The amount of nutrients such as calcium, nitrogen, carbon, phosphorus, etc., present in the soil at any given time is referred to as the standing state.
Amount of living material present in different trophic levels at a given time. It is expressed as the numbers or biomass of organisms per unit area. The biomass of a species is expressed in terms of either dry or fresh weight.
Productivity: It is the rate at which biomass or organic matter is produced.