Birch and Eucalyptus seedling responses to arginine phosphate direct-to-root applications at planting

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Veracel planter_600 mL hydrogel per tree.JPG  Veracel planting_600ml hydrogel per tree.JPG  

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Project host: Arevo - a local biotechnology company offering products based on research at SLU

Contact: jonathan.love@arevo.se

BACKGROUND AND MOTIVATION

Seedling and cutting survival rate together with vigorous early growth are key silvicultural objectives of efficient reforestation.  Arevo has developed a business around the arginine phosphate-based product arGrow® Granulat with this need in mind. Since filing the first patent related to the use of arginine phosphate as a plant nutrient in 2016, commercial applications to date have largely been concentrated on the Nordic Pine market, and now increasingly so for Spruce. Around 15 million doses were applied in 2020, and a total of 35-40 million doses are forecast for the 2021 season. Here, we are proposing to run extensive Birch and Eucalyptus arGrow® Granulat greenhouse-based trials in preparation for field trials with interested partners. One Birch field trial will be planned for this project.

In the case of boreal conifer forests, one dose refers to a precise application of 40 mg N/seedling at planting with safe, direct-to-root contact deployed using a modified Pottiputki planting tube. This is equivalent to 88 g N/ha at an initial stocking rate of 2200 stems/ha, for example. Multi-year data describing plant-soil responses to arGrow® Granulat transcend the direct nutritional value by improving root development and mycorrhizal associations. It is likely that this leads to greater acquisition of available water and ambient mineralized nutrition that becomes available as a post-harvest pulse. These benefits suggest arGrow® Granulat has significant impacts beyond those of any conventional fertilizer available on the market today. As such, we have chosen to register and label the product as a biostimulant, rather than a fertilizer, which has important consequences for our customers who value FSC and PEFC certification. In addition, arGrow® Granulat is aligned with the EU Green Deal aspirational goals of making step changes in reducing fertilizer inputs and nitrogen leaching by 2030.

Further exploration of wider silvicultural and management questions is worthwhile. It appears that adopting arGrow® Granulat may facilitate greater flexibility when selecting planting spot and thus creates an opportunity for foresters to consider site preparation techniques with reduced disturbance. Furthermore, it may be possible to increase uptake efficiency and reduce costs where conventional NPK fertilizers are used as part of the standard planting practice.

Birch and Eucalyptus present different biology to Pine and Spruce. Our preliminary work with arGrow® Granulat and earlier work with liquid arGrow® products suggests the general biology of amino acid uptake and metabolism extends to these genera. However, Birch and Eucalyptus are grown for industrial fibre supply under different and varied conditions and the full extent of the benefits of applying arGrow® Granular at planting are yet to be understood. We wish to address this knowledge gap in the project.

OBJECTIVES AND SCOPE

We aim to establish robust recommendations for the use of arGrow® Granulat under relevant silvicultural scenarios with a focus on short fibre species of Birch and Eucalyptus. Specifically, in this project we aim to:

  1. Establish effective dosing of arGrow® Granulat for relevant Birch and Eucalyptus genotypes under greenhouse conditions that mimic conventional NPK fertilizer applications at planting or as part of site preparation (amount, composition, release rate and physical placement relative to the seedling/cutting
  2. To describe basic responses to arGrow® Granulat under greenhouse conditions:
    1. growth rate (height and root collar diameter) and biomass allocation
    2. evaluate root system architecture
    3. quantify foliar N and P
    4. estimate nitrogen- and phosphate-use-efficiency if current practice includes co-application of conventional NPK fertilizer at planting or as part of site preparation
    5. estimation of mycorrhizal association
  3. Establish a single site, local Birch field trial at 2 dosing levels of arGrow® Granulat evaluating survival, height growth, root collar diameter and root/shoot biomass allocation
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