Re: Gary Zimmer, Jerry Brunetti on the OZ/NZ "Three-Up Tour"

[Soilculturebiody]

dry peat heads in the right direction in this case. Soils formed in ash, especially in sub tropics, have the clay species Allophane as the majority of the colloids in the soil. The Allophae along with SOM has worked out this sort of extreme aggregation and has actually hardened the aggregates to the point of removal of the nutrients from plant availability. The lab technique for measurment of "humus" breaks the aggregates and measures the surface area and minerals. But in the field, the minerals and surface areas is reduced due to the extreme nature of the aggregates. In these types of soils, it is even more important to add high quality and organic matter and to protect the soil surface from baking.

Compaction from farming can skew the apparent "good numbers" on soil analysis.

Yes, p in some clay species and sulfur especially in high rainfall.