Sulfate and mineralisable organic sulfur in pastoral soils of New Zealand .1. A quasi equilibrium between sulfate and mineralisable organic sulfur

A theory for a rapid quasi equilibrium between native sulfate and labile organic-S in New Zealand pastoral soils is proposed. It is supported by field and laboratory evidence of the relative constancy of sulfate and phosphate-extractable organic-S (and consequently their direct relationship), the restoration of values after positive and negative perturbations, and their correlation with both mineralised sulfate from laboratory incubation, and with annual pasture yield responses to sulfur fertiliser.