Biochar Type, Ratio, and Nutrient Levels in Growing Media Affects Seedling Production and Plant Performance

Antonios Chrysargyris,Munoo Prasad,Anna Kavanagh,Nikos Tzortzakis

doi:10.3390/agronomy10091421

Antonios Chrysargyris, Munoo Prasad + Show 2 more

Open Access

https://doi.org/10.3390/agronomy10091421

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Abstract

Biochar can be used as an alternative component in growing media, positively affecting plant growth/yield, but also media properties. In the present study, two commercial grade biochars (BFW-forest wood; and BTS-fresh wood screening), mainly wood-based materials, were used at 7.5% and 15% (v/v), adding nutrient in two levels (100% and 150% standard fertilizer level-Fert). Biochar affected growing media properties, with increases on pH and changes on the nutrient content levels. Biochar BFW enhanced the emergence of seeds in comparison to the control. Increased fertilizer levels benefited plant yield in BFW and BTS at 7.5%, but not at 15%. Leaf stomatal conductance was reduced at 150% fertilized biochars (BFW + Fert and BTS + Fert) at 7.5%, while total chlorophylls increased at BTS + Fert at 7.5% and 15%. The addition of biochars decreased the antioxidant activity in the plant. Lipid peroxidation in lettuce was increased in most cases with the presence of biochars (BFW, BTS) and 150% fertilization, activating antioxidant (superoxide oxidase and peroxidase) enzymatic metabolisms. The addition of Biochars in the growing media increased the content of nutrients in seedlings, as plants could absorb more available nutrients. Biochar of beech, spruce, and pine species (BFW) at 7.5% was more promising for substituting peat to produce lettuce seedlings. However, examining different species (tomato, leek, impatiens, and geranium) with BFW at 7.5%, the results were not common, and each species needs to be evaluated further.

Highlights

Biochar is produced with dry pyrolysis of the organic matter, in which plant or animal-based organic materials are subjected to high temperatures (450 to 600 ◦ C), under hypoxia or anoxia environment [1,2], whereas lower temperature (300 ◦ C) have been reported for biochar production [3]
Biochar increased plant growth at a low ratio (7.5%), while it reduced the emergence of lettuce seed and plant height at 15%
It seems better to use a wooden biochar of beech, spruce, and pine species produced at 700 ◦ C with the Schotteredorf process and to use the resulting Biochar (BFW) at a ratio of 7.5% for the production of lettuce seedlings

Summary

Introduction

Biochar is produced with dry pyrolysis of the organic matter, in which plant or animal-based organic materials are subjected to high temperatures (450 to 600 ◦ C), under hypoxia or anoxia environment [1,2], whereas lower temperature (300 ◦ C) have been reported for biochar production [3]. The initial organic material for biochar production is mainly wastes coming from intensive sectors, such as forest residues and wood industries, agriculture and food, and greatly contribute to the environmental management and recycling, reducing the greenhouse gas (GHG) emission and increasing carbon sequestration [4,5,6,7]. The use of biochar in the agriculture sector as an alternative container growing media adds value to the bioenergy business process [8]. Biochar can alleviate salinity stress in crops with important environmental, agriculture, and economic benefit [9]. Biochar has demonstrated the potential for inclusion in growing media, together with different materials such as peat [3,10], compost [8,11], coir [3].

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