Abstract

In Ethiopia, sorghum is the major crop next to teff grown all over the country. Though the productivity of sorghum has increased in the last few years, the overall national productivity of sorghum is low (2.106 t/ha) compared to the average production of 2.3 t/ha of developed countries. The low productivity of sorghum is attributed mainly to infestation by Striga. The annual yield loss and geographic distribution of Striga infestation in Sub-Saharan Africa is steadily increasing. The region is mainly characterized by poor soil fertility and structure, lower distribution and intensity of rain fall. The average yield loss of sorghum due to striga exceeds 50% and in severe cases complete cop failure can occur forcing farmers to abandon cereal production. A survey was conducted in 2014 to determine the interaction of Striga hermonthica infestation with basic chemical and physical properties of the soil and to assess the association of Striga infestation and population density of sorghum in relation to Tigray region. There was a strong association between the average Striga count and population density of sorghum per unit area of land. Similarly, strong association was observed between Striga infestation and soil pH, available phosphorous, percent organic matter, total nitrogen and soil texture. The influence of soil organic matter on level of Striga infestation was observed superior to other soil chemical and physical properties. The highest level of Striga infestation was recorded at kebeles which had got the highest population density of sorghum, low soil organic matter and available phosphorous and sandy textured soils. Therefore maintaining optimum population of sorghum and improving the fertility status of the soil have been suggested for controlling of S. hermonthica in the region.

Key words: Correlation, Striga infestation, sorghum planting density, soil properties, Tigray region.