparing with those in the U. S. and Australia.
In this study, we investigated growth of rice plant, and checked the labor hours involved and the production costs by non-tillage transplanting system.
The main results obtained were as follows:
1) A 27% of labor time and a 1.5% of production costs reduced by using the non-tillage system. But the cost of transplanting machine itself slightly increased.
2) The growth of rice plant in non-tillage system was restrained a little.
3) The field with the non-tillage system had much weeds after transplanting. However, they were destroyed throughly by the application of the herbicide at that time.
4) The grain yield with a non-tillage system was less a little than those with the conventional tillage system.

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In order to grasp the effect of the increase of field lot in size by different farm machinery and farm work machinery, the relation between field lot scale and the effective field effeciency is analyzed by the survey of field working. And from the analysis the effective field capacity of every field lot scale were roughly estimated by giving the operating speed and the farm work machinery width.
The results are as follows:
1) The effect of the increase of field log scale was recognized from the relation between field lot scale and the effective field efficiency. The relation between field lot scale and the correction value, the effective field efficiency corrected to the coefficient of field form corresponding to 1 was corelated strongly.
2) The effective field capacity of every field lot scale was roughly estimated by giving the operating speed and the farm work machinery width. From the foregoing result, the calculation of area of burden for the increase of production scale was possible. In order not to make an excessive calculation of the area of burden, it is preferable that the coefficient of field form remains 1.
The effective field capacity obtained from effective field efficiency conformed to standard effective field capacity.

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In order to find the best separating condition of brown rice in a lean year, an experiment was carried out with the trommel type separator. And we examined how to determine the best slit width of the cylinder using the hand sieve. The main results were as follows:
(1) In the separation of a poor crop they should make the slit width of the cylinder narrower. And they can relax separating degrees of grain using the higher feed rate and the shorter effective screen length.
(2) In order to determine the best slit width of the cylinder of the trommel type separator, they should separate brown rice using the separating cylinders or the hand sieves with various slit widths. And they have to measure mature grain percentage of oversize product, percentage of oversize product to feed material and bulk density of undersize product, and thereby calculate the cost per unit mass of brown rice.
(3) The narrower they make the slit width of the cylinder, the higher the cost per unit mass of brown rice is, if quality grade of overproduct is same.

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Tuberous roots of yacon (Polymnia sonchifolia) contain a large amount of oligofructans. They have a growing interested as a physiologically functional food and a raw material of oligofructans. Then it is necessary to establish yacon cultivation technique.
We tested on the influence of the number of times of weeding on the growth and yield of yacon on a Light-colored Andosol field.
Three experimental plots were made: four times of weeding plot (4 times plot), two times of weeding plot (2 times plot) and non-weeding plot. There replications were made on each plot.
The results were as follows:
1) The main stem length at harvest time was 112.2cm/plant in 4 times plot, 104.6cm/plant in 2 times plot and 91.1cm/plant in non-weeding plot.
2) The top dry weight was produced 89.7g/plant in 4 times plot, 80.4g/plant in 2 times plot and 26.4g/plant in non-weeding plot.
3) The largest leaf on the main stem on September 1 and after that was always the largest in 4 times plot, and the smallest in non-weeding plot.
4) In each plot, the relative illuminance at the base of the plants were the lowest on August 4, but at the top of the plants in non-weeding plot, it was the lowest on September 2.
5) The yield of yacon tuberous roots in the weight was produced 1772.2g/plant in 4 times plot, 1522.9g/plant in 2 times plot and 175g/plant in non-weeding plot.
6) The correlation of the top dry weight with the yield of the tuberous roots in the weight or numbers were very high and the correlation coefficient were over 0.99.
7) These results suggested that the weeding in yacon cultivation would be valuable work espcially early growing stage, and it must do three or four times by the beginning in September.

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The purpose of this study is to establish the mechanized working system of simultaneously planted Barley and Taro cultivation in Autumn on a practical scale, and to evaluate an effect on saving of the fuel consumption.
The results obtained are as follows;
1. The cultivation system of combined Barley and Taro by simultaneous planting were established without having a bad influence on the growth of both crops.
2. In the simultaneously planted Barley and Taro cultivation system, the machine working hours in test fields were ranged from 5.26 to 5.40hr/10a and the working hours were ranged from 24.20 to 27.14man·hr/10a. Fuel consumption were ranged from 11.53 to 11.83l/10a.
3. In the control test plot (Taro cultivation after barley harvesting), the machine working hours was 7.31hr/10a, the working hours was 23.18man·hr/10a and fuel consumption was 16.46l/10a.
4. Fuel consumption of simultanseously planted Barley-Taro cultivation was lesser than that of the control test plot (Barley-Taro cultivation).
5. It was found that the production of carbon dioxide of new cultivation system (simultaneously planted Barley and Taro cultivation) was 30% less than that of control test plot.
6. It was shown that the techniques, developed indivividual working researches, could be applicable to simultaneously planted Barley-Taro cultivation on practical scale.

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