In the 29th Annual GW Leeper Memorial Lecture, Professor Caixian Tang reported on his team’s research on the impacts of soil acidity (pH) on soil organic matter dynamics.
Almost half of the world’s potentially arable land area occurs on acidic soils. In Australia, 77–90 million hectares of agricultural land are affected by soil acidity, and these areas are expanding due to ongoing acidification.
This acidity affects agricultural productivity. Amelioration of soil acidity is expected to increase crop residue inputs (stems, roots and other plant matter left in the soil after harvests), but this may also accelerate organic matter decomposition.
In the lecture, Professor Tang provides an overview on the short and long-term impacts of lime application on the dynamics of soil organic carbon in acid soils, followed by a summary of the effects of crop residues on soil pH and associated mechanisms. Finally, he discusses how plant roots affect the decomposition of soil organic matter through the rhizosphere priming effect and by changing pH in the rhizosphere, the dynamic soil microbiome immediately adjacent to plant roots.
The Leeper Lecture was hosted by Soil Science Australia (Victoria Branch) and the Faculty of Veterinary and Agricultural Sciences as part of the Dean’s Lecture Series.
This annual lecture in Soil Science was established in the name of Professor Geoffrey Winthrop Leeper, and has been sponsored by the University and the Victorian branch of Science Australia since 1992.
Caixian Tang is a Professor in the Department of Animal, Plant and Soil Sciences, and the Centre for AgriBioscience (AgriBio), at La Trobe University. He completed his tertiary studies in agricultural science at Zhejiang (Agricultural) University in China in 1982, and obtained his PhD from the University of Western Australia in 1992. Professor Tang then worked as a research fellow in the CRC for Legumes in Mediterranean Agriculture and in the CRC for Plant-Based Management of Dryland Salinity before he joined La Trobe University in 2003.
His research has covered plant-soil interactions and soil and nutrient management. He has worked on the mechanisms and management of soil acidification, the role of organic amendments in soil pH change and the amelioration of soil acidity and subsoil constraints, the effects of elevated CO2 on soil carbon and nutrient dynamics and rhizosphere biochemistry and nutrient acquisition. He has served as an advisory committee member for the Australian Journal of Soil Research (2007–2010), and is currently an associate editor for the Journal of Soils & Sediments and Crop & Pasture Science, and a consulting editor for Plant and Soil.
Professor Tang enjoys student supervision and teaching soil science. He received the Dean’s award (2004) and Vice-Chancellor’s commendation for teaching excellence (2007), and the inaugural university award for excellence in research supervision (2019).
