Ground Cover Supplement : GC Supplement - International collaboration
GROUND COVER INTERNATIONAL COLLABORATION 10 COMMON INTEREST Associate Professor Daniel Murphy and colleagues at the Department of Food and Agriculture, Western Australia (DAFWA), are evaluating the influence of biochar on the herbicide simazine. Experiments tested different types of biochars from Australia and the UK at different rates, particle sizes and periods after incorporation. The aim was to establish how these factors influenced the sorption, biodegradation and leaching of simazine. At application rates for biochar of 10 to 100 tonnes per hectare it was found that biochar suppressed simzine breakdown and reduced leaching of the herbicide into soil water. These effects were greater with biochars consisting of fine particles. While holding the simazine in the soil may seem a positive for weed control and the environment, it was found that these responses were induced by rapid and strong sorption of simazine to the biochar. "This 'lock-up' limits the simazine's exposure to breakdown by microbes and potentially suppresses the effectiveness of soil-applied herbicides," Associate Professor Murphy says. The research team used simazine label with 14C and found that the simazine concentrated into 'hotspots' associated with biochar. The addition of biochar to the soil was found to have lasting affects for at least two years. This combination of hotspots and longevity can have negative effects on crop rotations as future crops may be susceptible to simazine. Results from the herbicide trials and other nutrient-cycling trials have found that the type of feedstock used to produce the biochar can have significant effects on the soil microbial interactions and stability of the biochar produced. Furthermore, different soil types will respond differently to biochar types and rates. Working together has enabled a greater range of biochars to be tested using different methods. GRDC-funded PhD student Daniel Dempster, who is part of the Australian biochar project, is working in Bangor with Professor Jones and his colleagues, conducting joint studies on biochars produced by both research teams. While the addition of biochar may offer benefits, more work is required to assess these against issues such as chemical binding. □ GRDC Research Code UWA00130 More information: Associate Professor Daniel Murphy, Institute of Agriculture, University of Western Australia, 08 6488 7083, firstname.lastname@example.org; www.grdc.com.au/UWA00130 PHOTO: EVAN COLLIS Trials have found that the type of feedstock used to produce biochar can have significant effects on the soil microbial interactions and stability of the biochar produced. Pictured is biochar made from wheat straw.
GC Supplement - Crop protection
GC Supplement - Farm business management