不同水分供应条件下夏玉米农田SPAC系统水热传输模拟
发布时间：2019-06-13 07:36
【摘要】：通过不同水分供应条件下SPAC系统水热传输的定量模拟,可以解释土壤-植物-大气不同交互界面的水热输送与转化过程,对阐明非充分灌溉方式的节水机理,优化解决作物产量与耗水量矛盾进而实现农业水资源高效利用具有重要意义。本研究以夏玉米田间非充分灌溉试验为基础,分析了玉米冠层光谱特征、气孔导度和蒸发蒸腾量变化规律,建立了基于光谱植被指数的夏玉米叶面积指数估算模型和不同水分条件下气孔导度改进模型,为SPAC模型提供了动态的作物参数驱动;在充分考虑土壤水汽热耦合运移的STEMMUS模型基础上加入了作物蒸发蒸腾计算模块(直接ET和间接ET计算方法)和根系吸水计算模块(宏观和微观根系吸水模型),最终建立了夏玉米田土壤-植物-大气连续体(SPAC)水热传输模型,实现了不同水分供应条件下SPAC系统水热动态变化的定量模拟。研究取得了如下主要成果:(1)夏玉米冠层高光谱反射率可见光波段“绿峰”、“红谷”和“红边”可作为反演叶面积指数的敏感波段范围;近红外波段(1600-1830nm)可作为指示植被冠层水分状态的敏感波段范围。选用了绿度植被指数(NDVI,RVI和EVI)、考虑土壤背景修正的植被指数(MSAVI,TSAVI和PVI)和水分植被指数(NDWI1240,NDWI1460和WI)三类植被指数,建立了各植被指数反演叶面积指数模型,结果表明:归一化植被指数NDVI能够有效的模拟本地区夏玉米叶面积指数的变化规律,考虑土壤背景修正的植被指数模拟效果有所提高,但不明显;水分植被指数反演叶面积指数模型的决定系数较高,表明在不同水分条件下,考虑冠层水分状态能显著提高叶面积指数的模拟效果。(2)利用三种水分指标(叶气温差、叶片尺度作物缺水指标、土壤水分指标)改进了Jarvis气孔导度模型并对其在不同水分供应条件下的适用性进行了验证分析。基于叶气温差和叶片尺度作物缺水指标的气孔导度改进模型模拟效果优于基于土壤水分指标的气孔导度改进模型。在夏玉米生育后期,土壤水分指标改进的气孔导度模型模拟值明显偏低,不适合该时段夏玉米气孔导度的定量研究。(3)夏玉米蒸发蒸腾量变化规律夏玉米蒸发蒸腾量和蒸腾速率均表现出单峰曲线的昼夜变化趋势,不同水分供应对蒸腾速率的影响主要体现在峰值大小和峰值发生的时间上。玉米蒸腾速率与环境因子的响应关系在不同水分供应条件下基本一致:光合有效辐射和气温影响较大,饱和水气压差影响较小。不同水分供应条件下夏玉米生育期内的实际蒸发蒸腾量和作物系数表现出一定的季节变化规律,均随着生育期的推进而增加,并在生育中期达到峰值。不同水分供应处理对实际蒸发蒸腾量和作物系数的影响主要表现在数值大小上。(4)比较分析了半干旱地区不同ET计算方法(间接ET方法和直接ET方法)、不同根系吸水模型(宏观根系吸水模型和微观根系吸水模型)对SPAC系统模型模拟结果的影响,为不同目标下SPAC模型的参数化方案选择提供了依据。基于宏观根系吸水模型的模拟表明:利用两种ET方法模拟的土壤含水率值和蒸渗仪实测值在20cm土层深度处变化规律基本一致,但是随着土层深度加深,SPAC模型模拟值和实测值差异增大。两种ET方法模型在不同土层深度的土壤温度模拟结果与实测结果相差不大,在生育前期土壤温度的模拟结果与实测结果吻合程度高,在较大的灌水过后,模型模拟结果出现了明显的高估,且随着土层深度的增加,与实测结果的差异性有增大的趋势。采用不同ET计算方法,SPAC模型模拟玉米蒸发蒸腾量的表现在灌水后有较大差异,采用间接ET方法的模型模拟结果明显低估了蒸发蒸腾量,而基于直接ET方法的模型效果较好。总体来看,两种ET方法均能够动态模拟小时尺度和日尺度的作物蒸发蒸腾量变化规律,采用直接ET方法估算效果较好,决定系数达到0.80以上。基于单根的微观根系吸水模型与宏观根系吸水模型模拟结果在土壤含水率、土壤温度和不同时间尺度的蒸发蒸腾量的表现相差不大。采用不同ET方法对土壤-植物-大气系统模型效果有显著影响,直接ET计算方法模型估算效果较好,比较适合该地区玉米蒸发蒸腾量的估算研究。(5)研究探讨了不同水分条件下SPAC模型的适用性。尽管在具体数值上有些差异,SPAC模型能够定量模拟不同水分条件下的土壤水分、蒸发蒸腾变化规律。研究发现生育前期降低土壤湿润频率能够显著降低土壤蒸发量。不同灌水量处理对玉米叶面蒸腾影响显著,表明蒸腾量的差异是造成不同灌水量处理条件下玉米生育期耗水差异的主要原因。
[Abstract]:Through the quantitative simulation of the hydro-thermal transmission of the SPAC system under different water supply conditions, the hydrothermal transfer and conversion process of the soil-plant-atmosphere interaction interface can be explained, and the water-saving mechanism of the non-sufficient irrigation mode is clarified, It is of great significance to optimize the contradiction between crop yield and water consumption and to realize the efficient utilization of agricultural water resources. Based on the experiment of the non-sufficient irrigation in the field of summer maize, the spectral characteristics, stomatal conductance and the change of the evaporation and transpiration of the corn were analyzed, and the model for estimating the leaf area index of the summer maize based on the spectral vegetation index and the porosity of the stomatal conductance under different water conditions were established. the dynamic crop parameter driving is provided for the SPAC model, a crop evapotranspiration calculation module (a direct ET and an indirect ET calculation method) and a root system water absorption calculation module (macro and micro root system water absorption model) are added on the basis of a STEMMUS model taking full consideration of the soil moisture thermal coupling migration, The heat transfer model of the soil-plant-atmospheric continuous body (SPAC) in the summer maize field was established, and the quantitative simulation of the hydrothermal changes of the SPAC system under different water supply conditions was realized. The main results are as follows: (1) The "Green Peaks", "Red Valley" and "red edge" of the high spectral reflectance of the summer maize crown can be taken as the sensitive band range for the inversion of the leaf area index; the near infrared band (1600-1830 nm) can be used as the sensitive band range for indicating the moisture state of the vegetation canopy. The vegetation index (NDVI, RVI and EVI), the vegetation index (MSAVI, TSAVI and PVI) and the water vegetation index (NDWI 1240, NDWI 1460, and WI) of the soil background correction were selected. The normalized vegetation index NDVI can effectively simulate the change of the leaf area index of the summer maize in the region, and the vegetation index simulation effect of the soil background correction is improved, but not obvious; the water vegetation index is higher in the determination coefficient of the leaf area index model, It is shown that under different water conditions, the simulation effect of the leaf area index can be obviously improved in consideration of the water state of the canopy. (2) Using three kinds of water indexes (leaf temperature difference, leaf scale crop water shortage index and soil moisture index), the air-conductance model of Jarvis was improved and its applicability under different water supply conditions was analyzed and analyzed. The improved model of stomatal conductance based on the air temperature difference and the water shortage index of the blade-scale crop is better than that of the stomatal conductance based on the soil moisture index. In the late stage of summer maize, the model of stomatal conductance model with improved soil moisture index is obviously low, and it is not suitable for the quantitative study of the stomatal conductance of summer maize in this period. (3) The change of transpiration and transpiration rate of summer maize showed the diurnal variation trend of single-peak curve, and the effect of different water supply on transpiration rate was mainly reflected in the time of peak and peak. The response relationship between the transpiration rate and the environmental factor of the maize is basically the same under different water supply conditions: the effect of the photosynthetic effective radiation and the air temperature is large, and the influence of the saturated water vapor pressure difference is small. The actual evapotranspiration and crop coefficient in the growing period of summer maize under different water supply conditions showed a certain seasonal variation, which increased with the development of the growth period and reached the peak in the middle of the growth period. The effects of different water supply treatments on the actual evapotranspiration and crop coefficient are mainly on the numerical value. (4) The effects of different ET calculation methods (the indirect ET method and the direct ET method) of the semi-arid area, the water-absorbing model of different root systems (the water-absorbing model of the macro root system and the water-absorbing model of the micro-root system) on the simulation results of the SPAC system are compared and analyzed, And provides the basis for selecting the parameterization scheme of the SPAC model under different targets. The simulation results of the water-absorbing model based on the macro-root system show that the variation of the soil moisture content and the measured value of the steam-measuring instrument is basically the same in the depth of the 20cm soil layer, but with the depth of the soil layer, the difference between the model value and the measured value of the SPAC model is increased. The results of the simulation of soil temperature in different soil layers of the two kinds of ET method are very different from the measured results, and the simulation results of the soil temperature in the early stage of the fertility have a high degree of coincidence with the measured results. After the large irrigation, the simulation results show a significant overestimation. And with the increase of the depth of the soil layer, the difference of the measured results has a tendency to increase. Using the method of different ET, the simulation results of SPAC model and SPAC model show great difference after the irrigation, and the model simulation results of the indirect ET method obviously underestimated the amount of evaporation and transpiration, and the model effect based on the direct ET method is good. In general, both of the ET methods can simulate the change of the evapotranspiration of the crop in the hour scale and the daily scale, and the effect of the direct ET method is good, and the coefficient of determination is over 0.80. The water content of soil, soil temperature and evapotranspiration of different time scales were not much different based on a single micro-root-system water-absorbing model and a macro-root-system water-absorbing model. The effect of different ET method on the model of soil-plant-atmosphere system is significantly affected, and the effect of the direct-ET calculation method is better, and the estimation of the evapotranspiration of the maize in the region is compared. (5) The applicability of SPAC model under different water conditions is studied. In spite of some differences in specific values, the SPAC model can quantitatively simulate the change of soil moisture and evaporation transpiration under different water conditions. The study found that the decrease of the soil wetting frequency in the early stage can significantly reduce the evaporation of the soil. The effect of different irrigation water treatment on the transpiration of maize was significant, indicating that the difference of transpiration was the main reason for the difference of water consumption in the growth period of maize under different irrigation water treatment conditions.
【学位授予单位】：西北农林科技大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：S513
本文编号：2498366
[Abstract]:Through the quantitative simulation of the hydro-thermal transmission of the SPAC system under different water supply conditions, the hydrothermal transfer and conversion process of the soil-plant-atmosphere interaction interface can be explained, and the water-saving mechanism of the non-sufficient irrigation mode is clarified, It is of great significance to optimize the contradiction between crop yield and water consumption and to realize the efficient utilization of agricultural water resources. Based on the experiment of the non-sufficient irrigation in the field of summer maize, the spectral characteristics, stomatal conductance and the change of the evaporation and transpiration of the corn were analyzed, and the model for estimating the leaf area index of the summer maize based on the spectral vegetation index and the porosity of the stomatal conductance under different water conditions were established. the dynamic crop parameter driving is provided for the SPAC model, a crop evapotranspiration calculation module (a direct ET and an indirect ET calculation method) and a root system water absorption calculation module (macro and micro root system water absorption model) are added on the basis of a STEMMUS model taking full consideration of the soil moisture thermal coupling migration, The heat transfer model of the soil-plant-atmospheric continuous body (SPAC) in the summer maize field was established, and the quantitative simulation of the hydrothermal changes of the SPAC system under different water supply conditions was realized. The main results are as follows: (1) The "Green Peaks", "Red Valley" and "red edge" of the high spectral reflectance of the summer maize crown can be taken as the sensitive band range for the inversion of the leaf area index; the near infrared band (1600-1830 nm) can be used as the sensitive band range for indicating the moisture state of the vegetation canopy. The vegetation index (NDVI, RVI and EVI), the vegetation index (MSAVI, TSAVI and PVI) and the water vegetation index (NDWI 1240, NDWI 1460, and WI) of the soil background correction were selected. The normalized vegetation index NDVI can effectively simulate the change of the leaf area index of the summer maize in the region, and the vegetation index simulation effect of the soil background correction is improved, but not obvious; the water vegetation index is higher in the determination coefficient of the leaf area index model, It is shown that under different water conditions, the simulation effect of the leaf area index can be obviously improved in consideration of the water state of the canopy. (2) Using three kinds of water indexes (leaf temperature difference, leaf scale crop water shortage index and soil moisture index), the air-conductance model of Jarvis was improved and its applicability under different water supply conditions was analyzed and analyzed. The improved model of stomatal conductance based on the air temperature difference and the water shortage index of the blade-scale crop is better than that of the stomatal conductance based on the soil moisture index. In the late stage of summer maize, the model of stomatal conductance model with improved soil moisture index is obviously low, and it is not suitable for the quantitative study of the stomatal conductance of summer maize in this period. (3) The change of transpiration and transpiration rate of summer maize showed the diurnal variation trend of single-peak curve, and the effect of different water supply on transpiration rate was mainly reflected in the time of peak and peak. The response relationship between the transpiration rate and the environmental factor of the maize is basically the same under different water supply conditions: the effect of the photosynthetic effective radiation and the air temperature is large, and the influence of the saturated water vapor pressure difference is small. The actual evapotranspiration and crop coefficient in the growing period of summer maize under different water supply conditions showed a certain seasonal variation, which increased with the development of the growth period and reached the peak in the middle of the growth period. The effects of different water supply treatments on the actual evapotranspiration and crop coefficient are mainly on the numerical value. (4) The effects of different ET calculation methods (the indirect ET method and the direct ET method) of the semi-arid area, the water-absorbing model of different root systems (the water-absorbing model of the macro root system and the water-absorbing model of the micro-root system) on the simulation results of the SPAC system are compared and analyzed, And provides the basis for selecting the parameterization scheme of the SPAC model under different targets. The simulation results of the water-absorbing model based on the macro-root system show that the variation of the soil moisture content and the measured value of the steam-measuring instrument is basically the same in the depth of the 20cm soil layer, but with the depth of the soil layer, the difference between the model value and the measured value of the SPAC model is increased. The results of the simulation of soil temperature in different soil layers of the two kinds of ET method are very different from the measured results, and the simulation results of the soil temperature in the early stage of the fertility have a high degree of coincidence with the measured results. After the large irrigation, the simulation results show a significant overestimation. And with the increase of the depth of the soil layer, the difference of the measured results has a tendency to increase. Using the method of different ET, the simulation results of SPAC model and SPAC model show great difference after the irrigation, and the model simulation results of the indirect ET method obviously underestimated the amount of evaporation and transpiration, and the model effect based on the direct ET method is good. In general, both of the ET methods can simulate the change of the evapotranspiration of the crop in the hour scale and the daily scale, and the effect of the direct ET method is good, and the coefficient of determination is over 0.80. The water content of soil, soil temperature and evapotranspiration of different time scales were not much different based on a single micro-root-system water-absorbing model and a macro-root-system water-absorbing model. The effect of different ET method on the model of soil-plant-atmosphere system is significantly affected, and the effect of the direct-ET calculation method is better, and the estimation of the evapotranspiration of the maize in the region is compared. (5) The applicability of SPAC model under different water conditions is studied. In spite of some differences in specific values, the SPAC model can quantitatively simulate the change of soil moisture and evaporation transpiration under different water conditions. The study found that the decrease of the soil wetting frequency in the early stage can significantly reduce the evaporation of the soil. The effect of different irrigation water treatment on the transpiration of maize was significant, indicating that the difference of transpiration was the main reason for the difference of water consumption in the growth period of maize under different irrigation water treatment conditions.
【学位授予单位】：西北农林科技大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：S513
【引证文献】
相关博士学位论文 前4条
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2 陈晟;基于机器学习的黑河中游作物需水量模型研究[D];中国科学技术大学;2018年
3 杨健;西北地区覆膜春小麦田间水热传输机制与模拟研究[D];中国农业大学;2018年
4 王秋玲;玉米叶片光合特性对干旱的响应及气孔导度模拟研究[D];中国气象科学研究院;2018年
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1 李谦;灌水处理下稻田水热交换特征与耦合模型研究[D];南京信息工程大学;2018年
2 陈光杰;夏玉米宽窄行集雨覆盖种植土壤水分运移及其模拟研究[D];西北农林科技大学;2017年
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