不同物候期的蘋果樹冠層氮素含量高光譜估測研究
發(fā)布時間：2019-04-13 17:15
【摘要】：氮素是植物生長發(fā)育所必需的大量元素之一,對于蘋果樹生長及果實品質的形成起著至關重要的作用。目前,利用高光譜對植被氮素含量的估測研究主要集中在大田作物,而對多年生的蘋果樹研究較少,且已有研究大都集中在果樹的某一個生長時期,而對果樹不同物候期的研究較少。因此對蘋果樹不同物候期的氮素含量進行高光譜估測研究,對快速、無損和準確地估測果樹氮素含量,從而確定氮素含量的最佳估測時期,對果樹的精準施肥具有重要意義。以山東省棲霞市為研究區(qū),以紅富士蘋果樹為研究對象。在2013年及2014年蘋果盛花期(4月下旬)、新梢旺長期(5月中下旬)、春梢停長期(6月中下旬)、秋梢停長期(9月中下旬)四個物候期,利用ASD FieldSpec 4便攜式地物波譜儀,對盛果期蘋果樹冠層光譜數(shù)據(jù)進行測定,同步采集蘋果樹冠的葉片,在室內對葉片N素含量進行測定。分析了不同物候期蘋果樹冠層N素含量變化規(guī)律及不同N含量蘋果樹冠層光譜特征;對原始光譜數(shù)據(jù)進行了預處理和15種變換,篩選了與氮素含量相關的敏感波長。同時選用了基于位置的和基于面積的高光譜參量以及其它三類植被指數(shù)。最后建立了不同物候期蘋果樹冠層氮素含量最佳估測模型。主要研究結果如下:(1)初步摸清了蘋果不同物候期的冠層氮素含量和高光譜特征的變化規(guī)律從盛花期到秋梢停長期,蘋果冠層氮素平均含量一直處于下降狀態(tài),其中從新梢旺長期到春梢停長期氮素含量降低幅度相對較小,相對比較穩(wěn)定。不同物候期蘋果冠層光譜反射率具有相似的變化趨勢。在350~780 nm波段范圍內,盛花期、新梢旺長期、春梢停長期以及秋梢停長期的反射率相差較小,但盛花期的光譜反射率要高于其他三個時期的光譜反射率,且在680 nm(紅谷)附近差值達到最大。在1000~1300 nm形成高的近紅外反射平臺,盛花期的光譜反射率要明顯低于其他三個時期的光譜反射率,而新梢旺長期、春梢停長期和秋梢停長期的反射率相差最大,表現(xiàn)為新梢旺長期光譜反射率春梢停長期光譜反射率秋梢停長期光譜反射率。在1419~2402 nm波段范圍內,四個時期的光譜反射率出現(xiàn)交叉。(2)明確了蘋果不同物候期冠層氮素含量的敏感波段及敏感高光譜參量綠光(500~560 nm)和近紅外區(qū)域(780~1100 nm)受冠層氮素含量影響較為顯著,是盛花期蘋果冠層氮素含量敏感波段,SDg,CIGREEN,GNDVI為盛花期蘋果冠層氮素含量敏感高光譜參量。新梢旺長期冠層氮素含量敏感波段主要集中在近紅外區(qū)域(780~1100 nm),冠層氮素含量敏感高光譜參量為DVI、MSAVI和TVI。春梢停長期蘋果冠層氮素含量敏感波長位于紅光區(qū)域(620~760 nm)和近紅外區(qū)域(780~1100 nm),λr,MCARI,TCARI為春梢停長期蘋果冠層氮素含量估測敏感高光譜參量。近紅外區(qū)域(780~1100 nm)為秋梢停長期冠層氮素含量敏感區(qū)域,DVI、MSAVI、TVI和MCARI這四種植被指數(shù)為秋梢停長期蘋果冠層氮素含量估測敏感高光譜參量。(3)建立了不同物候期蘋果冠層氮素含量的最佳估測模型通過對比不同物候期蘋果冠層氮素含量的估測模型的建模和估測精度發(fā)現(xiàn),最佳估測模型都是基于多元逐步回歸提取的敏感波長所構建的BP神經(jīng)網(wǎng)絡模型。蘋果冠層氮素含量估測精度呈現(xiàn)同樣的變化規(guī)律,春梢停長期模型精度新梢旺長期模型精度盛花期模型精度。秋梢停長期模型的估測精度較低,模型不穩(wěn)定。因此春梢停長期可作為蘋果冠層氮素含量估測的最佳時期。
[Abstract]:Nitrogen is one of the essential elements of plant growth and development, and plays an important role in the growth of apple trees and the formation of fruit quality. At present, the research on the nitrogen content of the vegetation by using the high-spectrum is mainly concentrated in the field crop, and the research on the perennial apple trees is less, and the research has mostly concentrated on a certain growth period of the fruit tree, and the research on the different phenological period of the fruit tree is less. Therefore, the high-spectral estimation of the nitrogen content in different phenological period of the apple tree is carried out, and the nitrogen content of the fruit tree can be estimated quickly, non-destructively and accurately, so that the optimal estimation period of the nitrogen content is determined, and the precise fertilization of the fruit tree is of great significance. The study area of Qixia City, Shandong Province, is the study object of the Red Fuji apple tree. In 2013 and 2014, the blooming period of the apple (late April), the long-term (late mid-late of May), the long-term spring tip (in late June), and the long-term (late September) period of the spring tip, and the use of the ASD FieldSpec 4 portable ground-feature wave spectrometer, The spectral data of the apple crown layer in the fruit stage was determined, and the leaves of the apple tree crown were collected synchronously, and the content of the leaf N was measured in the room. In this paper, the changes of N content and the spectral characteristics of the crown layer of apple in different phenological period were analyzed. The original spectral data were pre-treated and 15 kinds of transformation were carried out, and the sensitive wavelengths associated with the nitrogen content were selected. At the same time, the location-based and area-based high-spectral parameters and other three types of vegetation indices are selected. In that end, the optimal model of the nitrogen content of the apple tree crown layer of different phenological period was established. The main results of the study are as follows: (1) The changes of the canopy nitrogen content and the high spectral characteristics of the apple in different phenological period from the blooming period to the fall of the autumn and the average nitrogen content of the apple canopy have been in a descending state. The reduction of long-term nitrogen content from the new shoot to the spring tip is relatively small and relatively stable. The canopy spectral reflectance of apple in different phenological period has a similar trend. In the range of 350-780 nm, the long-term and long-term and long-term and long-term and long-term reflectance of the spring-tip and the long-term end of the spring-tip are relatively small, but the spectral reflectance of the blooming period is higher than the spectral reflectance of the other three periods, and the difference in the vicinity of 680 nm (red valley) reaches the maximum. a high near-infrared reflection platform is formed at 1000-1300 nm, the spectral reflectivity of the blooming period is obviously lower than that of the other three periods, And the long-term spectral reflectance of the new shoots and the long-term spectral reflectance of the spring tip stop long-term spectral reflectance. In the range of 1419 ~ 2402 nm, the spectral reflectance of the four periods is crossed. (2) It is clear that the sensitive wave band and the sensitive high-spectrum parameter green light (500-560 nm) and the near-infrared region (780-1100 nm) of the canopy nitrogen content in different phenological period of the apple are obviously affected by the nitrogen content of the canopy, which is the sensitive band of the nitrogen content of the apple in the blooming period, SDg, CIGREEN, GNDDVI is a sensitive high-spectral parameter of the nitrogen content of the apple in the blooming period. The sensitive band of nitrogen content in the long-term canopy of the new-tip-wang was mainly concentrated in the near-infrared region (780-1100 nm), and the sensitive high-spectral parameters of the nitrogen content of the canopy were DVI, MSAVI and TVI. The sensitive wavelength of nitrogen content in the long-term apple canopy at the spring tip is located in the red region (620-760 nm) and the near-infrared region (780-1100 nm). In the near-infrared region (780-1100 nm), the long-term canopy nitrogen content sensitive area, DVI, MSAVI, TVI and MCARI were the sensitive and high spectral parameters of the long-term apple canopy nitrogen content in the autumn. (3) The optimal estimation model of the nitrogen content of the apple canopy of different phenological period was established, and the model and the estimation accuracy of the nitrogen content of the apple in different phenological period were compared. The best estimation model is the BP neural network model constructed based on the multiple stepwise regression. The estimation precision of the nitrogen content in the apple canopy shows the same change rule, and the precision of the long-term model with the long-term model precision of the spring tip is higher than that of the long-term model. The estimation accuracy of the long-term model of the autumn-tip stop is lower, and the model is not stable. Therefore, it is the best time to estimate the nitrogen content in the apple canopy for a long time.
【學位授予單位】：山東農業(yè)大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：S661.1;S127
本文編號：2457780
[Abstract]:Nitrogen is one of the essential elements of plant growth and development, and plays an important role in the growth of apple trees and the formation of fruit quality. At present, the research on the nitrogen content of the vegetation by using the high-spectrum is mainly concentrated in the field crop, and the research on the perennial apple trees is less, and the research has mostly concentrated on a certain growth period of the fruit tree, and the research on the different phenological period of the fruit tree is less. Therefore, the high-spectral estimation of the nitrogen content in different phenological period of the apple tree is carried out, and the nitrogen content of the fruit tree can be estimated quickly, non-destructively and accurately, so that the optimal estimation period of the nitrogen content is determined, and the precise fertilization of the fruit tree is of great significance. The study area of Qixia City, Shandong Province, is the study object of the Red Fuji apple tree. In 2013 and 2014, the blooming period of the apple (late April), the long-term (late mid-late of May), the long-term spring tip (in late June), and the long-term (late September) period of the spring tip, and the use of the ASD FieldSpec 4 portable ground-feature wave spectrometer, The spectral data of the apple crown layer in the fruit stage was determined, and the leaves of the apple tree crown were collected synchronously, and the content of the leaf N was measured in the room. In this paper, the changes of N content and the spectral characteristics of the crown layer of apple in different phenological period were analyzed. The original spectral data were pre-treated and 15 kinds of transformation were carried out, and the sensitive wavelengths associated with the nitrogen content were selected. At the same time, the location-based and area-based high-spectral parameters and other three types of vegetation indices are selected. In that end, the optimal model of the nitrogen content of the apple tree crown layer of different phenological period was established. The main results of the study are as follows: (1) The changes of the canopy nitrogen content and the high spectral characteristics of the apple in different phenological period from the blooming period to the fall of the autumn and the average nitrogen content of the apple canopy have been in a descending state. The reduction of long-term nitrogen content from the new shoot to the spring tip is relatively small and relatively stable. The canopy spectral reflectance of apple in different phenological period has a similar trend. In the range of 350-780 nm, the long-term and long-term and long-term and long-term and long-term reflectance of the spring-tip and the long-term end of the spring-tip are relatively small, but the spectral reflectance of the blooming period is higher than the spectral reflectance of the other three periods, and the difference in the vicinity of 680 nm (red valley) reaches the maximum. a high near-infrared reflection platform is formed at 1000-1300 nm, the spectral reflectivity of the blooming period is obviously lower than that of the other three periods, And the long-term spectral reflectance of the new shoots and the long-term spectral reflectance of the spring tip stop long-term spectral reflectance. In the range of 1419 ~ 2402 nm, the spectral reflectance of the four periods is crossed. (2) It is clear that the sensitive wave band and the sensitive high-spectrum parameter green light (500-560 nm) and the near-infrared region (780-1100 nm) of the canopy nitrogen content in different phenological period of the apple are obviously affected by the nitrogen content of the canopy, which is the sensitive band of the nitrogen content of the apple in the blooming period, SDg, CIGREEN, GNDDVI is a sensitive high-spectral parameter of the nitrogen content of the apple in the blooming period. The sensitive band of nitrogen content in the long-term canopy of the new-tip-wang was mainly concentrated in the near-infrared region (780-1100 nm), and the sensitive high-spectral parameters of the nitrogen content of the canopy were DVI, MSAVI and TVI. The sensitive wavelength of nitrogen content in the long-term apple canopy at the spring tip is located in the red region (620-760 nm) and the near-infrared region (780-1100 nm). In the near-infrared region (780-1100 nm), the long-term canopy nitrogen content sensitive area, DVI, MSAVI, TVI and MCARI were the sensitive and high spectral parameters of the long-term apple canopy nitrogen content in the autumn. (3) The optimal estimation model of the nitrogen content of the apple canopy of different phenological period was established, and the model and the estimation accuracy of the nitrogen content of the apple in different phenological period were compared. The best estimation model is the BP neural network model constructed based on the multiple stepwise regression. The estimation precision of the nitrogen content in the apple canopy shows the same change rule, and the precision of the long-term model with the long-term model precision of the spring tip is higher than that of the long-term model. The estimation accuracy of the long-term model of the autumn-tip stop is lower, and the model is not stable. Therefore, it is the best time to estimate the nitrogen content in the apple canopy for a long time.
【學位授予單位】：山東農業(yè)大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：S661.1;S127
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