The Process of Balancing Soils

 

The Process of Balancing Soil

 

Previously we discussed the importance of balancing soil inputs of carbon and nitrogen in maintaining a consistent return of plant residues into the soil profile, along with regulating the rate of soil organic matter decomposition by microbes. Maintaining the mutualistic relationship between plants and biology is critical to achieving a balanced soil environment and ultimately maximizing plant health. What I would like to do now is define the basic process of balancing soils by first identifying specific action steps, and then identify specific products that can help support those actions.

1.    Evaluation – Chemical, Physical and Biological Parameters

·        Chemically evaluate soils for accessibility (soil test), availability (paste extract) and mobility (tissue test) of plant essential nutrients. Additional parameters are TSOC (total soil organic carbon) and carbon to nitrogen ratio.

·        Physical evaluation of soil structure, texture, and % organic matter (humus) - Saturated Hydraulic Conductivity (infiltration rates) http://www.turfdiag.com/ plays a critical role in maintaining a balanced soil and is directly impacted by these three soil parameters.

·        Biological evaluation of plant biomass (rooting, thatch and shoot density), soil biological function and sustainability. The Solvita CO2 Burst Test https://solvita.com provides the opportuninity to measure soil biological activity - respiration.

·        Continually monitor and remediate as needed any excessive accumulation of bicarbonates and sodium in the soil profile.

2.    Chemical Balancing with Inorganic Foundation Minerals

·        Utilize granular and liquid applied minerals to balance base cation nutrients (Ca, Mg, K, Na, and H). Insure a sufficient supply of phosphorus, sulfur and adequate availability of trace elements.

 

3.    Maintain Adequate Soil and Plant Energy

·        Both soil microbes and plants need sufficient nitrogen (proteins) to sustain growth and return residues to the soil profile.

·        Adjust soil applications of synthetic nitrogen relative to the amount of active organic matter present in the soil. Foliar applications of nitrogen should be carefully adjusted to maintain plant health with only a minimal amount of tissue growth.

·        Synthetic sources of nitrogen are less dependent on biological activity and quicker to provide the desired plant response.

  

4.    Build a Supply of Stable Soil Organic Carbon

·        The controlled decomposition of soil organic matter provides a stable source of carbon, nitrogen and other plant essential minerals. Both carbon (carbohydrates) and nitrogen (proteins) provide microbes with food and energy for sustainability, as well as the ability to build new cells and grow.

·        When active soil organic matter is depleted, exogenous applications of soil stable carbon is necessary to maintain biological stability. These carbon sources can come from humic substances (i.e. humin, humic acid, and fulvic acid) or non-humic substances (i.e. amino acids, proteins, starches and sugars).

·        The ideal soil carbon to nitrogen ratio that favors the controlled decomposition of organic matter by microorganisms is 20:1.

5.    Biological Enhancement

·        Bio supplementation with Holganix can speed up the process of achieving a balanced diverse population of beneficial soil microorganisms.

·        The limiting factors for sustaining a biologically active soil are maintaining favorable environmental conditions and adequate food sources (active soil organic matter – carbon, nitrogen, hydrogen and oxygen).

  6.    Increase Saturated Hydraulic Conductivity of Sand Profile Greens

·        The key to increasing infiltration rates in sand-based profiles is enhancing the selective process of lignin degradation.

·        Lignocellulose is the essential part of cell walls of plants and is one of the most abundant organic sources. Lignocellulose is composed primarily of cellulose (24-54%), hemicellulose (11-38%), and lignin (6-31%). 

·        The presence of lignin in plant cell walls (lignocellulose) restricts microbial degradation mechanisms. Lignin limits the accessibility of existing microbial degraders to more biodegradable plant materials, such as cellulose and hemicelluloses. When this occurs, the rate of organic matter inputs can exceed microbial degradation resulting in an accumulation of non-biodegradable organic matter within the rhizosphere. In addition, when the breakdown of cellulose and hemicellulose into sugar is restricted, access to available energy (organic carbon) from the potential fermentation process is reduced.

·        It is the gradual accumulation of these recalcitrant forms of organic matter that have greatly reduced the functionality of USGA and modified sand-based green profiles over the years. It becomes dramatically more intense when dealing with the Ultra-Dwarf Bermuda plants, due to their inherent higher content of lignin in cell walls. USGA greens were not designed to optimize surface drainage, so when infiltration rates go from 6"/hour to .5"/hour in a span of 20 years, there in lies the problem. This then becomes a greater issue when irrigation water quality is challenged.

·        Aggressive core aerification and other cultural activities can provide a short-term enhancement of infiltration rates, but it is highly disruptive to the soil biomass (roots and beneficial biology), deleteriously impacting the biodegradation process – especially detrimental to maintaining important soil fungi populations.  

·        There is some hope in being able to cost effectively utilize lignolytic enzymes which have been shown to selectively breakdown lignin in sand based profiles. These particular enzymes are gaining momentum due to their role in bioenergy production (i.e. bioethanol), which would increase their eventual availability.
 

The above outlined process is the road map in achieving a balanced soil and ultimately maximizing plant health. Many of our high profile soils today are severely challenged from a combination of excessive use of synthetic nitrogen fertilizers, aggressive cultural activities and reduced quality irrigation water. The end result is we have soils that are severely depleted in both active and passive organic matter, reducing the ability of the soil to support a balanced biologically active population of beneficial microorganisms. Without the support of soil biology, plant health is at risk from both reduced nutrient and water access, as well as exposure to pathogens and parasites. When both the carbon and nitrogen cycle breakdown, the entire soil food web is in jeopardy and soils are no longer working for us.