This study was made to investigate the effects of pan-breaking on soil condition in the temperate regions, 3 plots were prepared for this study in Shinden-bara, Fukuoka prefecture. These plots were provided with different conditions each other. Namely, field A has been penetrated by single standard pan-breaker at the mean depth of 43cm, and the mean distance between each pan-breaking was 206cm. Field-A was classified into 2 plots. One of them is A-A where subsoil has been oosened, the another is A-A′ the intermediate strips between the traces of penetration, where subsoil has not been loosened. Field-B is control plot. In these plots, the physical properties of soil were investigated just before and after the pan-breaking, and about eight months later, too. Moreover, a winter, wheat variety, Norin-61, was grown in these 3 plots, applying ordinary cultivation practice in this district, and the effect of pan-breaking upon growth and yield of this crop was examined. The results were as follows; 1. It is clearly pointed out that the pan-breaking is very promising in getting good crops, showing increases of about 20% in plant height and 36% in yield when these are compared with cropping in B plot. 2. However, A-A plot shows better cropping than A-A′ plot. 3. Therefore, it is necessary to study the reasonable method of pan-breaking and improvement of pan-breaker which may be able to loose subsoil uniformly.
The tractive faces of the wheel type 15 PS Japanese tractor were tested under the eight soil conditions. It was found that the tractive force per loads on the rear wheels (i. e. coefficient of tractive force) was almost constant under the same soil condition and it was not influenced by additional weights or travel speed. And we found that the difference in tractive force between 7-24 tire and 8-24 tire was very small on each soil condition. The results of tests on the coefficient of tractive force were shown in Table 1. The tractive force were measured at 20% slippage of the wheels.
In several conditions, area and form, of a paddy field, we researched the efficiency of plowing by the wheel tractor, and the ratio of the plowed area to the total area of paddy field and found that the wheel tractor was used most effectively in a field of 20m (width) 100m (length) section. In this field, the plowing efficiency was about 6-7hr per 1ha, and the ratio of the plowed area to the total area was 93-98% This report shoull be submitted for the purpose of that the wheel tractor in most effectively used in a paddy field.
Drawbar tests for the farm wheeled tractors (Tab. 1) were carried out on the farm road and the cultivated field (Tab. 2) The results are as follows: 1) Coefficient of rolling resistance (C1) is 0.0388 on the farm road and 0.153 on the cultivated field. Coefficient of impact resistance (C2) is 0.00971 on the farm road and 0.0198 on the cultivated field (Tab. 3). 2) Coefficient of rolling resistance shows a tendency to decrease with increasing total weight of tractor (Fig. 1). 3) On the farm road, the tiresize has little effect on tractive coefficient of driving wheel (Fig. 4) but on the cultivated field tractive coefficient of driving wheel increases with in creasing the tiresize (Fig. 5). Tractive coefficient of driving wheel for 7-24 tire and 8-24 tire at 20% slip is 58% on the farm road and 39% on the cultivated field.
Some torque measurements were taken on a Rotary cultivator with L-shaped blades. The results of tests show as follows. 1) The torque (at the drive shaft) was approximately linear with the forward speed, and with the number of blades. 2) Torque increased with the rotational speed of the blades despite of the decrease in the pitch of cut. 3) It is generally desirable to operate this machine at the peripheral speed of the blade below 6m/s (200rpm) in view of power consumption. 4) We must decide the forward speed and the rotaional speed of the blades with regard to the purpose of its use.
We made some investigations on four forage harvesters, the two of which were imported from U. S. A. and the other two were made for trial. 1. Power consumption at the tractor PTO was approxi-mately linear with the forward speed of the machine, and the fiructuation in it was great in each machine. Taking it into consideration, it seems that Ja will require about 20 to 25 HP JB about 20 HP and A, B about 15 HP at the tractor PTO at the forward speed, 40 to 60cm/sec. 2. JB, a flywheel chopper type machine, consistently gave the shorter and more uniform length of cut than the other lacerator type machines. 3. There was no great difference in silage quality among these machines. 4. Field losses were less in B type which has 24 fixed knives mounted on the rotor., than A type which has 14 flails.
We manufactured and tested Bean Cutter (fig1) and the results of the field tests are as follows: (1) This bean cutter operates well on the speed from 2.5 to 3.0m/sec. If cutting speed is too fast (over 5.0m/sec), row operation of tractor may be difficult. In the field speed outlet cutting beans varies 1.0/1.3 hectares per hour. (2) Whether cutting beans is well down or not, depending upon the time for harvesting. If it is too late, bean cutter could not cut the beans, but pull up them. (3) Harvesting loss is due to shatteing. In the testing result, shatting induced by the cutting operation should not occur, when the moisture content of pads is over 20%. Therefore, harvesting by this cutter may be down at the suitable time, before the moisture content of pads becomes below 20%, as early morning.