Recent Developments in Understanding Biochar’s Physical–Chemistry

2021

Biochar is a porous material obtained by biomass thermal degradation in oxygen-starved conditions. It is nowadays applied in many fields. For instance, it is used to synthesize new materials for environmental remediation, catalysis, animal feeding, adsorbent for smells, etc. In the last decades, biochar has been applied also to soils due to its beneficial effects on soil structure, pH, soil organic carbon content, and stability, and, therefore, soil fertility. In addition, this carbonaceous material shows high chemical stability. Once applied to soil it maintains its nature for centuries. Consequently, it can be considered a sink to store atmospheric carbon dioxide in soils, thereby mitigat…

Organic coating on biochar explains its nutrient retention and stimulation of soil fertility

2017

Amending soil with biochar (pyrolized biomass) is suggested as a globally applicable approach to address climate change and soil degradation by carbon sequestration, reducing soil-borne greenhouse-gas emissions and increasing soil nutrient retention. Biochar was shown to promote plant growth, especially when combined with nutrient-rich organic matter, e.g., co-composted biochar. Plant growth promotion was explained by slow release of nutrients, although a mechanistic understanding of nutrient storage in biochar is missing. Here we identify a complex, nutrient-rich organic coating on co-composted biochar that covers the outer and inner (pore) surfaces of biochar particles using high-resoluti…

Research and Application of Biochar in Europe

2015

Soil-Water Interactions Unveiled by Fast Field Cycling NMR Relaxometry

2017

Microstructural and associated chemical changes during the composting of a high temperature biochar: Mechanisms for nitrate, phosphate and other nutr…

2018

Recent studies have demonstrated the importance of the nutrient status of biochar and soils prior to its inclusion in particular agricultural systems. Pre-treatment of nutrient-reactive biochar, where nutrients are loaded into pores and onto surfaces, gives improved yield outcomes compared to untreated biochar. In this study we have used a wide selection of spectroscopic and microscopic techniques to investigate the mechanisms of nutrient retention in a high temperature wood biochar, which had negative effects on Chenopodium quinoa above ground biomass yield when applied to the system without prior nutrient loading, but positive effects when applied after composting. We have compared non-co…

Fourfold Increase in Pumpkin Yield in Response to Low-Dosage Root Zone Application of Urine-Enhanced Biochar to a Fertile Tropical Soil

2015

A widely abundant and invasive forest shrub, Eupatorium adenophorum, was pyrolyzed in a cost-efficient flame curtain kiln to produce biochar. The resulting biochar fulfilled all the requirements for premium quality, according to the European Biochar Certificate. The biochar was either applied alone or mixed with fresh cow urine (1:1 volume) to test its capacity to serve as slow release fertilizer in a pumpkin field trial in Nepal. Treatments included cow-manure compost combined with (i) urine-only; (ii) biochar-only or (iii) urine-loaded biochar. All materials were applied directly to the root zone at a biochar dry matter content of 750 kg·ha−1 before seeding. The urine-biochar treatment le…

Designing biochar properties through the blending of biomass feedstock with metals: Impact on oxyanions adsorption behavior

2018

Metal-blending of biomass prior to pyrolysis is investigated in this work as a tool to modify biochar physico-chemical properties and its behavior as adsorbent. Six different compounds were used for metal-blending: AlCl3, Cu(OH)2, FeSO4, KCl, MgCl2 and Mg(OH)2. Pyrolysis experiments were performed at 400 and 700 °C and the characterization of biochar properties included: elemental composition, thermal stability, surface area and pore size distribution, Zeta potential, redox potential, chemical structure (with nuclear magnetic resonance) and adsorption behavior of arsenate, phosphate and nitrate. Metalblending strongly affected biochars' surface charge and redox potential. Moreover, it incre…

Plant growth improvement mediated by nitrate capture in co-composted biochar

2015

AbstractSoil amendment with pyrogenic carbon (biochar) is discussed as strategy to improve soil fertility to enable economic plus environmental benefits. In temperate soils, however, the use of pure biochar mostly has moderately-negative to -positive yield effects. Here we demonstrate that co-composting considerably promoted biochars’ positive effects, largely by nitrate (nutrient) capture and delivery. In a full-factorial growth study with Chenopodium quinoa, biomass yield increased up to 305% in a sandy-poor soil amended with 2% (w/w) co-composted biochar (BCcomp). Conversely, addition of 2% (w/w) untreated biochar (BCpure) decreased the biomass to 60% of the control. Growth-promoting (BC…