Conservation Tillage for the New Generation
Steve Townsend, of Soil First Farming, lead agronomist an adviser and member of the BASE-UK group gave a lecture to undergraduate agriculture students at Newcastle recently on Conservation Agriculture Principles and Practice
Key points included:
- Soil management is simple – you need to put in more carbon than you take out in order to manage water and maintain soil health, workability and resilience.
- You can’t just add 40 T/acre of FYM to make it work.
- The interaction of 3 elements Minimum Soil Disturbance, Residue Cover and Rotations make it work. Zero tillage provides the maximum of these.
- Roots from the previous crop are preserved and these provide channels for the new crop roots, resist compaction and provide drainage channels.
- Soil organic matter is built and reduces carbon oxidation.
- Beneficial forms of carbon are maintained – the soil binders produced by roots and bacteria in the soil. These make the soil weather-proof and are broken by ploughing.
- Less weed germination.
- Soil always covered – as in all natural situations and so raindrops do not break the soil – their energy is dissipated by the cover.
- Weeds and Slugs.
Ways to reduce these include changing the rotation, using straw incorporation and cover crops to reduce weed growth and growing companion crops for the slugs to feed on.
- When the system works well it can often reduce pesticide and herbicide use.
- It takes 5 years of continuous conservation agriculture to gradually establish natural drainage and this often gets worse before it gets better. Average yields can, but not always, drop in the first 5 years.
- The C:N and C:P ratios in the soil change and extra Phosphorous and Nitrogen are needed until these ratios are adapted.
(photo of barley undersown with a cover crop species mixture, courtesy of the OSCAR project)