Christine Watson November 2015 Why does soil matter? Christine Watson November 2015

What is soil? What is soil made up of? Air Mineral Water Organic material Mineral “Each soil has had its own history. Like a river, a mountain, a forest, or any natural thing, its present condition is due to the influences of many things and events of the past.” - Charles Kellogg, The Soils That Support Us, 1956 Willie Towers, JHI

Why is soil organic matter important for production? Source of nutrients Soil structure – small changes give big effects Water holding capacity Cation/anion exchange capacity Soil organic matter = soil organisms + partially decomposed plant and animal residues

Soil carbon in Europe Globally, twice as much carbon is stored in soils as is present in the atmosphere. This is both a threat and an opportunity. The threat is land use change. The opportunity is carbon storage. (Smith, 2012) The world’s cultivated soils have lost 50 to 70 percent of their original carbon stock. (Lal, Ohio State Uni) Nearly 50% of European soils contain very low levels of SOM (0-2%), which has been caused by agricultural intensification (Quinton et al. 2010) Joint Research Centre, European Commission 2005

Soil biodiversity Soil is home to a quarter of our planet's biodiversity which is essential for food security and nutrition A single gram of soil may contain millions of individuals and several thousand species of bacteria. Soil is alive and it is the soil organisms (big and small) that are the engine Soil biodiversity is (generally) not cute!

Fertiliser & manure Crop rotation Variety Drainage Tillage Agrochemicals Drainage Tillage Biodiversity Soil fertility Soil organic matter Soil structure 6

Impact of crop diversification on soil carbon Monoculture Rotation Rotation + Cover crop Baseline +3.6% soil C + 5.3% total N +8.5% soil C + 12.8% N 20.7% soil microbial biomass McDaniel et al. 2014 Ecological Applications 24: 560–570

Inter-linkages between soil management, carbon flows and stocks, and crop yield (SMART SOIL project) OTHER ECOSYSTEM SERVICES CROP GROWTH YIELD Biological Chemical Physical Water Nutrients Health SOIL FUNCTIONS SOIL PROPERTIES SOIL TYPE CARBON FLOWS CARBON STOCKS CARBON STORAGE MANAGEMENT

Changes in soil organic carbon content in the plough layer (0–23 cm) in three treatments of the Broadbalk Wheat Experiment at Rothamsted Research, UK.). Annual treatments are: , no fertilizers or manure applied since 1844; , PKMg plus 144 kg N ha−1 since 1852; , farmyard manure at 35 t ha−1 fresh weight applied since 1885 plus 96 kg N ha−1 since 1968. Data from Rothamsted Research.

Changing soil organic carbon content CO2 emission C sequestration - + Monocrops Ploughing Burning residues Bare soil Residue removal Negative nutrient balance Cover cropping Green manures Leys Diverse rotation Manures/biosolids Min till Agroforestry Forage legumes

David Atkinson

Soil degradation

Trade-offs……great expectations www.blue-energyco.com http://www.morrisonconstruction.co.uk/infrastructure/energy

Some more challenges associated with soil and food security Joined-up approaches to soil protection and resource management Social acceptability (urban and peri-urban issues) - closing the loop – food waste and sewage Technology – precision approaches Diets…… Fundamental understanding – scientific frontiers Our ability to adapt to changes and challenges! - knowledge, technology, policy, ethics, economics…

SOIL is a non renewable resource “We abuse land because we regard it as a commodity belonging to us. When we see land as a community to which we belong, we may begin to use it with love and respect.” - Aldo Leopold, 1949. A Sand County almanac.