树盘覆盖对土壤温湿度与有机质含量的影响

采用碎石、草坪、麦秆、木屑作覆盖材料,对树盘进行覆盖,测定土壤温湿度变化,探讨覆盖处理对绿地土壤的影响。结果表明:麦秆覆盖和木屑覆盖能有效调节土壤温度、提高土壤湿度,土壤有机质含量比对照提高56.3%、37.5%,碎石覆盖后的效应与对照(露地)相似,草坪覆盖仅对土壤温度有一定的调节能力。       

朔州市林业土壤速效养分及土壤容重分析

系统采集0~20 cm土壤样本,分析朔州市市区林业土壤土壤容重和速效养分现状。结果表明,朔州市公园绿地、街头绿地和附属绿地土壤容重适宜,基本不会影响绿化植物的生长,但道路绿地土壤容重偏大,不利于绿化植物的生长;土壤速效氮含量总体上处于较低水平,大部分林业土壤速效磷和速效钾丰富。       

4种环境因子对景观水体绿藻生长繁殖的影响

为了控制绿藻繁殖,消除景观水体富营养化,采集景观水体在实验室培养,采用单因子实验法控制实验条件,探究N/P、温度、pH和Fe3+对景观水体中绿藻生长繁殖的影响。结果显示,绿藻生长的适宜N/P(氮磷比)为(51~10):1,温度为25℃~30℃,pH值为8.5,Fe3+浓度为500μg/L。在实际的景观水体治理过程中,应该适当调节这些影响因子的范围,从而达到抑制绿藻生长、控制水体富营养化的目的。       

土壤钻孔通气法对行道树生长的改善

硬覆盖路面下绿化树根际土壤环境是影响树体生长势衰弱的主要原因。以改良土壤透气性、调节土壤含水量、增加土壤养分为目的,对绿化树根际土壤实施钻孔通气,补充养料。研究结果表明,治理后的植物叶片增厚、颜色加深、叶中保持相对较高含水量,新梢生长旺盛,病斑恢复较快;但是钻孔不是导致土壤气体浓度变化的主要因素。       

汕头市城市绿地土壤调查

通过对市区主要绿地进行地下水位及土壤理化性状的调查,结果表明:本市常年地下水位偏高,平均雨季(0.83m)高于旱季(1.20m),越近海受大潮期的影响越大;土壤容重高于正常值0.12~0.42g/cm3,总孔隙度比正常值低近10%;土壤的pH值以微酸性为主,有机质含量极低。对本市园林土壤的主要特征有了较明确的了解,确定了土壤地下水位是影响绿化树种抗风性能的主要外因。       

四种草坪草抗盐能力的研究

为了筛选出适合天津盐碱地栽植的草坪草种类,在天津盐碱地土壤浸提液胁迫条件下,对国外四种草坪草的地上部含水量、脯氨酸和叶绿素含量变化进行了研究。结果表明:随着盐胁迫强度的增加,四种草坪草表现出含水量下降、脯氨酸含量和叶绿素含量上升的变化趋势。经分析认为:在天津盐碱地土壤浸提液胁迫下,四种草坪草均具有一定的抗盐能力,其抗盐能力强弱的顺序是‘回报’ > 无芒雀麦 > ‘交战Ⅱ’ > ‘博士’。       

城市绿化带对气候和环境因子的影响

以合肥市环城绿化带为对象研究其对城市气候和环境的调控作用,结果表明:1)环城林带0 cm地表温度日较差比市府广场低5℃;2)噪音大小及粉尘含量都与相距林带距离有显著线性关系;3)环城公园和芜湖路舒适度指数较低,而市府广场和二环路舒适度指数相对较高,但合肥主要景观的舒适度都达到舒适级别,十分适宜人居活动。       

几种乔木绿化树种抗寒性比较

本试验以银杏、悬铃木、香花槐、金叶复叶槭和玉兰等5种乔木绿化树种的一年生休眠枝条为试材,通过五个梯度的低温处理(-10℃、-15℃、-20℃、-25℃、-30℃),测定丙二醛、可溶性糖与脯氨酸含量和电导率,研究低温胁迫对这几种乔木绿化树种抗寒性的影响。结果表明:不同树种之间抗寒性存在差异性,5种绿化树种的抗寒性由强到弱的顺序为:悬铃木 > 香花槐 > 玉兰 > 银杏 > 金叶复叶槭。       

以色列——高效节水型的森林城市(1)

以色列国土面积20 403.93km2,人口700多万,是中东地区典型的人多地少、资源相对贫乏,但经济高度发达的国家。气候属于地中海型干旱气候,每年4~10月为干季,在内盖夫沙漠和死海盆地温度经常超过40℃。       

嘉兴市藤本植物应用

嘉兴市位于浙江省东北部,北邻太湖、南连钱塘江与杭州湾,处长江三角洲杭嘉湖平原中心地带,属中亚热带北缘,典型的亚热带季风气候。嘉兴市年平均气温15℃~16℃,极端最低气温-11℃~-12℃,最高气温为39℃~40℃。土壤pH值6.6~7.1,有机质含量1.97%~2.4%。       

武夷山甜槠天然林生态系统不同深度土壤CO_2浓度

选择福建武夷山天然甜槠林作为研究对象,对不同深度土壤CO2浓度、土壤温度、土壤含水量同步进行日动态观测。结果表明：0～60cm深度土壤CO2浓度随深度的增加而升高,60cm深度以下土壤CO2浓度有所降低;不同深度土壤CO2浓度的日变化均呈现单峰型;不同深度土壤温度变化幅度较小,各层日变化模式相似;不同深度土壤含水量变化很小,且日变化模式无明显规律性;指数拟合分析显示,10、20、60、80cm土壤CO2浓度与温度具有极显著相关性,5、10、40cm土壤CO2浓度与含水量的相关性显著。     

祁连山青海云杉林土壤理化指标空间变异性分析

通过对祁连山青海云杉分布带不同土壤剖面（0~40 cm）及不同海拔梯度上（2 500-3 100）土壤的温度、有机质、容重、水分等特征的分析,揭示土壤特性在空间上的变化规律。研究发现土壤温度随剖面深度的增加和海拔梯度的上升,都表现为明显的增大趋势。在0-10 cm,10-20 cm,20-40 cm土层内,土壤有机质含量分别为（135.2±24.6）g/kg、（111.2±14.3）g/kg、（91.7±12.9）g/kg,变异系数分别为18.23%、12.83%、14.10%;土壤有机质含量随土壤深度的增加逐渐降低,随海拔升高逐渐增加;土壤容重在剖面层次上具有明显的增大趋势,在海拔梯度上随海拔升高逐渐减小;土壤水分在0~40 cm土层内随着深度的增加逐渐减小,在海拔梯度上表现为波动变化,无明显的上升或下降趋势。     

Mulching effects on vegetation recovery following high severity wildfire in north-central Washington State,USA

Straw mulch application after high severity wildfire has gained favor in recent years due to its efficacy in reducing soil erosion hazards. However, possible collateral effects of mulching on post-fire vegetation recovery have received relatively little study. We assessed mulching effects on plant cover and species richness, tree seedling establishment, and exotic species densities in the second year following the 2006 Tripod Wildfire in north-central Washington State, USA, by observing vegetation responses to spatial variability in mulch cover and depth. Mulch cover averaged about 35%, with a median depth of 0.5 cm. Vegetation recovery was generally slow, with median plant cover of only 10%. Tree seedling densities were low and spatially variable. Vegetative cover, species richness, and seedling densities all declined with increasing elevation. Mulch cover was positively associated with plant cover, plant species richness, and conifer seedling densities when second year mulch cover did not exceed 40%. Only when mulch cover exceeded 70% did mulching begin to negatively affect vegetation recovery relative to areas with no mulch. Vegetation responses to mulch depth were minimal at depths under 3 cm, but quite strong when mulch depth exceeded 5 cm. Exotic plant frequency and density were positively associated with mulch cover, but exotic plant cover was low on average (<1%). In this study, mulch added significant cover to sites with slow natural recovery of vegetation, thereby likely reducing erosion hazard. Mulching also appears to have facilitated native plant recovery and conifer seedling establishment except at very high application levels, easing management concerns about longer-term impacts of mulching treatments on post-fire vegetation recovery.     

水曲柳人工林细根季节动态及其影响因素

2002年5-10月,采用连续钻取土芯法对帽儿山实验林场的水曲柳人工林细根(直径＜1 mm)生物量、比根长(SRL)和根长密度(RLD)的季节动态,以及它们与土壤N的有效性、土壤10 cm深处月均温度和含水量的关系进行研究.结果表明:水曲柳细根生物量在春季和秋季分别具有1个明显的高峰,但比根长和根长密度只有1个高峰.在春季和夏季,比根长和根长密度较高,显示细根直径较小,而秋季,这2个参数显著下降,表明细根直径次生增厚或组织密度增加.细根的季节变化与土壤N的有效性、土壤温度和土壤含水量有重要关系.其中细根生物量与土壤铵态氮含量显著相关;硝态氮含量、10 cm深处土壤的温度和土壤含水量与细根的生物量、比根长和根长密度的季节变化正相关,但均不显著(P＞0.05).4种因子的综合作用对水曲柳细根各参数的影响均达到了显著水平.不同季节细根生物量、比根长和根长密度的变化,显示出细根在生长季不同时期具有不同的生理生态功能.     

晋西北不同植被类型土壤水分空间分异

采用土钻法对晋西北朔州地区杨树林、柳树林、草地3种植被类型0~600 cm土层土壤水分动态进行研究。结果表明:土壤平均含水量表现为草地杨树林地柳树林地。草地土壤平均含水量比杨树林地高1.25%,比柳树林地高1.9%。随着土壤深度的增加,土壤含水量先减小后上下波动,然后趋于稳定。0~100cm土层范围内,土壤水分变异系数大小为草地柳树林地杨树林地;在200~300 cm、400~500 cm土层范围内,变异系数表现为柳树林地草地杨树林地;300~400 cm、500~600 cm土层范围内,变异系数大小为柳树林地杨树林地草地。越靠近表层,土壤干化现象越严重,柳树林地干化现象最明显,含水量变化最剧烈,杨树林地次之,草地最稳定。     

Okra production with pine straw mulch

Conventional planted okra in Booneville, Arkansas and Lorman, Mississippi were mulched with loblolly pine straw (Pinus taeda L.) and longleaf pine straw (P. palustris Mill.), respectively, at a rate of 11 t/ha or left bare. At Booneville, plant stand, season yields (18.6 t/ha), pod weight (16.3 g), plant dry weight (2.3 kg), or stem diameter (3.5 cm) were not affected by the loblolly pine mulch. However, mulch application increased pod number (1.22 vs. 1.06×10⁶/ha) and plant height (1.5 vs. 1.6 m), while reducing weed competition (0.05 vs. 0.40 t/ha) and visible plant stress, during periods of soil moisture deficits. Soil temperatures at 5 and 15 cm depth were reduced by mulch until mid-August when plant canopies covered the rows. Seasonal moisture at 30 and 45 cm depths was similar between mulched and bare soils, based upon unreplicated neutron probe measurements. At Lorman, season okra yield (29.8 vs. 24.6 t/ha), number of pods per ha (1.24 vs. 1.07×10⁶) and weed competition were reduced and soil pH lowered 0.56 units by longleaf pine straw mulch. Mulch reduced early season yield at both locations.     

生态垫覆盖对土壤酶活性及理化性质的影响研究

生态垫是一种新型的地面覆盖材料。为了检验生态垫对土壤的影响,在北京顺义双青林场示范区内设两个处理(M—覆盖生态垫,Mo不用生态垫),对土壤理化性质和土壤酶活性进行检测。结果表明:覆盖垫能够降低土壤温度、减小温度的空间变异;能够截留降雨,提高深于20～30cm的土壤水分含量;改善土壤肥力;对土壤易氧化碳和土壤酶活性有一定的影响,但是不显著。     

整地深度对土壤物理性质的影响

通过不同整地深度对土壤物理性质的影响研究,结果表明:深整地空白处的土壤含水率较对照空白处提高0.46个百分点;深整地较浅整地土壤垂直温度变化小,在0~70 cm范围内,每深10 cm,浅整地地温下降1.0 ℃,而深整地的下降0.9 ℃;深整地较一般整地土壤容重减小11%,土壤孔隙度增加5.5个百分点。研究结果还表明,适宜的整地深度以50~60 cm为宜,这有助于降低造林成本,提高经济效益。     

Soil properties under a Pinus radiata – ryegrass silvopastoral system in New Zealand. Part I. Soil N and moisture availability, soil C, and tree growth

Understanding the changes in soil properties in silvopastoral systems is important in regulating the interactions between tree and understorey pastures. In this study, the effects of understorey management on soil mineral N and moisture availability, soil temperature, soil C, and tree growth were investigated in a seven-year-old silvopastoral agroforestry experiment in Canterbury, New Zealand. The systems included understorey treatments of bare ground and ryegrass (Lolium perenne) pasture. Soil mineral N, moisture content, and temperature were monitored from July 1997 to July 1998 in two positions (0.9 and 3.5 m north of tree rows) and two soil depths (0–10 and 10–20 cm). Soil C and N in the 0–10 cm depth were higher in the ryegrass than in the bare ground plots, reflecting the organic C and N input in the ryegrass plots, as well as greater N loss from the bare ground plots in the form of nitrate leaching and/or denitrification. Soil C was higher in the position 0.9 m than 3.5 m away from the tree rows, possibly caused by the greater C input from decomposing fine tree roots and needle litterfall at the 0.9 m position. Soil moisture availability was greater in the bare ground than in the ryegrass plots in the summer. No effect of understorey management on soil temperature was found. Soil nitrate levels were lower in the ryegrass plots and may be limiting when soil moisture supply was adequate. Tree volume growth from winter 1997 to 1998 was significantly greater in the bare ground treatment, reflecting better soil moisture and N supply conditions. This revised version was published online in June 2006 with corrections to the Cover Date.     

机械运输对伊朗北部山林陡峭集材道土壤的干扰

A study was conducted to investigate the effects of skid trail slope and traffic levels on soil disturbances at two soil depths (0–10 and 10–20 cm). The treatments were set at four traffic levels (2, 7, 12 and 20), two slope classes (<20% and >20%) and two soil depths (0–10 and 10–20 cm). Results show that skidder traffic, longitudinal slope and soil depth have significant effect on soil bulk density in skid trail. Comparison of average soil bulk density in different traffic levels shows that there are significant differences in average bulk density between different traffic levels and control (p<0.05). The average bulk densities in different slopes and soil depths are significantly increased with increase in traffic levels, maximized at 12 passes (p<0.05), but there are no significant differences between 12 and 20 passes. The interaction effects between traffic and soil depth are significant (F _0.05,3=0.109, p<0.001). For all traffic treatments, there are significant differences in soil moisture content between the two slope classes and the two depths (p<0.001). However, the interaction effects between traffic levels and slope classes are not significant (p >0.05), although skidder traffic and slope affected soil moisture content.