Well, now being a person that loves gardening and also being one that teaches about highway construction materials, Yes! There is a huge difference between dirt, and soil... here it is, dirt is what you track into the kitchen after being in the garden working, and soil is the medium that allows a seed to develop into a healthy plant, and for that plant to provide a bountiful harvest. There is an old saying that my grandpa used to say "A bad gardener grows bad weeds, a good gardener grows good vegetables, and an excellent gardener grows excellent soil."
So let's take a close look at our soil. Soil consists of three phases: solids, liquids, and gases. Whoa, this sounds like a physics class, well it kind of is. To really understand soil we need to understand the components and how they work together to best serve the needs of the plants.
The solids are the mineral particles, the clay particles, and the organic particles. Plus anything else that is a solid, like the BB from the rabbit you missed last summer who was eating your freshly sprouted lettuce. These items serve to give your soil structure and helps to maintain void content so that air and water can freely move throughout the depth of the soil. The next is the liquids, or the water. Water is the vital for plant growth, along with sustaining other vital organisms and critters that take up home in your soil. The gases or air is the atmosphere that is allowed to take up space in the voids that are not filled with water. Air is important as it allows circulation of oxygen and carbon monoxide, both which are needed for life to be sustained in the soil of a garden.
Yeah, yeah, yeah, all that and a bag of doughnuts. What concern is this for me, I just want to grow things. Well soil structure needs to be in good balance to support optimum growing conditions in the garden. The soil structure must be such that it can provide a foundation for the plants to be supported, it also maintains voids so that roots can easily expand and push where they need to go to find the nutrients they need. The structure also allows worms and other critter to be able to move freely throughout the soil to do the magic that they do. It also makes it so that water can percolate into and out of the soil to provide drainage and water retention, which lets nutrient uptake into the plants happen. One more thing to remember about soil structure is that it allows air to move freely to allow the roots to breath, everything has to breath buddy. Roots that are kept submerged in water will eventually drown and the plant will die, it is better to let the plant breath than trying to figure out how to give it artificial respirations.
How do we maintain good soil structure? One of the simplest means of maintaining the structure is not to walk on it. If you walk on it the particles start to consolidate and compact, and this decreases the void content and makes the soil hard and much less permeable. Another thing that we can do is to eliminate as much of the rototilling as possible. Tilling is a great way to loosen the soil in a newly started be, but if done too often it destroys the structure and can actually kill many of the critters that make a soil healthy. Tilling can also aid in the development of hard pan, which is a well compacted, non permeable soil structure that forms just below the level of the reach of the tiller tines. THis hard pan will negatively affect drainage, and can limit root growth and the ability for critters and microorganisms to be able to pass through the hard ground.
How then do I incorporate more organic materials into my soil to make it more healthy?
I'm out of breath right now, so we will have to continue this discussion in another post.
Hey, no matter what we said about soil, don't forget to, "Keep Those Fingers Dirty!"