Soil Chemical Analysis

Soil amendment with biochar is evaluated globally as a means to improve soil fertility and to mitigate climate change. However, the effects of biochar on soil biota have received much less attention than its effects on soil chemical properties. A review of the literature reveals a significant number of early studies on biochar-type materials as soil amendments either for managing pathogens, as inoculant carriers or for manipulative experiments to sorb signaling compounds or toxins. However, no studies exist in the soil biologyliterature that recognize the observed largevariations ofbiochar physico-chemical properties. This shortcoming has hampered insight into mechanisms by which biochar influences soil microorganisms, fauna and plant roots. Additional factors limiting meaningful interpretation of many datasets are the clearly demonstrated sorption properties that interfere with standard extraction procedures for soil microbial biomass or enzyme assays, and the confounding effects of varying amounts of minerals. In most studies, microbial biomass has been found to increase as a result of biochar additions, with significant changes in microbial community composition and enzyme activities that may explain biogeochemical effects of biochar on element cycles, plant pathogens, and crop growth. Yet, very little is known about the mechanisms through which biochar affects microbial abundance and community composition. The effects of biochar on soil fauna are even less understood than its effects on microorganisms, apart from several notable studies on earthworms. It is clear, however, that sorption phenomena, pH and physical properties of biochars such as pore structure, surface area and mineral matter play important roles in determining how different biochars affect soil biota. Observations on microbial dynamics lead to the conclusion of a possible improved resource use due to co-location of various resources in and around biochars. Sorption and therebyinactivation of growth-inhibiting substances likelyplaysa rolefor increased abundance of soil biota. No evidence exists so far for direct negative effects of biochars on plant roots. Occasionally observed decreases in abundance of mycorrhizal fungi are likely caused by concomitant increases in nutrient availability,reducing theneedfor symbionts.Inthe shortterm,therelease ofavarietyoforganic molecules from fresh biochar may in some cases be responsible for increases or decreases in abundance and activity of soil biota. A road map for future biochar research must include a systematic appreciation of different biochar-types and basic manipulative experiments that unambiguously identify the interactions between biochar and soil biota.

http://www.css.cornell.edu/faculty/lehmann/pictures/publ/SoilBiolBiochem%2043,%201812–1836,%202011%20Lehmann.pdf

Biochar effects on soil biota – A review

Biochar as a sorbent for contaminant management in soil and water: a review.

The Environmental Protection Agency (EPA) provides access to information on a variety of topics related to the environment and strives to inform citizens of health risks. The EPA also has an extensive library network that consists of 26 libraries throughout the United States, which provide access to a plethora of information to EPA employees, scientists, and researchers. The EPA implemented a reorganization project to digitize their materials so they would be more accessible to a wider range of users, but this plan was drastically accelerated when the EPA was threatened with a budget cut. It chose to close and reduce the hours and services of some of their libraries. As a result, the agency was accused of denying users the “right to know” by making information unavailable, not providing an adequate strategic plan, and discarding vital materials. This case study explores the background of the digitization project, the practices implemented, and the critiques of the project.

/pdf/the-environmental-protection-agency-3gx4opzrjm.pdf

The Environmental Protection Agency

Nature And Properties Of Soils

Assessment of seasonal variations in surface water quality.

Although the major influence of black carbon (BC) on soil and sediment organic contaminant sorption is widely accepted, an understanding of the mechanisms and natural variation in pyrogenic carbon interaction with natural organic matter (NOM) is lacking. The sorption of a phenolic NOM monomer (catechol) and humic acids (HA) onto BC was examined using biochars made from oak, pine, and grass at 250, 400, and 650 degrees C. Catechol sorption equilibrium occurred after 14 d and was described by a diffusion kinetic model, while HA required only 1 d and followed pseudo-second-order kinetics. Catechol sorption capacity increased with increasing biochar combustion temperature, from pine < oak < grass and from coarse < fine particle size. At lower catechol concentrations, sorption affinity (Freundlich constant, K(f)) was directly related to micropore surface area (measured via CO(2) sorptometry) indicating the predominance of specific adsorption. In contrast, HA exhibited an order of magnitude less sorption (0.1% versus 1%, by weight) due to its exclusion from micropores. Greater sorption of both catechol and HA occurred on biochars with nanopores, i.e. biochars made at higher temperatures. These findings suggest that addition of BC to soil, via natural fires or biochar amendments, will sequester abundant native OM through sorption.

Catechol and Humic Acid Sorption onto a Range of Laboratory-Produced Black Carbons (Biochars)

Estimation des facteurs varies et des processus influencant la sorption du pentachlorophenol par des sorbants naturels en utilisant les donnees sur la sorption du pentachlorophenol en solution aqueuse et dans des melanges de solvants par des argiles et des materiaux solides

Influence of solvent and sorbent characteristics on distribution of pentachlorophenol in octanol-water and soil-water systems.

(10) Hopke, P. K. In Atmospheric Aerosol: SourcelAir Quality Relationships; Macias, E. S., Hopke, P. K., Eds.; American Chemical Society: Washington, DC, 1981; pp 21-49. (11) DeCesar, R. T.; Copper, J. A. In Receptor Models Applied to Contemporary Pollution Problems; Dattner, S. L., Hopke, P. K., Eds.; Air Pollution Control Association: Pittsburgh, PA, 1983; pp 127-140. (12) Hopke, P. K. Receptor Modeling in Environmental Chemistry; Wiley: New York, 1985. (13) Shard, M. A,; Illman, D. L.; Kowalski, B. R. Chemometrics; Wiley: New York, 1986; Chapter 6, pp 179-296. (14) Wold, S.; Sjostrom, M. In Chemometrics: Theory and Applications; Kowalski, B. R., Ed.; American Chemical Society: Washington, D.C, 1977; pp 243-281. (15) Wold, S.; Albano, C.; Dunn, W. J.; Edlund, U.; Esbensen, K; Geladi, P.; Hellberg, S.; Johansson, E.; Lindberg, W.; Sjostrom, M. In Proceedings of a NATO Advanced Study Institute on Chemometrics; Nowalshi, B. R., Ed.; Reidel: Dordrecht, Holland, Sept 1983; pp 17-25. (16) SIMCA-3B Pattern Recognition Programs; Principal Data Components: Columbia, MO. 929-943. (17) Lumpkin, T., U. W. Environmental Protection Agency, Research Triangle Park, NC, personal communication, 1987. (18) Friedlander, S. K. Environ. Sci. Technol. 1973, 7,235-240. (19) Watson, J. G. PbD. Dissertation, Oregon Graduate Center,

Influence of organic cosolvents on leaching of hydrophobic organic chemicals through soils

Safety-net role of tree roots: evidence from a pecan (Carya illinoensis K. Koch)-cotton (Gossypium hirsutum L.) alley cropping system in the southern United States

Peter Nkedi-Kizza

Papers

Assessment of seasonal variations in surface water quality.

Catechol and Humic Acid Sorption onto a Range of Laboratory-Produced Black Carbons (Biochars)

Influence of solvent and sorbent characteristics on distribution of pentachlorophenol in octanol-water and soil-water systems.

Influence of organic cosolvents on leaching of hydrophobic organic chemicals through soils

Safety-net role of tree roots: evidence from a pecan (Carya illinoensis K. Koch)-cotton (Gossypium hirsutum L.) alley cropping system in the southern United States