Soil Buiding 101

          Welcome back. Last week we talked a bit about the importance of soil, soil health, and how soil relates to climate stability, climate change, and water availability. We touched on some of the implications of soil degradation for societies worldwide, however focusing more on the U.S. as this where I live and know the most about. This week I want to cover ways of actively building soil while making the case that anybody, regardless of income, has the resources available to build healthy, biologically active, and highly productive soils. I argue that soil stewardship is more than an ability of all, it is the responsibility and obligation of all citizens of planet Earth. So lets take what we discussed last week and put it all together, lets cover some ways of actively building soil and using biological processes to speed up soil building to a few years or decades as opposed to the millennia of natural processes alone.

          To start with, Mulch, Mulch, Mulch. Mulch is the soils best friend. It creates a barrier that prevents evaporation of moisture from the soil, protects the soil from the harsh sun and wind, prevents soil compaction, insulates the soil, acts as a slow release fertilizer, creates a wonderful habitat for soil biology, and substantially builds organic matter directly on site. Earthworms will move mulch into the root zone in the form castings rich in nutrients and beneficial bacteria while red wigglers, pill bugs, and millipedes will break mulch materials down at varying surface levels. Disease has a harder time spreading through mulched soil, with noted exceptions, while beneficial fungi will run rampant. This is because biologically diverse ecosystems provide fewer vectors for disease and parasites while providing habitat for a wide variety of predatory species.

          From my own experience bringing in some fifty cubic yards of mulched wood and just under one hundred cubic yards of unmulched leaves, the biological activity on site absolutely exploded in just a few weeks and this was over the winter. Though I will caution that when bringing in so much raw organic matter from many sites, mine came from several locations near my house, you do increase the probability of introducing an unwanted disease or pathogen. For example, with the wood mulch came an aggressive mold that is no danger to my veggies or tree crops, however because of its tenacity I've had a very difficult time establishing the fungi species I want in that same wood mulch because they come in pure culture and the mold is already well established. This is a gamble you make when urban freesourcing raw materials, arborist companies wont do business with you if you pick and choose. If they bring it for free, then it's as is. I find the gamble worth the benefit of increased organic matter however, especially when with patience I can acclimate more aggressive fungi like oyster mushroom or king stropharia to out compete the mold for niche dominance and then transition to establishing more finicky mushroom species.

Making leaf mulch with the lawnmower in the driveway.

          Second to and in combination with mulching, if you already have a garden or are farming stop tilling your soil. At first this may seem counter intuitive, after all plowing or rototilling loosens compacted soil, allows for better root and water penetration, and increases yields. However this is short lived because the complex network of fungi, bacteria, protozoa, nematodes (tiny worms), and so on is delicate and easily disturbed or destroyed. This is also a false sense of security because it fails to address the real issue, depleted soil health and fertility. This is a lesson I learned the hard way. After several years of deep tilling to increase my yields, I effectively killed off most of my soil organisms, desertified my entire yard, and invited disease into my once backyard oasis. The only way I was able to grow anything at that point was by using synthetic fertilizers to replace what the soil biology did naturally. I replaced a free and low input, high output biological system with an expensive and high input, medium output synthetic system. A complex soil community is what gives healthy soil its loose and friable texture and nutrient holding capacity, without which my clay dominated soil was easily compacted, depleted of nutrients, and rendered useless.

          There are two primary, though not exclusive, solutions for no till systems. The first is to dedicate beds to intensively growing crops that never have heavy machinery or anything else that could compact the soil on them and to deliberately plant where you intend each plant to grow. This is more labor intensive and most appropriate for a home scale garden or urban farm, however by preserving and promoting biological activity and healthy soil structure while actively managing pests and disease as they appear, you hedge the labor costs with having no fertilizer or machinery costs. The second is more appropriate for commercial scale farming, though can be and is used for home gardening. This is a no till system with mixed species seasonal cover crops. Normally most farm fields are left bare for half the year or more, which leaves fields exposed to dessication, oxidation, an erosion from intense winter sun and winds, exposed to freezing winter temperatures that damage or destroy soil organism communities among many other negative impacts. Likewise, the already discussed effects tilling has on soil organisms. The idea behind cover cropping is to grow your own mulch on site with the added benefits of keeping the soil covered with a protective layer throughout the winter and spring, collecting sunlight and carbon while locking up valuable nitrogen and phosphorus, and feeding a mixed diet to the soil biology while dramatically increasing soil organic matter content. Annual crops are then seeded into the residues of the cover crops and benefit from the slow release of nutrients as the cover crop residues decompose.

Typical no till cover crop system with annual crop directly seeded in residues.

Photo credit and info: http://precisionagricultu.re/tag/no-till/

          The perfect companion to mixed species cover cropping is Allan Savory's intensive grazing concept, aka mob grazing. The idea here is again to mimic natural biological systems. Conventional grazing practices say to turn your livestock out on the whole acreage of your pasture, however this leads to uneven grazing due to preference, overgrazing, uneven distribution of manure, lowered productivity, and generally poor soil and pasture health. With intensive grazing, the entire pasture is separated on average into half acre paddocks where the livestock are cycled through two half acres per day. One half acre in the in the morning and the second in the evening. However there are many variations on this and you should look into what will work best for your site. The goal with paddocks is to graze the entire half acre paddock to no more than 50% and not graze it again for at minimum 60 days. In turn the entire paddock is well manured and not overgrazed while allowing ample time for the pasture crops to recover before being grazed again. This dramatically increases pasture productivity, soil organic matter, and animal health. Even better, you can have mixed species herds to increase the diversity in manure type and animal contributed soil biology while more effectively grazing different pasture crops. With a well planned out system, you could even rotate annual crops in for more diverse streams of income. I wonder if I could do this with my chickens on such a small scale as a 1/5 acre lot, hmmm.

Intensive/paddock grazing example.

Photo credit and more info: http://transterraform.com/permaculture-strategies-intensive-rotational-grazing/

Simple example of Allan Savory's concept.

Photo credit and more info: http://permaculturenews.org/2010/05/07/holistic-management-herbivores-hats-and-hope/

 

          And of course, no soil article is complete without discussing compost. I believe no home should be without a composting system of some sort. From a simple compost pile; to vermicomposting (worm composting); to deep bedding in the chicken coop; to all the crazy tumblers, bins, and barrels, there is a composting system for you. The best part is you're using a resource that otherwise would go to the landfill to become contaminated and unrecoverable while adding to methane emissions. Composting is as easy as putting your green and brown kitchen scraps in a pile and letting it rot over winter. As well, composting and especially vermicompost is by far one of the best ways to increase biological activity in the soil. My favorite form of composting is anaerobic digestion because you get the carbon rich humus out of it with the added benefit of capturing methane for later use. With digestion you double the productivity of the composting process with no extra inputs and because of how anaerobic bacteria work you can safely compost human, dog, and cat manure as well. However the initial cost and land needed are limiting factors for digestive composting, as such on the home scale I recommend sticking with tower style vermicomposting or standard composting bins.

          Currently, I fill my chicken run with deep bedding of kitchen scraps and wood mulch and I keep a giant hot pile of composting wood mulch, horse manure, kitchen scraps, brewery waste, and coffee grounds. All of these things are freesourced from my local area. Until I get more of my home infrastructure set up this will work just fine for me. Though there are serious drawbacks, namely having constantly changing available area to turn the pile in order to keep it hot, and the chickens kick the pile all over my work area. Ultimately I intend on building a three bin system to make turning hot compost easier, and a worm tower for keeping in the kitchen in place of the gross bucket that we use for collecting daily refuse.

         The hot compost pile with wheelbarrow on left, chicken coop and shed on the right, mulch madness along back fence.

          Well that in a nutshell is my Soil Building 101. It's by far not exhaustive as there are many ways to build soil that I'm sure I don't know about. I would love to go into greater detail on several of these because they are all worthy of a blog all in themselves. So in the future I will cover some or all of these. I did not go into soil amendments like biochar or rock dust, however I plan on dedicating an entire blog post to each of them as well. Next week, in light of Sao Paulo running out of water within the next month or two, California in a drought and running out of water within the year, the entire U.S. Southwest running dry within the next two to three years, and the U.S. Midwest following closely behind, I going to talk about water, drought, and some permaculture solutions. Have a great week and I look forward to sharing with you then.