Soil Biological Opportunities Summit on Canadian Soil Health 2017 Lori A. Phillips Guelph, August 23, 2017
What do soil microbes do for us? 1. Microbes cycle C by photosynthesis & decomposition 2. Microbes regulate plant nutrient supply & loss (eg. N, P, K, Fe) through symbiotic & asymbiotic interactions 3. Microbes capture & release greenhouse gases (carbon dioxide, methane, nitrous oxide) 4. Microbes improve soil structure (aggregate stability) 5. Microbes degrade pesticides 6. Microbes regulate water quality (e.g. filters nutrients) 7. Microbes suppress soil borne diseases
Soil Biodiversity and Agricultural Resilience Soil Structure Carbon transformation Nutrient Cycling Biocontrol Macro-fauna Meso-fauna Fungi Bacteria Macro-fauna Meso-fauna Micro-fauna Fungi Bacteria Micro-fauna Fungi Bacteria Archaea Increased biodiversity at all levels Predators Parasites
Agricultural Resilience and Human Health Soil Structure Carbon transformation Nutrient Cycling Biocontrol Loss of provided ecosystem goods and services Increased soil-borne pathogens Increased xenobiotic persistence and movement Human health impacts Increased risk of diseases: increased pests and pathogens, lack of clean air and water Reduced supply of food and clean water and air Modified from Wall et al. 2015
Soils contain 25% of our planet s biodiversity One teaspoon of soil contains: Millions of different species Billions of individual organisms critical for healthy soils These organisms are mainly invisible and mostly still unidentified Biotic group Size Estimated # individuals Estimated # species Global Species estimates Archaea 0.5-3 µm > 10 9 unknown >10,000 Bacteria 1-5 µm > 10 9 9000 >4,000,000 Fungi >4 µm > 10 6 250 >1,500,000 Protozoa 5-200µm > 10 6 1200 > 150,000 Nematodes 10µm-2mm >10 6 (m 2 ) 100 >20,000 Other Fauna 250µm-2mm 2mm-2m >10 6 (m 2 ) >200 >100,000
Technology for assessing soil biology has come a long way!
Our understanding of below ground ecosystems has fundamentally changed Long story short
Pseudomonas Nitrosomonas Pathogen suppression Actinobacteria Abiotic stress resilience Nitrification Flavobacterium Azospirillum Pathogen and disease resistance Nutrient acquisition Rhizobium Nitrogen fixation Plant growth promotion Bacillus
In the grand scheme of things
Soil microbial gold rush AAFC-ECCC Metagenomics based ecosystem biomonitoring Biomes of Australian Soil Environments (BASE): a database of Australian soil microbial diversity
But how is this information going to help us? AAFC-ECCC Metagenomics based ecosystem biomonitoring Biomes of Australian Soil Environments (BASE): a database of Australian soil microbial diversity
But how is this information going to help us? You can t manage what you can t measure
A tale of two soils South west Ontario North west Victoria Both cracking clays, both in cereal-legume rotations Researchers in both regions investigating nitrification inhibitors
A tale of two soils Inhibitors work Inhibitors don t work Both cracking clays, both in cereal-legume rotations Researchers in both regions investigating nitrification inhibitors
A tale of two soils Inhibitors work Inhibitors don t work Both cracking clays, both in cereal-legume rotations Researchers in both regions investigating nitrification inhibitors
A tale of two soils Nitrosomonas Nitrosospira Inhibitors work Inhibitors don t work Both cracking clays, both in cereal-legume rotations Dominant bacterial nitrifier populations differ DCD ineffective against Nitrosopira
A tale of two soils Nitrosomonas Nitrosospira Inhibitors work Inhibitors don t work Both cracking clays, both in cereal-legume rotations Australian soil: Large archaeal nitrifier populations Active at different depths Management-driven microbial activity
How can we use this information? Nitrosomonas Develop predictive models based on soil type x crop x tillage to better estimate where and when to use inhibitors Inhibitors work Nitrosospira Inhibitors don t work Both cracking clays, both in cereal-legume rotations Australian soil: Large archaeal nitrifier populations Active at different depths Management-driven microbial activity
Microbial communities respond to management This means that they can be managed, and if they can be managed they can be manipulated Understand where and under what circumstances specific microbial functions are most active Use that information to inform management Start with the basic principles that improve overall soil health
Soil biological challenges and opportunities Take advantage of molecular technology to: Develop baselines for healthy soils Predict where specific taxonomic groups are likely to dominate Predict where specific functional capacities are likely to dominate Relate microbial communities to pathogen levels Develop indicators for suppressive soils Develop indicators for soil resilience to climate stress Develop novel plant-specific co-inoculants to boost productivity, improve resilience, increase resistance Use management strategies to change the plant s core microbiome
AAFC Soil Biology Research: Agricultural management and soil health Pathogen interactions; Soil health indicators An ecological synthesis of agricultural and natural ecosystems Strategies to improve rangeland soil health and productivity Microbial SOM decomposition; Management and microbial function; Microbial N cycling Identification of biological processes influencing N and P losses Improving soil health Soil mycobiome Management practices and microbial diversity Optimizing soil health through manure management and innovative cover cropping Soil microbial properties after 10 years of manure application Microbepathogen interactions; Microbial N cycling Soil fingerprinting framework to track change in soil biological characteristics