广西芒果树叶片苔藓发生情况调查及药剂筛选试验

对广西芒果树叶片苔藓的发生情况及防治药剂进行了初步研究?调查了广西芒果主产区的南宁市(武鸣区?兴宁区)和百色市(田东县?田阳县?田林县和右江区)?在南宁市开展4种药剂的18种不同浓度或者配比组合的药剂筛选试验?结果表明, 南宁市芒果树叶片平均发病率达到88.5%, 右江区发病率为81.7%, 其后依次为田东县?田林县和田阳县, 发病率分别为56.1%?54.8%和34.2%?通过不同药剂及其不同配比药效试验, 80%乙蒜素乳油的防效极显著优于46%氢氧化铜水分散粒剂?32%唑酮·乙蒜素乳油和70%甲基硫菌灵可湿性粉剂?80%乙蒜素乳油500倍液?1 000倍液和1 500倍液的防效分别为93.37%?85.82%和51.85%?综上, 芒果树叶片苔藓已在广西全区普遍发生, 南宁市和右江区受害严重, 推荐使用80%乙蒜素乳油1 000倍液防治?     

喀斯特森林近地表层覆盖对碳酸盐岩红土蒸发过程的影响

蒸发是西南喀斯特地区薄层土壤水分损失的主要途径,浅层土壤水分的存蓄对喀斯特地区农业生产和生态恢复至关重要。以西南喀斯特森林碳酸盐岩红土为研究对象,基于室内蒸渗试验设置4个苔藓生物量(0,0.32,0.64,0.95 kg/m~2)和3个松针生物量(0,0.32,0.64 kg/m~2)共12种处理,分析森林近地表层覆盖对碳酸盐岩红土蒸发过程及表层温度时空分布的影响规律,并对比3种蒸发模型(Black、Rose、空气动力学蒸发模型)在喀斯特森林碳酸盐岩红土的适用性。结果表明:苔藓和松针覆盖显著降低累积蒸发量和蒸发速率(P0.05),接种苔藓0.95 kg/m~2和覆盖松针0.64 kg/m~2处理比裸土累积蒸发量小36.9%;苔藓和松针导致土壤含水量显著增加(P0.05);苔藓和松针增加了表层土壤的平均温度,松针对土壤温度的提升作用强于苔藓;Black、Rose和空气动力学模型均能较好地模拟碳酸盐岩红土蒸发过程,Black蒸发模型的拟合精度高于Rose和空气动力学蒸发模型。研究结果能为西南喀斯特地区的水量平衡分析提供理论支撑并加强对喀斯特森林地表水文过程的认知。     

肚倍蚜,美灰藓最佳生态条件与肚倍基地建设

肚倍蚜，美灰藓最佳生态条件研究表明，由光照强度、湿度以及风速等因素决定的环境是制约肚倍丰产、稳产的关键；据此对肚倍基地建设提出若干建议。     

毛乌素沙地苔藓结皮的野外人工培育技术

[目的]探索影响毛乌素沙地人工培育苔藓结皮的关键因子及其最优组合,为该区土地荒漠化的治理提供理论支持。[方法]利用正交试验设计方法,考虑遮阳、覆膜、营养液、浇水频率4个因子,分析不同因子对苔藓结皮株密度和生物量的影响。[结果](1)除Knop营养液外,遮阳、覆膜、浇水频率对苔藓结皮株密度、生物量有显著影响。(2)遮阳、覆膜、营养液、浇水频率4个因素对不同指标的影响顺序不同。(3)就株密度而言,野外培养最优条件为遮阳、不覆膜、Knop营养液和高频率浇水。就生物量而言,苔藓结皮野外培育最优因素组合为遮阳、覆膜、Knop营养液和高频率浇水。[结论](1)在野外苔藓结皮培育过程中遮阳、覆膜、浇水频率对结皮生长都有显著影响。(2)在提供适宜的生长条件的前提下,在干旱半干旱地区进行苔藓结皮人工培育是可行的。     

祁连山大野口流域青海云杉林苔藓枯落物及其土壤水热特征分析

为探讨森林生态系统中苔藓枯落物的生态属性与其下层土壤水热之间的关系,采用样地调查法及特征描述统计、相关系数等分析法,对祁连山大野口流域49块样地的青海云杉林苔藓枯落物及其土壤水热特征进行分析.结果表明:苔藓枯落物平均厚度(6.0±0.3)cm,平均含水率为(101.9±6.3)%;0~10、10~20、20~40、40~60、60~80cm土层深的土壤含水率平均值分别为(66.24±4.22)%、(57.62±3.23)%、(48.44±3.21)%、(42.81±6.48)%、25.89%,各土层温度平均值分别为(7.2±0.26)(5.2±0.27)(2.8±0.29)(2.0±0.61)(1.6±0.95)℃;苔藓枯落物厚度与海拔、坡向、坡度、胸径、树高、冠长、冠幅、郁闭度、土壤各层含水率和温度等因子均极弱相关,甚至认为不相关;苔藓枯落物含水率与海拔为中度正相关(P<0.05),与40~60cm深的土壤含水率存在显著正相关,与其温度成中度负相关.     

混配基质在一品红无土栽培中的应用

 为减少花卉无土栽培对泥炭资源的依赖和降低生产成本,研究了以锯末、玉米秆和小麦秆为主要成分的混配基质在一品红无土栽培中的应用效果。结果表明,2份玉米秆粉：1份锯末：1份珍珠岩和1份小麦秆粉：2份锯末：1份珍珠岩两种混配基质的各项理化指标均在无土栽培基质的理想范围内,用其栽培的一品红根系生长健壮,生长发育综合表现优于对照,可替代泥炭作为一品红的无土栽培基质。     

Vermicompost as a substitute for peat in potting media: Effects on germination,biomass allocation,yields and fruit quality of three tomato varieties

Commercial potting media often contain substantial amounts of peat that was mined from endangered bog and fen ecosystems. The main objectives of this study were to assess (1) whether the amendment of 0, 20, 40, 60, 80 and 100% (v/v) of vermicompost (VC) to a fertilized commercial peat potting substrate has effects on the emergence, growth and biomass allocation of tomato seedlings (Lycopersicon esculentum Mill.) under greenhouse conditions, (2) whether possible impacts on seedlings can affect tomato yields and fruit quality even when transplanted into equally fertilized field soil, and (3) whether effects are consistent among different tomato varieties. Amended VC was produced in a windrow system of food and cotton waste mainly by earthworms Eisenia fetida Sav. Vermicompost amendments significantly influenced, specifically for each tomato variety, emergence and elongation of seedlings. Biomass allocation (root:shoot ratio) was affected by VC amendments for two varieties in seedling stage and one field-grown tomato variety. Marketable and total yields of field tomatoes were not affected by VC amendments used for seedling husbandry. However, morphological (circumference, dry matter content, peel firmness) and chemical fruit parameters (contents of C, N, P, K, Ca, Mg, l-ascorbic acid, glucose, fructose) were significantly affected by VC amendments in seedling substrates; these effects again were specific for each tomato variety. Overall, vermicompost could be an environmentally friendly substitute for peat in potting media with similar or beneficial effects on seedling performance and fruit quality. However, at least for tomatoes, variety-specific responses should be considered when giving recommendations on the optimum proportion of vermicompost amendment to horticultural potting substrate.     

Pyrosequencing Reveals Significant Changes in Microbial Communities Along the Ecological Succession of Biological Soil Crusts in the Tengger Desert of China

Biological soil crusts (BSCs) have important ecological functions in arid and semiarid lands, but they remain poorly understood in terms of the changes in microbial communities during BSC succession under in situ field conditions. Here, 454 pyrosequencing was used to assess the microbial community composition of four BSC types in the Tengger Desert of China: alga, lichen (cyanolichen and green alga-lichen), and moss crusts, representing early, middle, and final successional stages of BSCs, respectively. The results showed the highest diversity of microbial communities inhabiting lichen crusts, whereas the lowest diversity was observed in moss crusts. Five phyla, Proteobacteria, Actinobacteria, Cyanobacteria, Bacteroidetes, and Acidobacteria, accounted for about 72% to 87% of total prokaryotic sequences in different BSCs. The most abundant eukaryotic microorganism was Ascomycota, accounting for 47% to 93% of the total eukaryotic sequences. Along the succession of BSCs, the abundance of photoautotrophic Cyanobacteria, Chlorophyta, and Bacillariophyta declined, and that of heterotrophic microorganisms such as bacteria and fungi increased. Statistical analysis showed clear divergency of microbial taxa at the class level among the different successional stages of BSCs. The clustering results at class level showed that the moss crusts were the farthest from the rest in prokaryotic composition; the alga crusts were the most different in terms of eukaryotic microorganisms and the two kinds of lichen crusts were relatively closer in both compositions. Ordination analysis showed that the main variations of community structure among BSCs could be explained best by the abundance of Cyanobacteria and Ascomycota and by physiochemical properties of BSCs, including mechanical composition, moisture, and electrical conductivity. In conclusion, our results indicate that Cyanobacteria and Ascomycota likely play an important role in the evolution of BSC structure and functions and highlight the importance of environmental factors in shaping microbial community structures of BSCs in the Tengger Desert of China.     

Effects of Coconut Husk and Sphagnum Moss-Based Media on Growth and Yield of Romaine and Buttercrunch Lettuce (Lactuca Sativa) in a Non-Circulating Hydroponics System

A comparison was made to investigate the effects of two potting methods: coconut husk/ sphagnum moss and a plastic forestry tube with a peat-based medium (Sunshine® mix #1, Sungro Horticulture, Agawam, MA, USA), on the growth and yield of Romaine ‘Ridgeline’ and Buttercrunch ‘UH Manoa’ lettuce (Lactuca sativa) using a non-circulating hydroponics system. Two-week old lettuce seedlings were transplanted into 5 cm holes, 20 × 30 cm apart on polystyrene bead boards fitted on top of a 0.6 m wide, 1.2 m long and 25 cm deep hydroponics tanks. A standard hydroponics nutrient solution was prepared using Chem Gro® (Hydro-Gardens, Colorado Springs, CO) (8-15-36 + micronutrients), calcium nitrate [Ca(NO₃)₂] and magnesium sulfate (MgSO₄). Each tank contained either one lettuce variety, replicated 12 times in completely randomized design. Growth and yields significantly increased in both lettuce varieties grown in coconut husk/sphagnum moss plugs which were attributed by their relatively greater water holding capacities and a more favorable media that allowed better root growth.     

黄土高原风蚀水蚀交错区农田生物结皮对土壤渗透性的影响

为了明确黄土高原风蚀水蚀交错区农田生物结皮的分布状况及其对土壤渗透性的影响,本文以该区农田（春玉米）土壤自然发育的生物结皮为对象,通过野外调查,探索了该区农田生物结皮盖度及组成。并在此基础上,以裸土为对照,采用环刀法和双环法测定了土壤水分入渗参数,研究了农田藻结皮及藓结皮对土壤渗透性的影响。结果表明：风蚀水蚀交错区水浇地和旱地中均有生物结皮分布,平均盖度为42.11%,其中藻结皮盖度为33.74%,藓结皮盖度为8.37%。生物结皮显著降低了农田土壤饱和导水率,与裸土相比,藓结皮和藻结皮覆盖下土壤0~5 cm土层土壤饱和导水率分别降低55.14%和23.54%;藓结皮使土壤的稳定入渗速率、平均入渗速率及累积入渗量分别显著降低了51.11%、47.71%和46.50%,藻结皮使土壤的稳定入渗速率、平均入渗速率及累积入渗量分别降低了 25.56%、21.10%和 20.91%,但与裸土差异不显著。藓结皮的形成能够降低农田土壤砂粒含量,提高土壤黏粒含量,进而降低农田土壤渗透性。综上,生物结皮的形成导致了农田土壤渗透性的降低,这可能会进一步影响农作物对土壤水分的有效利用。