The idea of separability is very useful in empirical demand analysis because it implies a two-stage budgeting model which narrows the focus and reduces the computational and data-requirement problems associated with estimating demand functions ; therefore many of the previous econometric studies on food demand implicitly assume separability for some commodity groupings. However, if the assumed separability is not consistent with data, empirical results of these studies would be misleading.

　In this study, using a nonparametric demand analysis, I test what groupings of food commodities are separable in Japanese representative consumer's utility function over the period 1965-1984. My test results suggest several important implications for the demand system application to food demand analysis. First, it is possible to analyze per capita food consumption pattern in Japanese households using a static demand system. Secondly, as weak separability obtains for various groupings of goods, empirical researchers might group food commodities depending on their research objects provided their groupings pass two-level GARP test. Thirdly, where households' per capita food consumption after 1975 is analyzed using a static demand system, the assumption of (block) additive preferences is inappropriate.

　Considering a worldwide wave of reducing agricultural protection and a chronic milk surplus, measuring the effects of milk support price reduction is an important topic. However, it seems inappropriate to employ either the perfect competition or monopoly model because there is some degree of price discrimination between fluid and manufacturing milk. In this paper, conjectural variations in the Japanese milk market are measured in order to know how imperfect the market is. Varian's "k " and Tsujimura's "λ " show that the Japanese milk market is under imperfect competition, but it is getting competitive gradually. This paper presents a model of the effects of milk support price reduction by means of conjectural variation parameters. Comparative static analysis using the conjectural variations model indicates that the declining rate of fluid milk price is much smaller than that in competitive equilibrium.

　Mergers of agricultural cooperatives are now on agenda in Japan to cope with the changing socio-economic conditions. Mergers are expected to realize scale economies to them, but most of the econometric studies about them are not necessarily successful to prove the existence of scale economies till now because of the difficulty to deal with multiproduct cases in econometric studies. But in recent years, Dr. Baumol and his colleagues have developed a new theory of multiproduct production and economies of scope. We used their theory to clarify the present state of economies of scale and scope in Japanese multipurpose agricultural cooperatives.

　In this paper, we presented a framework for the econometric study of agricultural cooperatives with the use of Dr. Baumol's multiproduct production theory. Then we estimated multiproduct translog cost functions of Japanese agricultural cooperatives from 1980 to 1987 F. Y. And we obtained several indicators of scale and scope economies.

　The main conclusions are as follows : First, we showed the existence of economies of scope among them at the points of sample means for every year. It is a supportive evidence for the mergers of agricultural cooperatives ; second, we found business-specific economies of scale only in the credit business among the four major businesses (credit, insurance, purchase, and marketing) ; third, we found a complementarity of cost between credit and purchase businesses ; and finally, we found the economies of scope in Japanese agricultural cooperatives every year in that period, and it means that Japanese agricultural cooperatives are realizing the merit of their multipurpose nature.

　This study examines the process of social systematization of technological innovations in regional agricultural development as seen in the functional link of individual, community, and regional nucleuses. The pioneering nucleus of each is conceptualized as nucleus farm, nucleus community, and nucleus region. A nucleus farm is an influential entity that serves as a source for propagating creative managerial techniques, technology, knowledge, and experience. A nucleus community utilizes this innovative behavior as its medium by adding to it communal systems to become the core for propagating these to surrounding communities and, thus, is noted for being able to exert influence in its region. Unlike the American communities that do not utilize a medium as depicted in E. Rogers' Diffusion of Innovation, Japanese communities require the assumption of this medium. In this manner, communities that contribute to their regional agricultural advancement are conceptualized as nucleus community. Further, a nucleus region is separated out as a region that collectively adds to this concept the characteristic of emergence while providing it to its region in a restrictive manner ; it propagates the results to cities, towns, and villages and, thus, is able to influence markets, consumers, prefectures, and the nation.

　The nucleus farm, nucleus community, and nucleus region have been examined by connecting them through the line of mental framework―behavior, social function, organization, and system―employed since T. Parsons when graphically illustrating concepts in American sociology. The motive behind this lies in having regional social systematization of innovative behavior as a requisite for a viable agricultural advancement region in view of the progress made in internationalization. The subject is approached through analysis of a case study (Nakano City).