Agrotextiles
A 40% shade net does not cut the crop light by 40%. Shade is rated on total radiation, and PAR passes at its own rate.
— µmol/m²/s
Photosynthetically active radiation reaching the canopy
Incident PAR is held flat across the photoperiod, so the daily integral it produces is an upper bound — real irradiance rises and falls through the day and cloud takes more out of it, and an hourly or measured integral will read well below this. PAR selectivity must come from a spectroradiometer trace of the actual net; it varies with colour, age and dust, and a weathered net is a different product from the one on the datasheet. Diffusing light is generally good for canopy penetration but the fraction here is an input, not a prediction.
Shade Net PAR Transmission & Daily Light Integral — free, with the formula and a worked example, at Textile School.