Sustainability South West Board Member and Organic Farmer, Cate le Grice Mack, presents on the value and importance of soil at the South West Observatory Land and Food Seminar.
11. Farming for food and biodiversity 1. biodiversity aiding food production
12. Farming for food and biodiversity 2. Biodiversity aiding the wider farm economy
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Notes de l'éditeur
Soil forms through the action of weather and micro-organisms on the bedrock. As it forms it acts as the life support for an ever expanding world of flora and fauna. . In turn it too expands, and managed well provides an ever growing blanket of fertility, water retention and purification.
What is missing from this slide is the biomass: the macrofauna (worms etc), mesofauna (small invertebrates such as nemotodes and moluscs) and micro fauna (soil animals less than 0.3 mm in length) and micro flora (bacteria ,fungi, viruses etc etc). We still don’t fully know and understand the complexity and scale of soil micro organisms, but with every bit we find out we realise how spectacular and valuable they are: and how naïve we are about their interactions.
Input: total precipitation, mist and fog intercepted by foliage some transpired through leaves, some involved in photosynthesis, and some evaporated off Direct to the ground: the more foliage there is the less will reach the ground That which does reach the soil: *some is evaporated off (depending on saturateion of air) *some infiltrates the soil, either reaching roots to be taken up by plants, or penetrating the soil to reach round water or contribute to baseflow *the rest becomes runoff
Flash flood effect – poor soil – more total water into river system in shorter time span Good soil structure effect – less water total, and even more critically, distributed over much longer period with lower peak flow But it isn’t only water that is under that red line: there will be tonnes of fertility: the softer top layers of soil will be washed away far more readily in the red scenario than in the green: larger particles will have been removed and often the underlying bedrock disturbed. The red colour of the Brue or the Exe is the farmers’ fertility being washed away
Tell Stroud soil story
Active soils gain contributions of minerals from the bed rock Deep rooting plants contribute to this: for example lucerne has 2 metre roots, breaks up plough pans, traps N from the atmosphere and fixes it through bacterial activity within the soil, ready for slower release over months and even years.
Protecting organisms – eg be wary of such things as livestock wormers – the ivermectin story
Cow pats and rented land story Australian cowpats and the introduction of dung flies Dung beetles play a remarkable role in agriculture. By burying and consuming dung, they improve nutrient recycling and soil structure. They also protect livestock, such as cattle, by removing the dung which, if left, could provide habitat for pests and parasites