SOIL BIOLOGY & SOIL BUILDING
by Bruce Kirk
Building soil is the main activity of any regenerative ecosystem. Loss of fertile soil is the biggest problem of the current agricultural systems. When we talk about soil building we are talking about getting large amounts of bio mass back into the soil. Technically this is putting carbon back into the soil, as well as bringing back the chemical balance and micro organism life in the soil.
This is something we do after integrating the water retention systems, to bring life back into the soil to support plant growth which we bring back organic materials into the ground.
Healthy soils are a result of a healthy, intact soil food web (microbiology) and are the foundation for all life. Its what connects everything that exists above ground to what exists below, It is the heart of the biosphere.
An incredible diversity of organisms make up the soil food web. They range in size from the tiniest one-celled bacteria, algae, fungi, and protozoa, to the more complex nematodes and micro-arthropods, to the visible earthworms, insects, small vertebrates, and plants. They are the ultimate recyclers of organic material and chemical elementsas they drive physical, chemical and biological processes. As these organisms eat, grow, and move through the soil, they make it possible to have clean water, clean air, healthy plants, and moderated water flow.
There are many ways that the soil food web is an integral part of landscape processes. Soil organisms decompose organic compounds, including manure, plant residue, and pesticides, preventing them from entering water and becoming pollutants. They sequester nitrogen and other nutrients that might otherwise enter groundwater, and they fix nitrogen from the atmosphere, making it available to plants. Many organisms enhance soil aggregation and porosity, thus increasing infiltration and reducing runoff.
The soil food web supports soil stabilisation, soil aeration, nutrient retention, nutrient cycling, Water retention and Plant fertility.
Soils are formed through the interaction of five major factors: time, climate, parent material, topography and relief, and organisms. The relative influence of each factor varies from place to place, but the combination of all five factors normally determines the kind of soil developing in any given place.
CLIMATE - particularly temperature, precipitation and frost action have a profound influence on the soil forming processes which occur within a region. The kind of climate largely determines the nature of the weathering processes that will occur and the rates of these chemical and physical processes. It directly affects the type of vegetation in an area which in turn will affect those soil forming processes related to vegetation
TIME - The formation of soils is a continuing process and generally takes several thousand years for significant changes to take place.
PARENT MATERIAL - is the unconsolidated mineral and organic deposits in which soils are developing. It determines the mineralogical composition and contributes largely to the physical and chemical characteristics of the soil. The kind of parent material also influences the rate at which soil forming processes take place.
TOPOGRAPHY & RELIEF - The shape of the land surface, its slope and position on the landscape, greatly influence the kinds of soils formed.
ORGANISMS - All living organisms actively influence the soil forming process. These organisms include bacteria, fungi, vegetation and animals. Their major influence is the effect on the chemical and physical environment of the soils.
The interaction of these five soil-forming factors; time, climate, parent material, topography, and plant and animal life, result in the development of a soil profile. A soil profile is a vertical section of the soil beginning at the surface and extending down into the unconsolidated underlying material to a depth of 60 inches or more.
Once we have an understanding of these five interacting factors we can accelerate the formation of soil by mimicking either one of these processes. All known human soil building techniques are activities which are manipulating or copying natural processes in a more controlled more concise time frame. Some examples of this are;
- Thermal composting (time, climate and organisms)
- Keyline design and patterning (topography and relief)
- Chop and drop (organisms)
- Bio fertilizers (parent materials)
- Irrigation (climate)
- Mulching (climate)
- Bokashi (time, climate and organisms)
- Microorganism extracts (time, climate and organisms)
- Holistic grazing (time. organisms)
- Swales (climate)
Everything is directly linked to something that is naturally happening already. A good designer or a successful, sustainable system is a direct consequence of how well we understand ecological processes and then how well we participate with these processes