Detection and Dynamic Variation Characteristics of Rice Nitrogen Status after Anthesis Based on the RGB Color Index

We aimed to elucidate the color changes of rice leaves after anthesis and create an algorithm for monitoring nitrogen contents whole plant. Hence, we provide a theoretical basis precise management fertilizer research development digital image nutrition equipment reference. selected leaf colors main stems four major varieties promoted in production, including Huaidao 5 (late-maturing medium japonica rice), Yangjing 4227 (early maturing late Changyou (late hybrid Yongyou 8 rice). Under different levels, R, G, B values at stages anthesis, dynamic RGB normalized values, correlations between SPAD content plant content, prediction model were studied. The results demonstrate following: (1) regardless B, NRI, NGI NBI followed order, G > R B. NGI, days heading could be fitted according logarithmic equation, y = aebx (0.726 ≤ R2 0.992); NBI, using linear + bx (0.863 0.992). Both fitting effects significant (except NGI). (2) A quadratic function (Y −1296.192x2 539.419x − 10.914; Y −1173.104x2 527.073x 12.993) was adopted construct 0.902 0.838, respectively. Exponential functions 5.698e7.261x; 3.371e9.326x) employed models 0.833 0.706, 5.145e4.9143x; 3.966e5.364x) also used plant, 0.737 0.511, obtained from tests by Determination Coefficient (R2), Relative Percent Deviation (RPD), Root Mean Square Error (RMSE) showed that it feasible, accurate, efficient use scanner measuring rice.