Site classification of commercial eucalypt plantations in the Congo. Use of layer depths and microelement deficiencies as productivity indices

Since 1978, 42,000 lia of clonal eucalypt plantations have been established in the Pointe-Noire region for pulp production. l'lie soils are sandy, acidic, very poor in reserves of available nutrients, and the benefît of applying NPK to the plantations has been shown. However, despite NPK fertilization, marked différences of production (10--) 25 m' ha" year-1 at the end of stand rotation) can bc observed between sites with comparable soil characteristics: texture, pli, some of cations, cation exchange capacity, phosphorus, total carbon and total nitrogen. So, a need of relevant site classification indices exists and has conducted to set up a pot experimentation in order to assess, in particular, macroelement deficiencies. (Résumé d'auteur

Synthèse bibliographique des essais fertilisation des Eucalyptus réalisés au CTFT-Congo

Différents types d'engrais ont fait l'objet de dispositifs expérimentaux afin de déterminer leur efficacité sur la croissanc

First report and preliminary evaluation of cassava root necrosis in Angola

Open Access ArticleCassava is a main staple food for 800 million people world-wide. Production is limited by pest and pathogens. The most devastating cassava viruses are Cassava Brown Streak Virus and Uganda Cassava Brown Streak Virusboth causing severe root necrosis called Cassava Brown Streak Disease. In the last 10 years, the Cassava Brown Streak Disease (CBSD)has spread across Africa from the east coast of Africa to central Africa. Similar root necrosis to cassava brown streak disease has also been identified in the Democratic Republic of Congo where the first symptoms were identified in 2002 in Kinshasa and Kongo central province. In 2012, the presence of CBSD was confirmed in eastern Democratic Republic of Congo. All attempts since 2002 in western Democratic Republic of Congo to identify the cause of these root necrosis have failed. In 2017, a team of scientists surveying the Songololo Territory in the Kongo central province at the northern Angola, identified the same root necrosis similar to CBSD in several localities bordering Angola. These unexpected results will foreshadow the presence of cassava root necrosis in Angola. This preliminary investigation in northern Angola was conducted specifically in the Zaire province and the territory of Mbanza Kongo at approximatively 62 kms from the Democratic Republic of Congo border in order to verify, whether or not, these root necrosis are present in Angola. Results obtained from this exploratory survey in several fields of the Zaire province and territory of Mbanza Kongo confirmed, for the first time, the presence of cassava root necrosis in Angola, similar to CBSD, as identified in western DRC