Nitrogen Status Detection of Corn Leaves By Reflectance Technique

摘要

A pot experiment with one maize hybrid grown with three N fertilizer rates (0, 4 and 10 mmol) was conducted. The objective of the experiment was to determine the feasibility of using reflectance of corn leaves to quickly estimate their N status. Leaf relative reflectance, leaf area, leaf weight and leaf N concentration were measured on V6 and VT growth stage. Reflectance was measured in the range of 600 to 1200 nm with a Quantum 1200 scanning spectrophotometer in laboratory. PLSR and PCR regression with different data pretreatment was used to build calibration models which express leaf N content as a function of relative reflectance. Multivariate regression coefficient in calibration for the data of (V6+VT) mixture, V6 and VT are 0.70, 0.86 and 0.81, respectively. The R2 coefficients in prediction for the above three data groups are 0.66, 0.74 and 0.84, respectively. Results show that leaf reflectance can be used to quickly predict the N status of corn and provide information needed for the development of variable-rate fertilizer N application technology.