氮运筹模式下冬小麦籽粒蛋白光谱监测及氮亏缺模型研究

发布时间：2018-11-16 10:36

【摘要】：粮食生产是社会可持续发展的基础,在提高产量的同时,籽粒品质受到越来越多的重视,实时监测作物籽粒品质,可以合理调整农田管理,实现粮食优质生产。氮素是作物生长重要元素之一,合理施用氮肥是农业增产的重要手段。然而氮肥的不合理施用,会造成氮肥利用效率降低及环境污染等现象,因此实时快速监测作物氮素亏缺状况,进行科学施肥管理,对提高小麦产量、改善品质和保护环境意义重大。本研究通过分析不同氮运筹模式下冬小麦各生育时期农学参数、氮亏缺量和冠层光谱的关系,运用多元统计分析方法提取农学参数光谱敏感波段,建立相应的光谱监测模型和氮亏缺模型,并利用“冠层光谱-农学参数-籽粒蛋白质产量”这一技术路线,建立了冬小麦籽粒蛋白质产量估测模型。结果表明：1、整个生育期不同氮运筹模式冬小麦冠层光谱曲线基本一致,随施氮水平增加,可见光区反射率降低,近红外波段升高,红边参数与吸收特征参数随施氮量增加而增大,但300kg·hm-2与225 kg·hm-2处理差异不明显；同一施氮水平下,5：5基追比处理在可见光波段反射率较7：3处理低,近红外波段反射率高。2、冬小麦叶面积指数(LAI)和叶绿素含量随生育时期的推进呈“先增后降”,地上千生物量与植株氮积累量(PNA)呈逐渐增加的趋势；不同生育时期LAI、叶绿素含量、干生物量和植株氮积累量变化趋势一致,随施氮量的增加逐渐增大；相同氮水平下,5：5基追比处理高于7：3处理。基于PLS-SMLR逐步回归分析提取的LAI、叶绿素含量和植株氮积累量光谱敏感波段分别为775、765、1060nm;675、935、725、560、865mm和550、445、400、725、975、530、840 nm。3、冬小麦籽粒蛋白质产量在300 kg·hm-2与225 kg·hm-2处理间差异不显著,与150 kg·hm-2不施氮处理间存在显著差异;同一施氮水平,5：5基追比处理高于7：3处理。籽粒蛋白质产量与灌浆期LAI和PNA具有较高的线性相关,与开花期叶绿素含量相关性最大；采用各参数为中间变量建立的籽粒蛋白质产量光谱估测模型精度(R2)较高,均方根差(RMSE)和相对误差(RE)均较低,其中尤以PNA-GPY光谱估测模型效果最佳。因此,可依据灌浆期小麦冠层光谱实现籽粒蛋白质产量的监测,为作物合理生产提供依据。4、开花前,冬小麦氮营养指数(NNI)随施氮量增加而逐渐增大,氮亏缺量(Nand)则逐渐减小；拔节期、孕穗期和开花期,同一施氮水平下5：5基追比处理NNI高于7：3处理.而Nand则反之。基于PLS-SMLR逐步分析,不同氮运筹模式冬小麦氮亏缺量光谱监测的主要波段为440 nm和610nm,所建立的估测模型R2较高,RMSE和RE均较低。因此,可通过冬小麦开花前各生育时期的光谱变化,适当施氮,以满足作物生长营养需求。
[Abstract]:Grain production is the basis of sustainable development of society. Grain quality is paid more and more attention at the same time of increasing yield. Monitoring crop grain quality in real time can adjust farmland management reasonably and realize grain quality production. Nitrogen is one of the important elements in crop growth, and rational application of nitrogen fertilizer is an important means to increase agricultural yield. However, the unreasonable application of nitrogen fertilizer will lead to the reduction of nitrogen use efficiency and environmental pollution. Therefore, real-time and rapid monitoring of crop nitrogen deficit and scientific fertilization management can improve wheat yield. It is of great significance to improve quality and protect the environment. By analyzing the relationship between agronomic parameters, nitrogen deficit and canopy spectrum of winter wheat in different nitrogen patterns, the spectral sensitive bands of agronomic parameters were extracted by multivariate statistical analysis. The spectral monitoring model and nitrogen deficit model were established, and the estimation model of grain protein yield of winter wheat was established by using the technique route of "canopy spectrum, agronomic parameter and grain protein yield". The results showed that: 1. The spectral curve of winter wheat canopy was basically the same during the whole growth period. With the increase of nitrogen application level, the reflectivity of visible light region decreased, and the near infrared band increased. The red edge parameter and absorption characteristic parameter increased with the increase of nitrogen application rate, but there was no significant difference between 300kg hm-2 and 225 kg hm-2 treatment. Under the same nitrogen application level, the reflectivity of the 5:5 base ratio treatment was lower than 7:3 treatment, and the near infrared band reflectivity was higher than 7:3 treatment. The leaf area index (LAI) and chlorophyll content of winter wheat increased first and then decreased with the development of growth period, and the biomass of thousands and (PNA) of plant nitrogen increased gradually. The chlorophyll content, dry biomass and plant nitrogen accumulation of LAI, were the same at different growth stages, and gradually increased with the increase of nitrogen application rate, and the 5:5 basal topdressing ratio treatment was higher than 7:3 treatment under the same nitrogen level. The spectral sensitive bands of chlorophyll content and nitrogen accumulation of LAI, extracted by PLS-SMLR stepwise regression analysis were 775 765 (1060 nm). 675935725560865mm and 550445400725975530840 nm.3, winter wheat grain protein yield had no significant difference between 300 kg hm-2 and 225 kg hm-2 treatments, and there was significant difference between the treatment with 150 kg hm-2 nitrogen application. At the same nitrogen level, the 5:5 basal topdressing ratio was higher than 7:3 treatment. There was a high linear correlation between grain protein yield and LAI and PNA at grain filling stage, and the highest correlation between grain protein yield and chlorophyll content at flowering stage. The precision (R2) of the spectral estimation model of grain protein yield was high, the root mean square difference (RMSE) and the relative error (RE) were lower, especially the PNA-GPY spectral estimation model was the best. Therefore, the grain protein yield could be monitored according to wheat canopy spectrum at grain filling stage. 4. Before flowering, the nitrogen nutrition index (NNI) of winter wheat increased with the increase of nitrogen application rate. The amount of nitrogen deficit (Nand) decreased gradually. At jointing stage, booting stage and flowering stage, NNI of 5:5 basal topdressing treatment was higher than 7:3 treatment under the same nitrogen application level. Nand is the opposite. Based on PLS-SMLR stepwise analysis, the main bands of nitrogen deficit monitoring of winter wheat were 440 nm and 610 nm in different nitrogen patterns. The established estimation model R2 was higher, and RMSE and RE were lower. Therefore, the growth and nutrition needs of winter wheat can be satisfied by the spectral changes of each growing period before flowering and the proper application of nitrogen.
【学位授予单位】：山西农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S127;S512.11

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