Soil plasma, the liquid portion of the soil, is the first product of anabolism.

Manufactured from finely pulverized, catabolized organic matter, soil plasma consists of proteins, salts, decomposed organic compounds, water, and the decomposed cell walls of organic matter.

Soil plasma binds the surfaces of clay crystals to one another, creating aggregate soil structures whose volume is about 50% porous, allowing aggregate rich soil to easily absorb materials applied to the soil.

However, it is now known that the threadlike mycelium of fungi create aggregates by winding around soil particles like stitching in cloth.

Aggregates created by fungi alone, though, are easily destroyed and become strong only in the presence of humic acids (complex organic acids found in soil plasma) which hold clay particles together electrostatically.

One reason aggregate structures are essential for healthy soil is because they create pores within the soil which allows air and water to penetrate soil.

Also, soil is tilled to improve its structure; therefore, good soil structure allows farmers to till less frequently. Water and fertilizer needs are also reduced by the sponge-like storage capacity of the pores within soil aggregates.

Water is not only held in the pores created by soil aggregates, but in humus itself, which acts as a sponge (100 lbs. of humus/compost holds 195 lbs. of water) soaking up water as it passes through the soil, storing it for the future use of plants and soil edaphon.

Because of this remarkable ability, plants grown in humus rich soil are able to continue growing throughout periods of drought while chemically fertilized plants are stunted.

Additionally, humus reduces the erosion caused by wind and water by absorbing water into the soil instead of shedding it - and by creating soil aggregates which are more resistant to wind caused erosion than individual soil particles.

Erosion robs our nation of an estimated 6,000,000,000 tons of soil annually, 69% of which is due to current agricultural activities. Therefore, using compost throughout US agriculture could help to prevent an annual 4,000,000,000 ton loss of soil.

Saving that amount of soil from erosion is a tremendous accomplishment, since topsoil is difficult to replace; it often takes more than a century for natural conditions to produce 1 inch of topsoil.

Supplying nutrients when, and in the amounts plants require, is another challenge facing agriculture today. This is because the majority of chemical fertilizers release too many nutrients too quickly.

Humus, on the contrary, is very effective at supplying nutrients to plants in the proper dosage at the right time. Humus is able to release its nutrients over time because they are held in place by soil aggregates.

Many of the nutrients found in humus are also partially stored in forms chemically unavailable to plants, which are then released in the greatest amount during the summer season, (due to temperature induced microbial activity), when plant growth and nutrient consumption level is at its peak.

Soil aggregates are able to hold nutrients in such an efficient way - partly because of the colloidal (very small) humus particles which they contain. These particles are negatively charged, and therefore attract positively charged elements including potassium, sodium, calcium, magnesium, iron and copper, effectively preventing these essential elements from leaching out of the soil.

The positively charged ions they attract, though not readily leached from soil, are readily available to plants via an ion exchange. In this exchange, plant roots exude positive hydrogen ions, which are replaced by positive mineral ions held by colloidal humus particles.