Abstract
PurposeTo examine the effects of the application of composted sewage sludge fertilizer (commercially sold as Kala compost) and inorganic (NPK) fertilizers on soil quality and on two crops (radish and beans) irrigated using groundwater and sewage treated wastewater (TWW) for irrigation by measuring heavy metals in the soil and plants and other parameters such as crops yield, TOC in soil, chlorophyll index and total nitrogen.MethodsThe field experiments were conducted in an open area in Agricultural Experimental Study at Sultan Qaboos University campus, Oman. In this research, “green beans and white radish” were examined under the application of Kala and NPK fertilizers. The experimental design was a randomized complete block with four replicates.ResultsThe results showed that the yield, TOC and chlorophyll contents of green beans and white radish increased when soil was amended with Kala compost compared to NPK. Chemical analysis of soil and the two crops did not show any risk of heavy metal accumulation.ConclusionsConsidering that the experiment was a short duration one, there is a need for more continuous long-term experiments (at least 5 years) that will improve the understanding on the effects of composted sewage sludge on soil fertility and crop yield to contribute to the development of sustainable agricultural practices in an arid environment of Oman.
Highlights
Water deficit causes significant problems in arid and semiarid countries especially with the acceleration of population and economy growth (Al-Busaidi and Ahmed 2014; Padmavathiamma et al 2014; Ahmed et al 2008; Prathapar et al 2005)
The results showed that the yield, total organic carbon (TOC) and chlorophyll contents of green beans and white radish increased when soil was amended with Kala compost compared to NPK
Chemical analysis of soil and the two crops did not show any risk of heavy metal accumulation
Summary
Water deficit causes significant problems in arid and semiarid countries especially with the acceleration of population and economy growth (Al-Busaidi and Ahmed 2014; Padmavathiamma et al 2014; Ahmed et al 2008; Prathapar et al 2005). Municipal sewage sludge fertilizers can improve the physiochemical properties of soil and affect crop yields and its growth (Antonkiewicz and Pelka 2014; Onwudiwe et al 2014; Baawain et al 2014a, b; Jaffar Abdul Khaliq et al 2017). These fertilizers are very rich in macro and micronutrients, which can supply nutrients to plants and increase their fertility (Al-Busaidi 2014b; Zhao et al 2012)
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