Net primary production is the rate of the production of the net useful chemical energy. This chemical energy is produced by all the autotrophic organisms present in the ecosystem. It is the difference of energy that is between the rate at which the autotrophic organisms produce chemical energy and the rate at which they utilize a proportion of it during cellular respiration.
It is directed towards the growth and reproduction of the primary producers. Plant productivity plays a crucial role in the carbon cycle by absorbing that carbon dioxide which is emitted during human activities like the burning of coal, fossil fuels, etc. This is then absorbed by the leaves and the other parts of the plants and ultimately becomes part of the soil.
Review figure 18.2, in which Rosenzweig (1968)
Field experiments demonstrate that variation in soil fertility influences terrestrial primary production
Why was precipitation alone, without temperature, sufficient to account for
How are the desert dune ecosystem and the arctic and alpine tundra
How would actual evapotranspiration and net primary production in the desert dune