Ground Cover Supplement : GC Supplement - Precision Agriculture 2005
GROUND COVER PRECISION AGRICULTURE 12 DISEASE RISK ASSESSMENT Spotlight on diseases SARDI-GRDC RESEARCH IS combin- ing DNA technology with PA zoning tech- niques to provide graingrowers with bet- ter risk assessment of soilborne diseases before sowing crops. Our studies of PA management zones have shown soilborne pathogens often segregate within different zones in a pad- dock. This has significant implications for development of robust sampling strategies for soilborne pathogens and planning the cropping program. High levels of soil- borne pathogens in potentially high-yield- ing zones pose a greater risk to paddock profitability than pathogens concentrated in low-yielding zones, especially where the latter are limited by physical or chemi- cal constraints. Improved risk assessment of soilborne diseases will help growers select the most profitable crop/cultivar to sow in specific paddocks. In combination with variable rate technology, the information will also help growers reallocate inputs from low to high potential yield zones and target treat- ments to reduce disease risks. This project aims to: 1. determine if yield losses vary between PA paddock management zones for spe- cific pathogen levels; 2. determine which data layers are best to map soilborne pathogen distribution; and 3. assist other PA projects assess soilborne pathogen levels in different zones in their focus paddocks. Project outputs will include recom- mendations on how to zone paddocks to target soilborne pathogens, and give general guidelines for prioritising zones by disease risk. This research is mostly conducted in South Australia in collaboration with SPAA (Southern Precision Agriculture Association), Australian Centre for Precision Agriculture (ACPA, Sydney University), Silverfox Solutions (WA), and other PA research projects. The DNA soil tests used in this project were developed jointly by SARDI, CSIRO and Bayer Crop Science, and are marketed in Australia as PreDicta® B. The main findings so far are: 1. soilborne pathogen levels usually vary between PA zones within a paddock, even when zones are created using simple PA layers (for example, EM38 maps, elevation maps); and 2. robust sampling methods for soil tests are critical: our current recommenda- tion is to collect 45 cores targeted where practical along the rows of the previous cereal crop. Target sampling within PA zones gives more useful information than samples taken across the whole paddock. DISEASES IN ZONES Paddock data layers fall broadly into two main groups -- "geo-data" (EM38, eleva- tion, gammaradiometric data, etc) and "bio-data" (biomass, yield maps, etc). GROWERS CAN PROFIT FROM MAPPING SOILBORNE DISEASE 'HOT SPOTS' AND PA TECHNIQUES CAN HELP, WRITE JOHN HEAP AND ALAN McKAY Harvesting of small fumigation plots (Rhizoctonia PA research) in the SA Mallee 2004.
GC Supplement - Nutrient Management 2006
GC Supplement - Grain Storage 2005