Silicon Status and its Relationship with Major Physico-Chemical Properties of Vertisols of Northern Highlands of Ethiopia

Abstract

Silicon is an essential mineral element for higher silicophile plant species and animals. Literature states that one of the most important functions of Si is the stimulation of plant’s defense mechanism against abiotic and biotic stresses. In addition, Si fertilization has a more positive effect than liming on the chemical and physical properties of the soil. There are only a few studies in Ethiopia that present silicon status of some Ethiopian soils. Hence this study was initiated with the objective of understanding Si distribution in the soils of the northern highlands of Ethiopia. To this effect, 32 soil samples were collected from five agro ecological zones of Tigray. Si in all the samples was determined in the Laboratory of Ethiopian Geological Survey. This study revealed that Si contents ranged from 79.8 to 87.5 g Si kg-1 in the cultivated Vertisols of Adigudom, from 97.7 to 115.2 g Si kg-1in Axum, from 113.7 to 117.2 g Si kg-1in Maychew, from 130.0 to 133.9 g Si kg-1 in Shire and from 137.3 to 166.3 g Si kg-1in Wukro. The highest concentration was hence found in Wukro where the sand content amounted to 50% whereas the lowest level was obtained from soils of Adigudom where the clay content exceeded 60%. The Si contents in all the studied soils are lower than the documented ranges of 200 and 300 g Si kg-1. Significant correlation was found between silicon status and organic carbon 0.84*(p<0.05), silt -0.84*(p<0.05) and clay 0.84*(p<0.05). Finally, based on the enormous role of Si in plant physiology and agriculture, this study suggests commencing Si fertilization in these soils for an expected increase in crop productivity.

Keywords: Essential nutrient, Silica, Silicophile plant species and animals, Si Fertilization