小兴安岭天然针阔混交林择伐后土壤呼吸动态变化

采用LI-8100土壤CO2排放通量全自动测量系统,针对小兴安岭带岭林业局东方红林场不同择伐强度的针阔混交林样地,测定林地生长季土壤呼吸速率以及10cm土深处的温度和湿度,探讨生长季土壤呼吸的日变化、季节变化和年通量。结果表明：土壤呼吸日变化动态与土壤温度日变化动态基本一致,呈明显的单峰曲线。采伐强度不同间接影响着土壤呼吸速率。研究表明：针阔混交林土壤呼吸速率均值在0．6—8．2μml·m^-2·s^-1之间,高于同纬度其他地区;雨季（6月、7月、8月、9月）土壤呼吸明显大于旱季（5月、10月、11月）;针阔混交林生态系统土壤呼吸不同月份通量值在1．68～18．82mol·m^-2之间,最大值和最小值分别出现在7月和11月。与北半球温带森林生态系统土壤呼吸变化趋势基本一致。2006年针阔混交林生态系统土壤呼吸通量为84．37mol·m^-2,与朝鲜半岛硬阔混交林土壤呼吸相似,但比一些热带地区的结果偏大。     

蔬菜大棚春季土壤动物群落结构与多样性分析

研究土壤动物群落的多样性,为蔬菜大棚土壤生态系统的健康维持提供参考材料。对延安5个不同蔬菜大棚的土壤动物群落进行调查,采集180个定点土壤样品,通过手拣法和干漏斗法,共获得大、中小型土壤动物标本3442只,隶属13个目。其中寄螨目、弹尾目为优势类群,两者占总捕获量的87%,常见类群为正蚓目和真螨目,其余为稀有类群。对调查结果分析表明：土壤动物的群落数量垂直分布有明显的表聚现象;土壤动物的多样性指数与均匀度指数呈正相关,与优势度指数呈负相关。     

广西岩溶区烟草栽培地土壤养分、微生物与病害发生的调查分析

对广西岩溶区靖西县栽培的烟草根际土壤养分、微生物数量和主要病害的发生情况进行了调查分析。结果表明：该地区土壤pH偏高,营养元素除了速效钾含量较低外,有机质、全氮、速效磷、有效锰、有效铁、有效铜、有效锌含量均为丰富,总体肥力较好,其中水田土壤的有机质、全氮含量显著高于旱田（P<0.01）。土壤中微生物总量为1.21×107~9.91×107个/g,其中细菌数量占绝对优势,放线菌次之,真菌最少,水田细菌数量显著高于旱田（P<0.05）。3种病害总体以马铃薯Y病毒病为主,发生范围最广,黒胫病次之,青枯病偶有发生。相关分析表明,土壤有机质和全氮含量对细菌数量或总量有很大的影响,土壤速效磷和pH值对植株发病率的影响较大。     

沧源蔗区土壤养分现状研究

为了解甘蔗产区土壤养分状况,并根据养分丰缺情况进行合理科学的施肥,最终实现甘蔗高产高糖,对云南省临沧市沧源蔗区采集的185份土壤样品进行养分测定,结果表明：沧源蔗区土壤大部分呈微酸性,53.51%土壤样品的pH在5.5~6.5;有机质含量平均为2.74%;全氮含量极低,75.14%的土壤样品小于0.050%,平均为0.042%;碱解氮含量中等,平均为101.43 mg/kg;全磷含量低,平均为0.082%;有效磷含量低,平均为6.33 mg/kg;全钾含量低,52.97%的土壤样品含量在1.01%~1.50%,平均为1.403%;速效钾含量中等,平均为146.32 mg/kg;微量元素有效锌缺乏,79.75%的含量低于1.5 mg/kg;有效锰、有效铁和有效铜93%以上的土壤样品都高于临界值,铜、铁和锰不缺乏。根据土壤养分分析结果,在沧源蔗区建议有机肥结合速效氮磷钾复合肥施用,有利于甘蔗的高产高糖。     

根系对土壤环境胁迫响应的研究进展

根系是土壤和植物的动态界面,植物根系具有锚定植株、吸收和运输土壤中的水分及养分、合成和贮藏营养物质等重要功能。近年来,随着研究方法的改进和现代根系定量分析技术的发展,对根系的研究日益受到重视和关注。因而,根系的研究在多个新的研究方向上展开。本文简要介绍了国内外近年来在根系对土壤环境胁迫响应的研究进展,以供根系研究参考。     

Soil water characteristics in glacial till at two forest sites in Sweden

Soil water characteristics were determined in 6 soil profiles along a Norway spruce forested sandy‐loamy till hillslope in Southern and Northern Sweden, respectively. The soil moisture class was mesic at both sites, i.e. having well drained soil water conditions. Two different Podzols; Leptic and Orthic, were developed at each site respectively. The vertical distribution of soil water retention capacity (SWRC) was similar in the different profiles at each site respectively. The SWRC of the mineral soil was significantly higher in the spodic B horizon compared to the other horizons. In concordance with the vertical distribution of SWRC, the largest amount of organic matter in the mineral soil, measured as ignition loss, was also found in the spodic B horizon. The significantly higher SWRC in the spodic B horizon, i.e. the ¡lluvial horizon, was suggested to depend on the accumulated organic‐sesquioxide material in this horizon. As SWRC reached maximum values in the spodic B horizon at all tensions applied, it was further suggested that soil formation in the studied profiles enhanced the formation of both micro‐ and macropores in the spodic B horizon. The variation of SWRC, at a certain level in the soil, was often larger within a profile than between the profiles at each site respectively.     

Nutrients in litterfall,forest floor and mineral soils in two adjacent forest ecosystems in Greece

The fluxes of masses and the nutrients Ca,Mg,K,N,P and S were determined in the litterfall of two adjacent forest ecosystems of Hungarian oak(Quercus frainetto L.)and European beech(Fagus sylvatica L.)in a mountainous area of northeastern Greece in 2010–2015.The foliar litterfall for both species reached about 70%of the total litterfall,and was significantly higher from the other two fractions(woody and rest litterfall).The fluxes of masses and nutrients were compared between ecosystems for each fraction separately.Only one significant statistical difference was found,that of K in the woody litterfall.In addition,the stocks of masses and nutrients were calculated in the forest floors and mineral soils of the two ecosystems.Likewise,the stocks of nutrients in the forest floors and mineral soils were compared between ecosystems.In the L horizon of the forest floors,statistical differences,as a result of species effect,were found for the stocks of Ca and N.In the FH horizons,the masses and all the nutrient stocks differed significantly,as the beech plot had much higher quantities of organic matter and nutrients.These higher quantities were probably due to low soil temperatures(microclimate)and high acidity in the beech plot(species effect)that slowed down decomposition.In the mineral soils,the propagation of random error derived from random errors of the individual soil layers was an important factor in the statistical comparisons.Because of the soil acidity in the beech plot,the stocks of exchangeable base cations were significantly higher in the oak plot,whereas the other nutrient stocks did not differ.     

Landscaping and performance of some aesthetic plant species in hot, arid conditions of India

Establishment of ornamental and aesthetic plants in hot, arid conditions of India is difficult due to the prevailing climatic, edaphic and biotic factors. Effect of turfgrass on the growth of ornamental plants in hot arid conditions has not been studied so far anywhere in the world. A study was conducted on the campus of Arid Forest Research Institute, Jodhpur, India to assess the performance of a few ornamental plant species in combination with turfgrass and without turfgrass with respect to different soil tilling intervals. Growth of plants was better with turfgrass than without turfgrass. We suggest adopting a soil tilling interval of 30 days to achieve optimum growth of ornamental plant species in terms of height and crown diameter. Our results can help reduce labor costs and achieving better landscapes in fewer days in hot urban conditions of Indian sub continent.     

林地土壤水分模型SWUF在晋西黄土高原的适用性

采用EnviroSMART土壤水分定位监测系统于2008-05-14至2008-10-11及2009-05-05至2009-08-05对晋西黄土区刺槐人工林、油松人工林(水平条整地)、天然次生林0～150cm土层的土壤水分进行实时监测。以这些监测数据为基础,分析SWUF模型参数的敏感性,进行参数率定,验证SWUF模型在晋西黄土高原水土保持林地的适用性。结果表明:SWUF模型中的蒸发参数、产流参数、非饱和水流参数属于高度敏感性参数,使用SWUF时必须对这些参数进行率定;SWUF模型对刺槐人工林20～150cm各土层、油松人工林和次生林0～150cm各土层土壤水分动态模拟效果较好,模拟值与实测值相对误差在20%以内;SWUF适用于模拟油松人工林和天然次生林各土层每日土壤含水量,也能够比较充分地模拟3种林地不同深度土壤层土壤水分的日变化趋势,但在模拟耗水量大的刺槐林表层土壤水分方面还需要改进。     

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.