Biochar Can Be a Suitable Replacement for Sphagnum Peat in Nursery Production of Pinus ponderosa Seedlings

R Dumroese,Arja Tervahauta,Karl Englund,Juha Heiskanen,Katherine Mcburney,Jeremiah Pinto,Deborah Page-Dumroese

doi:10.3390/f9050232

Abstract

We replaced a control peat medium with up to 75% biochar on a volumetric basis in three different forms (powder, BC; pyrolyzed softwood pellets, PP; composite wood-biochar pellets, WP), and under two supplies of nitrogen fertilizer (20 or 80 mg N) subsequently grew seedlings with a comparable morphology to the control. Using gravimetric methods to determine irrigation frequency and exponential fertilization to ensure all treatments received the same amount of N at a given point in the growing cycle, we successfully replaced peat with 25% BC and up to 50% PP. Increasing the proportion of biochar in the media significantly increased pH and bulk density and reduced effective cation exchange capacity and air-filled porosity, although none of these variables was consistent with resultant seedling growth. Adherence to gravimetric values for irrigation at an 80% water mass threshold in the container revealed that the addition of BC and WP, but not PP, required adjustments to the irrigation schedule. For future studies, we encourage researchers to provide more details about bulk density, porosity, and irrigation regime to improve the potential inference provided by this line of biochar and growing media work.

Highlights

IntroductionAs Haase and Davis [4] note, mitigating deforestation and other forms of forest degradation often requires active afforestation and reforestation, especially the outplanting of seedlings grown in nurseries
Deforestation is a global crisis [1,2,3]
We evaluated replacing peat with three types of biochar (BC, powder; PP, pyrolyzed softwood pellets; wood−biochar pellets (WP), composite wood-biochar powder pellets) up to 75% (v v−1 ) and under two exponential fertilization regimes that supplied either 20 or 80 mg N during the course of the experiment

Summary

Introduction

As Haase and Davis [4] note, mitigating deforestation and other forms of forest degradation often requires active afforestation and reforestation, especially the outplanting of seedlings grown in nurseries. The practice of reforestation is recognized as having, among management options relying on natural pathways, the greatest potential to mitigate changes in climate [5]. Growing seedlings for reforestation in nurseries using containers is a common practice worldwide, and a prominent method in, for example, Canada, Finland, Chile, and other countries with intensive forest management activities. While producing reforestation seedlings efficiently and economically has long been the prevailing practice, a conundrum for nursery managers is how to do so while reducing impacts to the environment. Several techniques have emerged to diminish the environmental impacts of seedling

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Discussion

Conclusion