Sustainable Crop production with biochar Research Papers (original) (raw)

The needs to develop more sustainable agriculture systems and improve weak rural economies necessitate major changes in agriculture management. Soil degradation, including decreased fertility and increased erosion, is a major concern in agriculture. Long term cultivation of soils could result in degradation, containing soil acidification, soil organic matter depletion, and severe soil erosion. Furthermore, the decrease in soil organic matter decreases the aggregate stability of soil, therefore, it is crucial to remediate the degradation soils by simple and sustainable methods. The thermal process that produces biochar is called pyrolysis, pyro, meaning fire and lysis, meaning separation. During pyrolysis, the crucial trace elements found in plants (over 50 metals) become part of the carbon structure, thereby preventing them from being leached out while making them available to plants via root exudates and microbial symbiosis. A range of organic chemicals are produced during pyrolysis. Some of these remain stuck to the pores and surfaces of the biochar and may have a role in stimulating a plant's internal immune system, thereby increasing its resistance to pathogens. The effect on plant defense mechanisms was mainly observed when using low temperature biochars.This potential use is, however, only just now being developed and still requires a lot of research effort. Soil mineral depletion is a major issue due mainly to soil erosion and nutrient leaching. The addition of biochar is a solution because biochar has been shown to improve soil fertility, to promote plant growth, to increase crop yield, and to reduce contaminations. We review here biochar potential to improve soil fertility. The main properties of biochar are the following: high surface area with many functional groups, high nutrient content, and slow-release fertilizer. Biochar is much too valuable for it to be just added to soil without using it at least once for other beneficial purposes. Basic uses include: drinking water filtration, sanitation of human and kitchen wastes, and as a composting agent. All of these uses have been documented in many different pre-industrial cultures. In the modern world, the uses multiply: adsorber in functional clothing, insulation in the building industry, as carbon electrodes in capacitors for energy storage, food packaging, waste water treatment, air cleaning, silage agent or feed supplement. All those uses could be part of more complex cascades when, after extended up-and down cycling, biochar can be used in a farmer's manure slurry pit or in a sewage treatment plant, before being composted and thus finally becoming a soil amendment. Biochar should only be worked into the soil at the end of such cascades, keeping in mind that some biochar uses, for cleaning up metal or chemical contamination, would render the biochar unsuitable for agricultural soils and need different recycling pathways.