Effect of natural and sesbania fallows and crop rotations on the incidence of root-knot nematodes and tobacco production in Tabora, Tanzania

Abstract

A three-year field study was conducted at Tumbi Agricultural Research Institute, Tabora, Tanzania to determine the effect of natural and Sesbania fallows and crop rotations on the incidence of nematodes (Meloidogyne incognita and Meloidogyne javanica) and tobacco production. Sesbania sesban provenance and tobacco support the reproduction of root-knot nematodes while maize and natural weeds are poor hosts. Nematode infections were consistently highest when tobacco was cropped for two consecutive seasons and after two years of Sesbania fallow. Cropping maize after tobacco and Sesbania significantly (P<0.05) reduced nematode infection of the following tobacco crop. The one year and two years natural fallow rotations produced the highest tobacco yields in 1996/97 and 1997/98 cropping seasons respectively, while the natural fallow-maize-tobacco rotation produced significantly (P<0.05) higher tobacco yields in the 1997/98 cropping season. These rotations recorded lower nematode infections. Sesbania fallows were more effective in restoring soil productivity and highest maize grain yields and yield components were obtained after the one year Sesbania fallow. The results of the study show that a rotation of natural fallow-maize-tobacco could be appropriate in managing root-knot nematode infections in the tobacco-cereal farming system in Tabora Region