Recent years most of the dairy farms have specialized in dairy production only and have been increasing in number of cows per farm to improve their productive efficiency for increasing their profit. However, this often causes the environmental problems such as pollution by livestock waste accumulation in the limited areas.
On the other hand, the material circulation sometimes can be seen in the mixed production area by exchanging livestock manure for wheat straw as bedding material or temporary land exchange between dairy farms and dry field crop farms, and it would reduce the nitrogen load in the area.
In this paper, the influence of the nitrogen load reduction by the material circulation between dairy farms and dry field crop farms was estimated to understand the situation of the nitrogen loads in one town.
Twelve percent of nitrogen (200MgN/year) included in total amount of livestock manure from dairy farms were used for the dry field crops as the result of exchanging livestock manure for bedding materials or temporary land exchange between dairy farms and dry field crop farms. Ninety percent of dry field crop farms growing wheat have supplied the wheat straw to dairy farms for bedding material, and the amount of nitrogen transported from dry field crop farms to dairy farms as the bedding materials containing both wheat straw and bean husk was 25[MgN/year].
Considering the material circulation between dairy farms and dry field crop farms in A town, it was estimated that 180[MgN/year] (40[kgN/ha]) of nitrogen load deceased at dairy farms. This results indicate the regional material circulation is effective to decrease the nitrogen load in the region.
For the future study the influence of the material circulation on nitrogen loads of dry field crop farms needs to be investigated to understand the situation of the nitrogen loads in whole A town.

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Typhoon 0221 reached Kawasaki City, Kanagawa at around 20:30 on October 1st, 2002, and went north through the Pacific Ocean side of the Kanto and Tohoku Districts. This typhoon, with an average wind speed of 35m/s near its center, was one of the strongest typhoons in the Kanto District since 1945. Because of the strong winds, many greenhouses, from pipe greenhouses, collapsed in the Toso region of Chiba and the Rokko region of Ibaraki, which were in a semicircular area experiencing the greatest wind speeds from the storm. To assist the development of greenhouse reinforcement techniques to withstand heavy wind, the authors analyzed seven groups of the greenhouses destroyed by the typhoon. Analysis of two key components of the structures, the strength of a joint between column and beam, and the pullout strength of the foundation, leads to the following conclusions:
1. Greenhouses were destroyed by south-south east winds with speeds over 35m/s.
2. Some foundations were pulled out by wind speeds of 50m/s, and the pullout strength of the foundation which footing was broken was less than 30% than that of a standard one.
3. The pullout strength of foundations buried more than 10cm deeper than the present state exceeded the pullout force caused by a 50m/s wind.
4. The strength of the joint between column and beam in a structure without bracing was less than the bending moment caused by a 50m/s wind.
5. Greenhouses with any opening in the leeward gable experience negative pressure inside, increasing load and collapsing the greenhouse roof.
6. There is a need for establishment of new wind force standards for reasonable design of greenhouses which are located close to tall windbreaks and structures.

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In order to clear characteristics of wheat bran as a typical fibrous biomass for a substrate of methane fermentation, some laboratory scale experiments were conducted under a continuous fermentation in mesophilic range. The experiments made progress in a steady fermentation under almost conditions of variations of total solids (TS) concentration and hydraulic retention time (HRT). The volumetric ratio of methane and carbon dioxide in the generated biogas was nearly one to one under all the conditions. The content of methane in the biogas was less than that from other organic wastes. The state of the fermentation became worse and the volume of methane became less, as the TS concentration became higher and HRT became shorter. Application of Chen-Hashimoto model for analysis of the fermentation almost cleared the optimum TS concentration and HRT.

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The evaluation of dairy production systems have been made mainly from farm economy only. This attitude have caused various environmental problems such as lowering self-sufficiency rate and high input fossil energy in dairy farming area.
In this paper three indexes; economic efficiency, fossil energy input and nitrogen surplus were applied to evaluate dairy production systems totally with considering sustainability.
Investigation object area is A-district (197 farms) in East Hokkaido Japan.
As a result, it became possible to evaluate fossil energy input per unit milk production [kg] (6.0[MJ/kg]) and nitrogen surplus per unit operating area [ha] (106[kg-N/ha]) by using multiple evaluation indexes. It was also found by multiple evaluation that farms having high evaluation in economy could not always have high evaluation in energy and environment.
These results insist that multiple evaluation indexes other than economy should be used when dairy farming systems are evaluated.

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