Wet anaerobic digestion is functioned with substrate contains high moisture content. In the case of substrates from stanchion barn, the mixing of bedding with manure increases total solids content (TS). Thus, large amount of water is required to dilute the mixture before its use in wet anaerobic digestion. In this study, the use of digested slurry recirculation in a wet anaerobic digestion without water dilution was examined. Continuous wet anaerobic digestion of dairy manure at a temperature of 55°Cwas carried out. The TS of dairy manure was adjusted using filtrated digested slurry. The obtained results show that the use of digested slurry to replace water in wet anaerobic digestion of dairy manure was effective.

In order to revitalize agricultural production activities in an inter-mountainous area, we built a cultivation facility utilizing regional resources with a view to developing ‘sixth industrialization’, and evaluated the effectiveness of the system.

For this research, idle facilities were used as horticultural facilities to cultivate sweet potatoes. Heat pumps were introduced to the cultivation environment with hot spring drain water and mountain stream water used as a heat source. In addition, a multi-stage cultivation system incorporating a subsurface heating device, also utilizing hot spring drain water heat, was constructed to promote tuberous root enlargement and increase yield. In conclusion, we examined how to efficiently utilize hot spring drain water as a heat source and confirmed the effectiveness of a system based on the use of regional resources on increasing yield.

Some rotten onion bulbs cannot be detected by visual inspection or palpation. Contamination of rotten bulbs into the shipping products diminishes the reliability of production area. In this study, the feasibility of using visible and near-infrared spectroscopy for the nondestructive detection of rotten bulbs on a belt conveyance system in a typical onion packing house was investigated. A partial least squares regression model for bulb rot was developed from the acquired spectra. Datasets including different sample sizes and temperatures with a ratio of sound to rotten bulbs of 3 : 1 supported the development of a robust discriminant model. The model achieved correct onion classification of 95.0% when the bulb rot presence-absence threshold was set to level 1.

In this study, grains with straws dusts were put into the shaking selection part of a combine harvester, and the cumulative flowing down rates were obtained by examination. The influence of changing control factors on the shaking selection performance was investigated. The 3D-discrete element method (DEM) simulations were performed in relative examination conditions, and they were then compared. The results of examinations show that the cumulative flowing down rates were higher in front of the chaff sieves, and the sieve opening and revolution of the shaking motion were more highly influenced. In the 3D-DEM simulations, similar results were obtained quantitatively and qualitatively. It was shown that the states of shaking selection were understood by using the 3D-DEM simulations with the non-spherical model.

The aim of this paper is to evaluate the weeding efficacy and power requirement of a three-row walking-type weeder under varying slippage. A driven cage wheel was installed by replacing an existing resistance bar to control the slippage of the rotor between 93% and 79% at a constant rotational speed around 200rpm. One test each was carried out in two paddy fields 10 or 21 days after transplanting. With a decrease in slippage, power requirement decreased from 0.62kW to 0.40kW. A reduction in weeding efficacy and grain yield was observed only in fields weeded 21 days after transplanting.

A land application system of treated piggery wastewater using flat spray hoses was developed to decrease costs and labor. The developed system consists of flat spray hoses with a length of 50m and diameter of 50mm, a tank, two engine pumps, and a 4-ton truck. Two types of hoses with hole of 4mm and 9mm diameters were tested. The flow rate of land application system was 4.0h/ha, which was similar to a septic tank truck. However, the new system has the advantage that one worker without manual operation in the field can operate it, while the septic tank truck needs two workers. Flow rates at the end of the furrow near the pump were 50% higher than at the end of the hose. An uneven distribution is unlikely to influence the growth of sugarcane. The flat spray hose was reeled up using a developed flat hose winder within 50-120s. A proper application of wastewater is achieved using electric conductivity as a simple index of total nitrogen (TN) (ppm). A multi-task 4-ton truck outfitted with inexpensive equipment allows an easy estimation of fertilizer matter from treated wastewater, which promotes cooperation system between crop farms and livestock farms.

We built a prototype pest preventive crawler for steeply sloped terrace garden, where Satsuma mandarin trees are planted. By using the sprayer, studied the impact on workers’ labor efficiency and labor intensity. The result showed the reduction in working hours by 21-71% from July to September, compared to the traditional manual spraying method. For workers’ labor intensity, the heart rate was reduced to 86% and was rated “strong” for work intensity, in comparison to the worker’s heart rate of 110% with “heavy” labor intensity for the traditional manual spraying method.

The study showed the use of small crawler sprayer for pest preventive work can make significant improvements in labor efficiency and labor intensity.

A compact combined machine for ratooning sugarcane was developed. The developed machine, attached to a 15kW class tractor, can shave stubble, apply fertilizer and spray herbicide at the same time. This has allowed sugarcane farmers to undertake ratooning earlier and at a more appropriate time. The stubble shaving device and fertilization apparatus are attached to the rear of the tractor and the tank for herbicide attached to the front of the tractor. The developed machine had been made smaller and lighter, thereby maintaining the stability of the tractor along the front-back axis. The fertilizer discharge rate is continuously adjustable due to PWM (Pulse Width Modulation). In addition, applying fertilizer under the ground prevents run-off. An inexpensive bilge pump is used in the herbicide sprayer allowing it to work effectively as a power sprayer.

The working efficiency of the developed machine is 1.48h/10a. The necessary labor was 55% compared to that using conventional machine. Extraneous matter on the stool is removed during ratooning practice, which increases the effectiveness of the herbicide. Hilling up the soil after stubble shaving allows the stools to be covered more effectively than without stubble shaving.

In head-feeding combines, we measured the force of vertical lifting by women in unlocking the threshing unit cover with only one hand. This is designed to protect farmers from sustaining severe injury if their hands are caught in the threshing unit during hand-fed threshing. We compared the force of vertical lifting by women with the control force of the unlocking lever for the threshing units of head-feeding combines already in the market. Based on the results of the comparison, we had to drastically reduce the control force of the unlocking lever of the threshing unit. In addition, the cost-benefit performance was low when we confirmed the effect of the brake on the threshing unit. Based on these results, we have produced final prototype threshing machines. These machines do not have a threshing unit brake; however, they can automatically unlock the threshing unit or pinching rod. This enables farmers to pull their hands out easily, if caught in the threshing unit. We believe that the automatic unlocking feature render these machines effective against severe injury.