RAPID ASSESSMENT OF THE RATE OF NITROGEN IMMOBILIZATION IN ORGANIC-COMPONENTS OF POTTING MEDIA .1. METHOD DEVELOPMENT

A method for rapid determination of the N immobilisation potential of organic materials used in soilless potting media is described. The method involves incubation of the material for one to four days in nursery tubes or pots. Standardised procedures of moistening, packing, leaching and addition of NO3--N have been developed and are described. The method produces a number which is referred to as the Nitrogen Drawdown Index (NDI).