高光谱定量研究土壤养分含量和冬小麦冠层光谱特征之间的关系, 可为冬小麦养分丰缺监测和科学合理指导施肥方案提供理论依据和技术支持。 基于35年长期定位试验, 研究黄土高原渭北旱塬土壤不同施肥处理对冬小麦冠层不同生育期光谱特征的影响, 结果表明： 在单一施肥条件下, 与不施肥（CK）相比, 冬小麦从拔节期到抽穗期, 单施P的CR500, CR670和CR550值均高于CK, 而单施N和M的光谱反射率显著低于CK。 拔节期单施P, N和M的CR500值分别为CK的1.2倍、 74.9%和70.5%； CR670值分别为CK的1.2倍、 66.8%和62.6%； CR550值分别为CK的1.2倍、 76.2%和76.9%。 冬小麦抽穗期各处理反射特征峰谷比拔节期明显增强, 单施P, N和M的CR500值分别为CK的1.2倍、 81.0%和53.5%； CR670值分别为CK的1.3倍、 76.8%和40.6%； CR550值分别为CK的1.2倍、 78.5%和63.4%。 冬小麦至灌浆期, 各处理反射特征峰谷均明显减弱； 至成熟期, 不同施肥处理下冬小麦光谱的“峰谷”差异不再明显。 包络线去除后单一施肥条件下的红谷光谱特征表明, 除成熟期外, 单施P的冬小麦红谷面积（A）、 红谷左面积（AL）和吸收峰对称度（S）均高于CK, 单施N和M均低于CK。 在组合施肥条件下, 所有施氮组合NMP, NP和NM均表现出相似的规律, 在可见光波段红、 蓝光吸收谷深度和绿光反射峰值以及近红外波段的光谱反射率均显著低于CK； PM组合光谱反射特征值略低于CK。 与CK相比, 冬小麦从拔节期到抽穗期, PM组合处理光谱反射率特征值略低于CK； NM, NPM和NP处理光谱反射率特征值之间差异较小但显著低于CK。 NM, NPM和NP处理的CR500值分别为CK的25.85%, 27.99%和26.07%； CR670值分别为CK的12.56%, 13.27%和13.98%； CR550值分别为CK的33.39%, 35.38%和37.04%。 而PM处理CR500, CR670和CR550值分别为CK的67.52%, 55.69%和79.40%。 冬小麦至灌浆期, 各组合处理反射特征峰谷较抽穗期均明显减弱； 冬小麦至成熟期, 不同施肥组合处理之间的光谱反射吸收特征差异不明显, 但均显著低于CK。 连续统去除后组合施肥条件下的红谷光谱特征表明, 各生长期冬小麦红谷面积（A）CK最大, PM处理次之, NM处理最小。

Quantitative study of the relationship between soil nutrient content and canopy spectral characteristics of winter wheat based on hyperspectral techniques can provide theoretical basis and technical support for winter wheat nutrient abundance monitoring and scientific and rational guidance of fertilization programs. In a 35-year long-term positioning experiment, the effects of different fertilization treatments on the spectral characteristics of winter wheat canopy in different growth stages of Loess Plateau were studied. The results showed that under single fertilization conditions, compared with no fertilization (CK), from the jointing stage to the heading stage of the winter wheat, the CR500, CR670 and CR550 values of single P application were higher, while the spectral reflectance of single N and M application was significantly lower. The CR500 values of single P, N and M application in jointing stage were 1.2 times, 74.9% and 70.5% of CK; CR670 values were 1.2 times, 66.8% and 62.6% of CK; CR550 values were 1.2 times, 76.2% and 76.9% of CK, respectively. The peaks and valleys of the reflex characteristics of winter wheat were significantly enhanced at heading stage than those at jointing stage, at heading stage, the CR500 values of P, N and M application were 1.2 times, 81.0% and 53.5% of CK; the CR670 values were 1.3 times, 76.8% and 40.6% of CK; CR550 values were 1.2 times, 78.5% and 63.4% of CK, respectively. At the filling stage, the peaks and valleys of the reflex characteristics of each treatment were obviously weakened; to the maturity stage, the difference between the peaks and valleys of the winter wheat spectrum under different fertilization treatments was no longer obvious. The spectral characteristics of the red band position absorption valley under single fertilization conditions after enveloping line removal showed that, except for the maturity period, the red band absorption valley area (A), the red band absorption valley left area (AL) and the absorption peak symmetry (S) of winter wheat with single P application were higherthan CK, both with N and Mapplication were lower than CK. Under the combined fertilization conditions, the NMP, NP and NM of all nitrogen application combinations showed similar patterns, and the red, blue absorption depth and green reflection peak and the near-infrared spectral reflectance in the visible light range were significantly lower than CK; the spectral reflectance eigenvalue of the PM combined treatment was slightly lower than CK. Compared with CK, the characteristic value of spectral reflectance of PM combined treatment was slightly lower from the jointing stage to the heading stage; the difference between the spectral reflectance values of NM, NPM and NP treatment was small but significantly lower than CK. The CR500 values of NM, NPM and NP treatment were 25.85%, 27.99% and 26.07% of CK; CR670 values were 12.56%, 13.27% and 13.98% of CK; CR550 values were 33.39%, 35.38% and 37.04% of CK, respectively. The CR500, CR670 and CR550 values of PM treatment were 67.52%, 55.69% and 79.40% of CK, respectively. At grain filling stage, the peaks and valleys of each treatment were significantly weaker than those at heading stage. At maturity stage, the spectral reflectance absorption characteristics of different fertilization treatments were not significantly different, but they were significantly lower than CK. The spectral characteristics of red band absorption valley under combined fertilization conditions after enveloping line removal showed that the area of red band absorption valley (A) of the winter wheat was the largest in CK, followed by PM treatment and NM treatment.