Sesbania Sesban Research Articles

Nitrogen mineralization ofSesbania sesban used as green manure for lowland rice in Sri Lanka

Sesbania sesban was evaluated as green manure crop for lowland rice in the Dry Zone of Sri Lanka. The legume was grown during a fallow period before lowland rice (Oryza sativa) and ploughed under just before transplanting. Weight loss and nitrogen content in litterbags containing leaves, stems and roots of the legume were monitored. Comparisons were made between rice yields from 20 m2 plots after green manuring in combination with different nitrogen fertilizer levels (0, 2.4, 4.8 and 7.2 gm−2) and nitrogen fertilizer (9.6 gm−2) alone. Above-ground biomass ofS. sesban was 440 gm−2 (dry wt) when ploughed under after 84 days growth. N-content in leaves, stems and roots was 3.76%, 0.41% and 0.73%, respectively. This gave a N-input fromS. sesban of 9.2 gm−2 (8.3 g from above-ground parts and 0.9 g from roots). The corresponding K and P inputs were 7.3 and 0.6 gm−2 respectively. The nitrogen rich leaves, which contained 88% of the nitrogen in the above-ground parts, decomposed and released its nitrogen much more rapidly than the stems and roots. After only four days the leaves had released 5.3 g Nm−2 and after 14 days they had released 6.4 g Nm−2. The highest rice yield (505 gm−2) was obtained usingS. sesban and 4.8 gm−2 of N-fertilizer. The yields with only N-fertilizer or onlyS. sesban were 442 gm−2 and 396 gm−2, respectively. Due to the rapid decomposition of the nitrogen rich leaves,S. sesban did not behave as a slow release fertilizer. Thus, it is not necessary to apply nitrogen fertilizers as a basal dose.

Yield, composition and feeding value of irrigated Sesbania sesban var. Nubia leaves harvested at latitude 38°N during a mediterranean summer

A Sesbania variety obtained in equatorial Kenya was grown for two summers in California at 38°N latitude. Leaves rich in protein (24–30%) and calcium (2.15–2.70%) were included at 15 and 30% of diets for broilers. When compared with a diet containing 15% alfalfa meal, the Sesbania-containing diets significantly depressed growth rates and increased mortality of broilers (to 100% mortality with 30% Sesbania). The possible role of canavanine or some unidentified alkaloid in these apparent toxic effects is discussed.

Fatty acid composition of yellow‐ and violet‐flowered sesbania sesban seeds

AbstractThe fatty acid composition of seed oils from yellow‐and violet‐floweredSesbania sesban varieties was determined. Their composition and properties were too similar to provide chemotaxonomic distinction between the varieties.

L’«Opération Éléphants » au Rwanda — 2e partie. Acclimatation et régime des jeunes éléphants introduits dans le parc national de l’Akagera

In 1975, twenty-six calves and immature elephants were captured in southern Rwanda and relocated in the Akagera National Park in northeastern Rwanda, where no elephants had been sighted for some decades. This paper is a preliminary report on the adaptation of these elephants to their new environment. The young elephants belonged to different family units but, in their new habitat, they formed stable social herds. During the study period, they remained on a 1200 ha home range on a peninsula in the large swampy depression of the Akagera River. Food habits were studied by direct and indirect observations. Eighty plant species were found to be eaten, and 3071 recorded observations were analysed. There were marked seasonal changes in the diet. The elephants did not seem to be affected by undernutrition in the dry seasons. Creepers, trees, shrubs, and swampy herbs and grasses were abundant and dominant in the diet. Grazing increased at the beginning of wet seasons when food plants were richest in nutritive value. Most of the grasses were avoided at the end of the rains and in dry seasons. The impact of browsing and grazing was most marked in the riverine vegetation utilized intensively all the year round, where some plants, such as Sesbania sesban, were heavily damaged. In the savanna woodland, the vegetation was only lightly damaged. The impact of browsing on the vegetation, was usually compensated by plant growth, but browsing nevertheless affected the stature of some plants. Ecological succession in the Akagera Park seems to evolve towards a natural reforestation and the clearings made by a small population of elephants might be beneficial for most grazing animals. The possibilities of local competition between elephant and buffalo for some swampy and riverine pastures during drought periods are evoked.