We construct a theoretical model of agricultural technology diffusion under liquidity constraints. The liquidity constraint using the concept of value at risk (VaR) causes the internal rationing problem where farmers restrict themselves from investment, fearing significant loss due to the uncertainty of new technology. It is shown that, under the liquidity constraint, farmers behave in a loss-averse manner, and their decision depends not on risk aversion but on their subjective probability distribution of profit. Some characteristics of agricultural production make the constraint more likely to bind, so focusing on the heterogeneity of liquidity conditions in the context of technology diffusion and investment in agriculture is essential. In terms of policy, it is implied that policy tools supporting liquidity storage, like long-term loans are effective.

This study explores the drivers of rapid rice production growth after 2008 in Sub-Saharan Africa (SSA) using a new growth accounting framework. The new method allows us to identify contributions of not only changes in input quantities but also the growth of input-embedded and input-free productivities. To investigate the effects of the global food crisis, we anlyze the effects of changes in rice prices on the productivity growth. The empirical results show the following findings: i) land and fertilizer productivities drastically improved in 2008; ii) the rice production frontier remarkably extended in 2008; iii) fertilizer quantity got an important growth driver after 2008; iv) the growth patterns were different between traditionally rice-producing countries and non-rice countries. These results imply that the global food crisis improved the profitability of rice production, and it triggered the expansion of rice production in SSA through the adoption of modern technologies.

This study considers the significance of agricultural policy finance. Traditionally, the rationale for policy intervention in agricultural financial markets has been the credit constraint, but it is considered less justifiable today. However, the current policy objective is to "foster efficient and stable agricultural management." It is expected that the concentration of resources in the hands of leading farmers will lead to the growth of the agricultural industry. In the case that the productivity growth of the leading farmers has a spillover effect on the surrounding farmers, the provision of low-interest loans to the leading farmers is significant in promoting agricultural productivity growth by internalizing the externalities. A cost function analysis of rice farming shows that the spillover effect of leading farmers justifies the significance of the policy financing in a wide area west of the Tokai region, although it is not nationwide.

In this study, we consider the problem whereby policy intervention in the financial market might hide the existence of credit constraints. We develop a theoretical model of the representative borrower utilizing credit from private banks and a governmental financial institution. Using the exogenous change in the transaction technology for borrowing from the governmental institution, we can identify the existence of credit constraints even if the policy remains in the market. Additionally, our model shows that the inefficiency of policy intervention is larger when we consider the borrower's choice of optimal effort.

The objective of this study is to analyze the effect of the expansion of the branch network of policy finance on the primary sector economy, using aggregated macro economic data. The findings are as follows. First, if we assume the branch network expansion affected only certain prefectures, such prefectures raised labor productivity compared to other prefectures. On the other hand, if we assume the branch network expansion had an influence on all prefectures, then the prefectures where the ratio of certified farmers was higher decreased labor productivity more. If the latter is correct, it indicates an inefficiency of policy finance.