【作者】 唐明星；

【导师】 周治国；

【作者基本信息】 南京农业大学 ， 作物栽培学与耕作学， 2009， 硕士

【摘要】 土壤盐渍化是限制作物生长和产量形成的主要环境胁迫因子之一,我国盐渍土总面积约1亿公顷,占全国可利用土地面积的4.88%,开发利用这部分土地对我国农业生产具有极其重要的意义。本研究采用盆栽和土柱栽培方法,以耐盐品种中棉所44和盐敏感品种苏棉12号为材料,于2007-2008年在江苏南京(118°50’E,32°02’N)南京农业大学牌楼试验站进行盐分水平(0%,非盐渍土壤；0.35%,轻盐渍土壤；0.60%,中盐渍土壤；0.85%,重盐渍土壤；1.00%,盐土)试验,研究了：(1)盐渍胁迫对棉花功能叶其它交换参数和叶绿素荧光参数的影响；(2)基于高光谱参数的盐渍土中棉花功能叶含水量监测模型；(3)基于棉花高光谱参数的棉田土壤电导率监测模型。主要研究结果如下：1.盐渍胁迫对棉花功能叶气体交换参数和叶绿素荧光参数的影响较低的土壤盐分含量(<0.35%),对棉花功能叶的气体交换参数和叶绿素荧光参数的影响较小；当土壤盐分含量高于0.35%时,不同生育期棉花功能叶最大光化学效率、量子产量和光化学猝灭系数均降低,最终导致净光合速率下降、不利于生物量的累积。耐盐品种中棉所44与盐敏感品种苏棉12号相比,土壤盐分含量低于0.35%时,受盐分影响差异不大,随土壤盐分含量进一步升高,耐盐品种中棉所44受盐分影响较盐敏感品种苏棉12号小。2.基于高光谱参数的盐渍土中棉花功能叶含水量监测模型研究在分析棉花功能叶等效水厚度与功能叶光谱反射率的相关关系基础上,筛选出适宜监测盐渍土中棉花功能叶EWT的敏感波段,并进一步综合各敏感波段提出了新的光谱参数(1-R759nm+R451nm)/R451nm,构建了棉花功能叶EWT监测模型：EWT=0.0019x (1-R759nm+R451nm)/R451nm+0.0096.同时分析棉花功能叶相对含水量与功能叶光谱反射率的相关关系发现,盐渍条件下单波段420、543、768、1164 nm是棉花功能叶相对含水量的敏感波段,差值植被指数DVI(768nm,543nm)与棉花功能叶RWC的相关性较好,进一步构建了棉花功能叶相对含水量监测模型：RWC=-16.083×DVI(768nm,543nm)+14.683,经检验两监测模型预测精度均较高。3.基于棉花高光谱参数的棉田土壤电导率监测模型研究综合2个棉花品种在不同生育期的土壤电导率和功能叶光谱反射率试验数据,发现单波段747 nm光谱反射率与土壤电导率的相关性最好,进而构建了以单波段74nm光谱反射率为自变量的土壤电导率线性监测模型EC=-5.4655 R747nm+3.6203.同时利用微分光谱技术,发现土壤电导率敏感波段主要存在于“三边”区域,筛选出棉田土壤电导率相关性较好的光谱参数红边面积SDr,并构建了基于SDr的棉田土壤电导率监测模型EC=-15.764SDr2+5.9843SDr+1.3416.对模型检验的结果表明,利用R747nm、SDr两个光谱参数均可以较好地监测棉田土壤电导率。更多还原

【Abstract】 Soil salinization is a key environmental stress factor that limits crop growth and population development, there are about one hundred million hectare saline soil in China, it is very important to exploit and utilize this soil. Two cotton cultivars with difference salt-tolerance (CCRI-44, Sumian 12) were used, and five salinity rates (0%,0.35%,0.60%, 0.80%,1.00%), standing for five levels respectively were applied. The study focused on:(1) Effects of soil salinity on the gas exchange and chlorophyll fluorescence parameters in cotton functional leaves at different growth stage; (2) Monitoring model study on water status of cotton functional leaves in saline soil with hyperspectral remote sensing; (3) Monitoring model study on soil electrical conductivity in cotton field based on cotton hyperspectral parameter. The main results were as follows:1. Effects of soil salinity on the gas exchange and chlorophyll fluorescence parameters in cotton functional leaves at different growth stageThe influence of low-salt treatment (<0.35%) to the gas exchange parameters and chlorophyll fluorescence parameters of cotton functional leaves was little, when soil salt content higher than 0.35 percent, the maximum photochemical efficiency of open photosystem (Fv/Fm), the quantum yield of electron transport (ΦPSII) and the photochemical quenching (qP) were decreased at different development stage, eventually leading to decline in net photosynthetic rate, so it is not conducive to the accumulation of cotton biomass. CCRI-44 compared to Sumian 12 was less affected by soil salinity when soil salinity higher than 0.35 percent.2. Monitoring model study on water status of cotton functional leaves in saline soil with hyperspectral remote sensingBased on correlationship of equivalent water thickness and the spectral of cotton functional leaves, the sensitivity bands of EWT were selected, and a new spectral parameter (1-R759nm+R451nm)/R451nm was found, the monitoring model on EWT as follows:EWT =0.0019×(1-R759nm+R451nm)/R451nm+0.0096. Correlationship between relative water content and the spectral of cotton functional leaves was revealed simultaneously, the sensitivity bands of RWC of functional leaves occurred at 420,543,768,1164 nm, and vegetation index DVI(768nm,543nm) correlated to RWC well, so the RWC monitoring model was RWC=-16.083 X DVI(768nm,543nm)+14.683, with vegetation index DVI(768nm,543nm) as independent variable. After practical testing, the predicted values of EWT and RWC by the models were very consistent with the observed values.3. Monitoring model study on soil electrical conductivity in cotton field based on cotton hyperspectral parameterCorrelationship between soil electrical conductivity and the spectral reflectance of cotton functional leaves under different cultivars and growth stages was revealed in this study. Results show that the spectral reflectance at 747 nm correlated to soil electrical conductivity well, soil EC monitoring model was constructed as EC=-5.4655×R747nm +3.6203, with vegetation index R747nm as independent variable. The sensitivity of soil EC mainly occurs at "three edge" region, vegetation index SDr was most correlation to soil EC during all derivative spectral parameters, so soil EC monitoring model was constructed as EC=-15.764SDr2+5.9843SDr+1.3416, with vegetation index SDr as independent variable. After practical testing, the predicted values of soil EC by the two models were very consistent with the observed values. The experiment shows that soil EC in saline cotton field can be effectively monitored by two hyperspectral parameters of R747nm and SDr.更多还原