【作者】 李广德；

【导师】 贾黎明； 马履一；

【作者基本信息】 北京林业大学 ， 森林培育， 2010， 博士

【摘要】 杨树是我国重要的速生丰产用材树种,在缓解我国木材供需矛盾,保障国家木材安全,促进地方经济发展,增加农民收入,固碳增汇等方面都发挥了极为重要的作用。但目前我国杨树人工林经营管理还比较粗放,生产力较低,限制了杨树人工林生产潜力的充分发挥。本文以三倍体毛白杨优良无性系为对象,着眼于三倍体毛白杨速生纸浆林可持续经营管理,采用热扩散式边材液流测定技术、自动气象站、压力室等研究方法和测定手段,通过连续2年的动态监测,对三倍体毛白杨速生纸浆林树木蒸腾耗水性进行了系统综合研究。初步摸清了三倍体毛白杨蒸腾耗水特性,最终建立了基于林木生长、蒸腾耗水特性等的三倍体毛白杨速生纸浆林节水灌溉设备及优化灌溉制度,以期提高三倍体毛白杨速生纸浆林的集约化经营水平和林分生产力,促进其可持续发展。主要结论如下：(1)利用热扩散式边材液流探针TDP-30监测三倍体毛白杨速生纸浆林树木蒸腾耗水量比较准确,是可行的,测定误差平均为6.79%。三倍体毛白杨树干边材液流速率呈现“单峰型”日变化,其峰值和日均值晴天极显著高于阴天和雨天相应值(P<0.01)。树干东、南、西、北4个方位树干边材液流速率极显著正相关,晴天与阴天,各方位间边材液流速率差异不显著,雨天东向液流速率显著大于南向。三倍体毛白杨边材液流速率与主要环境因子如太阳有效辐射、空气相对湿度、空气温度、水汽压亏缺、风速、土壤温湿度等呈现极显著的相关性。通径分析表明,晴天,影响三倍体毛白杨树干边材液流的主要环境因子为空气相对湿度和土壤温度,阴天和雨天为空气相对湿度和水蒸汽压亏缺。调节三倍体毛白杨树干边材液流速率日变化进程的主导环境因子为空气相对湿度和水汽压亏缺。(2)三倍体毛白杨林分蒸腾耗水量随季节推移呈现“低-高-低”的单峰型变化规律。2008年(贫水年)生长季三倍体毛白杨林分蒸腾耗水量为340mm；2009年(丰水年)蒸腾耗水量为410mm。三倍体毛白杨蒸腾耗水量季节变化与叶片气孔导度、叶面积指数、太阳有效辐射、空气温度、相对湿度、土壤水分含量及土壤温度、水汽压亏缺等都呈现出正相关性,而与风速负相关。通径分析表明,影响和决定三倍体毛白杨蒸腾耗水量季节变化的主要因素为气孔导度、空气相对湿度,以及空气水汽压亏缺。(3)利用2008年4-10月晴天树干边材液流速率与主要环境因子进行多元线性回归,得到三倍体边材液流速率与上述环境因子的多元线性回归模型,回归模型达到极显著水平,其判定R2都大于0.8。将2009年同期环境因子带入建模型中进行边材液流速率预测,预测值为0.00176 cm·s-1,实测值为0.00161 cm·s-1,误差8.3%。通过建立多元线性回归模型来对三倍体毛白杨树干边材液流速率进行预测是比较准确的。(4)三倍体毛白杨速生纸浆林叶片净光合速率春季和秋季呈“单峰型”,夏季呈“双峰型”日变化。叶片蒸腾速率呈现“单峰型”日变化。三倍体毛白杨净光合速率随季节变化呈现“高-低-高”的变化趋势,与蒸腾速率季节变化相反。单叶水分利用效率春秋较高,夏末最低,一天中早上最高,傍晚次之,中午最低。生长季三倍体毛白杨净光合速率、蒸腾速率、水分利用效率分别为(6.38±1.78)μmolCO2·m-2·s-1、(3.90±0.43)mmol H2O·m-2·s-1、(1.81±0.42)μmolCO2·mmol-1H2O。(5)三倍体毛白杨速生纸浆林枝条及叶片绝对含水量、相对含水量、水势、水容等水分特征呈现“V”型日变化。枝叶绝对含水量呈现“低-高-低”的季节变化,相对含水量、水势、水容则随季节推移逐渐减小。整个生长季,三倍体毛白杨枝条和叶片绝对含水量、相对含水量、水势、水容平均值分别为：55.89%±1.74%和65.20%±1.64%、83.36%±2.42%和73.84%±4.21%、(-1.51±0.24)Mpa和(-1.83±0.24)Mpa、(0.46±0.11)g·cm-3.MPa-1和(0.0049±0.0010)g·cm-3·MPa-1。三倍体毛白杨速生纸浆林树干边材液流速率与叶片蒸腾速率日变化相似,呈极显著的正相关关系。树干边材液流速率与枝叶含水量、水势、水容呈现一定的负相关性。在调节树干边材液流速率上,水容作用更大,而相比叶片来说,枝条发挥了更重要的作用。而在对蒸腾速率的调节上,叶片比枝条的作用更为明显。(6)综合考虑三倍体毛白杨水分利用效率、树冠结构、根系分布特点等因素,适用于带状配置的三倍体毛白杨速生纸浆林最优地下滴灌模式为：滴头间距50cm的“2行2带”或“2行3带”式地下滴灌。(7)地下滴灌可明显改善林地土壤水分条件,提高三倍体毛白杨树干边材液流速率和蒸腾速率,改善树木水分状况,增加净光合速率,促进林木生长,提高林地生产力,改善木材造纸性能。灌溉处理后,各处理林地生产力分别为11.02、13.43、17.97、13.68m3·(ha-2·a-1),灌溉效应为对照的1.36倍,最高为对照的1.63倍。灌溉量达到土壤田间持水量的70%-80%时的水分条件为三倍体毛白杨速生纸浆林的最适水分条件。(8)根据三倍体毛白杨生长季内土壤计划湿润层的水量平衡方程、生态系统蒸散量、有效降雨量、土壤含水量等特征参数分别确定了贫水年和丰水年地下滴灌条件下三倍体毛白杨速生纸浆林优化灌溉制度：贫水年灌溉定额为213mm(约182h),分6大次(5-11月除7月外每月一次),若干小次(每月根据气象条件将各月灌溉定额细化为若干次灌水)进行灌溉；丰水年灌溉定额为97mm(约83h),分5大次(3、5、9、10、11月每月一次),若干小次进行灌溉。更多还原

【Abstract】 As the important fast-growing and high yield plantation wood species, Popular played a most important part in relieveing the contradiction between wood supply and demand, ensuring wood safety, improveing local economic, increasing farmers income, increaseing carbon dioxide absorption and carbon sequestration, and so on. But the extensive management, low productivity of Popular plantation limited the higher productive potential of Popular plantation to a large extent.In order to improve the intensive and sustainable management of clones Triploid Populus tomentosa fast-growing pulpwood means and ways of thermal dissipation sapflow monitoring technology, automatic weather station, and so on, were used in superior hybrid triploids clones of Chinese White Popular plantation in Gaotang county (36°58’N,116°14’E), Shandong province from May,2008 to November,2009. Water use characteristics and its affecting and regulating mechanism of clones Triploid P. tomentosa were mastered, water-saving irrigation equipments and methods were selected, and scientifical irrigation schedules under subsurface drip irrigation were made. And the main conclusions were introduced as below.(1) The thermal dissipation sap flow velocity probe(TDP-30) was viable to monitor clones Triploid P. tomentosa sap flow and water use with the measured error 6.79 percent. The daily variation of clones Triploid P. tomentosa sap flow velocity was of one-peak pattern whose peak and average values in sunny days were significantly higher than that in cloudy and rainy days. The sap flow velocity diurnal variation was similar at different direction east, south, west, and north. The sap flow velocity of clones Triploid P. tomentosa at four orientations was highly correlated with each other, and the regression equations of sap flow velocity at four orientations were highly significant. There was no obvious difference among the four directions Vsp in sunny and cloudy days, but in rainy day, Vsp in east was significantly higher than that in the south.There were highly significant correlated relationship between Vsp and environmental factors such as solar radiation(Qs), air temperature(Ta) and relative humidity(RH), water vapor pressure deficit(VPD), wind velocity(WS), soil water content(SWC) and temperature(Ts). Path analysis showed that Vsp of triploid P. tomentosa was mainly affected by RH and Ts in sunny day, and RH and VPD in cloudy, and rainy day. The main environmental factors regulated the Vsp daily variation were RH and VPD. (2) The average daily water use of clones Triploid P. tomentosa varied with "low-high-low" tendency from spring to summer to autumn.The water use of clones Triploid P. tomentosa were 340mm and 410mm in 2008 and 2009 respectively. The seasonal change of clones Triploid P. tomentosa water use was positively correlated with stomatal conductance(Cond), leaf area index(LAI), Qs, Ta, RH, VPD, SWC and Ts, but negatively correlated with WS. The main factors regulated seasonal change of clones Triploid P. tomentosa water use were Cond, RH, and VPD.(3) The multivariable linear regression models were made used the Vsp and main environmental factors in sunny days from April to October in 2008. The Vsp was calculated by the models and the environmental factors in 2009. There was no obvious difference between calculated values and measured value by TDP, and there relationship could be described by highly significant liner correlation. The average predicted by the models and measured value of clones Triploid P. tomentosa Vsp was 0.00161 cm·s-1 and 0.00176 cm·s-1 respectively, and the error was 8.3 percent.(4) The diurnal variation of clones Triploid P. tomentosa net photosynthetic rate(Pn) was single-peak in spring and autumn, and double-peak in summer, and the transpiration rate(Tr) was single-peak. The seasonal change of Pn was high-low-high tendency which was contrary to the Tr seasonal change. The water use efficiency(WUE) of clones Triploid P. tomentosa was higher in spring and autumn, and at early morning and nightfall in dailychange. The average Pn, Tr, and WUE of clones Triploid P. tomentosa in growth season were (6.38±1.78)μmolCO2·m-2·s-1, (3.90±0.43) mmol H2O·m-2·s-1, and (1.81±042)μmolCO2·mmol-1H2O respectively.(5) The diurnal variation of clones Triploid P. tomentosa twig and leaf absoluteness water content(AWC), relative water content(RWC), water potential(Ψ), water capacitance(C) was "V" shape. The seasonal change of twig and leaf AWC was low-high-low tendency, and the twig and leaf RWC,Ψ, and C was decreasing gradually from spring to summer to autumn. The average AWC, RWC,Ψ, C of clones Triploid P. tomentosa twig in growth season were 55.89%±1.74%, 83.36%±2.42%, (-1.51±0.24)Mpa, (0.46±0.11)g·cm-3·MPa-1 respectively and the values of leaf were 65.20%±1.64%,73.84%±4.21%, (-1.83±0.24)Mpa, (0.0049±0.0010)g·cm-3·MPa-1 respectively.The diurnal variation of clones Triploid P. tomentosa Vsp and Tr was similar, and they were highly significantly positive correlated. The relationship between Vsp and twig and leaf AWC, RWC,Ψ, C was negatively correlated. C was of more important part in regulating Vsp, especially twig water capacitance, but leaf was more important in regulating Tr than twig.(6) The best subsurface drip irrigation schemes for clones Triploid P. tomentosa pulpwood belt plantation were 50cm between two emitters, and 2 lines of laterals with 2 rows trees or 3 lines of laterals with 2 rows trees, according to the clones Triploid P. tomentosa water use efficiency, stand crown characteristics, distribution of water absorbing roots, and so on.(7) The subsurface drip irrigation system can obviously improve the stand soil and trees water conditions, increase the sap flow velocity, net photosynthetic and transpiration rate of clones Triploid P. tomentosa, and promote the trees growth, improve the paper performance of clones Triploid P. tomentosa wood. It was the best water conditions for clones Triploid P. tomentosa pulp wood plantation when the irrigation amount achieveing 70-80 percent of the soil field capacity. After subsurface drip irrigation, the stand productivity of four treatments were 11.02m3·(ha-2·a-1), 13.43m3·(ha-2·a-1),17.97m3·(ha-2·a-1), and 13.68m3·(ha-2·a-1)respectively.(8) Scientifical irrigation schedules under subsurface drip irrigation system for clones Triploid P. tomentosa pulp wood plantation in poor and enrich rainfall years were formulated respectively according to the water balance equation of planned humidity soil layer depth, ecosystem water use and consumption, effective rainfall, soil water content in growth seasons. The irrigation water requirement was 213mm(about 182 hours) and 97mm(about 83 hours) respectively in poor and enrich rainfall years. The irrigation times was 6 in poor rainfall years, one times every months from June to November, but 5 times in enrich rainfall years, one times every months in March, May and September to November.To save water and increase the irrigation water use efficiency, the best time to irrigate were before sunrise and nightfall, and the irrigation principles of "more times but fewer amount" was recommended.更多还原