Arbuscular mycorrhizal fungi are an integral part of the rhizosphere and assist with nutrient uptake in plant roots, making them an attractive option for use as biofertilisers. This Washinton State University (USA) study evaluated commercially available strains and local inoculants for their effects on root growth, colonisation and nutrient uptake using living field soils in pot experiments.
Project layout
The project was conducted in a greenhouse, where young vines were planted in field soil. These soils were treated with three different commercially available mycorrhizal fungi strains. Two locally collected whole soil inoculants, one from vineyard soil and one from native undisturbed soil, were also included as treatments. Uninoculated and sterilised soil acted as controls. Vines were left to develop and grow for four months.
Results
- Inoculated soils showed no difference in plant biomass, root colonisation or foliar macronutrient concentration compared to the uninoculated controls.
- Vines grown with local inoculants had greater shoot biomass than those from soils treated with commercially available inoculants.
- Despite disturbance from commercial inoculates, the effect of native microbial communities in field soil outweighs the former.
- Local whole-soil inoculants may provide more growth benefits than commercially available arbuscular mycorrhizal fungi.
Significance of the study
This study suggests that adding microbes to your soil may not improve vine performance in all cases. One needs to have a strategy to promote the growth and development of the native microbe population already present by assuring soils are not compacted or waterlogged and that soil chemical attributes like pH and phosphates are corrected before planting, if possible. The principles that promote soil health, like live roots always, minimal surface disturbance, cover crop rotation, and mulching, should be integrated into a management system before inoculation of microbes is considered.
Reference
Lueck, M. R. (2024). An evaluation of mycorrhizal inoculants on the growth and nutrient uptake of European wine grapes (Vitis vinifera) when grown in live field soil [Washington State University]. https://rex.libraries.wsu.edu/esploro/outputs/graduate/An-evaluation-of-mycorrhizal-inoculants-on/99901124820001842#file-0
Image: Wikimedia Commons
