Deriving PAR use efficiency of wet season rice from bright sunshine hour data and canopy characteristics

Abstract

The net primary productivity, vis-à-vis crop growth rate is mainly dependent on radiation use efficiency (RUE). Considering the scarcity of instruments to measure RUE, the indirect approaches should be evolved to determine this important crop characteristic. Keeping this point in mind, Global Solar Radiation (GSR) was determined through indirect approach and field experiment was conducted during 2013-2015 at University Farm of Bidhan Chandra Krishi Viswavidyalaya, West Bengal, India to determine the light extinction coefficient plus RUE of two popular rice cultivars of the region. In the split-plot design, four dates of transplanting were allotted as main plot treatment and two rice cultivars (V1: Swarna; V2: Satabdi) were considered as sub-plot treatment. Statistical tests confirmed that Angstrom equation can be useful for estimation of GSR for this region. Above ground crop-biomass was linearly related to Intercepted photosynthetically active radiation (IPAR) for all of the data sets. Irrespective of years, Swarna cultivar used the radiation more efficiently than the Satabdi cultivar. The mean RUE values were 2.75 and 2.57 gm MJ-1 IPAR for Swarna and Satabdi cultivars respectively.