Various vegetables are cultivated in rural Tanzania. Since economic liberalization started in the 1980s, cultivation of fruit vegetables as cash crops has increased due to the development of cash economy in rural Tanzania. However, self-sufficiency in leafy vegetable cultivation has also continued. The objective of the present study was to elucidate the features of leafy vegetable cultivation by analysing their consumption and by observing farming practices in rural Tanzania. The results showed that leafy vegetables were important for use in side-dishes and that, in this area, nearly 30% of all the side-dishes included leafy vegetables. Leafy vegetable consumption increases in the rainy season and decreases in the dry season. Pumpkin leaves accounted for the largest proportion of leafy vegetable consumption, followed by cassava leaves, while wild herbs (e.g. Aeschynomene sp. and Corchorus sp.), leaves of amaranth, sweet potato, and cowpea were also used for side-dishes in the study area. Leafy vegetable cultivation plays an important role in providing foodstuffs for farmers by reducing the effects of socioeconomic changes, because the components of this type of vegetable cultivation can be grown easily and are not related to cash economy. Although leaves have been considered to be by-products of tuberous roots, fruits, and beans, it is necessary that such crops be considered as leafy vegetables because leaf production is as important as that of tuberous roots, fruits and beans.
Poor establishment of rice seedlings by the direct sowing method under submerged conditions in the field is a serious problem in Battambang province in Cambodia. In Toulsamron there was a low rate of establishment of rice seedling of 18 Indica varieties under submerged paddy soil conditions. Black and white gel matter developed in poorly established seedlings. Energy - Dispersive X - ray Fluorescence Spectrometer analysis suggested the black gel matter might be iron oxide. White gel matter was observed on established seedlings under submerged conditions without soil, and it was thought to be oozing matter from the seeds. However the white gel matter does not cause poor establishment of seedlings. Dissolved oxygen was lower than in pure water, when the water containing oozing matter was added to the Toulsamron paddy soil. Ethanol was found in the water containing oozing matter. The ethanol solution with Toulsamron soil decreased dissolved oxygen, also the oxidation-reduction potential decreased, the pH reached to near neutrality and the amount of Fe2+ increased. These phenomena suggested low dissolved oxygen conditions at seed germination.