Productivity concept

There are three fundamental concepts of productivity:

1. Standing crop: It is the abundance of the organisms existing in the area at any one time. It may be expressed in terms of number of individuals, as biomass of organisms, as energy content or in some other suitable terms. Measurements of standing crop reveal the concentration of individuals in the various populations of the ecosystem.

2. The materials removed: The second concept of productivity is the materials removed from the area per unit time. It includes the yield to man, organisms removed from the ecosystem by migration, and the material withdrawn as organic deposit.

3. The production rate: The third concept of productivity is the production rate. It is the rate at which the growth processes are going forward within the area. The amount of material formed by each link in the food chain per unit of time unit area or volume is “the production rate”.

Three aspects of this steady state may be recognized:

(i) The steady state of populations of climax communities in which equal birth and death rates in population keep the number of individuals relatively constant,

(ii) The steady state of energy flow,

(iii) The steady state of the matter of community, where addition of material by photosynthesis and organic synthesis is balanced by loss of material respiration and decomposition.