Feeding microbes is only half of their survival.  Beneficial soil microbes require air to breath.  No different than humans, these tiny creatures need air to survive.  The air we breathe, however, is different than the air in the soil.  While both contain nitrogen, oxygen, argon and other gases, soil air contains approximately a hundred times as much carbon dioxide as atmospheric air.  The high concentration of carbon dioxide is necessary for plant production.

The higher concentration of carbon dioxide comes from the soil microbial respiration.  Soil air containing one hundred times more carbon dioxide than atmospheric air is a testament to just how many soil microbes exist in a “healthy” soil.

A healthy soil will have a deep aerobic zone, ample biological activity, and diverse carbon forms “food”.  This is the soil environment necessary to grow high quality high °BRIX crops.

ABSOLUTE ESSENTIALS:

• Soil air contains one hundred times more carbon dioxide (CO2) than the atmosphere.
• Soil microbes breathe oxygen and release carbon dioxide.  This is the reverse of photosynthesis and an important part of the global carbon cycle.

Measuring your soil structure and pore space can be the first step in understanding your soil mineral ratios, aerobic zone, and the effects of your agriculture inputs.  If your soil inputs do not increase the aerobic zone of your soil they should not be used.  Monitor your soil’s structure by measuring your aerobic zone and focus your soil management on building the deepest aerobic zone possible.

The penetrometer is one of the most expensive tools in our soil management tool bag, coming in at just under 300 dollars, however it is irreplaceable.  The use of a penetrometer is a wonderful tool to measure the depth of your aerobic zone.  The penetrometer is essentially measuring the pounds per square inch (PSI) of pressure in the soil.  The depth of the soil’s aerobic zone correlates to the PSI of the soil.  The depth of the aerobic zone is no more than 300 PSI.

ABSOLUTE ESSENTIALS:

• Plant feeder roots feed in the aerobic zone of the soil, less than 300 psi. Feeder roots can not penetrate more than 300 psi.
• The aerobic zone is no more than 300 psi.
• If your soil inputs do not increase the aerobic zone, you should ask yourself why are you using them?

The soil’s structure greatly influences the amount of air in the soil.  In soil there exists pore space.  The larger the pore space the more particles, solutes and air can pass through.  A tight soil with very small pore spaces restricts the amount of air in the soil.  Poorly structured soil will have a small aerobic zone and is a poor environment for microbes.  Soil microbes need a deep aerobic zone to survive, thrive, and store nutrients.

A soil’s aerobic zone can be changed based on the ratio of minerals in the soil and their electrical charge.  Based on the ratio of soil minerals, the soil will either be compacted or flocculated.  Flocculated soil is healthy soil and provides the soil environment necessary for the proliferation of soil microbes.

ABSOLUTE ESSENTIALS:

• Soil pore space is the “home” for soil microbes.
• All of our inputs effect the soil’s pore space.  Some inputs are beneficial and others detrimental.

 

Flocculated soil with ample pore space full of solutes, microbes, and air is characterized by soil high in available calcium.  Due to the size of the hydrated radius (small) and charge (2+) calcium is held tighter to the soil colloid over other cations.

When available calcium fills the soil colloid, the soil environment is electrically strong.  The soil colloids will not disperse when saturated they will aggregate or clump together.  By clumping together, the soil’s pore space increases and the aerobic zone increases.  The soil will be flocculated and possess a good “crumb”.  The soil will be teaming with microbial activity and have a high degree of carbon storage.  The soil will be spongy with good tilth.  Water will not run, it will infiltrate the soil.  This soil type is healthy, productive, and ready to produce high °BRIX crops.

Soils with excess sodium, potassium and magnesium will not be flocculated.  These minerals all have large hydrated radius’ and are weakly charged. When these minerals fill the colloid, the colloid swells.  Under saturated conditions, these colloids will have a weak electrical charge and be easily dispersed (erode).  These colloids will fill in all of the pore space in the soil, creating compaction and shrinking the aerobic zone of the soil.