Various social changes have taken place in the rural areas of Southeast Asia since the late twentieth century. There is an academic view that the whole of these changes can be understood as “de-agrarianization”, in view of the labor shift out from the agricultural sector, decreased economic dependence on agriculture, and so on. On the other hand, considering the continuing growth of the agricultural area and production, the aspect of “agriculturalization” is also apparent during the same period. This study aims to examine this seemingly paradoxical view of contemporary rural Southeast Asia, the paradox of de-agrarianization. Based on national-level statistics, some relative values in the region, such as the ratio of the rural population and share of GDP in the agricultural sector, have decreased drastically (namely, relative de-agrarianization); however, the actual size of the rural population has not decreased and the agricultural sector has been developed in terms of area and yield. The continuous agricultural development behind industrialization can be explained partly by rich endowments of ecological resources in the region. Under uncertain natural conditions in the tropics, applying the theory of risk homeostasis from applied psychology to the livelihood strategy of rural households, the expansion of a household’s share of non-farm income (less farming-associated risk) can proceed alongside agricultural intensification using modern technology (risk-taking behavior). This suggests that the paradox may reflect the coexistence or co-prosperity of agriculture and the non-farm sector, or “co-agrarianization”, in contemporary Southeast Asia.

This experiment was aimed at establishing the method of producing large fruits of loquat (Eriobotrya japonica (Thunb.) Lindl.). Using ‘Nagasakiwase’ (open field cultivation), ‘Mogi’ (open field cultivation), and ‘Natsutayori’ (plastichouse cultivation), we investigated the effects of different branch managements (only central shoot, central shoot + one lateral shoot, and central shoot + two lateral shoots) and flower cluster thinning rates (50%, 30%, and non-treatment) on fruit weight, branch structure and the canopy of the loquat. All cultivars in the treatment of a few bearing shoots had the largest diameters, fruit weight and number of leaves in both that and per fruit than other treatments. ‘Nagasakiwase’ at 50% and ‘Natsutayori’ at 30% flower cluster thinning rates had heavier fruit weights and larger bearing shoot diameters than other treatments. There was no significant difference in any of the treatments of ‘Mogi’. The relationship between the branch structure and fruit weight of all the cultivars was under r = 0.54, or uncorrelated. In ‘Mogi’ at 50% flower cluster thinning rate, plant coverage rate was low, and the sky factor area rate and photosynthetic active radiation (PAR) were high, but the leaf area index was the same in all treatments. All branch managements of ‘Mogi’ had the same plant coverage rates, sky factor area rate and PAR. Indicating that in order to produce large loquat fruits, it is effective to have fewer branches and improved light from the receiving environment of the canopy with a low fruit cluster rate.

Avocado cultivation is expected to expand in Japan because of steadily increasing consumption there. However, there are several problems to resolve before its promotion. In particular, low temperatures in winter seem to be the most critical issue. Therefore, we evaluated the cold tolerance of avocado by means of several methods. Seven avocado cultivars were used as material in the analyses of chlorophyll fluorescence and electrolyte leakage of leaves and the FDA staining of the cross-section of stems. The damage index of the leaves was measured using these seven and 12 additional cultivars. As a result, there was no significant difference at -3°C in the Fv/Fm value of chlorophyll fluorescence in any of the cultivars. The Fv/Fm value of ‘Ferute’ at -6°C was significantly higher than that of ‘Bacon’. The Fv/Fm value of ‘Mexicola’ at -9°C was significantly higher than that of the other cultivars. Regarding the damage index of the leaves, ‘Mexicola’, ‘Fuerte’, ‘Winter Mexican’, and ‘Ettinger’ looked healthy, although there were 15 cultivars, which showed low-temperature damage at -6°C. There was no significant difference in electrolyte leakage in any of the cultivars. On the evaluation of the FDA staining of the cross-section of stems, ‘Hass’ was damaged at -5°C, whereas ‘Mexicola’ tolerated temperatures as low as -8°C. These results were similar to those of previous studies. Therefore, all the except for electrolyte leakage, used in this study, were considered to be useful for, evaluation of cold tolerance in avocado.

We attempted to develop a sugarcane yield prediction model based on the logistic curves produced from the growth data in a long-term cultivation test. Judging from the logistic curves of the stalk length, the inflection points of the sugarcane growth in spring planting appeared at 144 days after planting (DAP) when irrigated and at 153 DAP under rain-fed conditions, respectively, whereas those in ratooning were observed around 134 days after harvest (DAH) in both of the irrigation and non-irrigation plots. In summer planting, the growth curves possessed two peaks and the first and second inflection points appeared at 87 and 293 DAP, respectively, irrespective of irrigation. Similarly, logistic curves were generated using the data of the weight of millable stalks obtained after October. The inflection points were 177 DAP in spring planting; 139 DAH in the irrigation and 154 DAH in the non-irrigation plots in ratooning; and 346 DAP in the irrigation and 296 DAP in the non-irrigation plots in summer planting, respectively. Simple correlation analyses were then performed using the growth data recorded around the inflection points in each case. As a result, the weight of millable stalks at harvest was significantly correlated with the product of the stalk length, stalk diameter, and the number of millable stalks in September and October for spring planting, in August and September for ratooning, and in June to August for summer planting. On the other hands, the summer-planted irrigation plots showed higher correlation coefficients when using the estimated stalk volumes in June and July as explanatory variables instead. From these, it is concluded that growth data obtained around the inflection points of logistic curves is useful for early prediction of sugarcane yield.