Characteristics of Healthy Soil
Healthy soil does not just occur by accident. When farming practices cause imbalance and destruction to soil biology and chemistry, the natural ability for the soil to heal and produce healthy plants is greatly decreased. The end result is soil that no longer can produce quality food without the use of expensive fertilizers, herbicides, pesticides and fungicides. Particular attention needs to be used to reduce the damage caused by current farming practices.
- Healthy soil drains well and warms up quickly in the spring. Soil temperatures need to warm as quickly as possible in the spring to allow for even germination and increase in activity of the microbes. Moisture from winter snow and early spring rain is valuable both at germination and later in the growing season. Soil structure and conditions should facilitate the retention of moisture throughout the growing season. An interesting note - aerobic bacteria play a large role in the production of ammonia nitrate. Ammonia nitrate has a unique quality that it cools when heated, but warms when cooled. Having adequate amounts of this mineral in the soil will regulate the soil's temperature year round. Creating a soil environment that is conducive to soil microbes has wonderful effects.
- Healthy soil does not crust after planting. The aerobic zone is an interface between the atmosphere and the earth. The action of "breathing" occurs when barometric pressure increases and decreases. Removal of the crust allows the soil's aerobic zone to take in air (containing oxygen and 78% nitrogen) and releasing carbon dioxide (determined by the microbe activity). A crust on the top of the soil prevents this interaction from occurring and the result is loss in soil productivity and efficiency. Usually this crust is caused by a "back-up" of salts that accumulate on the top portion of the soil. Correction of this situation requires the removal or dissipation of these mineral salts.
- Healthy soil soaks up heavy rains with little run off. Heavy rains and run off are becoming a bigger concern each year. Compaction of the soil limits the ability to absorb and hold larger volumes of water. By flocculating the soil, the soil becomes able to hold and retain moisture. Reversing hard compacted areas will also allow the soil to manage water saturations more effectively.
- Healthy soil stores moisture for dry spells. Soil structure that is flocculated will hold and conserve water in larger volumes than soil that is tight and compacted.
- Healthy soil resists erosion and nutrient loss. Erosion is caused by an unbalanced polarity in the soil. Balancing the mineral content in the soil will reduce incidence of soil erosion. Nutrient loss can be minimized by developing a practice of incorporating plant residues into the aerobic zone of the soil. The incorporation of plant residues allows the soil microbes to come in contact with the plant residue, effectively breaking down trash and recycling nutrients. Microbes in the aerobic zone will recycle plant nutrients back into plant available nutrients that do not leach. Plant residue left on the top of the soil will oxidize, resulting in nutrients loss.
- Healthy soil does not require ever increasing amounts of fertilizer to maintain good yields. Soil that is balanced and well engineered will require less "additives" to maintain a healthy crop with a good yield. As soil conditions correct, the more able the soil becomes to provide the needed nutrients and energy for the crop, positively impacting quality and yield.
- Healthy soil produces healthy, high quality crops. Nutrition is based on the plant's ability to fix minerals from the soil into its tissues and to create high sugar content. Soil that is balanced and properly managed will provide the energy and nutrients to support the creation of higher sugar content in the plant. Sugar is the plant's own store of energy and is needed for the plant to be able to complete its functions and reproduce.
The aerobic zone is the layer of soil that is in contact with the atmosphere, where oxygen is able to penetrate between soil particles and atmospheric air makes up 25% of the overall soil composition.
This is the profile of the soil where plant feeder roots spread out and where water soluble nutrients are transported into the plant through diffusion and absorption. The aerobic zone is able to support millions of microscopic, air-breathing beneficial organisms that perform many vital roles in the growth of healthy crops.
A healthy aerobic zone is soft and mellow without crusting or lumps. Ideally, aerobic soil should be comprised of 6-10% humus content and therefore capable of holding half its weight in water. The soil should smell like fresh air; a soil with no aroma at all is a dead soil.
The depth of the aerobic zone varies from field to field and varies within fields as well. It is important that you become familiar with the depth of aerobic zone in your fields to ensure that your tillage practices do not result in lumps of anaerobic soil being turned up and deposited on the surface (see Anaerobic Soil).
Anaerobic soil is an environment that has no oxygen and is found horizontally below the aerobic layer. In areas that have had heavy chemical application or with high erosion, the anaerobic layer can be found very close to the surface. Any decaying plant material that is worked into this layer will not decay properly. Rather it will be preserved in formaldehydes and alcohols, the by-products of anaerobic organisms living in this layer of soil.
The anaerobic soil will smell musty, it may be sticky, slimy and or have a shiny appearance. Tap roots may penetrate this layer, but feeder roots are generally not found in the anaerobic zone.