Biosolids application and soil organic carbon dynamics: a meta-analysis.

Abstract

Soil carbon sequestration has been recognized as a potential “direct action” tool in mitigating climate change. Organic matter rich biosolids from wastewater industry has been applied to soils as one of the strategies to the carbon sequestration. However, most of the short- and long-term studies as influenced by land application of biosolids have been showed quite inconsistent results in carbon increments in soils. Therefore, soil carbon sequestration resulted by biosolids application is yet to be needed further studies to elucidate. This study presents a comprehensive MetaAnalysis (MA) on soil carbon sequestration as influenced by biosolids application. Datasets comprised with 175 independent paired-treatments across 25 countries were fed in to Comprehensive Meta-Analysis (version 3) programme and modelled. The MA compared Soil Organic Carbon (SOC as g/kg) changes as the functions of time after biosolids application and its rate over twelve groups under two categories: application age (time after application) as <1, 1-3, 3-5, 5-8, 8-11, >11 year, and cumulative application rate as <1-50, 51-100, 101-150, 151-200, 201250, >251 tonnes/ha.The fixed model is applied to explicate overall effects of analysed data derived from the MA. The MA showed overall positive influences on soil carbon sequestration towards increasing SOC. For example, the highest effect on SOC was observed at 1-3 age group suggesting the need of short term biosolids application to develop carbon storage in soils. Overall, this study shows that land application of biosolids can be used to increase soil carbon storage and therefore has the potential to be a strategy for mitigating climate change towards carbon sequestration in soils.