Managing soils and soil fertility

One of the principle aims of organic agriculture is to sustain and enhance the health of soil, plant, animal and humans as one and indivisible whole. As the first step in the chain, a healthy soil is the foundation of all organic production systems.

Crop nutrients come through indirect routes using relatively insoluble nutrient sources that are made available to the plant by the action of soil micro-organisms. This implies that a fertile soil is also a biologically active soil with high organic matter content, a good open structure that allows air to circulate and optimal moisture levels; in short the things that make a good environment for soil organisms to live and thrive in. As far as possible the nutrients should come from on-farm sources and not be brought in. In practice this means a combination of legumes and green manures as part of rotation, with livestock manures, composts playing a supporting role. Inorganic minerals, such as lime and P and K bearing fertilisers can be used, but these are seen as a last resort, and organic producers need permission from their organic control bodies to use them.

Monitoring is vital for soil health; soil analysis is recommended and nutrient budgeting, which shows the balance of nutrients coming on and off the farm, is an important and very under used tool. The health and vigour of the crop is an obvious indicator of soil health, but the presence or absence of particular weeds can tell you just as much about the condition of your soil. Get into the habit of digging holes to keep an eye on your soil conditions; look at the structure, colour and the numbers of earthworms and other soil organisms. Feel the texture and use your sense of smell to get an idea of the biological health.

Follow these links for more…….

PROSOIL website and Newletter
A new project looking at how grassland farming practices affect soil health and the quality of livestock products, including: management strategies for healthier soils; promoting collaboration between farmers, scientists and the agricultural supply chain; development farms and farmer discussion groups

Recognising and solving soil physical problems
A factsheet on how to identify, avoid and remedy some common problems including: including compaction, smearing, surface capping

Soil assessment and analysis
A factsheet on various aspects of soil assessment including: terminology; assessing soil structure; sampling techniques; choosing the right soil test; soil test providers

Grass-clover leys in organic rotations
A factsheet on many aspects of grass- clover leys including: Rotation design and planning; constraints and opportunities for using grass clover leys; choosing mixtures for short and medium term leys.

Soil Fertility Building Crops in Organic Farming
Technical leaflet summarising the results of a DEFRA research project on fertility building crops, including: Quantities of N fixed by different legumes, Management systems that optimise N accumulation, rotations, considerations of costs, pests & diseases and interactions with other nutrient sources; pros and comes of the main legumes.

Compost, The Effect on Nutrients, Soil Health and Crop Production
A technical leaflet summarising the latest research on composts and composting including: benefits of composting; composting processes and systems; potential contributions for different nutrients; application and management.

Managing manure on organic farms
A technical guide on using animal manures on organic farms including: nutrient value of manures; Nutrient supply to soils and crops; management practices; Nutrient planning; organic regulations; minimising nutrient losses.

Phosphorus and potassium in organic systems: Getting the best from your soils
A factsheet on managing soils to make the most of P & K reserves

Providing information on organic food and farming in Wales