What is primary productivity? Give brief description of factors that affect primary productivity.

Primary productivity is defined as the amount of energy accumulation in photosynthetic organisms, by the process of photosynthesis, as biomass or organic matter per unit area over a period of time. It varies in different types of ecosystems because of the different factors that influence it like

• Plant species composition and succession: type of species determine rate and type of photosynthetic pathway.
• Photosynthetic activity: greater the activity, higher the primary production.
• Availability of nutrients, sunlight and precipitation: determine photosynthetic activity and hence, govern primary productivity.
• Type of soil and a number of environmental factors also determine primary productivity.
• eg. Primary productivity is greater for a grassland than a desert.