Biochar from pyrolysis of biomass amended in soils to improve nitrogen use efficiency for enhancing crop productivity and mitigate climate change in agriculture has been well documented. However, application for soil amendment of biochar at high rates could be challenged with cost-effectiveness for small-scale household farmsUse of biowaste-converted biochars for organic/inorganic compound fertilizer can be an option to achieve high productivity and low carbon intensity along with saving N nitrogen fertilizer use in Chinese rice agriculture
As I understand,biochar need not be applied every year like fertilizer.From carbon sequestration point of view, biochar once applied should remain intact in soil for at least a few hundred years.Biochar need to be applied in several tons to get the required benefit (including water holding capacity).Fortifying a huge amount of biochar with fertilizers is a difficult proposition.How long the nutrient enriched biochar will supply nutrients-one year or several years?.If you apply biochar alone( without fortified nutrients),it may help in retension and release to plants of regular applied nutrients every year asper recommendation.If one applies small amounts(not so small) of biochar every year with fortified fertilizers,it may take several years to get the benefit of waterholding capacity or climate change mitigation.
Dear Robin, biochar as a soil amendment has deeply been discussed on Research Gate. I think you don't need a compound biochar fertilizer. You can compare biochar alone or with fertilizer with recommended fertilizer and other organic amendments, including compost, compost + biochar and co-composted biochar- compost. Prepare your own biochar, and then you can conduct a trial on biochar either in a greenhouse or field. These recent articles may be helpful for your plan.
I have also a good contact for you. The researcher is Bruno Glaser. He researched in different biochar since several years and he has a really great experience in biochar. He is also on researchgate. Here is the link:
Dear Dr. Rao, it is always nice to read intellectual input provided by you in RG questions. It is surprising to now for me as a plant breeder that biochar need not be applied every year like fertilizer.From carbon sequestration point of view, biochar once applied should remain intact in soil for at least a few hundred years. It is interesting.
Why short-term biochar application has no yield benefits:evidence from field-grown crops.Jay,C.N. et al. Soil use and Management doi: 10.1111/sum.12181 2015
These papers may be available on reasearchgate.net