Does the physical properties of the soil really matter?
A few weeks ago I talked about the chemical nature of the soil and how important it was to a healthy productive soil. This week I want to share with you how the physical properties or structure of the soil is a very important piece of the puzzle. Soil is composed of approximately 50% solid and 50% poor space. The solid portion is roughly 45% mineral and 5% organic matter.
This can vary depending on the quality of the soil and the amount of rainfall and warm temperatures in the environment. Warmer temperatures and more consistent rain fall tends to burn up organic matter, reducing its volume in the soil. That is why soil in the Southeast tend to be red in color verses our darker Midwest soil with higher organic matter. The remainder of the soil is poor space. This is composed of 25% water and 25% air. It is a 50/50 balance of air and water that give the best environment for root growth and home for the biological organisms to thrive.
Soil Type affect the Physical Properties of the Soil
The solid portion of the soil can be broken up into three main categories: sand, silt and clay. The reality is that most soils are rarely one particle type but a combination of two or more. A soil with a higher amount of clay in it has the ability to hold more nutrients. This smaller practical size is prone to reduced amounts of oxygen due to compaction. The sand, which is larger in size, holds fewer nutrients. It also has more oxygen present, making nutrients more available. The type of soil you have cannot be changed, but through building organic matter, soils can improve their nutrient-holding capacity.
How these soil particles hold together is called soil structure.
The soil particles are held together by glues which are exuded from growing plant and the soil biology. These arrangements of soil are called aggregates and play a big role in how healthy the soil is. The more aggregated the soil is, the more it can be drained of excess water, eliminate erosion and reduce compaction. The less aggregated the soil is, the more erosion can occur due to runoff. This reduces drainage, as well as risk of compaction. Stable aggregates are what we are shooting for in a well-structured soil.
The chemical nature of the soil, as well as the biological activity in the soil, have an impact on soil structure. As I have talked in previous weeks, it is a balanced soil that is the most healthy and most productive. Each property of the soil affects everything else, and achieving this balance is critical to a productive soil. Partnering with the right tenant who understands these realities is important to you and the long-term productivity of your soils.