Volcanic Ash as a Material for Soil Conditioner and Fertility

Abstract

A field trail was conducted to test the effect of volcanic ash application on some soil properties and potato crop grown in The Res. Station, Fac. of Agric., Cairo Univ. located at Wadi El-Natron region, El-Behira Governorate, Egypt. The results show that iron oxides, silica and alumina represented 91.5, 6.0 and 2.5% of the total amorphous materials, respectively. Molar ratio of SiO 2 /Al 2 O 3 of volcanic ash was 2.08. Light minerals are mainly composed of feldspars and quartz and having a specific gravity less than 2.85 g/cm 3. Opaque, pyroxenes and amphibole heavy minerals represented about 70% of the total heavy minerals. kaolinite predominated the clay minerals followed by montmorillonite, while cholorite was detected in trace amount. Zeolite of volcanic ash has high alumina content and low Si/Al ratio (less than 4) which is considered a hydrophilic soil conditioner. The texture of volcanic ash is considered coarse with bulk density value of 1.36 g/cm 3 and total porosity value of 41.25% (65.90 % macro-pores and 34.10 % micro-pores). The electric conductivity (EC) of volcanic ash was low value (0.45) and reaction value (pH) of 5.9. There was no symptom of nutrients deficit in potato leaves or tuber as a result of using volcanic ash. Therefore, volcanic ash might be used safely to increase soil fertility and improve soil properties as soil conditioner. Moreover soil productivity might be augmented by applying volcanic ash to the soil