Biochar is a highly aromatic, carbon-rich, porous solid particulate material generated by the pyrolysis of carbon-rich biomass under anaerobic or hypoxic conditions at high temperatures. It contains a large amount of carbon and plant nutrients, has a rich pore structure, a large specific surface area, and numerous oxygen-containing active groups on its surface, making it a multifunctional material. It can not only improve soil quality, enhance fertility, adsorb heavy metals and organic pollutants in soil or sewage, but also has a good fixation effect on carbon and nitrogen. When applied to the soil, it can reduce the emissions of greenhouse gases such as CO₂, N₂O, and CH₄, thus mitigating global warming. Thanks to its unique structure and extensive application value, biochar has been hailed as “black gold” in the academic community and has become one of the hot research fields.
Biochar is rich in organic carbon, which can increase the soil organic carbon content, as well as the content of soil organic matter and humus, thereby enhancing the soil’s nutrient-holding capacity. Most biochar is alkaline or has a large lime equivalent value and can be used as a substitute for lime. By increasing the soil base saturation and consuming soil protons, it can raise the pH of acidic soil, thus improving the availability of some nutrients in acidic soil. Biochar has a certain water-absorbing capacity, especially oxidized biochar can increase the water-holding capacity of sandy soil and improve the soil’s water-holding ability.
Relevant scholars have studied the impact of adding biochar on the transformation of phosphorus forms in different phosphorus source compound fertilizers in the soil and the utilization rate of crop phosphorus fertilizers from the perspective of the combined application of biochar and chemical fertilizers, aiming to provide a reference for the development of fertilizer-saving, efficiency-enhancing, and environmentally friendly fertilizers.
Phosphate rock resources have characteristics such as non-renewability and non-recyclability, and the soil easily fixes or specifically adsorbs phosphorus, resulting in a generally low utilization rate of phosphorus fertilizers in the current season. Therefore, increasing the utilization rate of phosphorus fertilizers in the current season has always been an urgent problem to be solved in agricultural production. Biochar has a large specific surface area and many functional groups. If the addition of biochar can improve the effectiveness of phosphorus in compound fertilizers.
Soil incubation experiments show that adding 5% and 10% biochar to compound fertilizers with different phosphorus sources can improve the availability of phosphorus in the soil, and the contents of H₂O-P and NaHCO₃-P are increased to varying degrees, while the contents of NaOH-P and HCl-P do not change significantly. Under the same phosphorus source, the fresh and dry matter masses of flowering Chinese cabbage in the treatment with biochar addition are not significantly different from those in the treatment without biochar addition, but the treatment with biochar addition improves the utilization rate of phosphorus by flowering Chinese cabbage to varying degrees.
In future research, there are still issues such as production process technology, cost, and the acceptance of farmers in the research on the combined application of biochar and chemical fertilizers, which require deeper innovation and exploration. It is necessary to conduct in-depth research on the compounding process of biochar and traditional chemical fertilizers. For example, considering different regional environments, climate, soil quality, and the characteristics of crops themselves, new processes should be developed. The production process should be optimized from multiple perspectives such as the mixing method of raw materials, the composition and source of materials, and the compounding process, ultimately achieving the goal of cost reduction and efficiency improvement.
Dora Agri will continue to research the biochar product, contact us if you have more idea.