Postgraduate Profiles

Sanjutha Shanmugam

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Thesis: Impact of Lime amended BioClay (LaBC®) in soil biological processes

The primary aim of my Ph.D project is to investigate the influence of LaBC® on soil biological processes in a sandy soil environment. LaBC® is an advanced, treated sewage sludge, which comprises biosolids amended with lime and clay. It has been demonstrated that LaBC® plays a potential role in improving physico-chemical properties of soil such as water holding and nutrient retention capacity. However, knowledge of the interaction between LaBC® and soil microbial processes is not been well understood.

First, this study is being conducted in a controlled environment to understand the relationship among nutrient mineralisation, microbial biomass and microbial diversity in a sandy soil in response to application of LaBC® to soil. Second, changes in soil organic carbon fractions, soil microbial biomass, in particular AM fungi, and seasonal changes in microbial activities in the field level will be studied. Ultimately this study will help to determine the optimum quantity of LaBC® applied to soil. The bioavailability and extractability of heavy metals will also be investigated.

Why my research is important

Soil quality influences surrounding environmental quality. Ellen Brook catchment in Western Australia has been identified as a major contributor of nutrient load to the entire Swan-Canning estuary located near Perth and therefore soil management needs to be improved. Furthermore, the disposal of sewage sludge in a safe way is another important environmental issue. Land application of biosolids is considered a potentially useful means of waste disposal and nutrient recycling which could be combined in a timely manner with restoration initiatives related to water quality. In order to better exploit the product-blend, it is necessary to understand the knowledge gap related to soil microbial processes in sandy soil after application of LaBC® as the microbial-soil interactions are considered to be linked to sustainable land use.