Understanding Dr. Elaine Ingham's Recommended Ranges for Plant and Microbial Successions in BioComplete Compost

Healthy soil depends on a thriving community of microorganisms that support plant growth and ecosystem balance. Dr. Elaine Ingham, a leading soil microbiologist, has developed detailed guidelines for the ranges of microbial and plant successional stages that indicate soil health. These recommendations also tie directly into the biological requirements for BioComplete™ Compost, a product designed to restore and maintain soil vitality. This post explores Dr. Ingham’s recommended ranges, explains their significance, and compares them with the minimum biological standards for BioComplete™ Compost.

Figure 1. Summary of Dr. Elaine Ingham's Recommended Ranges pf microbial biomass for different plant successional sand BioComplete™ Compost.

What Are Plant and Microbial Successional Stages?

Succession in ecology refers to the natural progression of species composition in an environment over time. In soil, this means the gradual change in microbial populations and plant communities as the ecosystem develops or recovers.

• Plant succession tracks the changes in plant species from pioneer species to mature, stable communities.

• Microbial succession involves shifts in the types and abundance of bacteria, fungi, protozoa, nematodes, and other microorganisms.

• Various chemical and physical changes are also occurring in succession over time.

  
  

Dr. Ingham’s work identifies specific ranges of microbial and plant populations that correspond to healthy soil at different successional stages. These ranges help farmers, gardeners, and soil scientists assess soil condition and guide management practices.

Why Microbial Communities Matter for Soil Health

Microbes are the engine of soil fertility. They break down organic matter, cycle nutrients, suppress diseases, and improve soil structure. Different microbes play distinct roles:

• Bacteria decompose simple organic compounds and fix nitrogen.

• Fungi break down complex materials like lignin and form symbiotic relationships with plants.

• Protozoa and nematodes regulate microbial populations and release nutrients through predation.

  
  

The balance and diversity of these groups indicate soil function. For example, a dominance of bacteria suggests early successional soil, while a balanced fungal presence signals mature, stable soil.

Dr. Elaine Ingham’s Recommended Ranges Explained

Dr. Ingham’s recommended ranges provide target values for microbial biomass, diversity, and activity at various stages of soil development. These include:

• Bacterial biomass measured in micrograms per gram (ug/g) of soil

• Fungal biomass measured in ug/g of soil, often explored as a ratio compared to fungal-to-bacterial ratio (F:B)

• Protozoa and nematode populations indicating predator-prey dynamics

• Plant species diversity and cover reflecting above-ground succession

  
  

These ranges serve as benchmarks for soil health assessments. For example, early successional soils might have high bacterial counts but low fungal biomass, while mature soils show a balanced fungal-to-bacterial ratio around 1:1 or higher.

Comparing with BioComplete™ Compost Minimum Biological Requirements

BioComplete™ Compost is formulated to meet or exceed Dr. Ingham’s minimum biological requirements to ensure it supports soil restoration effectively. These minimums include:

• Sufficient microbial biomass to jumpstart soil activity

• Balanced fungal and bacterial populations to promote nutrient cycling

• Presence of beneficial protozoa and nematodes to maintain microbial balance

• Diversity of microorganisms to support plant health and disease resistance

  
  

By meeting these standards, BioComplete™ Compost helps soils progress through successional stages toward a healthy, resilient state.

It should be noted, however, that BioComplete™ Compost is a trademarked name that cannot be used unless a license is approved. It also incorporates HOW the compost was made and stored, the protocols which are outlined in the Soil Food Web School's Courses.

Practical Applications for Gardeners and Farmers

Understanding these ranges allows practitioners to:

• Test soil microbial populations and compare them to recommended ranges

• Select composts and soil amendments that meet biological minimums

• Adjust management practices such as crop rotation, cover cropping, and organic inputs to support microbial succession

• Monitor plant succession to gauge ecosystem recovery and soil health

  
  

For example, a farmer noticing low fungal biomass might introduce BioComplete™ Compost to boost fungal populations and improve soil structure.

Tips for Measuring and Interpreting Soil Microbial Data

• Get your soil tested by a certified Soil Food Web microscopy lab.

• Compare results to Dr. Ingham’s recommended ranges to identify successional stage.

• Look for balanced fungal-to-bacterial ratios as a sign of mature soil.

• Monitor changes over time to assess the impact of compost and soil management.

  
  

Challenges and Considerations

• Soil microbial communities vary over space and time, by climate, soil type, and land use.

• Successional stages are dynamic; ranges provide guidance but not absolute rules.

• Testing methods differ in accuracy and cost; choose appropriate tools for your needs.

• Biological amendment quality varies; ensure products meet biological minimums for best results.