農業経済学

Kajii (1973) insists that large difference in average net return to land between large-scale and small-scale rice farming increases fundamentally the mobility of land by tenancy, and that farming people of Japan are gradually divided into many landed labors, which is regarded as future state of small-scale landed part-time farmers, and a few entrepreneurial tenant farmers, which is regarded as future state of large-scale full-time farmers. But the mobility of land by tenancy has been very weak in spite of large difference in average net return to land between large-scale and small-scale rice farming in Japan. Sakamoto (1958, 1961, 1978) and Ueno (1973) pay special attention to piecemeal tenancy of small parcels of land under small scattered field system in Japan. Against Kajii's opinion, they insist that marginal net return to land of large-scale rice farming is fairly higher than average net return to land of the rice farming, that competition among large-scale rice farmers for piecemeal tenancy of small scattered parcels of land brings about high rent, the level of which can go up theoretically to the level of marginal net return to land of large-scale rice farming, and that the mobility of land by tenancy can not be increased fundamentally by such a difference in average net return to land because of the above mentioned high rent which is termed "Marginal Rent" by Ueno (1973). In Section Ⅱ of the present paper, w e reexamine the justifiability of Kajii's opinion by econometric method, from the standpoint of Sakamoto and Ueno's opinion, through a case study of rice farming of Saga Prefecture based on the Report of the Survey on Rice Production Cost in 1986-Saga Prefecture-. In Section Ⅲ, we also examine the major factors which form high "Marginal Rent" by linear programming method, through a case study of rice farming in the Chikugo Plain based on the Farming Pattern No. 8 of Fukuoka Prefecture in 1986 (rice＋wheat＋soybean, planned by Mizuma Agricultural Extension Office for southern part of the Chikugo Plain) and other several statistical reports. Findings of this study are summarized as follows. 1. Appropriate index to measure the competitive power of large-scale rice farming for piecemeal tenancy under small scattered field system in Jap an is not average net return to land but marginal net return to land. Kajii's opinion has a weakness in this point. 2. It is fully possible that the stock of a fixed resource such as a set of agricultural machines and equipments is introduced profitably into rice farming, though the stock has excessive working capacity compared to land area because of it's indivisible nature. Introduction of such indivisible stock of a fixed resource necessarily saves agricultural labor, and raise shadow price of land. High shadow price of land means high "Marginal Rent". 3. Profitability of the introduction of indivisible stock of a fixed resource can not be measured in general by shadow price of it's services. Excessive working capacity of the indivisible stock is apt to reduce shadow price of it's services below the actual value of it, and low shadow price of services of the indivisible stock does not necessarily mean over investment in the indivisible stock. 4. We can show theoretically that the mobility of land by tenancy can not be increased fundamentally under high "Marginal Rent" on the basis of the above findings and duality theorem of linear programming.