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Better soil | microbial biomass improves available nutrients & carbon levels

Trial conducted by: Creative Innovation Agriculture & Forestry (CIAAF) Adelaide.

Trial aim

On a range of soil samples including sandy soil, loam, clay loam, to ascertain the effect of BioAg’s Soil & Seed on:

  • microbial population in soils (microbial biomass)
  • soil nutrients within the microbial population
  • soil carbon levels

Treatments

Control
1 x 120 l/ha water

Treated
1 x 100 l/ha water
1 x 15 l/ha Soil & Seed

Methodology

In each trial, a control soil and a treated soil was used. All soil samples were collected from non-production areas of the respective farms.

Soil & Seed was applied to the treated samples after collection.

Over a 20-day period, there were no further applications however there were rainfall events during that time.

 

Results

Using protein clipping, biochemical analysis and DNA analysis, CIAAF determined the changes in the microbial biomass (fungi and bacteria) in each sample.

Average total fungi increase +82%

Average total bacteria increase +58%

On average, the total number of microorganisms (bacteria and fungi) increased by 77% above the control.

Why are these results important?

An increased number of micro-organisms in the soil (microbial biomass) improves a number of factors that affect crop production. A higher microbial biomass:

  • improves nutrient supply from the soil to the plant
  • extends the volume of soil from which nutrients are drawn
  • breaks down organic matter
  • stores nutrients in plant-available form
  • suppresses disease-causing soil pathogens
  • increases plant tolerances to heavy metals, drought & salinity
  • converts nitrogen into a plant-available form
  • binds soil into aggregates, improving soil structure

Microbial biomass improves access to nutrients: Even when a nutrient (such as phosphorus) is deficient, plants in soil with a larger soil microbial biomass are more able to access and take up the available nutrients, resulting in better plant health and productivity.

Observations prior to testing

While mixing the soil samples at the end of the trial period the test soil:

  • felt and appeared more friable
  • seemed to have a slightly higher soil temperature
  • seemed to have a higher water holding capacity.

Nutrient increases

Based on trial results, CIAAF are able to estimate the effect on the total amount of soil nutrients that form part of the microbial biomass, and when compared to the control.

Graph 1: Nutrient increases in biomass (T/ha) across soil types analysed in the trial.

Soil carbon

Based on trial results, CIAAF are able to estimate the effect on the total amount of soil carbon that forms part of the microbial biomass, and when compared to the control.

Soil carbon was increased in sandy soil, loam and clay loam by a minimum of 1,516 kg/ha and up to 18,928 kg/ha in clay loam soil.

Graph 2: Increases in soil carbon (T/ha) across soil types analysed in the trial.

Read Soil & Seed success stories

These farmers have all used Soil & Seed and seen the benefits to their soil and improvements in productivity on their farm.