不同生育时期玉米洪涝胁迫遥感监测与评估

为建立玉米洪涝灾害遥感监测和评估技术,本研究开展不同生育期不同程度的模拟试验,持续活体监测叶片叶绿素、冠层光谱和覆盖度并测产。结果表明,拔节期洪涝胁迫可显著降低叶绿素含量,最大程度相对变化值达-56.30%,吐丝期胁迫对叶绿素无影响,灌浆期胁迫促使叶绿素下降但并不明显。洪涝胁迫能降低覆盖度,拔节期影响最大,胁迫严重的覆盖度仅46.33%,吐丝期次之,灌浆期较小。洪涝胁迫造成的减产,生育前期影响比后期严重。拔节期和吐丝期各波段反射率与洪涝胁迫程度呈负相关关系,近红外平台波段达到极显著水平,绿峰波段次之,达到显著水平。灌浆期各波段反射率与洪涝胁迫程度呈正相关关系,相关性未达到显著水平。与胁迫程度呈极显著相关的光谱反射率和植被指数可以用于监测玉米洪涝灾害。最终基于胁迫之后与胁迫前的结构不敏感色素指数SIPI的差值DSIPI,建立拔节期和吐丝期洪涝胁迫产量损失率评估模型。

Remote sensing monitoring on maize flood stress and yield evaluation at different stages

In order to set up remote sensing monitoring and evaluation technology of maize flood stress and loss,a simulation experiment with different flood stress degrees was developed at different stages.Chlorophyll content,canopy spectral reflectance and coverage were monitored in vivo,and yield level was tested finally.The results showed that chlorophyll content decreased under flood stress at jointing and filling stages.The decreasing extend was significant at jointing stage and the value of maximal relative change reached-56.30%.There was little influence on chlorophyll at silking stage.Flood stress could reduce the coverage,especially at jointing stage,the most serious treatment was only 46.33%,followed by silking stage and filling stage.Flood stress reduced production at last,and the reduction was more serious in the early stage than in the later stage.There was a negative correlation between reflectance and flood stress degree at jointing stage and silking stage.It was extremely significantly difference at near infrared platform bands and significantly at green peak bands.There was no significant positive correlation between reflectance and flood stress degree at filling stage.Reflectance and spectral indexes with extremely significant correlation can be used to monitor flood.Two models with DSIPI were set up to evaluate flood loss at jointing and silking stage separately.