UWA Trial Results

Research Summary

“Response of Wheat to a Multiple Species Microbial Inoculant Compared to Fertilizer Application”

Frontiers in Plant Science

Original Jounral Authors: Salmabi K. Assainar, Lynette K. Abbott, Bede S. Mickan, Andrew S. Whiteley, Kadambot H. M. Siddique, and Zakaria M. Solaiman

For full article access: https://www.frontiersin.org/articles/10.3389/fpls.2018.01601/full

Process

Recently a research experiment was conducted to investigate the effect of microbial inoculant relative to a rock-based mineral fertiliser and a chemical fertiliser on wheat growth and yield, and on microbial diversity in the rhizosphere. This trial was conducted by the University of Western Australia (UWA) as an independent research project. The project replicated soil, fertiliser and overall conditions on a property in Dowerin, situated in the Western Australian Wheatbelt region. The soil used in the trial was described as ‘moderately nutrient-deficient, loamy sand with a pH of 5.7’. This document is a condensed version of the findings, with reference and interpretation to the products used in the trial. For more information please refer to the full Frontiers in Plant Science journal article.

Products Tested

The research project included a control plot (no additives), a biological inoculant (Grow Safe® Premium Ag Blend), a mineral fertiliser (Grow Safe® NPK Crop) and a conventional chemical fertiliser (Summit Gusto Gold).

Biological Inoculant – Microbes

Grow Safe® Premium Ag Blend

Grow Safe® Premium Ag Blend is a freeze-dried powder containing a concentrated combination of bacteria & fungi to improve soil health and plant performance. There are 120 billion Colony Forming Units (CFU/g) of beneficial microbes including the species Azotobacter, Bacilli, Mycorrhizae, Pseudomonas, Rhizobium and Trichoderma.

Mineral Fertiliser – MF

Grow Safe® NPK Crop

Typical Analysis

N

%

P

%

K

%

Ca

%

S

%

Mg

%

Fe

%

Si

%

Mn

%

Zn

ppm

Cu

ppm

B

ppm

Ni

ppm

Mo

ppm

Bulk

Density

7.5 7.5 4.5 5.0 8.0 0.9 2.6 6.7 0.4 430 430 17 30 1.5 1.1

Chemical Fertiliser – CF

Summit Fertilizers GustoGold

Typical Analysis

N

%

P

%

K

%

S

%

Cu

%

Zn

%

Mn

%

Bulk Density
10.2 13.1 12.0 7.6 0.07 0.14 0.01 1.11

Application Rates

Control

No soil amendments applied

Microbial Inoculant (Microbes): Grow Safe® Premium Ag Blend – Freeze-dried Concentrate

Seed coating as recommended by Grow Safe®

Mineral Fertiliser (MF): Grow Safe® NPK Crop

Applied Rates: MF: 75kg per/ha

Chemical Fertiliser (CF): Summit Fertilizers – Gusto Gold.

Recommended rate for on-farm use by Summit Fertilizers (CF1)

Applied Rates: CF1: 75kg per/ha, CF2: 55kg per/ha, CF3: 43kg per/ha

The chemical fertiliser was applied at three different rates. The lower rates were to match the N and P content of the mineral fertiliser (CF2 & CF3).

Based on current market pricing (2020), the price-per-tonne of the Grow Safe® mineral fertiliser is on par with the chemical fertiliser tested (<$20/tonne variance).

Table 1.0 –  Applied NPK Fertiliser

Findings

Yield Outcome

Microbes

‘The microbial inoculant significantly increased grain yield without increasing shoot growth’

This is a desirable grain outcome that is likely attributed to the improved nutrient transfer facilitated by the soil microbes. The Grow Safe® soil microbes are also known to enhance Nutrient Use Efficiency, and will divert energy to where the plant requires it most – in this case towards grain production rather than excessive leafy growth, which can be a side-effect of excessive nitrogen during the early stages of plant development.

Mineral Fertiliser

‘For grain yield, the mineral fertilizer was as effective as all of the chemical fertilizer treatments’

As is expressed below (Table 2.0) the result is particularly polarising given the mineral fertiliser (MF – Grow Safe® NPK Crop) had an NPK analysis of N:7.5 P:7.5 K:4.5 consisting of both mineral and soluble nutrients, compared to the chemical fertiliser (CF1 – Gusto Gold) at N:10.2 P:13.1 K:12. Similar yield was achieved with Grow Safe® NPK Crop, with  36% less nitrogen, 75% less phosphorus and 167% less potassium content than the Gusto Gold Fertiliser. The nutrient comparison is expressed in table 1.0 and both fertilisers were applied at the same rate of 75kg/ha.

Table 2.0 – Grain Yield expressed as g/pot-1

Soil Health

‘Mycorrhizal colonization of roots increased with application of the microbial inoculant at an early stage of plant growth (tillering) where benefits to the plant could be expected’

 The inoculant used – Grow Safe® Premium Ag Blend – contains mycorrhizae fungi (Rhizophagus irregularis) to enhance soil colonisation, as well as a range of additional beneficial species. Mycorrhizae fungi assist mineral uptake and nutrient recycling processes in plants, including locked-up or in-soluble elements.

 ‘The chemical fertilizer decreased mycorrhizal colonization, which could reduce potential benefits compared to plants with higher AM fungal colonization’

 This statement highlights some of the detrimental effects chemical fertilisers can have upon soil biology. Grow Safe® mineral fertilisers use select soluble nutrients based upon their biological compatibility and Nutrient Use Efficiency, rather than selection based on total N, P or K. Biology can also act as a buffer during periods of plant stress, therefore maintaining good soil health is an important function of modern agriculture.

Analysis

In their conclusion, UWA researchers were surprised at how well the mineral fertiliser performed given its lower analysis and less soluble characteristics, as well as the response the microbial inoculant had upon wheat yield. The performance of Grow Safe® products have been independently verified for over twenty years and this project represents yet another independent example.

The research clearly identifies;

  • Increased grain yield with the Grow Safe® Premium Ag Blend microbial inoculant.
  • Highest grain yield with Grow Safe® fertiliser yet substantially less applied nitrogen, phosphorus and potassium.
  • Superior microbial and soil health outcomes with the Grow Safe® mineral fertiliser in comparison to the equivalent chemical fertiliser.

In summary, the combination of both the Grow Safe® Premium Ag Blend (microbial inoculant) and the Grow Safe® NPK Crop (mineral fertiliser) are the logical choice for crop production – improving the yield, creating a healthier soil outcome and greater utilisation of soluble nutrients.

The supplementary benefits of a Grow Safe® program go beyond yield and soil health. On a cropping system these can include building soil carbon, a reduced requirement for chemical intervention, nutrient density for marketability, improved natural plant immunity and cell structure to resist pest, disease and instances of frost. These benefits can also be achieved in other agricultural programs such as horticulture, viticulture and pasture operations. A Grow Safe® mineral and microbial program is one designed to sustain and improve performance through soil health.

For more information and current pricing for products tested in this trial, please get in touch with your local field advisor or contact us.

A copy of this summary can be downloaded below;

UWA Trial Summary