Tropical Agriculture and Development
Online ISSN : 1882-8469
Print ISSN : 1882-8450
ISSN-L : 1882-8450
59 巻 , 4 号
選択された号の論文の8件中1~8を表示しています
Original Article
  • A Case Study in Pingelap Island, Pohnpei State
    Sota YAMAMOTO, Motohiro KAWANISHI, Satoru NISHIMURA
    2015 年 59 巻 4 号 p. 161-169
    発行日: 2015年
    公開日: 2016/04/02
    ジャーナル フリー
    Before the 1950s, the population of the Federated States of Micronesia (FSM) consumed a traditional diet based on starch staple crops and marine resources. This began to be replaced by a modern food in the 1960s and this phenomenon accelerated after a Compact of Free Association was signed between the FSM and the United States in 1986. Previous researches on dietary patterns in the FSM were undertaken only for a very short-period and they did not indicate the dietaries for the whole year. Therefore, a detailed study of household food consumption for every meal over a period of 18 months was conducted to understand the dietary patterns of the inhabitants of Pingelap Island, Pohnpei State, the FSM. Inhabitants of Pingelap Island were partially dependent on imported rice, but they all consumed banana, breadfruit, mweiang (Cyrtosperma merkusii; giant swamp taro), and fish obtained locally at a high frequency. Breadfruit was available seasonally, so the frequency of its consumption fluctuated, and consumption of banana and mweiang increased depending on the availability of breadfruit. The consumption frequencies of imported fresh meat, canned fish, and canned meat were very low. These observations suggest that the dietary patterns on Pingelap Island resemble traditional diets, with a reliance on food available locally and favorable for food security.
  • A Case Study Conducted on Piis-Paneu Island, Chuuk Atoll, Chuuk State
    Sota YAMAMOTO, Motohiro KAWANISHI, Satoru NISHIMURA
    2015 年 59 巻 4 号 p. 170-178
    発行日: 2015年
    公開日: 2016/04/02
    ジャーナル フリー
    It is considered that a “traditional” diet based on staple starchy crops and marine resources has been replaced by a “modern” diet in the Federated States of Micronesia (FSM). However, research on FSM dietary patterns has previously been short-term in nature; diet has not been surveyed over a full year. Therefore, a detailed study of household food consumption at every meal for 12 months was conducted to discover present dietary patterns on Piis-Paneu Island, Chuuk Atoll, in the FSM. We compared our data to those of previous studies in an effort to understand real food behavior in the FSM. People on Piis-Paneu Island often consumed imported food, especially rice, canned fish, and instant noodles. However, they also often consumed local resources, including breadfruit, banana, Cyrtosperma merkusii, fish, and other marine resources. Moreover, they still cooked Alocasia macrorrhizos in a traditional manner, to remove calcium oxalate. A. macrorrhizos is a form of famine food that is plentiful on the island. Dietary patterns on Piis-Paneu Island seem to be basically “traditional”, but incorporate “modern” food, rather than being intermediate between “traditional” and “modern”. Breadfruit is often emphasized as a very important crop in Chuuk State or Micronesia in general, but it is noteworthy that the fast growth and stable production of banana throughout the entire year supports subsistence on small islands of the FSM.
  • Nhung Thi Hong NGUYEN, Susumu ARIMA, Tenji KONISHI, Yuko OGAWA, Shinic ...
    2015 年 59 巻 4 号 p. 179-189
    発行日: 2015年
    公開日: 2016/04/02
    ジャーナル フリー
    The variation of oxypinnatanine (OPT) concentration in daylily (Hemerocallis spp.) influenced by ploidy levels, growth stages, waterlogged soil, relative light intensity, and temperature was examined. Experiments were performed using pots and a net-house with a completely random design. The quantitative estimation of OPT by high-performance liquid chromatography revealed that the ploidy level did not affect the daylily’s OPT accumulation. The OPT production by daylily plants varied significantly with growth stages. The OPT accumulated during the vegetative and flowering periods was higher than that during the post-flowering period. Waterlogged soil did not influence the production of OPT. The light intensity and the temperature markedly affected the OPT concentration in H. fulva var. sempervirens. The plants grown under 100% and 40% relative light intensity (RLI) produced significantly more OPT than those grown under 75% and 60% RLI. The OPT concentration in plants exposed to 40°C was the highest, followed by that in plants exposed to 15°C. The lowest OPT was observed in plants treated at 10°C. Plants exposed to the temperature range of 20°–35°C synthesized OPT at 1.72–1.89 mg g-1, which is lower than those of the plants treated at 15° and 40°C. These results suggest that to accumulate high concentrations of OPT, daylily could be grown in both waterlogged and well-watered soils in non-shade or severe shade conditions, and harvested during the vegetative and flowering stages. Before harvesting at 10 days, plants should be exposed to 15° or 40°C.
  • Mika KOKUBO, Shuichi MIYAGAWA, Mari HARADA, Chisato TAKENAKA, Nobumits ...
    2015 年 59 巻 4 号 p. 190-198
    発行日: 2015年
    公開日: 2016/04/02
    ジャーナル フリー
    Numerous trees have been left standing in paddy fields in central Laos. An inventory of animals living in trees was conducted, and the abundance and differences among trees were determined by survey in which the numbers of animals and species, mainly insects and spiders, inhabiting the trees in the paddy fields were investigated. The greatest numbers of individuals and species were collected from Ficus religiosa, and the fewest individuals and species were collected from Dipterocarpus obtusifolius. A significant negative relationship was found between the number of species per tree and the photosynthetic photon flux density ratio between inside and outside of tree canopy. Differences in dry litter weight and litter chemical composition in the vicinity of the trees were correlated with the number of individual animals. Information obtained from villagers about the number of animals inhabiting the trees was consistent with the survey results. The difference in the number of animal inhabitants between trees corresponded to the difference in the effect of tree-animal ecosystems on rice yield.
  • Vu Tuan MINH, Kei MIZUNO, Shinya FUNAKAWA, Hitoshi SHINJO, Ueru TANAKA ...
    2015 年 59 巻 4 号 p. 199-206
    発行日: 2015年
    公開日: 2016/04/02
    ジャーナル フリー
    The present study examined the growth performance of a new cash crop in Central Vietnam to improve livelihoods. As a new cash crop, Vanilla planifolia was first Cultivated in Thua Thien Hue province in 2006 with the participation of Hong Ha farmers. In the study, farm trials were conducted in four villages belonging to the commune with about 59 host trees planted in 2007 and 164 host trees up to 2013. Between 2007 and 2013, vanilla was found to be a suitable cash crop, allowing farmers to use their land effectively, to diversify their gardens, and to develop a new source of income. Vanilla plants grew quickly on appropriate host trees in humus soil with compost fertilization and sufficient shading. Vine length and the number of leaves increased to an average of 4.71 m and about 75 leaves, respectively. Vanilla plantsbore flowers every year, as farmers took careof them well, in addition to controlling the shading level and managing the garden canopy in the beginning of January. The farmers’ pollination skill should be improved to increase the probability of fruiting. The fruiting rate was 33.1%, the longest fruit was 16.4 cm, and the widest showed a diameter of 1.3 cm. Mature fruits were picked and processed, and were classified using a private standard for Thua Thien Hue province devised by researchers. This activity allowed farmers to create new cultivation techniques for their gardens and increase their confidence in developing vanilla products.
  • Ryo MATSUMOTO, Hidehiko KIKUNO, Olugboyega Success PELEMO, Malachy Ogh ...
    2015 年 59 巻 4 号 p. 207-211
    発行日: 2015年
    公開日: 2016/04/02
    ジャーナル フリー
    Mass propagation techniques are required to alleviate seed yam challenges. To validate the field performance of mini-seed tubers (MSTs) from vine cuttings in yams, the growth and tuber productivity were investigated. From results of influence of MST weights on sprouting rate and tuber yield in white yam (D. rotundata), the MST showed a high sprouting rate even in tubers less than 5 g. Also, the fresh shoot weight and tuber yield was influenced by MST weights. In addition, productivity of MST was evaluated by comparing between MST and minisett which was cultivated under staking and non-staking cultivation condition on the sprouting rate and tuber yield in field with two varieties each of white yam and water yam (D. alata). The sprouting rate of MSTs was higher than minisetts in three of the selected varieties (P < 0.05). From the result of the comparison of tuber productivity between MST and minisetts, it was clarified that MST under staking cultivation was able to harvest tuber, which comparable yield of minisett under no-staking cultivation. To shorten the breeding cycle and to early distribute new varieties with desired traits is expected through seed tuber production from MSTs.
  • Yusufujiang YUSUYIN, Ngai Paing TAN, Mum Keng WONG, Arifin Bin ABDU, K ...
    2015 年 59 巻 4 号 p. 212-220
    発行日: 2015年
    公開日: 2016/04/02
    ジャーナル フリー
    In oil palm plantation, palm fronds are pruned off upon fruit bunch harvest and heaped up in-between palm trees, which is called as a frond heap. This study examined the amounts of nutrients contained in frond heaps and their influence on the underlying soil fertility at an 18-year-old oil palm field in Central Pahang, Malaysia. Based on biomass measurement and nutrient analysis, the amounts of C, N, P, K, Ca, and Mg in the frond heaps were estimated to be 697, 11.8, 0.810, 18.9, 8.05, and 2.73 g m-2, respectively. Meanwhile, the surface soils below the frond heaps showed higher levels of pH, EC, total C, N, exchangeable Ca, Mg, and K than those at harvest path, which is operation path for workers to harvest, while available P was more accumulated at weeded circle, to which fertilizer is applied under the palm canopy. These tendencies were more obvious compared with our previous study conducted at a 10-year-old field located in the same region. This study reveals that the nutrients released from decomposing frond heaps could contribute to build-up of the major nutrients except for P in the underlying soils to be recycled by palm trees.
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