Spectral Characteristics Comparison of Two Summer Corn Cultivars under Different Fertilization Treatments

This study is aimed to explore the spectrum reflection characteristics of summer corn leaves in different fertilization conditions. Using hyperspectral remote sensing technology, the experiments were conducted in fields to collect the hyperspectral images of Denghai 605 (DH605) and Ludan 981 (LD981) in different growth period under five fertilization treatments, and then the reflectance of corn ear leaves was extracted by ENVI software. The five fertilization treatments included the control (CK) with no fertilization, 40 kg and 30 kg of controlled-release fertilizer per 666.67 m2 as base (K40 and K30), 50 kg and 40 kg of compound fertilizer per 666.67 m2 as base with 15 kg urea as seed fertilizer (F50 + N and F40 + N). The reflectance spectrums of the two corn cultivars under different fertilization treatments showed the approximately same changing trend with a reflection peak at green band (550 nm) and a higher reflection platform at near infrared band (760 nm -1050 nm). At the heading to filling stage, the reflectance of DH605 and LD981 was the highest under the CK, followed by the K30 and F40 + N respectively. At the filling to dough stage, the reflectance of DH605 and LD981 was the highest under the treatment K30 and F40 + N respectively, which was obviously higher than that of the other treatments. In the conditions of compound fertilizer, except the late filling stage, LD981 had little higher reflectance than DH605 at the other stages. In the conditions of controlled-release fertilizer and at dough to mature stage, LD981 had obviously higher reflectance compared to the other stages, and also higher than that of DH605; there was not obvious difference in reflectance LD981 and DH605 at the other stages.