闽北毛竹林枯落物层持水功能研究

以杉木林和常绿阔叶林为对照,对闽北典型毛竹林(杉竹混交林、毛竹纯林、竹阔混交林)林下枯落物储量、持水特性及其对降雨的拦蓄能力进行研究,结果表明:(1)各林分未分解层、半分解层和已分解层枯落物储量、最大持水量和有效拦蓄差异较大,但均以半分解层最高,分解层次之,未分解层最小;杉木纯林枯落物总储量、最大持水量和有效拦蓄均最高,分别为14.6 t·hm^-2、2.668 mm和1.43mm,竹阔混交林次之,分别为7.0 t·hm^-2、1.298 mm和0.76 mm,毛竹纯林最低,分别仅为4.7 t·hm^-2、0.916 mm和0.58 mm。(2)5种林分各层枯落物持水量与浸泡时间的关系为:S=k ln(t)+p,在0 - 2 h内,枯落物持水量迅速增加,此后增加速度逐渐减缓;其吸水速率与浸泡时间的关系为:V=at^-1+b,在0 - 1 h内,枯落物吸水速率迅速下降,2 h后下降速度逐渐减缓。(3)竹阔混交林枯落物持水能力虽小于杉木纯林但在竹林中最强,对此,在竹林改造和竹林经营过程中应加以重视。     

毛竹林等不同森林类型枯落物水文特性的研究

2002年12月采集位于浙江省富阳市毛竹产区试验林分枯落物,测定毛竹纯林、竹阔混交林枯落物的水文特性并与阔叶林对照,结果表明:24h内枯落物持水进程可以分为两个阶段:阶段Ⅰ(0～8h)和阶段Ⅱ(8～24h)。阶段Ⅰ不同林分枯落物持水量约占饱和持水量(24h)的比例范围为:23.85%～30.39%。枯落物持水量随浸泡时间延长而增加,6～8h后基本趋于稳定。枯落物浸泡1h的平均持水率为1.958g·g-1·h-1,浸泡4h后降低为0.419g·g-1·h-1,降低至初始值的22%。在浸泡2～8h后,毛竹纯林枯落物持水率是竹阔混交林的1/3～1/8。阶段Ⅱ各林分枯落物在不同时段的持水量表现出相似规律,即在8～12h呈现下降趋势,12h后各时段枯落物持水量又有所回升至24h达到饱和。相比之下竹阔混交林枯落物持水量下降幅度最快。各森林类型枯落物对降水的拦蓄能力依此排序为:常绿阔叶林>竹阔混交林>未垦复毛竹纯林>垦复毛竹纯林。从林地枯落物的现存量及饱和持水量着眼,竹阔混交林的水文生态效应优于毛竹纯林而次于常绿阔叶林,垦复毛竹林不利于枯落物水文效应的发挥。     

华北落叶松枯落物覆盖对地表径流的拦阻效应

在宁夏固原六盘山叠叠沟小流域坡面径流小区(长0.9 m、宽0.5 m)内进行了10种枯落物覆盖量(0.0、0.5、1.0、3.0、5.0、7.0、10.0、15.0、20.0、25.0 t·hm-2)、5个入口流量(10、20、30、40、60 mL·s-1)的地表径流试验.结果表明:当枯落物覆盖量从0.0 t·hm-2增加到25.0 t·hm-2时,地表径流流速与无枯落物覆盖相比减小了57.50%～72.27%;地表径流流速随入口流量增加而明显加大,尤其是无枯落物覆盖时增加最快;在坡度为14°的条件下,枯落物覆盖对地表径流流速的阻延值△V(cm·s-1)与单宽流量q(mL·s-1·cm-1)、枯落物覆盖量G(t·hm-2)的关系为:△V=3.617 7q0.507 5G0.431 5(R2=0.910 2);枯落物覆盖量增加使地表曼宁阻力系数n值加大,在枯落物覆盖量小于10.0 t·hm-2时,n值随枯落物量增加而急剧加大;当枯落物覆盖量在10.0～25.0 t·hm-2范围内增加时,n值的加大趋势逐渐变缓;n值与枯落物覆盖量之间呈较好的二项式关系.     

落叶松人工林枯落物特征研究

本文研究了落叶松人工林枯落物的酸度变化、浸提液的离子含量、腐殖质组成以及微生物含量的变化，并与混交林的枯落物特征进行了比较，探讨了枯落物的矿质养分及水溶性物质的含量，为进一步研究落叶松人工林地力问题提供了借鉴。     

广州七种园林植物枯落物的水文效应

文章分析了广州7种园林植物枯落物的水文效应。结果表明：（1）7种园林植物枯落物最大持水量的大小顺序为：白兰（278．43mm）〉羊蹄甲（278．03mm）〉潺槁树（210．58mm）〉小叶榕（198．64mm）〉塞楝（166．97mm）〉腊肠树（132．52mm）〉印度橡胶榕（128．31mm）,其吸水速率的大小顺序亦同;（2）枯落物的最大持水率、最大拦蓄率和有效拦蓄率的大小顺序均为白兰〉羊蹄甲,潺槁树,小叶榕〉塞楝〉印度橡胶榕,腊肠树;（3）枯落物持水量随浸水时间的增长而增加,吸水速率随之而减少。     

森林枯落物的水文功能

从森林枯落物的蓄水量、雨水截留量、阻延径流流速、改善土壤结构、减沙减流作用5个方面,叙述了森林枯落物的水文功能,提出森林经营中,应采取措施,促进林分森林枯落物的积累。     

油松侧柏人工林下枯落物对森林土壤的影响

对油松侧柏人工混交林及纯林下的枯落物调查结果表明,不同林分组成的枯落物贮量、分解速率、持水量各异,从而对土壤发育层次产生不同程度的影响,弱酸淋溶作用、腐殖质侵染及营养元素下移程度,侧柏纯林高于混交林和油松纯林;枯落物层中微生物数量,混交林>侧柏林>油松林;枯落物中水溶性营养元素的绝对量,油松林>混交林>侧柏林,相对量则是混交林>油松、侧柏纯林。     

湖南湘西地区马尾松林枯落物动态估算模型研究

以湖南省湘西地区马尾松人工林为研究对象,对其2014—2017年森林生物量、森林枯落物凋落量与现存量等进行调查,并对森林枯落物凋落量与森林生物量二者之间的关系进行了研究。结果表明：森林枯落物凋落量与森林乔木地上原有生物量及增加量之间存在着显著相关关系,通过森林乔木地上原有生物量W_U0及增加量W_U△、林分密度N等林分因子来估算森林枯落物凋落量K_W具有很好的效果,其线性回归模型为K_W=0.003N+0.026W_U0+0.159W_U△+0.101,相关系数R=0.923。同时,可根据森林枯落物凋落量和现存量计算森林枯落物的分解速率,进而建立森林枯落物的动态变化预测模型及消长系数模型,对森林枯落物的动态变化过程及消长规律进行分析与预测。通过林分因子来估算森林枯落物凋落量和现存量,对于及时掌握森林枯落物的状态,进而对与之相关的物质循环、能量流动和生态服务功能进行分析与评价具有重要...     

升温处理对辽西沙地油松枯落物分解效应的影响

为了探索温度升高处理下油松枯落物的响应机制,通过应用开顶箱人工模拟升温处理,以自然温度条件作对照处理,开展了沙地油松枯落物分解试验研究.结果表明:升温处理下油松枯落物的枝、叶中含水率及质量残余率均高于对照处理,且叶的含水率大于枝的含水率,叶的质量残余率低于对照的质量残余率.可见,升温条件抑制了油松枯落物的分解,其中对油...     

西藏自治区森林枯落物碳储量估算

利用典型样地采样,建立了枯落物碳密度与厚度关系方程,并结合森林资源连续清查的样地坡度与枯落物厚度因子,估算出西藏自治区森林枯落物碳储量.结果表明,西藏自治区丰富的森林植被生产了巨大的枯落物层碳库,有机碳分解和碳库消耗缓慢.研究该部分碳库状况,为估算和评价陆地生态系统碳储量并据此制定相应的对策提供了基础数据.     

不同林分林下枯落物持水功能研究

对鹰嘴界自然保护区阔叶林、杉木毛竹混交林和杉木林的林下枯落物贮量与持水性能等进行了研究。结果表明：3种不同林分林下枯落物总贮量在5．13～6．50t／h㎡之间,其大小顺序为：杉木毛竹混交林〉阔叶林〉杉木林。枯落物最大持水量差异明显,其大小顺序为阔叶林（19．00t／h㎡。）〉杉木毛竹混交林（15．72t／h㎡）〉杉木林（11．09t／h㎡）。枯落物有效持水量在0．93～1．62mm之间。     

Characteristics of runoff and sediment generation of forest vegetation on a hill slope by use of artificial rainfall apparatus

We studied the impact of forest vegetation on soil erosion,surface runoff, and sediment generation by using field simulated rainfall apparatus. We measured runoff and sediment generation of five 4.5 × 2.1m runoff plots (a bare soil as a control; two Pinus tabulaeformis forestplots and two Platycladus orientalis forest with row spacing of 1 m × 1m and 1.5 m × 1.5 m, respectively) in Beijing Jiu Feng National ForestPark under three rainfall intensities (0.42, 0.83, 1.26 mm per minute).Forest vegetation significantly reduced soil erosion and sediment yield.Mean total runoff volume in the four tree stand plots was 93% of that inthe control plot, demonstrating the limited effectiveness of forest vegetation in runoff control. With increasing rainfall intensity, runoff reductionin forest plots declined from 28.32% to 2.1%. Similar trends in runoff coefficient and the relationship between runoff volume and rainfall duration was observed. Mean total sediment yield and mean sediment yield reduction rate under different treatments was 55.05% and 43.17% of those in the bare soil control plot, respectively. Rainfall intensity playedan important role in runoff and sediment generation processes, and had agreater impact on runoff than on soil erosion and sediment generation.When considering several factors in runoff and sediment transport processes, the P. tabulae form plot with row spacing at 1 × 1 m had a greater effect on soil and water conservation than did other forested plots.     

辽东山区不同森林植被类型枯落物层截留降雨行为研究

对辽宁东部山区具有代表性的油松林、落叶松林、红松林、柞木林及杂木林5种森林植被类型枯落物层截留降雨行为进行了比较研究。结果表明，枯落物截留量随林内雨量的增加而增加，呈显的线性关系；枯落物截留率在低的林内雨量级时下降梯度较大，以后随林内雨量增大而逐渐减少，最后趋于某一定值，枯落物截留达到饱和。曲线估计的饱和截留率为：杂木林30％，柞木林23％，落叶松林20％，油松林15％，红松林10％。林冠层与枯落物层截留量依林外雨变化呈显的线性关系，总截留率在低雨量级时保持在较高的水平，随后急剧下降，并逐渐趋于某一稳定性，达到最大截留能力。由曲线推算的最大总截留率，杂木林和 柞木林为45％，落叶松林为40％，红松林和油松林约为30％。枯落物生长季相对于林内雨的截留率为14．31％－43．15％，平均值为31．15％，相对于林外雨量的截留量为11．15％－32．30％，平均值为24．05％。     

Experimental studies on rain splash erosion of forest soils after clearing in Okinawa using an artificial rainfall apparatus

The main island of Okinawa, in southwestern Japan, is characterized by a subtropical climate, coral reefs, and reddish soils, which contain Acrisols and Cambisols (FAO/UNESCO classifications). Recently, due to soil erosion on hilly lands, the coral reefs have been damaged by an inflow of reddish soil. Forest clearing is thought to one of the factors increasing rain splash erosion rates on hilly lands, because it is believed that clearing disturbs the forest floor and causes the supply of litter to stop. After clearing, A0, A and B horizons will be denuded, one after the other, by rain splash. In this study, we measured rain splash erosion rates of undisturbed samples of A0, A and B horizons using an artificial rainfall apparatus. The results of experiments on rain splash erosion clarified several aspects of the erosion process in a clearing site. First, it was found that the rain splash erosion rates were higher in fresh litter than in decomposed litter, in decomposed litter than in the A horizon, and in the A horizon than in the B horizon. Thus, the erosion rate increases with soil depth. Secondly, surface-gleyed red and yellow soils are mostly vulnerable to rain splash erosion. The erosion rates of these soils are two to three times higher than those of the red soil and the yellow soils. Thirdly, the erosion rates are affected mainly by bulk density and saturated hydraulic conductivity, not by clay ratio and dispersion ratio. Lastly, the difference between erosion rates of surface-gleyed red and yellow soils and other soils will be even greater if a soil crust has formed, because the formation of a soil crust increases the rain splash erosion rate.     

“蜀南竹海”毛竹林土壤物理性质及其影响因子

以四川“蜀南竹海”毛竹林土壤为研究对象,探讨了土壤表层(0 ～20 cm)和下层(20～ 40cm)的黏粒含量、密度、孔隙度、持水量的变异性,它们之间的相关关系以及海拔、土壤类型、枯落物厚度和土壤有机质对上述物理性质的影响.结果表明:研究区毛竹林土壤物理性质变异系数在10.28％～ 56.21％之间,属于中等变异性;总孔隙度、非毛管孔隙度、毛管持水量、最大持水量表层显著高于下层,而土壤密度表层显著低于下层;各土层物理因子之间有着密切关系,并且它们之间的相关关系基本不因土层差异而发生变化;海拔、枯落物厚度只对毛竹林表层土壤物理性质有显著影响,有机质对两土层土壤物理性质均有显著影响,而土壤类型只对两土层土壤密度、黏粒有显著影响.     

水蚀风蚀交错区典型人工林土壤水分亏缺特征

为充分了解水蚀风蚀交错区典型林地土壤水分差异性及其生态水文效应,选择陕西省延安市吴起县水蚀风蚀交错区长城镇退耕还林后形成的典型人工林(小叶杨、山杏、山桃、柠条、河北杨和沙棘林)为研究对象,采用烘干法测定土壤含水量,分析0~300 cm土层土壤水分季节变化特征、贮水量特征和土壤贮水亏缺程度。结果表明:在0~300 cm土层,6种林地土壤水分具有明显的垂直变异特征,即随着土层深度的增加,土壤含水量先升高后降低;6种林地各土层的土壤含水量均具有明显的季节变化特征,且变异系数在表土层较大,随着深度的增加而减小;6种林地土壤水分活跃层存在一定的差异性;其中,沙棘林土壤水分活跃层最深(0~80 cm),其它林地相对较浅(20~40 cm);在0~100 cm土层,各林地土壤贮水量垂直变化趋势差异较大,且小叶杨、河北杨与沙棘林差异显著(P<0.05),沙棘各季节土壤贮水量随着土层深度的增加呈现先增大后减小的趋势。不同植被类型土壤贮水亏缺度存在差异,土壤水分亏缺度在季节上表现为秋季>春季>夏季。     

湖州市主要林分类型枯落物和土壤持水能力

对湖州市7种主要林分类型植被的枯落物层持水性能和土壤层蓄水能力进行了研究.结果表明:7种林分类型林地枯落物层和土壤层的持水量存在差异,枯落物现存量变化范围为5.92～ 9.88 t/hm2,土壤总孔隙度的变化范围为49.00％ ～58.11％,土壤最大持水量的变化范围为1 934.8～2 324.4 t/hm2.枯落物最大持水量依次为针阔混交林＞常绿阔叶林＞疏林＞马尾松林＞灌木林＞杉木林＞毛竹林,林地水源涵养能力依次为针阔混交林＞常绿阔叶林＞疏林＞灌木林＞毛竹林＞马尾松林＞杉木林,毛竹林的林地持水能力要好于马尾松林和杉木林.全市非毛管总蓄水量为12 919.2万t,最大蓄水量为43 617.7万t.     

不同海拔毛竹土壤酶活性与土壤理化性质关系的研究

以江西省大岗山地区的毛竹林为研究对象,利用相关分析和主成分分析对不同海拔(300、400、500、600、700m)土壤纤维素酶、蔗糖酶、淀粉酶、β-葡糖苷酶和多酚氧化酶活性的变化特征进行了分析,探讨了其与土壤理化性质的关系。结果表明:土壤化学指标表现出随海拔的升高而增加的变化特征,除碱解氮外,其他各指标均处于较低水平,但物理指标的变化各不相同;随海拔升高,β-葡糖苷酶与多酚氧化酶活性呈现出增加的趋势,而纤维素酶、蔗糖酶和淀粉酶活性无明显变化规律;几种土壤酶对土壤肥力的指示效果不同,β-葡糖苷酶在评价毛竹林土壤肥力上具有重要指示效果,其后依次为蔗糖酶和多酚氧化酶、纤维素酶,但淀粉酶不适宜用来评价土壤肥力状况;通过主成分分析计算综合得分,不同海拔毛竹土壤肥力随海拔的升高而增加。     

Effects of mulching with multipurpose-tree prunings on soil and water run-off under semi-arid conditions in Kenya

The effect of adding leaf mulches ofGrevillea robusta, Cassia siamea andGliricidia sepium on the rate of soil and water run-off from a crop field were studied during two cropping seasons in an alfisol under semi-arid conditions at Machakos, Kenya. The experiment was conducted in a randomized complete block design with three replications; two rates of mulch of each species (2.24 t and 4.48 t, on dry matter basis, per ha) and a no-mulch control constituted the seven treatments. Soil and water run-off losses after each major rainfall event and the changes in ground and crop cover were measured. Rainfall erosivity and changes in soil bulk density and infiltration rate were also determined.Soil losses from the plots with mulches ofCassia siamea, Gliricidia sepium andGrevillea robusta were significantly lower than those from the control (p=0.10). Over the two seasons, the cumulative soil losses from plots mulched with cassia, gliricidia and grevillea were 11%, 57% and 81% lower than that of the control plot. Similarly, water run-off losses from cassia, gliricidia and grevillea mulch plots were 28%, 48% and 58%, respectively, lower than that of the control plot. Thus, cassia was found to be better than gliricidia and grevillea in reducing both soil and water run-off losses.Soil bulk density did not change while infiltration rate at the end of the experiment was significantly more than in the beginning; however, there were no significant differences in these soil physical properties among the treatments.     

毛竹林地土壤水土流失的初步研究

采用人工模拟降雨装置,对毛竹林地土壤流失进行了试验,结果表明:林地坡度是影响林地土壤流失的主要因子,坡度在30耙陨鲜?极易造成林地土壤冲刷;地表覆盖能有效地降低地表径流中的泥沙含量;大雨、陡坡、全垦造成的水土流失非常严重.