Relationships between Agronomic Practices, Soil Chemical Characteristics and Striga Reproduction in Dryland Areas of Tanzania

The parasitic weed Striga poses a serious threat to cereal production in sub-Saharan Africa. For many years, technological packages for the control of this weed were proposed and implemented on farmers' fields. A survey was carried out in farmers' fields in 2010/2011 cropping season in selected dryland areas of Tanzania to: (a) determine the Striga plant counts, number of capsules/Striga plant and agronomic practices used by farmers to control Striga; and (b) evaluate the relationship between Striga reproduction, soil chemical characteristics and agronomic practices. Soil samples at 0-20 cm depth were collected from 20 different farmers' fields. The soil samples were analyzed for pH, organic carbon, N, P and K. Results showed that there was low adoption of recommended Striga control methods. Regression analysis of agronomic practices and soil chemical characteristics revealed a positive improvement of soil N and organic carbon and reduction of soil P and K content as one shifted from sole planting to intercropping. The results showed that potassium was highly positively related to number of capsules/Striga plant. There was a reduction in the number of capsules/plant as one moved from sole planting to intercropping. Based on these findings, K in the Striga infested in soils positively influenced Striga reproduction and seed bank replenishment, hence high soil K levels may lead to high Striga incidence.