不同林分类型及土层对土壤养分的影响

在中山五桂山保护区选择4个不同的林分类型,分别进行土壤采样,测定土壤养分指标,分析不同林分类型及土层对土壤养分的影响,为林分改造、土壤养分改良提供理论和数据支撑。结果表明:(1)四种土壤养分指标在四种林分类型间均有显著性差异,四种林分类型的土壤养分指标含量大小排序大致为:沟谷季雨林阔叶混针阔混针叶林,只有有效磷含量是阔叶混大于沟谷季雨林。(2)四种土壤养分指标在针叶林、针阔混交林、沟谷季雨林这3种林型中的5个土层间变化均有显著性差异,而在常绿阔叶林中仅速效钾在5个土层间有显著性差异。(3)四种林分类型中,沟谷季雨林各指标含量相对较高,处于"中下"等级,而针叶林各指标含量低,处于"很低"等级。总的来说,四种林分类型的土壤养分含量偏低,特别是针叶林,各项土壤指标含量均为"很低",可以参考群落演替方向对针叶林进行林分改造来提高土壤养分。     

洱源县山区典型地带不同利用类型土壤养分的时空动态变化

利用IN—SITU技术,以洱源县山区典型地带保存较好的旱冬瓜阔叶林为参照,选择自然植被破坏后形成的坡耕地、针叶林地、针阔混交林地、按树林地等不同利用类型土壤性质变化的样地进行长期定位研究,测定土壤有机质、全氮、水解氮、速效磷、速效钾．研究其水平空间变化、垂直空间变化及季节动态变化规律．     

洱源县山区典型地带不同利用类型土壤养分的时空动态变化

利用IN-SITU技术,以洱源县山区典型地带保存较好的旱冬瓜阔叶林为参照,选择自然植被破坏后形成的坡耕地、针叶林地、针阔混交林地、桉树林地等不同利用类型土壤性质变化的样地进行长期定位研究,测定土壤有机质、全氮、水解氮、速效磷、速效钾.研究其水平空间变化、垂直空间变化及季节动态变化规律.     

北京城市不同绿地类型土壤常量元素变化的研究

通过实地采集土壤样品,选取山地样本作为对照,分析了北京市7种不同绿地类型土壤的全氮、速效磷、速效钾含量的变化,同时分析了除生产用地外的6种绿地土壤的钙、镁含量。研究结果表明:山地风景林地的土壤全氮含量的平均值最大为1.73g/kg,显著高于其他6种绿地类型,但土壤速效磷含量(5.49mg/kg)和钙含量(0.98%)显著低于其他绿地类型,不同绿地类型土壤中的速效钾和镁的含量无明显差异。建议在城区绿地施肥时减少磷肥和钙肥的施用。     

华北平原沙地治理工程初期的改良土壤效应

分别在北京市郊的房山区、顺义区和昌平区选择沙地治理工程示范区,以附近的荒地为对照,测量不同植被类型下的土壤有机质、全氮、速效氮、速效磷和速效钾含量等指标,以对华北平原沙地治理工程初期土壤改良效应进行研究。结果表明：在3个示范区,不同类型的植被都在一定程度上改良了土壤。其中,房山区的毛白杨增加土壤有机质和全氮的效果最佳,刺槐增加土壤速效氮和速效钾的效果最佳,而油松增加土壤速效磷的效果最佳。顺义区的华山松,国槐和垂榆均有效增加了土壤有机质、全氮、速效氮和速效钾,而华山松和国槐增加土壤速效磷的效果较好。昌平区的桧柏增加土壤有机质、全氮、速效氮、速效磷和速效钾的效果最佳。因此,在沙地治理工程初期,植被即可在一定程度上改良林下土壤。     

6种典型盐生植物生长对盐土养分的作用研究

选择盐角草、盐地碱蓬、二色补血草、中亚滨藜、獐毛、星星草等6种典型盐生植物,采用野外原位种植,研究各生育期土壤速效氮、速效磷、速效钾、有机质、全氮含量的变化特征。结果显示,与生长初期相比,植物生长末期的盐角草、二色补血草、中亚滨藜、獐毛、星星草群落的土壤速效氮显著降低,中亚滨藜、獐毛、星星草群落的土壤速效磷显著降低,土壤速效钾虽有所降低,但并未达显著水平,土壤有机质和全氮随植物生长基本无变化。该结果可为未来盐碱地改良和治理提供参考。     

不同土地退耕类型对土壤物理性质的影响

为了对辽西地区不同退耕林地土壤物理性质变化趋势进行评价,选择了3种退耕还林林型,以农田为对照,对土壤密度、土壤总孔隙度开展了分析,结果表明:退耕还林地土壤密度在前3年稍有增加,之后逐渐降低,土壤总孔隙度与之相反;退耕还林10～15 a对土壤的物理性质有不同程度的改善,而后趋于稳定;各退耕还林林分中,以混交林对土壤的改良...     

用土壤养分系统研究法评价杨树人工林土壤养分状况

A study was conducted to evaluate the soil nutrient status of poplar plantation by Soil Nutrient Systematic Approach(SNSA) in Jianghan Plain, Hubei Province, China. Soil physiochemical properties were analyzed in laboratory through collection soil samples of study site. Ten treatments of application different fertilizers were designed such as CK, optimum treatment (N, P,K, Zn), -N(P, K, Zn), -P(N, K, Zn), -K(N, P, Zn), Mg(N, P, K, Zn, Mg), -Zn (N,P,K), 2P(N, 2P, K, Zn), 2K(N, P, 2K, Zn), and 2N 2P 2K(2N, 2P, 2K, Zn) for field experiment to test the effect on tree height, diameter (DBH) growth, and dry weight of poplar.The results showed that there was no significant difference in tree heights between treatments with different fertilizers, diameter growth of poplar trees in treatments of lack of N and Zn was significantly slower than that of trees in optimum treatment, and dry weight of poplar dropped significantly for treatment of CK as well as treatments without application N and Zn. It is concluded that N and Zn were main limiting factor for poplar growth. Results from laboratory analysis and field experiment were uniform perfectly, which proved that SNSA was reliable in evaluating soil nutrient status of poplar plantation.     

红松天然林与白桦次生林土壤养分差异性研究

对丰林国家级自然保护区内具有代表性的红松天然林和白桦次生林的土壤pH值、有机质、速效氮、有效磷进行研究的结果表明:3个土层的土壤pH值、有机质含量、速效氮含量、有效磷含量均表现为红松天然林大于白桦次生林;在同一林型内,随土层加深土壤有机质、速效氮、有效磷含量均有所降低。     

章古台沙地针叶人工林对土壤养分的影响

对科尔沁沙地东南部章古台地区草荒地、40年左右的赤松(Pinus densiflora)、油松(Pinus tabulaeformis)、樟子松(Pinus sylvestris var.mongolica)人工林的0~10cm、10~20cm土层的养分进行测定分析。结果表明:与草荒地比较,赤松、油松和樟子松人工林0~20cm土层中有机质与全氮的含量增加显著;赤松林0~20cm土层中全磷的积累比较明显;3种针叶人工林对速效钾和速效磷的消耗都较大。     

磷添加对南亚热带森林土壤有机碳氮矿化影响的培养实验研究

采用室内培养的方法,分析了磷添加对南亚热带鼎湖山马尾松林（PMF）、针阔叶混交林（PBMF）和季风常绿阔叶林（MEBF）土壤（0～10cm）CO小CH4排放／吸收和有机氮矿化的影响。结果表明：28周的培养,100mg磷添加处理土壤C—CO2累积排放量依次为PMF、PBMF和MEBF对照的82．4％、84．4％和102．8％,2000mg磷处理土壤依次为其对照的107．2％、101．2％和109．1％;100mg磷处理土壤CH4累积排放量依次为其对照的69．9％、102．7％和66．3％,2000mg磷处理土壤依次为其对照的-57．4％、25．3％和22．4％,其中,磷在处理初期较一致的提高土壤CO2和CH4排放,磷对土壤有机碳矿化的影响与森林的土壤状况有关,添加的磷浓度越高,其促进作用越强。1周的培养,100mg磷处理土壤有效氮净矿化量依次比PMF、PBMF和MEBF对照少37．06％、39．60％和28．62％,2000mg磷处理土壤依次比其对照少70．97％、84．14％和187．97％,100mg磷处理土壤硝态氮净矿化量依次比其对照少48．06％、40．45％和28．03％,2000mg磷处理土壤依次比其对照少254．09％、115．32％和238．50％,磷显著的抑制土壤有机氮的矿化和硝化。结果建议,在研究P对土壤有机碳氮矿化过程时应充分考虑土壤对P的吸附作用。     

石家庄市退耕还林生态效益评价研究

以石家庄市为例,采用土壤蓄水量法、影子工程法等方法对退耕还林工程取得的水源涵养、水土保持、改良土壤、改善环境等方面的效益分别进行量化评估,确定工程建设取得的数量化的生态效益。     

退耕还林中经济林比重过高问题的探讨

退耕还林工作不仅关系到千家万户的当前收入和长远生计，还涉及农村经济结构调整、区域经济发展以及扶贫战略目标的实现等一系列重大问题，笔者仅就退耕还林工程中经济林过热问题作探讨，以保证退耕还林工作得以顺利进行。     

退耕还林效益评价指标体系研究

以现行林业工程评价指标为基础，结合退耕还林工程管理需要，运用Delphi法、AHP法、AHP-Delphi法、把握度-梯度法和最大熵-最大方差法，通过对指标体系科学筛选，确定权重，利用专家知识库和实测数据库，确定可以量化评价的退耕还林效益评价指标体系。     

亚热带地区杉木人工林和阔叶林土壤活性有机质研究(英文)

土壤活性有机质对土壤养分如氮、磷、硫的生物化学循环具有作用,其含量和质量影响土壤的初级生产力。本试验在中国科学院会同森林生态实验站通过对第一代、第二代杉木纯林和地带性阔叶林土壤活性有机质组分的对比研究,发现杉木纯林土壤活性有机质的含量低于地带性阔叶林。第一代杉木纯林易氧化有机碳、微生物生物量碳、水溶性有机碳和水溶性碳水化合物的含量分别比第二代杉木纯林高35.9%、13.7%、87.8%和50.9%,比地带性阔叶林的低15.8%、47.3%、38.1%和30.2%。在调查的三种林地内,土壤微生物生物量碳和水溶性有机碳含量下降幅度较大,其次为水溶性碳水化合物,而易氧化有机碳的变化最小。同时,杉木纯林土壤养分等理化性质也比地带性阔叶林低。这表明在杉木纯林取代地带性阔叶林以及杉木纯林连栽后林地的土壤肥力降低。图3 表2参26。     

Relating sulfate adsorption to soil properties in Japanese forest soils

The relationship of sulfate adsorption capacity to the presence of aluminum, iron oxides, and organic carbon in four Japanese forest soils was investigated. Sulfate adsorption capacities were higher in subsoils than in surface soils, and their profiles were the inverse of those of organic carbon content. The black soil derived from volcanic ash had high sulfate adsorption capacity and showed no release of sulfate, while some of the surface horizons of the other soils desorbed sulfate. Oxalate extractable aluminum (Al₀) and iron (Fe₀) and ditionite-citrate-bicarbonate (DCB) extractable iron (Fe_d) were positively correlated with the sulfate adsorption capacity, and their correlation coefficients were almost identical (0.58–0.61). The lack of significant correlation between Al_d and the adsorption capacity suggests that DCB is unsuitable for extracting aluminum compounds which have the ability to adsorb sulfate. In contrast with oxides, organic carbon correlated with sulfate adsorption capacity negatively, and had a negative coefficient in a multiple regression equation, insignificantly. Furthermore, H₂O₂-treated samples containing decomposed organic matter adsorbed more sulfate than untreated samples. These results clearly indicated that organic matter hinders sulfate adsorption. A comparison of theβ value (standard regression coefficient) of organic carbon with that of Al₀ showed that the negative contribution of organic matter to sulfate adsorption capacity was slightly less than the positive contribution of oxides.     

对退耕还林工程中种草的探讨

分析种草在退耕还林工程中的重要地位和作用，提出退耕种草的草种选择和种植模式，并探讨发展草产业的途径和方向。     

Dynamics of soil carbon in a beechwood chronosequence forest

Accurate estimates of forest soil organic matter (OM) are now crucial to predictions of global C cycling. This work addresses soil C stocks and dynamics throughout a managed beechwood chronosequence (28–197 years old, Normandy, France). Throughout this rotation, we investigated the variation patterns of (i) C stocks in soil and humic epipedon, (ii) macro-morphological characteristics of humic epipedon, and (iii) mass, C content and C-to-N ratio in physical fractions of humic epipedon. The fractions isolated were large debris (>2000 μm), coarse particular OM (cPOM, 200–2000 μm), fine particular OM (fPOM, 50–200 μm) and the mineral associated OM (MaOM, <50 μm).     

Effect of conversion of farmland to forest or grassland on soil erosion intensity changes in Yanhe River Basin, Loess Plateau of China

Dynamic changes of soil erosion affected by conversion of farmland to forest or grassland in the Yanhe River Basin were analyzed based on the revised universal soil loss equation (RUSLE). The RUSLE variables were selected and calculated reasonably using the GIS technique. Results show that: 1) After the conversion of farmland to forest or grassland, soil erosion decreased greatly. Compared with soil erosion in period of 1986 to 1997, the soil erosion amount had been reduced on the average by 30.6% by 2000; 2) Of the different land uses, slope farmland, especially the steep slope land had the greatest impact on soil erosion. The conversion of forest or grassland was the main driving force for the reduction of soil erosion; 3) In the short term, soil erosion was mainly controlled by C-factor, implying that the adjustment of land use structure might be an effective approach to reduce soil erosion. __________ Translated from Science of Soil and Water Conversation, 2007, 5(4): 27–33 [译自: 中国水土保持科学]