干旱区棉花冠层高光谱反射特征研究

Characteristics of Reflection Spectrum of Cotton Canopy in North Xinjiang

为揭示棉花冠层高光谱特征,建立棉花高光谱估算模型,促进高光谱技术在棉花长势监测和估产中的应用。基于新疆棉花生长发育规律,对棉花各生育期冠层进行高光谱反射率的测定,研究不同灌水量、氮素营养条件及品种对棉花冠层光谱反射特性的影响。结果表明:在可见光区(400-700nm),适度缺氮(N1)条件下的棉花冠层光谱反射率相对较高,而氮过量(N3)条件下的冠层光谱反射率相对较低;随着灌水量的增加,在近红外波段(700-800nm),棉花冠层光谱反射率呈上升趋势,在盛蕾期和盛花期不同灌水量处理的光谱反射率差异明显;不同棉花品种冠层光谱反射率存在一定差异,在近红外区新陆早13与新陆早10只在吐絮后期光谱反射率差异不明显,在前3个生育期差异较明显。

Based on investigating the characteristics of reflection spectrum of cotton canopy in different cotton varieties,irrigation and nitrogen levels,the results showed that there was a marked difference in the reflection spectrum of the canopy at different growth stages of cotton.The reflection spectrum of the canopy increased before flower and boll stage,decreased after flower and boll stage with the growth of cotton.The reflection spectrum of the canopy decreased in the near infrared region（700-800nm） and increased in the visible region（400-700nm） with increasing the irrigation level.There were some differences in the reflection spectrum of the canopy for different cotton varieties.The reflection spectrum of the canopy for the treatments of N1（135kg·ha-1 nitrogen） and N3（540kg·ha-1 nitrogen） had a marked difference in the near infrared wave bands..