Every gardener experiences problems. It takes some time to learn, and it also takes some time to improve your soil. Most of us are inherently impatient, so let me give some basic needs for soil, and look at some of the "normal" ways of gardening, that are quick fixes, but end up not being the best. Todays topic, tilling. I'll try to stick to the facts, and point out the good and bad fairly.
Basic soil needs: Living microorganisms, nutrients, air, and water. How do we get there?
Tilling- The good: Tilling is the most common first step to gardening, though boxed raised beds are becoming more popular. So tilling does work, and it works by getting rid of competing weeds, and allowing air into the soil. It also decimates the soil ecosystem, and while that sounds bad, the microbe death creates a short term boost of nutrients, which if timed right can give your plants a shot of growth. Also not all tilling is equal, a shallow cultivation method is much less harmful, and if there is any way you can till broad acres following the contour of the land (a level curving path), it will drastically reduce runoff and thus erosion.
The Bad:#1 It takes a lot of time for natural systems of organic deposition and decomposition to create healthy soil, especially if mature trees aren't nearby (think leaf fall). If the soil becomes quickly bare from tilling or any other major disturbance it only takes a few heavy rain storms to wash out all that "work", and the soil is what the rest of life depends on. By weight it is estimated that soil is America's "#1 export" is top soil (look at aerial maps of the Mississippi River dumping tons of soil into the gulf, or closer to home, the Chesapeake Bay). A major part of the solution to this erosion is plant roots, and natures solution is what we call weeds, fast growing ground covers.
#2 The weeds. You must understand that their are hundreds of weed seeds in every square foot of your garden (or lawn). These seeds stay dormant until all of their germinating conditions are met (temp/moisture/soil contact, etc.) Tilling normally satisfies all these conditions, so a week after tilling the "green fuss" is showing up everywhere, and the battle continues/repeats. Although weeds are "evil" to gardeners, they play an important role in nature, and if we want to control them, we need to understand what that is are various types of weeds/ weed roots, and they normally, thrive in conditions where they could improve the soil if left alone. For example, dandelions thrive in compacted soil, and send down that deep tap root that many hate. But if allowed to stay there, the plant will eventually die and that tap root decomposes into a tap root shaped natural compost. Think of it as natures aerification machine, that also adds organic material instead of a hole. Weeds with a hair net type structure thrive in very loose sandy soils, and hold it together. Others thrive after a fire, and boosts nutrients that the fire destroys...pretty awesome system.
#3 The microorganisms, are what create the coveted "crumb structure" of great soil, when you see it once you just know its good. Its dark, smells like fresh earth, and it almost looks like a dark batch of biscuit dough, with all the little lumps of butter holding the pea sized clumps together. In a healthy soil the microorganisms give off sticky substances to hold the crumb structure together, which creates air pockets (good), and prevents nutrients and water from just running right through. The organisms also have a complex relationship with the plants growing in it. The plant roots can actually expel starches and sugars to attract certain types of organisms that they can benefit from. These sugars help give the organisms energy, and in return the organisms have been breaking down organic matter and other organisms into forms of nutrients the plants can't get by itself. Beneficial fungi are a whole other topic, and the more you learn the more it blows your mind. They are like the highway system of the soil and also like the internet, where information can actually be shared among plants, warning each other of pests, so chemicals can be emitted to deter them. I know... sounds sci-fi, but its not.
One last downside of tilling is compaction of soil beneath the depth that the tiller can reach. Compaction, shuts out air and water, and turns the soil ecosystem to an anaerobic environment, which becomes more acidic, and overall not good.
Feel free to post a comment and let me know what you think, have questions, or disagree.
Everybody knows that "healthy soil" makes it easier to grow healthy plants. However there is a major flaw in the thinking of many gardeners about what makes soil "healthy". Too many falsely believe that the chemistry of the soil and right balance of nutrients is the key. Soil life is the key.
Most soils have all the nutrients they need. These nutrients are simply not in a form the plant can take up. In a similar way to how our digestive tracts need "probiotics", a healthy soil ecosystem is needed for the plants to take up the nutrients. One example of this in the key nutrient of Nitrogen, it is the N of NPK fertilizers. 80% of Earths atmosphere is nitrogen! The problem is this nitrogen is not in a form that the plants can use. The legume family of plants and trees however have a symbiotic relationship with a bacteria that is capable of taking atmospheric nitrogen and converting it to the form plants can use. That is why these plants can thrive in almost any soil, and a lot of them end up on invasive plant lists, because they grow so well with access to this key nutrient.
Unfortunately, many that try to grow things run into problems, and the attempted solutions end up waging war on soil biology instead of cultivating it. This is also a very similar with the treatment of human health and the lifestyle that would produce a healthy gut ecosystem. I'm pleased to see the growing trend of education in this area.
In my next post I'll talk in more detail about problems with current "quick fixes" and what other solutions are possible.