数字图像技术在夏玉米氮素营养诊断中的应用

基于6个不同水平的氮肥田间试验,采用数码相机获取夏玉米6叶期和10叶期的冠层图像,分析了不同供氮水平下夏玉米冠层图像色彩参数指标与施氮量、叶片SPAD值、植株硝酸盐浓度、植株全氮含量、0～90cm土壤硝态氮含量之间的关系。结果表明:在6叶期,玉米冠层数字图像色彩参数指标B/(R+G+B)、G/B、R/B、B/L均与施氮量、叶片SPAD值、植株硝酸盐浓度、植株全氮含量、0～90cm土壤硝态氮含量存在极显著的线性相关关系,其中B/(R+G+B)与各营养参数的相关关系最好,其次是B/L。因此,运用数字图像技术进行玉米的氮素营养诊断是可行的。夏玉米6叶期冠层图像色彩参数指标与上述营养参数间的相关性明显高于10叶期,可作为应用数字图像技术进行氮素营养诊断的关键时期,而蓝光标准化值B/(R+G+B)]是进行夏玉米氮素营养诊断的最佳冠层图像色彩参数指标。

Diagnosis of N nutrient status of corn using digital image processing technique

Canopy images of summer corn were taken in the 6-leaf and 10-leaf stages in a field experiment with six N application levels. And the relationships between color parameter indexes of corn canopy images and N application level, leaf SPAD, stem sap nitrate concentration, plant total N content and nitrate N content in 0~90 cm soil were determined. The results show that in the 6-leaf stage, color parameter indexes of B/(R+G+B), G/B, R/B, B/L are significantly linearly correlated with N application level, leaf SPAD, stem sap nitrate concentration, plant total N content and nitrate N content in 0~90 cm soil (P<0.01). And B/(R+G+B) presents most significant correlation, and B/L is next to it. In 10-leaf stage, the correlations are not so significant as those in 6-leaf stage. The results suggest that it is feasible to use digital image processing technique to diagnose N nutrient statues of summer corn. The 6-leaf stage is crucial period with B/(R+G+B) as the index for the N nitrogen diagnosis using digital image processing technique.