KMS XINJIANG INSTITUTE OF ECOLOGY AND GEOGRAPHY，CAS
| 新疆绿洲覆膜滴灌棉田水-热传输特征与作物生长模拟研究 | |
| 吴娜 | |
| Subtype | 博士 |
| Thesis Advisor | 罗毅 |
| 2018-06-05 | |
| Degree Grantor | 中国科学院大学 |
| Place of Conferral | 新疆乌鲁木齐 |
| Degree Discipline | 理学博士 |
| Keyword | 冠层温度 作物蒸散，水热传输 覆膜滴灌 新疆 canopy temperature crop evapotranspiration water-heat transfer mulched drip irrigation Xinjiang |
| Abstract | 覆膜滴灌技术由于其高效节水的特点在新疆广泛应用。水热传输特征与作物生长模拟研究可为作物灌溉管理提供参考依据。本文在新疆玛纳斯河绿洲覆膜滴灌棉田用涡度相关等设备观测潜热通量、显热通量、 CO2 通量、 长短波辐射、表层温度和土壤水分的动态变化过程，并监测作物生长过程，建立数学模拟方法，研究棉田水热传输和作物生长过程特征。1. 解析了棉田生长季能量分配特征。生长季平均日净辐射(Rn)为 139.8±13.6 W·m-2， 潜热(LE)通量为 63.5±18.2 W·m-2，显热(Hs)通量为 23.9±14.1 W·m-2，土壤热通量(G)为 3.2±4.2 W·m-2。 不同生育期 LE 和 Hs 通量日内变化过程与 Rn 相似， 峰值出现在中午 12:00 以后，而 G 变化相对平缓。在作物生长初期和收获末期，棉田能量耗散以 Hs 为主，通量为 41.4±14.9 W·m-2，占净辐射比率为 39％~55％；在作物生长旺盛期， 能量耗散以 LE 为主，通量为 117.3±28.8 W·m-2，占净辐射比率为 79％。2. 解析了棉田生长季冠层温度动态变化特征。 在不同生育时期，棉田冠层温度/地表温度的大小、起伏变化等存在不同程度差异。在夜间，整个生长季地表/冠层温度均低于气温， 约 3～5℃； 在日间， 上午随着太阳辐射增强， 冠层温度回升， 在 8:00左右与大气温度持平后，在萌发期、苗期、收获期快速超越气温至 15:00 开始低于气温，在蕾期、花铃期与吐絮期与气温相当，到 13:00 开始低于大气温度。3. 综合分析了生长季棉田四个阶段的蒸散变化动态特征。 第一阶段， 7 月之前，实际蒸散低于潜在蒸散，大于潜在蒸腾，棉田蒸散主要来自田间未覆膜的土壤蒸发，阶段平均蒸散强度为 2.41 mm·d-1，占整个生育期棉田总蒸散的 24%；第二阶段， 7 月初至 8 月下旬，实际蒸散与潜在蒸散、潜在蒸腾接近，蒸散主要来自于冠层蒸腾，阶段平均蒸散强度为 4.54 mm·d-1， 占整个生育期棉田总蒸散的 55%；第三阶段， 8 月下旬之后，实际蒸散低于潜在蒸腾，阶段平均蒸散强度为 3.34 mm·d-1， 占整个生育期棉田总蒸散的 16%。第四阶段， 9 月中旬以后，棉田蒸散由蒸腾为主转变为以土壤蒸发为主，阶段平均蒸散强度为 1.44 mm·d-1， 占整个生育期棉田总蒸散的 5%。不同生育期的棉田日蒸散过程与太阳辐射变化过程相近，呈单峰模式，起伏变化稍微滞后于太阳辐射变化。 太阳辐射(SRad)、水汽压亏缺(VPD)、 根区土壤水分(REW)和叶面积指数(LAI)是影响棉田蒸散的主要因素。 与太阳辐射基本成线性关系，随着辐射增加而增加；与水汽压亏缺、根区土壤水分都呈两段函数关系。4. 综合阐述了棉田 CO2 通量、 同化物合成动态特征及其与环境因子关系。 棉田净生态系统生产力(NEP)在不同生育期有较大差异：在萌发期与采摘期 NEP 值较小，为负，这是由于呼吸产出量超出吸收量造成的；在蕾期与花铃期 NEP 值较大，这时叶面积最大、叶片活性最强。萌发期、苗期、蕾期、花铃期、 吐絮期和采摘期日均值分别为-3.7±1.6、 2.7±6、 25.1±7.7、 20.8±8.5、 4.6±3.2 和-0.3±1.9 gC·m-2·d-1。 生长季棉田净初级生产力 NPP 变化过程与 NEP 相似，萌发期、苗期、蕾期、花铃期、 吐絮期和采摘期日均值分别为 3.1±1.4、 9.8±6、 32.1±8.2、 27.5±8.5、 11.1±3.7 和 5.9±2.3 gC·m-2·d-1。 NPP 日内过程基本与辐射同步，均呈单峰特征，峰值出现在午后 12:30 左右，蕾期、花铃期峰值最大。5. 改进了模拟计算方法的一些过程。基于能量平衡，给出了一个棉田温度计算公式，可以很好的模拟计算萌发、苗期地表温度日动态过程，较好地模拟蕾期、花铃期的下午与夜间冠层温度变化，上午模拟温度偏高。基于气孔导度与净光合速率的关系，改进了光能利用模型中的水分胁迫项计算方法，建立了一个同化物合成模型；模拟的率定与检验结果表明该模型可以在小时与日尺度上有效模拟覆膜棉田的同化物合成过程。 |
| Other Abstract | Xinjiang Province is a typical arid agricultural irrigation zone of arid northwest China.Drip irrigation technology has been widely used in Xinjiang in recent years because of itshigh efficient water-saving. The study on water and heat transfer characteristics will help todevelop sound irrigation schemes for drip irrigation crop. Therefore, it is of big significanceto accurately understand the mechanism of water-heat transfer in cotton fields and toestablish a dynamic estimation model in the region.In this study, the eddy correlation observation and mathematical model simulationmethods were used to study the characteristics of the water-heat transfer process and cropgrowth process in cotton field under mulched drip irrigation in Xinjiang oasis. The mainconclusions are outlined as follow:1. The characteristics of the energy distribution in the growing season of cotton fieldwere analyzed. The average daily net radiation (Rn) was 139.8±13.60 W·m-2, and the latentheat (LE) flux was 63.5±18.2 W·m-2, and the sensible heat (Hs) flux was 23.9±14.1 W·m-2,and the ground heat flux (G) was 3.2±4.2 W·m-2 in the growing season. The daily variationsof LE and Hs fluxes showed similar pattern with Rn at different growth stages. The peakvalue appeared at 12:00 at noon. At the early stage of crop growth and the end of harvest,the energy dissipation of cotton field was mainly Hs, which was 41.4±14.9 W·m-2 and theratio to net radiation was 39%~55%. In the period of crop both growth, the energy dissipationwas mainly LE, which was 117.3±28.8 W·m-2 and the ratio to net radiation was 79%.2. The dynamic characteristics of canopy temperature during the growing season wereanalyzed. At different growth stages, there were different degrees of variation in canopy/surface temperature in the cotton field. At night, the surface/canopy temperature of thewhole growing season was lower than the atmospheric temperature, about 3-5℃. In themorning, the canopy temperature went up with the increase of the solar radiation and wasequivalent to the atmospheric temperature at about 8:00. In the afternoon, the canopytemperature began to fall below the atmospheric temperature at 15:00 after increased fastly above it at the stage of germination, seedling and harvest, while it began to fall belowatmospheric temperature at 13:00 and was approximately same with it in the morning at thestage of bud, flowering and boll-forming and boll opening.3. The dynamic characteristics of evapotranspiration in four stages during the growingseason were comprehensively analyzed. The first stage, the actual evapotranspiration waslower than potential evapotranspiration, greater than potential transpiration before July. Theactual evapotranspiration in the cotton field mainly from the soil evaporation withoutmulching. The average evapotranspiration during this period was 2.41 mm·d-1, accountingfor 24% of the total evapotranspiration in the cotton field during the entire growing season.The second stage was from early July to late August, with an average evapotranspiration of4.54 mm·d-1 accounting for 55% of total evapotranspiration, in which the actualevapotranspiration and potential evapotranspiration were close to potential transpiration, andevapotranspiration mainly came from canopy transpiration. In the third stage after lateAugust, the actual evapotranspiration was lower than the potential transpiration. The averageevapotranspiration is 3.34 mm·d-1 which accounts for 16% of the total evapotranspiration.In the last stage after mid-September, the evapotranspiration of cotton fields changed fromtranspiration to soil evaporation, with an average evapotranspiration of 1.44 mm·d-1,accounting for 5% of the total evapotranspiration.The daily evapotranspiration process of cotton fields at different growth stages wassimilar to that of solar radiation. Solar radiation (SRad), vapor pressure deficit (VPD),readily evaporable water (REW) and leaf area index (LAI) were the main factors affectingevapotranspiration in the cotton field. The evapotranspiration is basically linear with solarradiation and increased with the increase of radiation. There were two different functionalrelationships with water vapor pressure deficit and same with readily evaporable water.4. The dynamic characteristics of CO2 flux and assimilate synthesis and theirrelationship with environmental factors in the cotton field were comprehensively expounded.The net ecosystem productivity (NEP) of cotton field had great difference in different growthstages. The NEP value was smaller and negative in the the period of germination and picking,which was due to the excess of respiratory output. The NEP value was larger in the the period of bud and boll, when the leaf area was the largest and the leaf activity was the strongest.The daily mean NEP at the stage of germination, seedling, bud, flowering and boll-forming,boll opening and harvest were -3.7±1.6, 2.7±6.0, 25.1±7.7, 20.8±8.5, 4.6±3.2 and -0.3±1.9gC·m-2·d-1, respectively. The NPP change process of net primary productivity of cotton fieldin growing season was similar to that of NEP. The daily mean NPP at the stage of germination,seedling, bud, flowering and boll-forming, boll opening and harvest were 3.1±1.4, 9.8±6.0,32.1±8.2, 27.5±8.5, 11.1±3.7 and 5.9±2.3 gC·m-2·d-1, respectively. The intraday process ofNPP was basically synchronous with radiation, showing a single peak character. The peakvalue appeared at about 12:30 in the afternoon, and the maximum value appeared at the budstage and flowering and boll-forming stage.5. Some process of the simulation calculation method were improved. Based on theenergy balance, a calculation formula of cotton field temperature was given. It couldsimulate and calculate the daily dynamic process of surface temperature at the germinationand seedling stage. At the stage of bud and flowering and boll-forming, it could simulate thechange of canopy temperature better in the afternoon and night, while the simulatedtemperature was higher in the morning. Based on the relationship between the stomatalconductance and the net photosynthetic rate, a method of water stress calculation in the lightenergy utilization model was improved. And an assimilate synthesis model was established.The calibration and verification results of the simulation showed that the model couldeffectively simulate the synthesis process of the cotton field on the hour and the daily scale. |
| Subject Area | 自然地理学 |
| Language | 中文 |
| Document Type | 学位论文 |
| Identifier | http://ir.xjlas.org/handle/365004/14940 |
| Collection | 研究系统_荒漠环境研究室 |
| Affiliation | 中国科学院新疆生态与地理研究所 |
| First Author Affilication | 中国科学院新疆生态与地理研究所 |
| Recommended Citation GB/T 7714 | 吴娜. 新疆绿洲覆膜滴灌棉田水-热传输特征与作物生长模拟研究[D]. 新疆乌鲁木齐. 中国科学院大学,2018. |
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