The objective of this review is to show in a general way how biochar (BC) can be obtained and its effects on the physicochemical properties of soils and physiological behavior of cultivated plants. BC is a product rich in carbon that comes from the pyrolysis of biomass, generally of vegetable origin. BC is obtained by the decomposition of organic matter exposed to temperatures between 200-900 ºC in an atmosphere with low oxygen availability (pyrolysis), which can be slow, intermediate or fast. Depending on the biomass and the temperature used in its production, BC can contain high levels of elements such as carbon, nitrogen, oxygen, hydrogen, sulfur, among others. The main sources to produce biochar are forest, agroindustrial and manure residues. BC quality and physical-chemical characteristics will depend not only on the type of waste or plant material for production, but also on the plant photosynthetic apparatus. The high carbon contents present in organic matter, which are more resistant to biological and chemical decomposition, are stabilized by the pyrolysis process. When incorporated into the soil, BC remains stable for longer periods of time and is not volatilized into the atmosphere; this allows BC to be considered as an important compound for the mitigation of the impacts of polluting substances. Additionally, it has been found that BC application improves the physicochemical characteristics of the soil, including fertility. This improvement generates positive responses in the physiological behavior of cultivated plants such as the increase of germination, accumulation of dry matter, photosynthetic rate, yield and quality of the harvested organ. BC use opens important doors for the sustainable management of agriculture in Colombia. It can be considered in production systems exposed to heavy metals such as vegetables and perennial species, in order to reduce the impact of these substances on human health.

No abstract

A field experiment was conducted for 2 years (2019 and 2020) to determine the response to the application of Biochar (BC) obtained from the coffee pulp in combination with chemical fertilization (CF) in coffee trees. The established treatments were the edaphic application of different doses of BC (0, 4, 8, and 16 t ha−1) and levels of CF (0, 33, 66, and 100% of the nutritional requirements) on the physical (bulk density (ρa), stable aggregates), chemical (nutrient availability), and biological (respiration) properties of soil from a coffee crop. Regarding the physical properties, it was mainly observed that BC doses of 8 or 16 t ha−1 reduced ρa (0.82 and 0.83 g cm−3, respectively) and increased the aggregation status (96.5% and 96.84%, respectively) in comparison to 0 t ha−1 in 2020. The chemical properties showed that the application of 16 t ha−1 BC decreased about 60% of the exchangeable acidity (EA) compared to the control (0 t ha−1) whereas the pH (4.96 and 4.92) and organic carbon (OC) (4.41 and 4.59) were higher than in the control soil (EA: 0.58 and 0.54 meq/100 g; pH: 4.63 and 4.55; OC: 4.17 and 4.32% in 2019 and 2020, respectively). Soil respiration (biological property) strongly increased (around 50–60%) with the combination of 66% CF and BC doses between 8 and 16 t ha−1 in both years. Doses between 8 and 16 t ha−1 BC of the coffee pulp can improve the quality of soils for coffee cultivation and provide an alternative and more sustainable amendment that may help reduce chemical fertilization.