Assessing soil fertility status and pest infestation levels in selected banana growing regions of Tanzania

Abstract

A study was conducted between December, 2017 and April, 2018 in four regions namely Kagera, Mbeya, Arusha and Kilimanjaro, to assess the status of soil fertility, disease and insect pest infestations. A total of 560 banana fields were assessed for nematodes, banana weevil damages, black sigatoka disease, soil nutrient status and water conservation practices. A total of 5040 banana plants were assessed for nematodes and weevil damages, and black sigatoka. Moreover, 1168 composite soil samples each weighing 500g, were collected using soil auger at depths of 0-20 cm and 21-50 cm. The soil samples were analyzed using Alpha Spectrometer method which utilizes Mid-Infrared. The results showed that nematode and weevil damages, and black sigatoka disease were found in all surveyed districts. This is the first survey reporting the presence of black sigatoka in Kilimanjaro and Arusha. Weevil and nematode damages positively correlated with mulch cover (P<0.05). Nutrients like nitrogen, potassium, magnesium, calcium, zinc and boron in the soils were insufficient however; phosphorus was in medium levels in all districts except Arumeru and Misenyi. There was low percentage Organic carbon in all districts except in Misenyi (2.0%) and Bukoba rural (1.9%) which had medium levels. Soil pH was optimal for banana production in all soils of the study area. There was less use of water conservation practices except mulch in all surveyed districts. This result recommends that there is a need for developing quick interventions with regards to pests and soil fertility management so as to improve banana production in Tanzania.