不同钾素处理春玉米叶片营养元素含量变化及其光谱响应

目的是研究不同钾营养水平春玉米典型生育期叶片的光谱响应,探索叶片内营养成分与叶片光谱反射率的相关性。方法是设置了不同梯度钾处理的盆栽试验,按玉米生育期进行光谱测定和取样分析。结果,通过对不同钾处理间玉米叶片养分含量的差异性分析表明,随着施钾的提高,叶片钾含量差异性达到显著水平。分析不同钾营养水平不同生育时期春玉米叶片光谱反射率与叶片钾含量的相关关系,并建立了喇叭口期利用叶片光谱反射率估测叶片钾含量的数学模型;以及分析了该处理下喇叭口期叶片内水分、叶绿素、氮、磷、钙、镁、锌、锰、铜、铁含量与叶片光谱反射率的相关性。结果表明：不同生育时期叶片钾含量与其光谱反射率的相关关系在光谱维方向存在明显差别,730—930nm和960—1100nm两波段为春玉米喇叭口期评价钾营养状况的敏感波段,光谱变量R767＋R1057,（R767＋R1057） /（logR767＋logR1057）和（R767-R1057） /（logR767-logR1057）均能很好的预测喇叭口期叶片钾含量;该时期叶片内不同成分与光谱反射率相关分析表明：550nm,710nm,950nm三波段处是各个相关曲线的突变点;叶片内各成分间高度相关的,它们的光谱相关曲线趋势也极为一致或对称。

Nutrients Change and Spectral Response of Spring Corn Leaf for Varying Amounts of Potassium Fertilization

The application of spectral properties as a diagnostic tool in nutrient deficiency diagnosis requires further understanding of the relationship between spectral properties and nutrient concentration in plant tissue. Therefore, to examine the effect of variable potassium fertilization on corn(Zea mays L.) leaves and the response on leaf spectral reflectance. We designed an experiment to examine the effect variable amounts of potassium fertilization during four stages of corn growth. Our results showed that the difference in potassium leaf content is significant at the 0.05 probability level with increasing potassium fertilization. We then examined the correlation between corn leaves spectra reflectance and nutrient content as a function of variable levels of potassium fertilization over the entire corn growing season by potted plant experiment. Digital models were constructed to assess potassium content in leaves by utilizing leaves spectral reflectance in the booting stage Our results showed that there was a correlation between the spectral reflectance of corn leaves and corresponding leaf inner moisture, chlorophyll and other nutrient content including nitrogen, phosphorous, potassium, calcium, magnesium, copper, iron, manganese, and zinc. These differences in the spectral reflectance held for the entire growing season. 730-930 nm and 960-1100 nm were defined as sensitive wave bands to assess potassium nutrition condition in booting stage, and spectral variables including R767+R1057,(R767+R1057)/(logR767+logR1057) and (R767-R1057)/(logR767-logR1057) could predict accurately corn leaf potassium-content in the booting stage. Our analysis indicated a correlation between various components in the inner leaves and spectral reflectance at this stage. Inflection points occurred at 410nm, 550nm, 710nm, 950nm in every curve. When correlations between the various components were high, their spectra correlation curves were coincident or symmetrical.