Suad Jaffar Abdul Khaliq - Department of Soils, Water and Agricultural Engineering, College of Agricultural and Marine Sciences, Sultan Qaboos University, Muscat, Oman
Ahmed Al-Busaidi - Department of Soils, Water and Agricultural Engineering, College of Agricultural and Marine Sciences, Sultan Qaboos University, Muscat, Oman
Mushtaque Ahmed - Department of Soils, Water and Agricultural Engineering, College of Agricultural and Marine Sciences, Sultan Qaboos University, Muscat, Oman
Malik Al-Wardy - Department of Soils, Water and Agricultural Engineering, College of Agricultural and Marine Sciences, Sultan Qaboos University, Muscat, Oman
Hesham Agrama - Department of Crop Sciences, College of Agricultural and Marine Sciences, Sultan Qaboos University, Muscat, Oman
B.S Choudri - Center for Environmental Studies and Research, Sultan Qaboos University, Muscat, Oman

Purpose To examine the effects of the application ofcomposted sewage sludge fertilizer (commercially sold asKala compost) and inorganic (NPK) fertilizers on soilquality and on two crops (radish and beans) irrigated usinggroundwater and sewage treated wastewater (TWW) forirrigation by measuring heavy metals in the soil and plantsand other parameters such as crops yield, TOC in soil,chlorophyll index and total nitrogen.Methods The field experiments were conducted in an openarea in Agricultural Experimental Study at Sultan QaboosUniversity campus, Oman. In this research, ‘‘green beansand white radish’’ were examined under the application ofKala and NPK fertilizers. The experimental design was arandomized complete block with four replicates.Results The results showed that the yield, TOC andchlorophyll contents of green beans and white radishincreased when soil was amended with Kala compostcompared to NPK. Chemical analysis of soil and the twocrops did not show any risk of heavy metal accumulation.Conclusions Considering that the experiment was a shortduration one, there is a need for more continuous long-termexperiments (at least 5 years) that will improve theunderstanding on the effects of composted sewage sludgeon soil fertility and crop yield to contribute to the developmentof sustainable agricultural practices in an aridenvironment of Oman.

Sewage sludge Soil quality Kala compost Green beans White radish Oman