Okay, welcome back. Good morning, good afternoon, good evening, whatever time it is there. Let's talk about some of those soil ecosystem services that we've been alluding to for a while now. With a few exceptions, everything we eat traces back to fertile soil. Not just plant foods, but also foods derived from animals. Who in turn, depend on grasses, feed crops, and other plants. Now plants grown in soil provide material not only for food, but also clothing and shelter. In the words of one soil scientist who goes by, Doctor Dirt, quote, without soil we'd be hungry, naked, and homeless. That's one of my favorite quotes about soil. I just find it funny that the gentleman goes by Doctor Dirt, but his real name is Clay Robinson. Well if your first name is already Clay, do you need to call yourself Doctor Dirt? I don't know. It baffles me. But anyway, it's a great nickname. Anyway, back on topic. Despite the valuable services that soil provides, it is frequently overlooked, under appreciated, abused, and literally stepped on without a second thought as to why soil is so essential to public health. And I think anyone who is passionate about food and agriculture can benefit from knowing about some of these soil science basics. Soil quality or what farmers call soil health refers to soil's capacity to perform a range of important functions. And as we covered in a previous section, many of these services are tied to organic matter which refers to the fraction of soil that is either living, dead, or decomposed. Now here are the reasons why organic matter is so beneficial. The first is that the organisms in soil decompose. Crop residues and other organic materials cycling nutrients. Remember how we talked about the soil food web and how everything in soil becomes food for something else? This is that quote, fountain of energy, flowing through a circuit of soils, plants, and animals as Aldo Leopold described it. Organic matter also binds with nutrients and retains water that would otherwise leach downward. This sponge-like capacity of organic matter provides plants with a steady supply of resources for growth. The capacity of soilular organic matter to retain water is particularly important during droughts. This, again, sponge like capacity is the reason why organic farms have a much greater capacity to withstand drought conditions compared to conventional farms. Organic matter also improves soil structure, something called tilth. And that makes soil more porous. Helping to aerate roots, that is, provide them with oxygen. Improve drainage, so we don't have problems of flooding. Absorb rainfall and irrigation water that would otherwise runoff the surface. And this ability of organic matter to slow run off also helps to reduce erosion, keeping fertile soil from getting washed away. Organic matter can also bind with certain contaminants, such as lead, reducing its bio availability. Such that if someone were to ingest, for example lead contaminated produce, the presence of organic matter could actually reduce the amount of lead that is taken up into the body. This is particularly important for farmers and gardeners in urban settings which tend to harbor higher levels of heavy metals and other certain contaminants. Further more, not unlike trees, soil organic matter is a carbon sink, storing carbon that would otherwise contribute to climate change. Now this is not a comprehensive list but it provides a general picture of what soil can do for us. Thus we can see looking at this list that healthy soil is crucial for the long term sustainability of our food supply. Now building and maintaining organic matter and healthy soil in general requires care and attention on the part of farmers. Throughout history and to this day, common farming practices have degraded this important resource and often with catastrophic results. When we come back, we'll be talking more about this challenge of soil degradation.