Before the Second World war, there were many public storehouses, generally so-called Gokura _??__??_ in Tohoku district of Japan. The Gokura existed ubiquitously in wide rural areas of Japan in feudal age. Peasant farmers stored constantly rice crops, barleis, millets, and the like in the Gokura, and used them for saving their lives in disasters. Gokuras were established by peasant farmers and feudal lords. They lived in a near-subsistence society and rice crops exchanged only in a restricted area. Therefore they got into danger when the rice crop was short. lt is apparent that the Gokura was indispensable to the old rural society.
Most of Gokuras were co-operated by the small group of peasants around it, or the rural community (Mura _??_ or Oaza _??__??_ ). It was unusual that the public storehouse was co-operated over the wide area in which several rural communities were contained. One rural community generally co-operated one Gokura.
The government of Japan made efforts to consider several counter-measures of disaster from 1867. Rice crops became to be exchanged in a greater distance. The peasant farmers were free from the feudal lords. The rural community gradually took to pieces. Therefore the Gokura rapidly falled over time for the 1867-1935 period.

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Recent eutrophication of lakes is prompted by the increases of nutrient loads associatng with man's activites in the catchment areas. However, the studies investigated the relationship between nutrint loads and eutrophication of lakes have been scarce. In the preceding paper, the author tried to examine the relation of the two for the past 60yr about Lake Suwa which has been heavily eutrophicated. At that occation, the loads of COD as a organic matter index and plant nutrients such as nitrogen and phosphorus were caluculated by using effluents of the various industrial wastewater, domestic sewage, and hot-spring discharges in the catchment area. As the results, the caluculated loads of organic matter and nutrients to Lake Suwa of late were 11, 000kg/day as COD, 1, 570kg/day as total N (nitrogen), and 360kg/day as total P (phosphorus). In this case, it may be practically reasonable to regard these caluculated values as the loading from the urbanized area in the basin.
In this paper, the author measured COD values and the concentrations of the both of inorganic N (NH₄+NO₂+NO₃) and phosphate (PO₄-P) of inflowing rivers to the lake, and evaluated the average inputs 9, 800kg/day, 1, 500kg/day, and 80kg/day, respectively. Since the both inputs of total N and total P were estimated at about two times as much as the inorganic amounts, approximately 3, 000kg total N/day and 160kg total P/day flow into the lake. On the other hand, the discharges of COD from the lake change seasonally from 8, 400kg/day to 12, 300kg/day. The output of inorganic N changes in proportion to the amounts of input, the output/input ratio is about 0.5. The output of PO₄-P is relatively constant in spite of the changes of its input annually.
On the basis of these results, following two points were mainly considered; the concerning of the differences between the caluculated and observed nutrient inputs, and as to the mutual relation between the organic matter and nutrient budgets and the eutrophication. First, it was found that nearly 60 percent of COD input and 50 percent of inorganic N input were derived from the rural area in the catchment, whereas in case of PO₄-P, only 20 percent of the input was derived from that area. It is assumed that the most part of the rest is originated from the urbanized area where the wastewater of the various types of machinery and food products industries and domestic sewage flow into the lake. Therefore, the finding is that the caluculated loads of COD and total P originated from these effluents are considerably excessive. The caluculated loads of total N in the basin is approximately equal to the observed one. Next, in the nutrient budgets of Lake Suwa, it is suspected that phosphorus content is disposed to be in somewhat short supply. It may still control the much more increases of the primary production in the lake water. Nearly 80 percent of phosphorus input, however, depends on the discharges from the urbanized area, it is considered that the recent increasing of this load has facilitated the progress of eutrophication. Then, in order to regulate this problem, it may be necessary to restrict the loading of phosphorus caused by man's daily activities. In addition to, careful reviewal for the phesphorus concentrations of various types of wastewater is required in calucuating of the load.

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