Key Research

This page presents an overview of research or projects we find compelling, particularly from a social, environmental or economic standpoint, and is often updated. These are guideposts to real-world, practical implementation of biochar, wood vinegar and organic humates.

Third of Earth's soil is acutely degraded due to agriculture

A third of the planet’s land is severely degraded and fertile soil is being lost at the rate of 24bn tonnes a year, according to a new United Nations-backed study that calls for a shift away from destructively intensive agriculture.

Ameliorating physical and chemical properties of highly weathered soils in the tropics with charcoal

This review from 2001 explores early research on the use of charcoal to improve soil fertility, noting the high soil organic matter contents and soil fertility of anthropogenic soils (Terra Preta) found in central Amazonia. It provides an early foundation for the explosion of research that followed, having been cited in over 2500 subsequent papers.

Analytical electron microscopy of black carbon and microaggregated mineral matter in Amazonian dark Earth

Black carbon (BC) is one of the most stable forms of soil organic matter. Its surface functional groups and structure have been well characterized by a range of analytical methods. In this paper a range of microscopy techniques were used to investigate the possible reactions of BC particles within microaggregates (<2 mm) found in Amazonian dark Earth.

Aggregate‐occluded black carbon in soil

This study found that the majority of black carbon or char from wildfires found in the soils sampled is comprised of very small particles less than 53 μm (micrometers) contained within soil aggregates. As a comparison, thin human hair is 40 to 60 μm in diameter. Proportionally much less char had a particle size more than 2 mm, and only 3% of the char was not aggregated.

FAO Soils Bulletin: The importance of soil organic matter

This soils bulletin concentrates on the organic matter dynamics of cropping soils. In brief, it discusses circumstances that deplete organic matter and the negative outcomes of this. The bulletin then moves on to more proactive solutions. It reviews a "basket" of practices in order to show how they can increase organic matter content and discusses the land and cropping benefits that then accrue.

The Terra Preta phenomenon: a model for sustainable agriculture in the humid tropics

Many soils of the lowland humid tropics are thought to be too infertile to support sustainable agriculture. However, there is strong evidence that permanent or semi-permanent agriculture can itself create sustainably fertile soils known as Terra Preta soils. These soils not only contain higher concentrations of nutrients such as nitrogen, phosphorus, potassium and calcium, but also greater amounts of stable soil organic matter.

Anthropogenic soils in the Central Amazon: from categories to a continuum

Amazonian Dark Earths (ADE), one of the best‐known examples of anthropogenic (man‐made) soils, are the result of Amerindian settlements in the pre‐Columbian period. Scholars tend to divide ADE into two categories: terra preta and terra mulata, however we show that ADE along the Middle Madeira, Brazilian Amazon are extremely diverse. We also assess local perceptions and classifications of anthropogenic and surrounding soils using ethnographic data.

Environmental and Economic Costs of Soil Erosion and Conservation Benefits

Soil erosion is a major environmental threat to the sustainability and productive capacity of agriculture. During the last 40 years, nearly one-third of the world's arable land has been lost by erosion and continues to be lost at a rate of more than 10 million hectares per year. With the addition of a quarter of a million people each day, the world population's food demand is increasing at a time when per capita food productivity is beginning to decline.

Acceleration of Biochar Surface Oxidation during Composting?

Pyrogenic carbonaceous material (known as biochar) is a direct key factor for the high cation exchange capacity (CEC) of ancient Amazonian Dark Earths (Terra Preta de Indio) in Brazil. The increased CEC of biochar-rich soils is closely related to the formation of O- and H-containing functional groups, such as carboxylic and phenolic groups, and the relative decrease of C content on the biochar surface. High surface oxidation of ancient biochar particles in Terra Preta is the key factor of its increased cation exchange capacity. Our results show that composting seem to be a suitable method to accelerate the formation of organically bonded oxygen containing functional groups on the surface of fresh biochars.

Biochar: Pyrogenic Carbon for Agricultural Use - A Critical Review

Biochar (carbonized biomass for agricultural use) has been used worldwide as soil amendment and is a technology of particular interest for Brazil, since its inspiration is from the historical Terra Preta de Índios (Amazon Dark Earth). In the last decade, numerous studies on biochar have been carried out and now a vast literature, and excellent reviews, are available. The objective of this paper is therefore to deliver a critical review with some highlights on biochar research, rather than an exhaustive bibliographic review. To this end, some key points considered critical and relevant were selected and the pertinent literature condensed, with a view to guide future research, rather than analyze trends of the past.

Application of sustainability indicators, soil organic matter and electrical conductivity to resource management

We report here 2 case studies that demonstrate the significance of sustainability indicators in discerning trends in land and water resources. Soil organic matter declined exponentially as the cultivation period for cereal cropping increased. This resultedin a reduction in soil nitrogen supply, and lower grain protein and cereal grain yields. The associated effects werereduced soil aggregation and increased soil sodicity. Electrical conductivity of the soil as well as stream watershowed weak but declining trends with time. Groundwater level from the long-term monitoring bore near the streamand groundwater salinity showed significantly declining trends over the 35 years sampling period.

Ridgedale Permaculture

Ridgedale Farm is a high quality local food producer and pioneering educational site. We facilitate the next generation of entrepreneurial young farmers getting set up profitably on the land through powerful and focused learning experiences. Here at our farm in Sweden we demonstrate and teach Farm Scale Permaculture Design, Regenerative Agriculture, Keyline Design, Agroforestry, Pasture based livestock enterprises, Holistic Management, No-Dig Market Gardening as well as operating our own on-farm poultry processing facility. Our foremost responsibility is regenerating our landscape, ecosystem processes and soils through resilient, replicable, scalable and profitable farm enterprises. Our secondary function is to educate, facilitate, inform and empower people into action through regenerative design, enterprise and holistic decision-making that fosters and stimulates local community, economy and resilience.

Dirt: The Erosion of Civilizations by David Montgomery

This seminal book is an engaging natural and cultural history of soil that sweeps from ancient civilizations to modern times, documenting how we are using up Earth's soil. Once bare of protective vegetation and exposed to wind and rain, cultivated soils erode bit by bit, slowly enough to be ignored in a single lifetime but fast enough over centuries to limit the lifespan of civilizations. A rich mix of history, archaeology and geology, Dirt traces the role of soil use and abuse in the history of Mesopotamia, Ancient Greece, the Roman Empire, China, European colonialism, Central America, and the American push westward. We see how soil has shaped us and we have shaped soil—as society after society has risen, prospered, and plowed through a natural endowment of fertile dirt. David R. Montgomery sees in the recent rise of organic and no-till farming the hope for a new agricultural revolution that might help us avoid the fate of previous civilizations.

Biochar builds soil carbon over a decade by stabilising rhizodeposits

Field-aged biochar enhanced the belowground recovery of new root-derived C by 20%, and slowed soil organic carbon mineralization by 5.5%. Retention of root-derived C in the stable organo-mineral fraction (<53 μm) was also increased by 6%. We demonstrated that biochar accelerates the formation of microaggregates via organo-mineral interactions, resulting in the stabilization and accumulation of soil organic carbon. The long-term stabilization of rhizodeposits by biochar amendment has significant implications for increasing SOC sequestration potential beyond the recalcitrant C contained in the biochar. Pasture systems may allocate nearly 40% of the fixed carbon absorbed from atmosphere as rhizodeposits (that is, exudates, soluble lysates, mucilage, sloughed-off root cells and tissues). Hence, the retention of belowground C inputs by the application of biochar could play a major role in C sequestration in grasslands, which occupy an area of 3.5 Gha worldwide.

Black carbon in sustainable soils of the Brazilian Amazon region

In the Brazilian Amazon, patches of highly fertile anthropogenic soils, known as Terra Preta occur within the Oxisol and Ultisol landscape. Since Terra Preta soils are characterized by a large and stable soil organic matter (SOM) pool, we assumed that this is a key factor for the sustainability of these soils. In the present study, we analyzed finely divided residues from burning (black carbon) in the fine earth and particle size separates in Terra Preta as compared to adjacent Oxisols. The SOM of Terra Preta consists up to 30% of black carbon, which remains as residue after incomplete burning of biomass. Due to its highly aromatic structure, it is chemically and microbiologically inert and persists in the environment over thousands of years. Thus, a part of the labile carbon pool in the biomass has been converted into a stable SOM pool. Weak oxidation during this time produces carboxylic groups on the edges of the aromatic rings, which increases the cation exchange capacity. Therefore, we conclude that black carbon is a key factor for sustainable and very fertile soils in the humid tropics, which could be established even on highly weathered, very infertile Oxisols.

Chemolithotrophic processes in the bacterial communities on the surface of mineral-enriched biochars

Biochar and mineral-enriched biochar (MEB) have been used as soil amendments to improve soil fertility, sequester carbon and mitigate greenhouse gas emissions. Such beneficial outcomes could be partially mediated by soil bacteria, however little is known about how they directly interact with biochar or MEB. We therefore analyzed the diversity and functions of bacterial communities on the surfaces of one biochar and two different MEBs after a 140-day incubation in soil. The results show that the biochar and the MEBs harbor distinct bacterial communities to the bulk soil. Communities on biochar and MEBs were dominated by a novel Gammaproteobacterium. Genome reconstruction combined with electron microscopy and high-resolution elemental analysis revealed that the bacterium generates energy from the oxidation of iron that is present on the surface. Two other bacteria belonging to the genus Thiobacillus and a novel group within the Oxalbacteraceae were enriched only on the MEBs and they had the genetic capacity for thiosulfate oxidation. All three surface-enriched bacteria also had the capacity to fix carbon dioxide, either in a potentially strictly autotrophic or mixotrophic manner. Our results show the dominance of chemolithotrophic processes on the surface of biochar and MEB that can contribute to carbon sequestration in soil.

Nanoscale analyses of the surface structure and composition of biochars extracted from field trials or after co-composting using advanced analytical electron microscopy

Biochars have been recognized as an important material to improve soil properties. In a number of studies their beneficial properties have been found to increase with residence time in soil and during the composting process. The beneficial properties have been correlated with surface functional groups resulting from the interactions between char particles, inorganic and organic matter in the soil and soil biota. These interactions result in the formation of organo-mineral phases on the internal and external surfaces of the biochar. To characterize the structure of, and interface between, the carbon and mineral phases, we examined biochars recovered from two field trials and after composting from different countries using high resolution scanning electron microscopy (SEM), atomic resolution transmission electron microscopy (TEM) and scanning TEM (STEM), energy electron loss spectroscopy (EELS) and energy dispersive X-ray spectroscopy (EDS) at resolutions of 1–20 nm. The work revealed the formation of porous agglomerates of different minerals/inorganic compounds bound together with organic compounds on the surfaces of the biochar. In some cases, these agglomerates were bound together to form organo-mineral associations. The analyses also showed that the organic compounds containing both N and C functional groups and mixed valence iron oxide nanoparticles are possibly interacting with the organic compounds. The analysis also showed the formation of pores at the interface of the carbon matrix and organo-mineral aggregates.