Comparison of ground-based LAI measuring methods on winter wheat

This paper compared three ground-based LAI measuring methods (lamina mass per unit area method (LMA), a photographic method and SUNSCAN measurement) from three aspects: maneuverability, error sources and suitable condition and presented a preliminary analysis result. It was found that the LMA method and photographic method can be used during the whole growth stage of winter wheat, while SUNSCAN method should be further studied at the early growth stage before sealing ridges. SUNSCAN measurement was taken once per hour in a day, and the result showed the best time for measurement is from 13 to 15 o’clock. The photographic method revealed higher accuracy than LMA method. It is suggested that the measurement of SUNSCAN needs to process a revision of the anger distribution parameter according to the characteristic of winter wheat in different growth stage. This paper presented a method to revise the angle distribution parameter of SUNSCAN, and applied this method to three varieties of winter wheat on three typical growth stages.