4.2. Ag-Index (Nutrients/Na+Cl)
Proper application of the Agricultural Index or Ag-Index requires optimum edaphic conditions of target soil and the compost in question, (e.g., optimal compost and soil texture, porosity, aeration, bulk density, pH, etc.). Factors that commonly limit crop growth after compost application include: (1) high sodium or chloride levels; (2) biologically unstable material (rapid oxygen uptake and carbon dioxide evolution); and (3) the presence of toxins generally associated with anaerobic conditions or immature compost products. The Ag-Index is used to diminish the probability that sodium and chloride or deficient nutrients become the limiting factor (Thompson et al., 2003).