Dr Zakaria Solaiman1,2, E/Professor Lynette Abbott1,2, Dr Natasha Pauli1, Mr Rob Rex3, Mrs Caroline Rex3
1SoilsWest, UWA School of Agriculture and Environment, University of Western Australia, Perth, Australia, 2UWA Institute of Agriculture, University of Western Australia, Perth, Australia, 3Westendale Grazing, Wagin, Australia
This study investigated the quantification and prediction of changes in soil carbon in perennial pastures under cell grazing. Limited data are available to quantify the amount of carbon that could be stored in WA wheatbelt soils using cell grazing practices. The objective was to measure the change in soil carbon associated with pasture management practices for different aged mixed perennial and annual pastures using a chronosequence of pastures sown in 2003, 2005, 2007, 2008, 2011 and 2012. Inclusion of perennial grasses in pastures is uncommon in the Arthur River region of Western Australia but they have potential to increase soil carbon. Soil carbon was highest in the oldest established perennial pastures in the chronosequence. An increase in soil carbon was measured between 2012 and 2014 for 2 of the 6 sites in the chronosequence. An increase in soil carbon between 2012 and 2014 measured for perennial pastures established in 2005 and 2007 was likely to be associated with improved soil management (including liming) that resulted in increased productivity at these sites. Both sites had a history of poor soil conditions but this had recently been observed to improve.
The farmer-researcher collaboration in this project provided two-way exchange of knowledge that has led to a number of suggestions for further investigation relevant to pasture management. For example, inconsistencies in relationships between pasture management practices and soil chemical measurements, the potential requirement for soil disturbance in management of perennial pastures, the time required for improvement in relation to soil quality, limitations in perennial productivity, the economic potential for management of perennial pastures compared with annual pastures (on soils of different quality), tipping points in relation to improvements in soil carbon and pasture production, were all areas of further potential research identified in the final workshop by farmers, consultants and researchers.
Dr Zakaria Solaiman is a soil microbiologist with over 20 years’ research experience in arbuscular mycorrhizal symbiosis, soil carbon sequestration, biochar and plant nutrition. After completing his PhD in Agriculture (soil microbiology and plant nutrition), he held several postdoctoral positions in Japan before joining The University of Western Australia in 2000. He is currently working as a Research Fellow in an ARC (Australian Research Council) Linkage Project on “Characterisation of soil microbial interactions for increased efficacy of herbicides using novel fertiliser management practices”. He also worked as a Research Associate at The University of Adelaide on an ARC Discovery Project on “Plant-soil-microbe interactions at rhizosphere” before returning to UWA in 2006. Since then, Zakaria is working in a range of research in collaboration with researchers from the Department of Primary Industries and Regional Development, Western Australia and many other industry partners.