Effet du labour et du mode de bouturage sur les rendements en racines et en feuilles de manioc dans les zones de savane et de jacheres forestieres de la Republique Democratique du Congo.

Abstract

In Democratic Republic of Congo (DRC), cassava covers more than half of the area under cultivation and is permanently consumed by more than 70% of the population for its roots and about 80% for its leaves, which are one of the main vegetables in the country. National cassava production suffered a setback in the early 1990s and an annual arithmetic reduction of the cassava production, from this period to the start of a program on the rehabilitation of the crop. The main objective of the program was to develop varieties with high dry yield and resistant to cassava diseases and pests mainly the cassava mosaic disease (CMD) because the latter was identified as the major cause for the low production recorded. As and when the program gained momentum, many other factors appeared to have important role for the effective recovery of cassava production. Soil fertility management and cultural practices are amongst them. This study was conducted in this context in two different agro-ecological zones (Litoy in Kisangani hinterlands in forest zone and Plateau de Bateke at the East of Kinshasa in savannah zone). The soil of Litoy is heavier than the one of Plateau des Bateke whose sand content is higher than 90%. The method of land preparation influenced the production of cassava roots and leaves in the grassy fallows of the forested areas of the Kisangani region. A 45% increase of the root yield was obtained in this area when the soil was plowed. An stable yield of 14 t/ha was obtained in the Bateke plateau savannah regardless of the land preparation method. The position/orientation of cuttings at planting did not indicate significant statistical differences. However, higher gross profit margins were obtained on plowed land with US$2500/ha compared to US$1500/ha on no tilled land.