Of the total incident solar radiation the proportion of PAR is

Explanation

The source of energy in all ecosystem is solar energy. About 50% of the solar energy incident over earth is present in PAR (Photosynthetically active radiation). About 1-5% of incident solar radiation or 2 - 10% of PAR is captured by the photosynthetic organisms in the synthesis of organic matter (gross primary productivity). Roughly 20% of it is consumed in respiration so that net capture of energy (net primary productivity) is 0.8 - 4% of incident radiation or 1.6 - 8% of PAR.