磷和土霉素对小麦和紫花苜蓿幼苗生长和根系发育的影响

采用盆栽试验的方法,研究不同磷添加量(0,20,80 mg/kg)和土霉素添加量(0,40,160 mg/kg)对小麦和紫花苜蓿幼苗生物量及根系发育的影响。结果表明:所有水平土霉素处理中,20,80 mg/kg磷处理的小麦地上部生物量均比不加磷时高,分别高22.7%～34.1%,10.0%～30.0%和9.1%～18.3%。除160 mg/kg土霉素加80 mg/kg磷的处理外,所有处理的苜蓿根生物量均小于不加磷和土霉素的对照。小麦的根长和根表面积随着土霉素添加量的增加总体上呈减少的趋势。总体来看,施磷显著促进了小麦幼苗地上部的生长,但对苜蓿幼苗生长的影响不显著。土霉素对苜蓿幼苗的根系发育有抑制作用。研究结果可为评价土壤中土霉素残留对作物早期生长的影响和指导合理施用磷肥提供理论依据。     

碳酸氢铵和氨水在土壤中的扩散和损失

在田间条件下,定量检测施用化学氮肥后土壤的氨气损失,往往需要很多设备,试验周期也较长^[3-6]。我们在研究碳酸氢铵、氨水在土壤中的扩散损失时,采用了J.H.Baker研究液氨的方法^[2]。     

豆科植物和根瘤菌在生态环境中的地位和作用

随着我国人口的增加和城市化进程的加快,人类对土地资源的需求不断增加,土地使用的透支趋势明显;另一方面大量使用农用化学物质,对生态环境的胁迫增大。豆科植物在根系中因其可与根瘤菌共生形成特殊结构---根瘤,具有生物固氮作用而受到广泛关注。种植豆科植物,利用豆科植物和根瘤菌形成的共生固氮体系可以减少氮肥的投入,增加土壤的有机质含量,改善土壤生态环境,是一种天然的利于生态环境的农业生产方式。本文介绍了豆科植物和根瘤菌的一些重要特征,论述了豆科植物与根瘤菌共生的关系,表明发展豆科植物对于生态环境的修复、维持土地的生产力以及节能减排方面的重要作用,以期为改善生态环境提供一些可参考的方法和依据。     

红麻对Cu和Cu-EDDS的吸收和富集

生物可降解特性螯合剂[S,S]-乙二胺二琥珀酸(EDDS),被推荐用作污染土壤强化植物修复中的重金属活化试剂。我国能源经济作物红麻具有较高的地上生物产量,可望用于重金属污染土壤的植物吸取修复或稳定修复。通过水培试验研究了红麻对水培营养液中Cu及Cu-EDDS的吸收和富集效应。试验结果表明,能源植物红麻各组织中Cu的富集浓度依次为:根>叶>茎(皮)。扫描电镜-能谱分析表明,红麻根系从水培溶液中吸收的Cu主要经木质部导管向地上部运输。EDDS处理及Cu/EDDS摩尔比<1时,对红麻生长无急性植物毒性。红麻纤维皮层内Cu含量低于其他组织内的Cu含量,并低于纺织产品Cu含量标准(HJBZ30-2000)。预测在Cu污染土壤上种植红麻,可望实现红麻纤维的安全生产,同时有可能实现对轻度Cu污染土壤的植物稳定和吸取修复。     

污染和食物中毒

<正> 发展中国家,由于环境污染使很多成年人的健康受到危害,在印度,由于有毒气体(如氮氧化物、硫氧化物、一氧化碳和铅氧化物等)的污染使咽喉症发病率为其它国家的12倍、癌症患者高达150万。如果再不加强监督和控制,可以预料,到本世纪末将增加两倍。近代,为了增产粮食,农业生产实行高投入。由于农业化学品的过量使用,引起了各种污染问题,也影响到动植物种群的生存     

大豆灰霉病和黑斑病拮抗菌株的筛选和鉴定

生物防治病虫害是当前农业可持续发展的重要方向之一。大豆灰霉病(Botrytis cinerea)和黑斑病(Alternaria tenuissima)是大豆上的主要病害,为了控制灰霉病和黑斑病对大豆的危害,通过生物防治的方法,采用土壤稀释法从江西省东乡野生稻根际土壤中分离获得64株拮抗菌,经反复筛选及平板对峙法测定菌株A2、A6、A10、F7和G6对大豆灰霉病菌和黑斑病菌有稳定拮抗作用。通过菌株发酵滤液和化学农药抑菌效果比较,菌株发酵液的抑菌率远超化学农药,其中拮抗菌的发酵滤液对灰霉病最佳抑制率达91. 7%,对黑斑病最佳抑制率在60. 9%～87. 0%之间;而灰霉病特效素和苯醚甲环唑对灰霉病和黑斑病的最佳抑制率仅为68. 0%和47. 3%。根据菌株的生理生化特征及16S r DNA分子鉴定,5株菌分别为米修链霉菌(Streptomyces misionensis)、绛红产色小单孢菌(Micromonospora purpureochromogenes)、圈卷产色链霉菌(Streptomyces ansochromogenes)、链霉菌(Streptomyces sp.)和类芽孢杆菌(Panenibacillus sp.)。本研究为大豆灰霉病和黑斑病的生防菌开发和利用提供了一定的支撑。     

泰乐菌素和土霉素在农业土壤中的消解和运移

长期施用禽畜排泄物可导致抗生素在土壤中的积累, 对环境产生不良影响.为了解进入农田后抗生素的去向及残留动态, 选择2个典型农业土壤, 利用田间小区试验, 研究了田间实际状况下泰乐菌素和土霉素2种抗生素在土壤中的消解与运移行为.研究表明, 抗生素在土壤中的消解和运移与抗生素种类和土壤性质有关.抗生素在砂质土壤(清水砂)中的下移明显高于粘壤土(泥质田), 泰乐菌素在土壤中的垂直迁移强于土霉素.表层土壤中抗生素因降解和下移随时间逐渐下降, 消解速率在试验初期大于后期, 并且土霉素消解速率大于泰乐菌素.砂质土壤中抗生素的消解速率在试验初期明显高于粘壤土, 但至试验后期, 二者渐趋相似.田间条件下测得的抗生素消解速率明显低于实验室条件下, 这可能与抗生素进入田间深层土壤后稳定性增加有关.农田施用抗生素初期产生的径流中含较高浓度的抗生素, 但随时间(10 d之内)很快下降至检测下限以下; 试验初期径流中抗生素浓度为泰乐菌素大于土霉素, 砂质土高于粘壤土.     

Influence of Quercus ilex trees on herbaceous production and nutrient concentrations in southern PortugalElena Cubera1, 2

In an open woodland in Portugal, the nature of interactions between Quercus ilex trees and herbaceous plants was assessed during 2 years by studying how manipulation of incident solar radiation, water and nutrient supply affect the herbaceous biomass and N, K, P, Ca, Mg, and Mn concentrations. Measurements were carried out in three environments consisting of (1) open grassland, (2) beneath the tree canopy, and (3) under artificial shade. Each of these environments was subjected to two regimes of fertilization and two water levels in a factorial design. The fertilizer treatment consisted of application of no fertilizer or a combination of 200 kg calcium ammonium nitrate ha^–1 (26% N) and 350 kg superphosphate ha^–1 (8% P), while the water‐supply treatment consisted of either no irrigation or irrigation fortnightly from February 1 to April 30. Grasses showed significantly lower nutrient concentrations than forbs. However, nutrient concentrations of the whole herbaceous community were within the recommended ranges for cattle nutrition. A negative effect of shade on herbaceous biomass production was observed. The effect of watering on herbaceous biomass was less prominent than the effect of fertilization, irrespective of the environment, suggesting that Q. ilex does not compete for soil‐water resources with herbaceous biomass in this ecosystem. Fertilization increased total biomass by 106%, 49%, and 97% in the open grassland, beneath the tree canopy, and under artificial shade, respectively. During the first and second year, fertilization increased herbaceous P concentrations by 24% and 83%, respectively, if compared with concentrations obtained at the unfertilized plots. Higher K and Mg concentrations were observed in herbaceous plants beneath the tree canopy than in the open areas, indicating a positive effect of trees on pasture quality. The positive and negative effects of trees on understory forage are discussed.     

河北坝上地区不同植被类型土壤持水性能研究

以河北坝上地区不同植被类型土壤为研究对象,使用离心机法测定不同土层深度不同吸力下的土壤含水率,利用Van Genuchten模型拟合土壤水分特征曲线,分析土壤水文特征。研究表明:(1)研究区土壤为砂土,土壤容重为1.59 g/cm3,土壤水分特征曲线呈现"迅速下降–缓慢下降–稳定"的形态,不同植被类型土壤水分特征曲线相似;(2)农地的持释水能力最强,杨树样地的持水能力最差,柠条样地的释水能力最差,研究区内非农地的土壤凋萎系数平均为8.69%,随着土层深度的增加,土壤的持水能力、释水能力和凋萎系数都逐渐减小(P0.05)。(3)坝上地区应逐步减少高耗水乔木,建立起可持续发展的乔灌草防护体系。本研究可以为确定张北地区土壤凋萎系数和土壤干层,并合理选择种植植被提供理论依据。     

宁东矿区天然植物群落特征及其与土壤理化性质的关系

[目的] 研究宁东矿区天然植物群落特征与土壤理化性质的关系,为宁东矿区植被重建过程中植物种的选择提供科学依据。[方法] 以宁东矿区6种典型的天然植物群落和土壤为研究对象,采用野外调查结合室内试验的方法,对比分析不同群落的植物群落特征及其与土壤理化性质的关系。[结果] 宁东矿区6种天然植物群落共调查到植物55种,隶属于15科48属,集中分布于菊科、豆科、藜科和禾本科4科。细枝岩黄耆（Hedysarum scoparium）+柠条锦鸡儿（Caragana korshinskii）—白莲蒿（Artemisia sacrorum）群落灌木层植被盖度和高度在6个群落中均最高,其数值分别为48%和202.54 cm,灌木物种柠条锦鸡儿在其中5个群落中均有分布且生长良好。灌木层Patrick丰富度指数与土壤碱解氮、砾石含量、速效钾和有机质呈正相关,与pH值呈负相关;草本层植物种Patrick丰富度指数与土壤有机质、田间持水量和速效磷呈正相关关系。[结论] 宁东矿区煤矸石山植被重建时,对于覆土土质为壤质砂土或砂质壤土,优先选择柠条锦鸡儿、细枝岩黄耆、黑沙蒿（Artemisia ordosica）和沙拐枣（Calligonum mongolicum）等灌木树种;覆土土质为少砾质砂土时选沙冬青（Ammopiptanthus mongolicus）和柠条锦鸡儿;覆土土质为多砾质砂土时可选藏锦鸡儿（Caragana tibetica）、裸果木（Gymnocarpos przewalskii）和胡枝子（Lespedeza bicolor）等灌木物种。土壤容重对灌木物种多样性贡献率较大,土壤田间持水量和有机质对草本植物多样性贡献率较大。     

Influence of forest cover and herbaceous vegetation on the microbiological and biochemical properties of soil under Mediterranean humid climate

The effects of different Mediterranean vegetation cover on the biological and biochemical quality of soil is not well understood. The aim of this work is to evaluate the effects that different types of vegetation (forestry plots, mainly dominated by Spanish black pine (Pinus nigra Arn. ssp salzmannii) and herbaceous plots, where overstorey density is lower and natural herbaceous percentage is higher than in forestry plots) have in the biological properties of soil in Mediterranean humid climate. The impact of these plant communities on the biological soil quality was determined by several sensitive parameters related to the microbial activity of the soil such as soil respiration and some enzyme activities (urease, phosphatase and dehydrogenase). Development of vegetation (herbaceous and pines) was also determined and correlated with microbiological and biochemical indicators. Organic matter content in herbaceous sites was significantly higher than in forestry sites, ranging from 5.27 to 6.70 g 100 g^?1 in herbaceous sites to 1.64–2.81 g 100 g^?1 in forested areas. Herbaceous sites showed higher values of basal respiration and dehydrogenase activity than pine areas. However, the decrease of organic carbon content in pine areas led microbial activity enrichment per unit of carbon. These results conclude that vegetation cover significantly impacts soil microbial processes in Mediterranean humid climates, herbaceous vegetation having a more positive influence than forest vegetation on the biochemical and microbial activity of the soil, principally due to the higher accumulation of organic matter from plant remains.     

不同植被对红壤养分含量及吸附-解吸 性能的影响

植被类型和生长状况, 对土壤养分和土壤对 H2PO4- 的吸附-解吸及对 K +的缓冲特性均具有较大影响。 草灌 乔植被下土壤中氮磷钾等养分的含量均较高, 白茅植被下土壤有机质含量较高(21.16g/ kg), 无植被处理下土壤有 机质和养分含量均较低。 3 种类型植被下, 土壤对 H2PO4-吸附的 b 值以无植被>白茅>草灌乔, 不同 H2PO4- 吸附 范围内的解吸率以草灌乔相对较高, 而无植被处理下则相对较低 ;对 K +缓冲的 Q/ I 曲线参数比较, Δk0 值以草灌 乔>白茅>无植被, AR0 值为白茅>无植被>草灌乔, PBCk 值为无植被>白茅>草灌乔。     

Seedling recruitment and survival of two desert grasses in the monte of Argentina

In the Monte Austral Neuquino, Argentina, vegetation is arranged in patches. Understanding the mechanisms involved in their distribution is critical for preventing desertification. The working hypothesis was that vegetation patches reduce environmental stress on the plants. Plant patches were classified into four microenvironments: windward; below the dominant shrubs (subcanopy); vegetation at the patch periphery (canopy edge) and bare patch interspaces (open). We determined seedling survival of the dominant species in each microenvironment, using a marking method of seedlings established from sown seeds. In addition, we measured the environmental characteristics in the four microenvironments, and associated them with seedling survival. Study species were the perennial grasses Leymus erianthus (Phil.) Dubcovsky, Stipa neaei Nees ex Steudel and Poa ligularis Nees ex Steudel, and the shrubs Larrea divaricata Cav. and Atriplex lampa Gill ex Moquin. Results supported the hyphothesis only for L. erianthus and S. neaei (but not for the other three species that showed higher seedling survival in the subcanopy than in the patch interspaces after 1 year from sowing). This study determined that (1) reduced environmental stress does not guarantee seed germination and seedling survival of a given species in the plant community and (2) seedling establishment will not be possible for any species of the plant community in the patch interspaces under the study conditions in the region. This is mostly because soil temperatures can reach up to 50°C in the patch interspaces in years of scanty precipitation during late spring and summer. Copyright © 2010 John Wiley & Sons, Ltd.     

晋西黄土残塬沟壑区刺槐人工林土壤水分植被承载力研究

为明确在干旱缺水地区,植被对深层土壤水分的过度消耗以及水资源的承载能力,在晋西黄土残塬沟壑区选取林分密度1 300株/hm~2的刺槐人工林为研究对象,以裸地为对照,利用Enviro-SMART土壤水分监测系统(FDR)和热扩散探针(TDP)技术对当地刺槐人工林地0—150 cm范围内各土层体积含水量与树干液流量进行长期连续定位观测,采用土壤有效水与单株刺槐耗水量的比值来衡量研究区刺槐人工林土壤水分植被承载力。结果表明:(1)月降水量和月土壤储水量是决定刺槐人工林土壤水分植被承载力的主要环境因子,且二者与土壤水分植被承载力之间均呈现显著的正比例关系(P0.05)。(2)根据构建的刺槐人工林土壤水分植被承载力模型,计算出当地林龄为19年的刺槐人工林0—150 cm土层深度的土壤水分植被承载力为1 224株/hm~2,稍小于研究区实际林分密度(1 300株/hm~2),为保证当地刺槐人工林分耗水深度控制在0—150 cm土层范围内,同时也为促进当地林分生产力处于最优水平,建议在今后的营林造林过程中将刺槐人工林密度控制在当地土壤水分植被承载力范围之内,在减少林地深层水分消耗、调整林地土壤水资源平衡的同时,促进当地林业产业的合理发展。     

北京市松山天然油松林生态系统的碳储量

[目的]分析北京市松山地区天然油松林生态系统碳储量,为研究区天然油松林的碳固定和碳储量管理研究提供理论依据。[方法]以北京市松山天然油松林生态系统为研对象,设置标准样地进行乔木。灌木。草本。凋落物调查,采集并分析0—100cm土层土样,根据相关方程计算出生态系统以及各个层次的碳储量。[结果]植物体含碳率变化在42.39%~49.95%,0—100cm土壤含碳率变化在0.26%~1.31%。天然油松生态系统碳储量为147.24 Mg/hm2,其中植被碳储量为57.14 Mg/hm2,占生态系统碳储量的36.7%,植被各层碳储量的顺序为乔木(54.93Mg/hm2)灌木(0.45Mg/hm2)草本(0.29Mg/hm2);土壤碳储量为66.35 Mg/hm2,占生态系统碳储量的46.30%,分别是植被碳储量的1.16倍和凋落物碳储量的2.79倍,且随着土层深度的增加而递减;凋落物碳储量为23.75 Mg/hm2,占生态系统碳储量17%。[结论]松山地区天然乔木对植被碳储量的贡献率最大,松山地区天然油松林植被含碳率表现为:乔木灌木草本凋落物。     

晋北丘陵风沙区不同植被恢复模式的水土保持效应

通过对山西右玉贾家窑阳坡退耕还林约20年后的4种植被恢复模式(自然恢复草地、油松林、柠条灌丛和油松—柠条林)土壤水分、理化性质、径流量和侵蚀量的测定,探讨了不同植被恢复模式的水土保持效应。结果表明:(1)4种植被恢复模式0—100cm土层土壤平均含水量无显著差异,油松林和自然恢复草地的土壤容重高于油松—柠条林和柠条灌丛,土壤总孔隙度的变化趋势与容重相反;(2)4种植被恢复模式0—20cm土层土壤粒度组成、pH、有机质、铵态氮和速效磷无显著差异,硝态氮和速效钾差异明显(P0.05);(3)4种植被恢复模式径流量没有明显差异,但土壤侵蚀量自然恢复草地和油松林显著高于柠条灌丛和油松—柠条林(P0.05);(4)覆盖度相似条件下,根系密度、近地表植被盖度和枯枝落叶层厚度是影响林草植被水土保持效应的主要因素。     

宁南黄土丘陵区3种典型林分的结构与水文影响比较

为分析宁南黄土丘陵区林分结构的水文功能影响关系及差异,以彭阳县3种典型林分(山杏纯林、山杏柠条混交林、山杏沙棘混交林)为对象,在2017年生长季观测了林下草本生物量和生物多样性、冠层降雨再分配、林下蒸散、土壤湿度的变化特征。结果表明:(1)林分地表覆盖度大小顺序为山杏沙棘混交林(0.81)山杏柠条混交林(0.71)山杏纯林(0.67);草本植物地上生物量为山杏沙棘混交林(0.86)山杏纯林(0.62)山杏柠条混交林(0.41);草本植物生物多样性为山杏柠条混交林山杏沙棘混交林山杏纯林。(2)3种林分类型的冠层都相对稀疏,降雨穿透率均90%,穿透雨量与林外降雨呈线性正相关;干流量和林冠截留量与林外降雨呈对数关系。(3)林下蒸散的季节变化呈"单峰型",研究期间林下蒸散表现为山杏沙棘混交林(245.0mm)山杏纯林(227.7mm)山杏柠条混交林(220.9mm),其中山杏柠条混交林的月际间差异最小。(4)生长季内土壤湿度在中上层(0—80cm)表现为逐渐降低趋势,在深层则相反;深层土壤水分的林分差异为山杏纯林山杏沙棘混交林山杏柠条混交林。在干旱缺水、侵蚀严重的黄土区,要恢复以水土保持为主要功能的稳定植被时,既要考虑植被配置模式对地表覆盖和草本生物量及物种多样性的影响,也要考虑对土壤湿度的影响,因此建议在植被恢复中尽量选择山杏沙棘混交林和山杏纯林。