Environmental constraints to net primary productivity at northern latitudes: A study across scales of radiation interception and biomass production of potato

• Scale study of plant growth with CASA: NPP = RUEopt × Ipar environmental constraints . Field-, air- and spaceborne data provided comparable estimates Maximum air temperature diffuse radiation were major potato ranged from 4.19 to 4.98 g MJ -1 in relation scale. Potential extend approach for quantifying fertilization irrigation need. Intercepted photosynthetically active ( , m -2 d ) is a key biophysical variable governing photosynthetic rate net primary productivity NPP, ). Under optimal conditions, scales proportionally by factor termed ‘optimum use efficiency’ RUE opt The Carnegie-Ames-Stanford (CASA) considers moisture has been widely used remote sensing studies estimate various ecosystems. However, scale effects on the CASA have not sufficiently investigated nor quantified. In this study, at field (Rapidscan reflectance data), (unmanned aerial vehicle (UAV) imagery) (Sentinel-2 imagery), as well several constraints, utilized develop test CASA. was grown multiple years sandy soils Denmark. results showed that all daily fraction f most important factors constraining potato. Taking these into account considerably improved prediction R 2 increase 25–32 % compared no constraints), whereas stress due soil vapor pressure deficits less (relative improvement 2–3 %). Hence, 4.66, Rapidscan, UAV Sentinel-2, respectively, which about 47 %–59 higher than observed actual efficiency. This offers an operational method deriving species level since meteorological are both readily available, demonstrates does vary, depending region. can be predict dry matter production in-season other crops well, potential extending determine demands.