夏玉米叶片分层氮素营养的高光谱诊断

建立能够快速诊断作物氮素状况的光谱估算模型，对指导有效施肥具有现实意义。应用高光谱技术在夏玉米生育期研究了氮素在上下层叶片的分布规律及其氮素含量与植被指数的关系，并建立了叶片氮含量的估算模型。结果表明：夏玉米四个生育期(拔节期﹑大喇叭口期﹑抽雄期和灌浆期)上层叶氮含量均高于下层叶氮含量，抽雄期的下层叶片对氮素的缺乏反应敏感，生产上在抽雄期可以通过对下层叶片氮含量的监测来指导施肥。构建了三个时期(拔节、大喇叭口和抽雄期)各自最佳的估测叶片氮含量的模型。研究结果为作物氮素营养诊断及合理施肥提供了参考。

Diagnosis of Nitrogen Content in Upper and Lower Corn Leaves Based on Hyperspectral Data

Based on the spectral characters of corn leaf nitrogen content in the space，the spectral models for rapid estimating crop nitrogen content were set up, which is practically meaningful to effectively providing the guidance in fertilization. Spectral technology was applied to explore corn leaves nitrogen content distribution regularity and the relationship between the nitrogen content and plant index was analysed and then the estimation models were built. The results showed N content in upper leaves is higher than that in lower leaves in four growing stages; lower leaves at tassel emerge stage are sensitive to nitrogen losses，which could be used in guiding fertilization in grain production; optimum estimation models were built atjointing stage，the full-grown stage and tasseling stage, The research results provided the proof of crop nutrient analysis and rational fertilization.