Tropical Agriculture and Development
Online ISSN : 1882-8469
Print ISSN : 1882-8450
ISSN-L : 1882-8450
57 巻 , 2 号
選択された号の論文の4件中1~4を表示しています
Original Article
  • Tomohiro KONDO, Hirokazu HIGUCHI
    2013 年 57 巻 2 号 p. 49-53
    発行日: 2013年
    公開日: 2013/07/18
    ジャーナル フリー
    High-quality passion fruit, with low acidity and an aesthetic appearance, is important for fresh consumption. Thus, the effects of nitrogen (N)-form in nutrient solution on the juice quality and external appearance were examined. Passion fruit plants were grown in 10-L pots filled with river sand. Nutrient solutions containing 25 mM N with different NH4-N:NO3-N ratios of 100:0, 75:25, 50:50, 25:75, or 0:100 were applied. The numbers of flowers and fruits per bearing-vine were counted and fruit-set percentage was recorded. After harvest, fruit weight, dimensions, and peel color were measured. After a 10-day storage, total soluble solid (TSS), titratable acidity (TA), juice content, peel color, and wrinkle degree were measured. TA was the lowest at NH4-N only, and the sugar/acid ratio increased as the NH4-N ratio increased. TSS was not significantly affected by the N-form. Therefore, high NH4-N ratio, such as NH4-N alone or 75 % NH4-N, was beneficial for juice palatability, while juice content decreased as the NH4-N ratio increased. High NH4-N ratio could improve not only the juice palatability but also the fruit’s external appearance. Fruit at high NH4-N ratio wrinkled less and had deeper color on the peel. However, with NH4-N solely, leaf necrosis appeared, and the SPAD index, photosynthetic rate, and total dry weight were lowest; thus, NH4-N should not be applied alone. With NO3-N solely, flower number, fruit size, and yield were smallest among the treatments. These results indicated that NH4-N-dominant fertilizer can be used to produce high-quality passion fruit while NH4-N should not be applied alone.
  • Yooko TSUCHIYA, Makoto GODA, Kenji IMOU
    2013 年 57 巻 2 号 p. 54-60
    発行日: 2013年
    公開日: 2013/07/18
    ジャーナル フリー
    For the promotion of the development and utilization of biofuels, it is important to secure a supply of biomass feedstock from which biofuels will be derived. In the present study, analysis of the energy balance and of CO2 emissions for the management of Jatropha plantations was carried out, assuming that the Jatropha plantations would be developed in the Philippines where the climatic and farming conditions are suitable for the plant growth. The evaluation was conducted for the reclamation of farmland, Jatropha cultivation, and oil mill processing. The value of the energy profit ratio (EPR), defined as the ratio of energy input to energy output for the entire system, was determined to be 7.3, which could be increased by reducing chemical fertilization. However, because biodiesel fuel conversion consumes a substantial amount of energy, production of unprocessed oil may be preferable. CO2 emissions for the production of Jatropha oil were estimated at 20 g CO2/MJ, with a low negative environmental impact.
  • A Case Study of Namulonge in Central Uganda
    Yusuke HANEISHI, Atsushi MARUYAMA, Kisho MIYAMOTO, Shunsuke MATSUMOTO, ...
    2013 年 57 巻 2 号 p. 61-73
    発行日: 2013年
    公開日: 2013/07/18
    ジャーナル フリー
    Using data collected from farmers in Central Uganda, this paper looks into how NERICA (New Rice for Africa) was introduced into a multiple-cropping upland farming system and what impacts it had on farmers’ income. NERICA was introduced into the traditional cropping pattern of the banana-coffee system by replacing mainly maize and sweet potato, resulting in an increase in cropping intensity and bringing hitherto uncultivated land into cultivation. After nearly a decade since its dissemination began, strong enthusiasm to adopt NERICA still remains among upland farmers in the study area, large and small farmers alike. The incidence of land leasing is increasing mainly to grow NERICA. Behind such enthusiasm is the high profitability resulting from NERICA production. This paper makes it clear that NERICA’s high-yielding characteristic was realized in farmers’ fields such that the profitability of NERICA production was highest among the upland crops grown in the study area, in spite of its higher input requirements relative to other crops, resulting in substantial increases in farmers’ household income. Thanks to the pro-smallholder nature of NERICA technology, this income increase was particularly distinct for smallholders. The introduction of NERICA increases their crop income by 40 to 60%, contributing to ameliorating the income distribution in the study area.
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