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31.
[目的]探讨不同发酵时间白腐真菌对玉米和油菜秸秆的降解效果。[方法]设置6个时间点(0、20、25、30、35和40 d),测定油菜和玉米秸秆的木质素含量和降解率变化。[结果]随着发酵时间的延长,玉米和油菜秸秆的木质素降解率均呈下降—上升—再下降的趋势。在发酵培养20 d时,油菜秸秆的木质素降解率达到最大,为58.07%;在发酵培养35 d时,玉米秸秆的木质素降解率达到最大,为33.62%。[结论]白腐真菌对玉米和油菜秸秆的降解效果显著,其中对油菜秸秆的降解效果尤为突出。 相似文献
32.
The present study was conducted on the Van Gujjar tribe inhabiting a sub-Himalayan tract in the North Western Himalayas of Uttarakhand State,India.The Van Gujjars have been practicing transmigration over hundreds of years.They migrate each year with their households and livestock between summer and winter pastures.A few years ago with the announcement of the establishment of the Rajaji National Park,the tribe has been forced out of the forest area and rehabilitated outside the park,which has affected their lifestyle.The newly established rehabilitation colony in the Gandikhata area of Haridwar District of Uttarakhand State was taken as a case study.The aims of the present study were to understand and evaluate the socio-economic status of the Van Gujjars in their newly established rehabilitation colony,the utilization pattern of forest resources by the tribe and their relative preference for selective trees for various uses.A total of 176 households were interviewed (giving equal weight to all economic classes and family every size) by using pre-structured questionnaires.The education level was very low (12.9%) and the average income per household was recorded as Rs.36000 (approximately $ 803) per year.The major source of income was dairy production (80.6%) followed by labor employment (13.9%),NTFPs (4.2%) and agricultural production (1.4%).More than 90% of fuel wood and fodder is extracted from the forest.The average fuel wood and fodder consumptions per household per day were recorded as 25.86 and 21.58 kg,respectively.A total of 35 species of cultivated plants and 89 species of wild plants were found to be utilized as food sources.Selectively 25 wild tree species are well known as being used by the Van Gujjars as fodder,fuel wood,agricultural implements,household articles,dye,medicine,fiber and other products.According to their utility value,the most preferred and useful tree species is Ougeinia oojeinensis,followed by Terminalia alata,Bombax ceiba,Shorea robusta and Dalbergia sissoo. 相似文献
33.
Smouldering wildfires propagate slowly through surface and subsurface organic layers of the forest ground and severely affect the soil, producing physical, chemical and biological changes. These effects are caused by the prolonged heating and the large loss of soil mass but are poorly documented in the literature. A series of smouldering experiments with boreal peat have been conducted under laboratory conditions to quantify these effects using small-scale samples. Peat samples of 100 mm by 100 mm in cross section and 50 mm in depth of different moisture were exposed to an external ignition source. Thermocouples placed throughout the sample bed measured the temperature evolution and tracked the peat ignition, intensity and spread of the smouldering front. The results show that moisture content controls peat ignition and that moisture below 125 ± 10% (in dry base) are required. The severity of the smouldering peat on the soil has been quantified in terms of temperature vs. residence time curves and mass loss. The measurements show temperatures in excess of 300 °C for residence times of 1 h leading to sterilization of the soil and mass loss in burnt layers above 90%. 相似文献
34.
采用单纯形格子混合设计法(SLMD)对纤维素、半纤维素和木质素3种生物质组分进行复配优化设计,并在综合热分析仪上进行了热解试验。分析了3组分混合热解特性,建立了由生物质3组分比例直接计算动力学参数的预测模型,对模型进行了试验验证。结果表明:纤维素热解反应级数较低(1.20),活化能较高(134.50 k J/mol),指前因子较大(3.49×1012s-1),热解较为迅速与剧烈;半纤维素和木质素热解的反应级数较高(1.30、1.32),活化能较低(33.51、19.98 k J/mol),指前因子较小(9.43×103、107 s-1),热解较为缓慢;3组分在混合热解中对动力学参数存在交互影响,纤维素对活化能和指前因子的影响较为显著,而半纤维素与木质素对反应级数的影响较大;动力学参数预测模型精度较高,可有效预测生物质热解动力学参数。 相似文献
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37.
沙地植物功能群及其多样性对微地形变化的响应 总被引:1,自引:0,他引:1
以内蒙古锡林郭勒盟中国科学院生态系统定位站长期围封的沙地样地为研究对象,通过测定植物群落的生物量、盖度、密度和株高等相关指标,探讨群落的物种组成、生物多样性等对沙地微地形变化的响应情况,以阐明沙地微地形对植被的影响机理.结果表明:沙地微地形对生物量、生活型、功能群及生物多样性均有影响.其中,总生物量顺序为:阴坡 > 坡底 > 阳坡 > 坡顶;植物多样性指数坡底显著低于阴坡、阳坡和坡顶(P < 0.05),而阴坡、阳坡和坡顶三者之间无显著差异;丰富度指数和均匀度指数阴坡、阳坡和坡顶显著高于坡底,阴坡、阳坡和坡顶三者之间差异不显著;坡底以多年生杂类草占优,阴坡以灌木、半灌木及多年生禾草为主,阳坡以灌木、半灌木、多年生禾草及一、二年生植物为主,坡顶以多年生禾草和一、二年生草本植物为主. 相似文献
38.
[目的]为了了解外源Ca^2+对干旱下矮牵牛幼苗生长的影响。[方法]采用盆栽控水的方法,研究了在干旱胁迫和复水条件下,施用不同浓度CaCl2对矮牵牛幼苗抗旱性和生物量的影响。[结果]随着干旱胁迫的加深和时间的延长,施加CaCl2均能显著降低矮牵牛的旱害指数,增加矮牵牛幼苗的干物质积累量和干物质根冠比,减小干旱胁迫对矮牵牛造成的伤害;复水处理后,施加CaCl2的各处理旱害指数均显著低于对照,干物质积累量和干物质根冠比均显著高于对照。[结论]在干旱胁迫过程中,施用CaCl2能增加矮牵牛幼苗的干物质积累量和干物质根冠比,并减小干旱胁迫对矮牵牛造成的伤害,其中以40mmol/LCaCl2对矮牵牛效果最好。 相似文献
39.
文章基于岳阳市2009年森林资源统计数据,对全市森林植被类型的生物量、碳贮量和碳密度进行初步估算。结果表明:岳阳市森林植被碳贮量为9.238Tg,其中,平江县的森林植被C贮量最大,为3.606Tg,占总C贮量的39.03%。各森林类型的C贮量来看,松木林的C贮量最大,为2.754Tg,占总C贮量的29.81%。岳阳市森林植被平均C密度为16.02t.hm-2,各县市区森林植被的C密度为13.39~27.10t.hm-2,森林植被平均C密度最大是云溪区,为29.02t.hm-2,各森林类型中阔叶树的C密度最大,为27.24t.hm-2,是全市森林植被平均C密度的近2倍。
相似文献
40.