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1.
晋西黄土丘陵区不同植物群落的土壤分形特征   总被引:3,自引:0,他引:3  
为研究晋西黄土丘陵区不同植物群落与土壤结构特性和入渗特性的关系,探索土壤结构的定量化描述,运用分形学原理和方法,研究晋西黄土丘陵区油松纯林、刺槐纯林、油松+刺槐混交林、侧柏纯林、黄刺玫灌丛、柠条灌丛及荒地7种植物群落的土壤分形维数与土壤质地、密度、孔隙度、含水量及饱和导水率的关系.结果表明:1)植物群落具有改善土壤颗粒结构的作用,其改善作用以针阔混交林(油松+刺槐混交林)最好,阔叶林(刺槐纯林、黄刺玫纯林)次之,针叶林(油松纯林、侧柏纯林)最低.2)研究区土壤颗粒分形维数在2.799 ~ 2.805之间,黏粒(<0.002mm)质量分数偏高.3)土壤颗粒分形维数与土壤黏粒质量分数呈显著正相关关系,与土壤砂粒(2.00~0.02 mm)质量分数、土壤总孔隙度、含水量及饱和导水率呈显著负相关关系.因此,土壤颗粒分形维数可以表征土壤结构特性和入渗特性的好坏.不同的植物群落对土壤的改良效果不同,研究结果可为研究区域植树造林提供参考依据.  相似文献   

2.
砒砂岩区主要造林树种枯落物及林下土壤持水特性   总被引:13,自引:2,他引:11       下载免费PDF全文
为了探究砒砂岩区不同造林树种水文特征,以该地区油松、侧柏、青杨、山杏、沙棘、柠条为研究对象,通过浸泡法和环刀法,对比分析了不同树种枯落物层和土壤层的持水特性。结果表明:砒砂岩区主要造林树种枯落物蓄积量变动范围为1.55~7.89t/hm~2,青杨林下枯落物最大持水率最高为281.26%,其他树种枯落物最大持水率依次为油松(217.14%)、侧柏(201.05%)、山杏(202.79%)、沙棘(170.96%)、柠条(158.08%)撂荒地(143.88%)。油松林下土壤层容重最小为1.46g/cm3,总孔隙度和毛管孔隙度最大分别为43.55%和36.99%,毛管持水量最大为14.50mm;山杏林下土壤非毛管孔隙度最大为13.12%,非毛管持水量最大为6.86mm。油松枯落物及其林下土壤层持水能力良好,更适宜作为砒砂岩地区植被建设树种。  相似文献   

3.
河西走廊中部的临泽绿洲位于巴丹吉林沙漠西南缘,在沙漠-绿洲过渡带上生长发育了大量的防风固沙植物。以梭梭、沙拐枣、泡泡刺三种固沙植物根区的土壤为研究对象,探究不同固沙植物根区土壤物理性质指标和持水特性的变化规律及其相互间的关系,旨在为防沙治沙工程实践中固沙植物的选择和空间配置提供科学依据。结果表明:(1)三种固沙植物根区的土壤容重均随土层深度增加而降低,均值表现为:沙拐枣 > 泡泡刺 > 梭梭;土壤孔隙度均随土层深度增加而增大,均值表现为:梭梭 > 泡泡刺 > 沙拐枣;三种固沙植物根区的土壤物理性质指标随土层加深差异性增大。(2)0 ~ 120 cm土层深度范围内,梭梭根区的土壤持水特性最好,泡泡刺次之,沙拐枣最低;0 ~ 40 cm土层深度范围内三种固沙植物根区的土壤持水特性均不存在显著差异;40 ~ 60 cm土层深度范围内梭梭与沙拐枣根区的土壤持水特性存在显著差异;60 ~ 80 cm土层深度范围内三种固沙植物根区的土壤持水特性均存在显著差异。(3)三种固沙植物根区的土壤持水特性均与土壤容重、总孔隙度和毛管孔隙度呈显著相关关系(P < 0.01),但与非毛管孔隙度的相关性却不同,其中梭梭根区的土壤持水特性非与毛管孔隙度呈显著正相关(P < 0.01),而沙拐枣、泡泡刺根区的则呈不显著相关关系。  相似文献   

4.
新泰土门林场四种林地土壤蓄水性能及渗透速率的研究   总被引:3,自引:0,他引:3  
研究了新泰市土门林场内麻栎、刺槐、侧柏和油松四种林地土壤的蓄水性能和渗透速率。结果表明:四种林地土壤的蓄水能力和渗透速率均明显高于荒坡地。四种林地0~20 cm土壤层的土壤含水量均高于20~40 cm层;四种林地0~20 cm和20~40 cm土壤层的蓄水能力从大到小的顺序均为刺槐林〉麻栎林〉侧柏林〉油松林。四种林地土壤的渗透系数从大到小依次为刺槐林〉麻栎林〉侧柏林〉油松林。  相似文献   

5.
不同林龄白桦次生林土壤特性及其水源涵养功能   总被引:10,自引:0,他引:10       下载免费PDF全文
以小兴安岭地区4个林龄的白桦次生林为研究对象,对其土壤特性、土壤贮水性能、凋落物持水量进行研究。结果表明:白桦次生林凋落物的蓄积量、最大持水量均以38 a为最大,70 a相对较低,凋落物蓄积量与最大持水量有显著正相关关系;土壤非毛管孔隙度随林龄变化呈波动性变化,38 a白桦次生林0-30 cm土层非毛管孔隙最大,有利于降水的下渗,而25 a白桦次生林0-30 cm土层非毛管孔隙最小,不利于水分下渗。土壤水源涵养功能大小排序为70 a(3 628.445 t/hm^2)〉56 a(3 524.015 t/hm^2)〉25 a(3 433.626 t/hm^2)〉38 a(3 275.820 t/hm^2)。  相似文献   

6.
运用对比和统计分析方法,研究小兴安岭红松阔叶混交林进展演替系列4个阶段(形成阶段、发展阶段、稳定阶段和顶级群落阶段)的土壤肥力、林木生长以及土壤肥力与主要树种生长的关系。结果表明:随着林分演替进展,林分中针叶树种(红松、云杉和冷杉)树高、胸径、蓄积量增加,白桦、山杨等阔叶树种蓄积量则不断减小;土壤物理性状得到改善,土壤渗透性、饱和持水量、毛管持水量、毛管孔隙度、非毛管孔隙度增大;土壤有机质、全氮、硝态氮和铵态氮含量逐渐增加;表层(0—10cm)土壤pH值逐渐减小。红松阔叶混交林各演替阶段土壤密度、pH值与林木树高、胸径呈负相关;土壤饱和持水量、毛管持水量、非毛管孔隙度、毛管孔隙度、有机质、铵态氮、硝态氮、全氮均与林木平均树高、平均胸径呈正相关。相关性因树种不同而有所差异。运用主成分分析方法证明。土壤饱和持水量、毛管孔隙度、有机质和硝态氮是影响林木生长和不同演替阶段土壤肥力的主要因子。不同演替阶段土壤肥力排序为原始林〉稳定阶段〉发展阶段〉形成阶段。土壤肥力向着良性发展。  相似文献   

7.
在大田条件下,研究了白膜覆盖和黑膜覆盖对欧美I-107杨林下土壤0—40cm土层的温度、含水量、容重、孔隙度和土壤呼吸速率的影响。结果表明,在两种覆膜方式中,白膜覆盖的增温效应优于黑膜覆盖,而对土壤含水量的影响无显著差异。0—20cm土层白膜覆盖和黑膜覆盖处理均显著提高了土壤总孔隙度、毛管孔隙度和非毛管孔隙度,而土壤容重却明显降低,分别比对照降低15.44%和9.56%;此外,白膜覆盖的土壤呼吸速率与对照差异不显著,而黑膜覆盖显著低于对照。20—40cm土层与0—20cm土层表现出基本一致的变化规律,但两种覆膜方式与对照之间的差异均变小,表明随着土层的加深,覆膜的影响作用减弱。说明白膜和黑膜覆盖均可明显改善表层土壤的物理性状,但黑膜覆盖明显抑制了土壤呼吸。在两种覆膜方式中,白膜覆盖的作用效果明显优于黑膜覆盖。  相似文献   

8.
三峡库区等高绿篱技术对土壤物理性质的影响   总被引:3,自引:0,他引:3       下载免费PDF全文
等高绿篱是目前国内外广泛采用的一种十分有效的坡耕地植被恢复和水土保育技术,被认为是三峡库区农业生态系统持续发展的有效途径之一。以等高绿篱(新银合欢和黄荆)篱前淤积土为研究对象,评估等高绿篱一坡地农业复合种植模式下不同土层深度、不同距篱(坎)距的土壤水分及物理性质变化特征。结果显示:绿篱处理的土壤非毛管孔隙度、饱和入渗率、饱和含水量和自然含水量均高于石坎梯田处理,而土壤密度和田间持水量均小于石坎梯田处理,尤其在表层和第2层,其差异更明显,等高绿篱保育土壤效益显著;同一土层,随距篱(坎)距延长,绿篱处理的土壤密度、自然含水量逐渐增大,土壤非毛管孔隙度、饱和入渗率和饱和含水量逐渐减小,而石坎梯田处理的变化不明显;随土层加深,各处理的土壤密度、自然含水量均相应逐渐增大,土壤非毛管孔隙度、饱和入渗率和饱和含水量均相应逐渐减小,且处理之间差异也逐渐缩小;距篱(坎)远近间接反映了绿篱处理对土壤水分及物理性质的影响程度,距篱越近,影响越大;新银合欢处理与黄荆处理之间相比,效应相当。  相似文献   

9.
贵州西部四种典型林地土壤水文特性研究   总被引:1,自引:0,他引:1  
对贵州省西部地区桦木林、柳杉林、华山松林和杉木林4种典型林地土壤的物理性质和水文特性进行了初步研究。结果表明:4种林地土壤容重、毛管孔隙度、贮水深和毛管持水深均随土壤深度的增加而增大,总孔隙度、非毛管孔隙度、最大持水深和渗透性具有随土壤深度的增加而减小的趋势。综合评价4种典型林地土壤物理性质和水文特性,桦木林地土壤平均非毛管孔隙(16.29%)和渗透性(2.77mm/min)最大,表现出较强的蓄水能力;华山松林地土壤平均总孔隙度(66.70%)最大,表现出较大的持水深。  相似文献   

10.
晋西北不同土地恢复管理措施下土壤物理性状分析   总被引:1,自引:0,他引:1  
【目的】晋西北丘陵风沙区由于受风蚀影响,土壤沙化十分严重,生态恢复是缓解此问题的主要措施之一。研究不同土地恢复管理措施旨在为提高晋西北黄土高原丘陵风沙区农田土壤质量及植被恢复提供理论依据。 【方法】本研究以晋西北五寨县作为研究区,设置4种土地恢复措施:传统翻耕播种玉米 (CTC)、免耕播种玉米 (NTC)、免耕播种苜蓿 (NTA)、撂荒地 (WL)。通过野外和室内分析的方法,分析了0—50 cm土层土壤粒度组成、粒度参数和土壤质量含水量、土壤饱和持水量、毛管持水量。 【结果】1) 晋西北地区土壤主要以砂粒和粉粒为主。撂荒地砂粒含量最大,且随着深度的增加变化不明显;其它3种措施下的土壤表层砂粒含量均小于深层。不同土地恢复措施间粒度参数差异较大,翻耕分选较差,免耕玉米和免耕苜蓿属于分选中等到分选较好范围,表明翻耕地块土壤受到人为扰动较大,导致土壤偏细,其粉粒含量在0—50 cm土层变化范围为6.5%~15.3%,而免耕苜蓿和免耕玉米土壤环境相对较好。2) 4种土地恢复措施下表层 0—40 cm的土壤容重均低于深层土壤,翻耕、免耕播种玉米和免耕播种苜蓿的土壤容重范围在1.10~1.50 g/cm3之间,表现为WL>NTA>NTC>CTC,撂荒地土壤容重与其它三种处理措施的土壤容重差异显著 (P < 0.05),其他三种措施间差异不显著,40—50 cm土层四种土地恢复措施之间无显著差异;表层 0—30 cm的土壤孔隙度以翻耕总孔隙度最大。翻耕地块土壤孔隙度显著高于其它三种恢复措施,其它三种恢复措施间无显著性差异,40—50 cm土层四种土地恢复措施之间无显著差异。3) 不同土地恢复措施之间土壤质量含水量、饱和持水量和毛管持水量存在较大差异,翻耕地块表层0—20 cm土壤毛管持水量显著高于其它三种恢复措施;免耕苜蓿和免耕玉米地块毛管持水量无显著差异,两者均显著高于撂荒地,20—30 cm土层免耕苜蓿地块显著低于翻耕和撂荒地,30—40 cm土层撂荒地与免耕玉米显著低于翻耕和免耕苜蓿,40—50 cm土层四种土地恢复措施之间无显著差异。4) 土壤毛管持水量和饱和持水量与毛管孔隙度和非毛管孔隙无显著相关关系,与总孔隙度呈显著正相关关系。土壤质量含水量和毛管持水量与粘粒含量无显著相关;与砂粒含量呈极显著负相关,相关系数分别为–0.619和–0.474;与粉粒含量呈显著正相关,相关系数分别为0.639和0.584。 【结论】晋西北丘陵风沙区翻耕、免耕玉米和免耕苜蓿三种土地恢复措施都不同程度地降低了表层土壤砂粒含量,提高了土壤孔隙度,降低了土壤容重,改善了土壤的保水和供水能力,7年常规耕种和免耕种植作物都显著改善了土壤的物理性状,有助于生态的恢复和提高土壤的生产力。因此,在晋西北地区不提倡土地撂荒。  相似文献   

11.
应用Wenner结构原理估计沙地松树人工林土壤含水量   总被引:3,自引:0,他引:3  
To estimate the mean value of surface soil water content rapidly, accurately, and nonintrusively, field investigations on soil electrical resistivity (SER) with the Yokogawa 324400 earth resistivity meter and the surface (0-150 cm) soil water content (SWC) with time domain reflectometry (TDR), together with the abiotic factors including soil texture, structure, and salinity concentrations were conducted in the Mongolian pine (Pinus sylvestris var. mongolica) plantations on a sandy land. The measurement of SER was based on the 4-probe Wenner configuration method. Relationships between the values of SWC and SER were obtained based on analysis of the abiotic factors of the research site, which play a key role in affecting the soil electrical resistivity. Results indicate that the SER meter could be used to estimate the mean value of SWC in the Mongolian pine plantations on the sandy land during the growing seasons. The bulky nature of the equipment simplified the cumbersome measurements of soil water content with the general methods. It must be noted that the Wenner configuration method could only provide the mean values of the SWC, and the soil texture, structure, temperature, and solute concentrations influenced the SER and further affected the estimation of the SWC by the SER meter. Therefore, the results of this study could be applied on a sandy land during the growing seasons only. However, the SWC of other soil types also may be obtained according to the individual soil types using the procedures of this study.  相似文献   

12.
Information on the distribution patterns of soil water content (SWC), soil organic matter (SOM), and soil exchangeable cations (SEC) is important for managing forest ecosystems in a sustainable manner. This study investigated how SWC, SOM, and SEC were influenced in forests along a successional gradient, including a regional climax (monsoon evergreen broad-leaved forest, or MEBF), a transitional forest (coniferous and broad-leaved mixed forest, or MF), and a pioneer forest (coniferous Masson pine (Pinus rnassoniana) forest, or MPF) of the Dinghushan Biosphere Reserve in the subtropical region of southern China. SWC, SOM, and SEC excluding Ca^2+ were found to increase in the soil during forest succession, being highest in the top soil layer (0 to 15 cm depth) except for Na^+. The differences between soil layers were largest in MF. This finding also suggested that the nutrients were enriched in the topsoil when they became increasingly scarce in the soil. There were no significant differences (P = 0.05) among SWC, SOM, and SEC. A linear, positive correlation was found between SWC and SOM. The correlation between SOM and cation exchange capacity (CEC) was statistically significant, which agreed with the theory that the most important factor determining SEC is SOM. The ratio of K^+ to Na^+ in the topsoil was about a half of that in the plants of each forest. MF had the lowest exchangeable Ca^2+ concentration among the three forests and Ca^2+:K^+ in MPF was two times higher than that in MF. Understanding the changes of SWC, SOM, and CEC during forest succession would be of great help in protecting all three forests in southern China.  相似文献   

13.
土壤水分对柑橘叶片生长及多胺代谢的影响   总被引:3,自引:0,他引:3  
周静  崔键  梁家妮 《土壤》2009,41(5):796-800
本文以2年生宫川温州蜜柑(Citrus unshiu Marc.cv. Miyagawa Wase)盆栽幼树为材料,研究了土壤相对含水量(Soil Water Content,SWC)对橘叶生长和叶片多胺(腐胺Put,亚精胺Spd,精胺Spm)代谢的影响.结果表明:SWC由30%增加到90%,橘叶面积、叶周长、叶宽值均在75%时达最大值12.25 cm2、13.84 cm、3.19 cm,且叶面积、叶周长、叶长、叶宽均与SWC呈显著线性正相关;橘叶Put在SWC=75%时最低(228.95 nmol/g,FW),Spd和Spm均随土壤水分递增呈抛物线变化,其最大值分别出现在45%和60%.(Spd+Spm)/Put的比值与叶面积、叶周长、叶长、叶长/宽间呈显著或比较显著负相关,且当SWC≤75%时,此比值(t)与SWC(x)间呈显著正相关(t=0.0112x + 0.173, p<0.05).因此,(Spd+Spm)/Put比值可视为柑橘对土壤水分环境敏感度的指标之一.  相似文献   

14.
黄土半干旱区油松苗木蒸腾特性与影响因子的关系   总被引:4,自引:0,他引:4  
 为分析土壤水分与气象因子对油松蒸腾作用的影响程度,提高造林成活率,并为林地水分管理提供科学依据。在2004年生长季典型晴天,采用盆栽试验,人为控制土壤水分,利用针叶Li-1600稳态气孔仪和BP-3400精密天平等仪器,对黄土半干旱区油松苗木的蒸腾特性及其影响因子的关系进行研究。结果表明:在不同的土壤水分条件下,油松蒸腾速率和气孔阻力的日变化曲线分别呈“双峰型”和“W”型;在典型晴天下,蒸腾速率与土壤含水量的关系呈三次曲线相关,7、8和10月份,油松叶片蒸腾速率达到最大值时所对应的土壤含水量分别为17.7%、19.8%和17.5%。蒸腾速率除自身生理特性的影响外,还受土壤水分和气象因子综合影响,当土壤水分充足时,蒸腾速率与气象因子相关性高;当土壤水分产生胁迫时,蒸腾速率与气象因子相关性降低。在严重土壤水分胁迫下,7和8月份气温对蒸腾作用的影响最大,10月份光合有效辐射的影响最大。在土壤充分供水的条件下,7月份空气相对湿度对蒸腾作用的影响最大,8月份是气温,10月份是叶温。  相似文献   

15.
为揭示黄土高原农田转变为苹果园后土壤水分及硝态氮剖面变化特征,以洛川县为研究区,采集农田(对照)和8,17,25年苹果园共40个0-600 cm剖面土样,分析土壤水分、NO_3~--N浓度及其储量。结果表明:与农田相比,8年苹果园0-600 cm土壤水分含量及贮水量偏高(旧县镇)或相当(槐柏镇),而NO_3~--N浓度及其累积量则没有显著差异;17,25年苹果园0-600 cm土层贮水量则显著降低(P0.05),分别下降150,230 mm,且该差异主要与300 cm以下土层水分变化有关;0-500 cm土层NO_3~--N浓度随苹果种植年限显著增加,17,25年苹果园0-600 cm土层NO_3~--N累积量分别为6 830,8 370 kg/hm~2,二者显著高于农田(695 kg/hm~2)和8年果园(440 kg/hm~2)。综合可知,农田转变为苹果园这一土地利用方式变化可导致深层土壤水分亏缺(300 cm)和硝态氮累积,黄土高原大力发展苹果种植过程中应重视蓄水保墒及氮肥减施等措施。  相似文献   

16.
The measurement of saturated water content (SWC) is necessary in the estimation of soil water retention and unsaturated hydraulic conductivity curves. In several studies, pedotransfer functions (PTFs) were developed to predict SWC. Among them, evolutionary polynomial regression (EPR) is one that can operate on large quantities of data in order to capture nonlinear and complex interactions between the variables of the system. In this study, the evolutionary data-mining technique was used to derive new PTFs and different methods were evaluated, such as the soil porosity method, Rosetta method, and others, for the estimation of SWC. For this purpose, 270 soil samples (3:1 ratio for development and validation) from three data sets were used. Among 190 PTFs provided by EPR, one equation with the highest accuracy and the least number of inputs was selected. The EPR predictions were compared with the experimental results as well as the PTFs proposed in previous studies. Comparison of the statistical indicators showed that the ‘proposed PTF’ and ‘porosity method’ are the best and worst methods for the prediction of SWC, respectively. Also, good predictions were achieved from the proposed approaches by the groups of Scheinost, Vereecken, and Williams.  相似文献   

17.
红松人工林腐殖质组成及其结合形态研究   总被引:4,自引:0,他引:4       下载免费PDF全文
 运用野外调查与实验分析相结合的方法,对不同生长发育阶段红松人工林(林龄25、45、58、68 a)和红松混交林(林龄60a)根际与非根际土壤有机质含碳量、腐殖质组成与结合形态进行了研究。结果表明:不同年龄阶段红松人工纯林、红松混交林土壤有机质含碳量、腐殖质各组分含碳量随土层深度的加深而降低,并且根际土壤高于非根际土壤。就土壤腐殖质组成而言,除林龄58a红松人工林根际土壤和45a红松人工林非根际土壤外,其他林型土壤胡敏酸含碳量均高于富里酸含碳量;胡敏酸与富里酸比值(HA/FA)在1.00~2.45之间;土壤重组腐殖质、松结态腐殖质、稳结态腐殖质含碳量大小顺序为林龄58>68>25>45a;红松混交林除紧结态腐殖质外,其他腐殖质各组分含碳量均高于红松人工林。  相似文献   

18.
The central moments of soil water content (SWC) variability at the field scale are determined by soil texture, considering both smooth topography and groundwater table position. The characteristics of variability are governed by other soil factors like soil structure, micro relief, preferred water flow paths, root system characteristics, rock content, etc. This paper shows the integral effect of all these hardly quantifiable factors on SWC variability simulated by the processes of evapotranspiration and groundwater–root zone interaction using the HYDRUS ET model. SWC and soil hydraulic characteristics were spatially determined over a 4.5 ha field during two sampling campaigns under different atmospheric and groundwater conditions, and data distributions were compared to SWC distributions provided by mathematical modeling. The entire spring–summer period of 2003 was then examined for changes of SWC spatial variability. It was found that evapotranspiration influences SWC spatial variability only if SWC is under the critical value when wetter parts of the field evaporate more water than drier parts, resulting in smoothed SWC variability. Under wet conditions the spatial variability of SWC increases by drainage, as those parts of the soil with coarser texture drain faster than finer-textured parts.  相似文献   

19.
引进更新树种形成混交林是解决人工纯林连栽障碍问题的根本途径,为了了解陕西秦岭山区日本落叶松、油松、灰楸和锐齿栎4种典型人工林树种混交的可行性,本项研究尝试通过不同针阔树种林地腐殖质层土壤的原位混合培养来模拟混交造林试验,从土壤生物化学和枯落叶分解的角度探讨了4种树种种间关系的协词性。结果表明:(1)在针叶林地引入阔叶林树种后可以促进土壤微生物量、酶活性和原林地枯落叶年分解速率的提高,而且随着引入阔叶树种比例的增加促进作用增强,引入树种灰楸的作用大于锐齿栎;(2)在阔叶林地适量引入针叶树种后虽然也可以促进土壤微生物量、酶活性和原林地枯落叶年分解速率的提高。但是随着引入针叶树种比例的增加促进作用减弱,引入树种油松的作用大于落叶松;(3)从土壤生物化学性质和枯落叶分解的角度综合表明,4种典型人工林树种的针阔种间关系均表现为协调,而且油松与灰楸的种间协调性最好,其次为落叶松与灰楸、油松与锐齿栎,而落叶松与锐齿栎的种间协调性较差。  相似文献   

20.
Soil microorganisms play a key role in soil organic matter dynamics, nutrient cycling, and soil fertility maintenance in forest ecosystems, and they are influenced by stand age and soil depth. However, few studies have simultaneously considered these two factors. In this study, we measured soil microbial biomass carbon (SMBC), soil microbial biomass nitrogen (SMBN), soil basal respiration (SBR) rate, and potential extracellular enzyme activity (EEA) in soil to a depth of 60 cm under 10-, 30-, and 40-year-old Scots pine (Pinus sylvestris var. mongolica) stands (Y10, Y30, and Y40, respectively) in plantations in northern China in 2011. Soil water content (SWC), soil pH, soil organic carbon (SOC), and soil total nitrogen (STN) were also measured to explore their effects on soil microbial indices across different stand ages and soil depths. Our results showed that SMBC, SMBN, and the SBR rate were generally higher for the Y30 stand than for the Y10 and Y40 stands. Potential EEA, except forα-glucosidase, decreased significantly with increasing stand age. Soil organic carbon,STN, SWC, and soil pH explained 67%of the variation in soil microbial attributes among the three stand ages. For the same stand age, soil microbial biomass and the SBR rate decreased with soil depth. Lower microbial biomass, lower SBR rate, and lower EEA for the mature Y40 stand indicate lower substrate availability for soil microorganisms, lower soil quality, and lower microbial adaptability to the environment. Our results suggest that changes in soil quality with stand age should be considered when determining the optimum rotation length of plantations and the best management practices for afforestation programs.  相似文献   

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