This is an interesting revelation (to me, anyway). We all know there are cations and anions in the soil that we need to lock up so it doesn't wash away. Cations such as Ca+, Na+, K+, Mg+ are well known to be sequestered to the humus in compost, as well as to clay. But what about the anions? Specifically N- , P-, S- and B-.
There has been data to show that aspects of the soil can hold anions, but then along comes this revelation from my Tazmanian pal SilverSurfer:
The large surface area of biochar can attract and hold all mineral ions - not only cations
(+) such as ammonium, calcium, magnesium and potassium, but also anions (-) such as nitrogen, phosphorus, sulfur, and boron. By attracting and holding both positive and negative nutrient ions in the soil, biochar can reduce both leaching (into groundwater) and out-gassing (into the atmosphere). These loosely-held nutrients are bio-available to microbes and plant roots in the complex root zone.
http://c.ymcdn.com/sites/www.echocommunity.org/resource/collection/F6FFA3BF-02EF-4FE3-B180-F391C063E31A/Biochar-An_Organic_House_for_Soil_Microbes.pdf
This is a BIG deal. Get the biochar activated in high N and some EWC.