Pb、Cd复合污染对龙须草光合作用的影响

通过九组不同水平的重金属Pb、Cd复合污染土壤种植龙须草试验,以检测对龙须草光合作用的影响,检测龙须草对重金属复合污染的耐性,从而探讨龙须草修复重金属污染环境的能力。光合分析的结果表明：随着Pb、Cd复合污染含量的升高,龙须草的光合综合指标下降幅度较小,说明龙须草对重金属复合污染具有较强的耐性,且Cd对龙须草的影响大于Pb。     

软木/龙须草纤维复合材料的研究

为了降低软木材料的生产成本,将龙须草纤雏和软木粒子混合,进行了软木/龙须草纤维复合材料的开发研究.以复合材料的耐水性、抗拉强度、可压缩系教、回弹率等为指标,考察了龙须草纤维的比例、施胶量、热压温度和热压时间的影响.得出较佳的工艺条件为:龙须草纤维比例20%,施胶量8%,热压温度150℃,热压时间15 min.     

龙须草与造纸

龙须草与造纸马成战龙须草为我国特种多年生宿根性优质长、中纤维经济植物和常用的草类造纸工业原料之一，被造纸行业称为“群草之冠”、“草中之王”。龙须草叶长无节，纤维含量高达５６．７８％，纤维细胞形态既细又长，为草类纤维所罕见。龙须草纤维与木本植物纤维相比...     

龙须草叶片电镜扫描样品制备方法及扫描电镜下电压选择

探讨了龙须草叶片扫描电镜样品的制备技术以及扫描电镜下电压的选择。结果表明:取叶组织直接镀金观察的效果与通过戊二醛固定经丙醇脱水后再镀金观察的效果相差不大,研究龙须草叶片结构可以用直接制片法。为了获得清晰的龙须草叶片扫描电镜图,在扫描电镜下选择用10 k V的电压为最佳。     

龙须草营养钵容器育苗技术

龙须草（Eulalmpslkhi；。ata）为一种丛生野草，系禾本科多年生叶脉植物。80年代前生产上多采用分荣移栽，80年代末生产上用种子播种育苗成功。随着现代育苗技术的发展，塑料袋营养钵容器育苗在龙须草生产中得到了应用。现将龙须草营养钵容器育苗技术介绍如下。1采集良种选择优良的龙须草母株进行采种。生产上多在3年生以上的老草坡上选择生长健壮、叶片长、茎种粗壮结实的优良母株采集饱满的种穗。采种最适时间为5月底～6月上中旬。此时种穗由青色变为黄褐色，手摸穗轴开始脱节。采收过早，种籽为白色，幼嫩，不成熟，播种后体能出苗或出…     

龙须草栽培技术

龙须草是绿化荒山荒坡理想的先锋植物,在种植农作物与造林难于成活的地方和崎岖不平的山区与陡峭的悬崖上则生长良好。对保护环境,保持水土,维护生态平衡有着现实的意义和作用,并且是优良的造纸原料。 龙须草的生物学特征 龙须草(Eulaliopsis binata)为禾本科多年生草本植物一拟金茅,一些地方俗称蓑草、蓑衣草或羊胡子草。世界上分布于中国、印度、克什米尔、阿富汗、土耳其与菲律宾等国家的局部地区。我国主要分布于四川、云南、贵州、陕西、河南、湖北、湖南、广西、广东、福建、台湾、甘肃、宁夏等     

辽宁西部半干旱地区油松和樟子松整地造林效果分析

通过分析油松和樟子松整地造林对土壤理化性质的影响及造林成活率的调查,对辽宁西部半干旱地区油松和樟子松整地造林效果进行了试验研究。结果表明:整地比对照提高造林成活率22.4~25.1个百分点,保存率提高18.0~19.5个百分点,整地造林效果显著;造林整地后土壤容重降低6.62%~12.58%,土壤孔隙度增加25.13%~32.89%,土壤全氮提高45.92%~61.60%,速效氮提高7.87%~38.05%,速效磷提高5.02%~36.33%,速效钾提高16.35%~46.22%,不同整地方式均能改善土壤的理化性质。     

猕猴桃园套种蕺菜对土壤养分、酶活性及果实品质的影响

为了提高猕猴桃果实产量与品质,在猕猴桃园以套种蕺菜、清耕和对照作为试验处理,测定不同时期猕猴桃根际土壤养分含量、微生物数量、酶活性和果实产量及品质,分析其相关性。结果表明:套种蕺菜后猕猴桃根际土壤碱解氮、速效磷、速效钾含量分别比对照处理提高13.95%、7.92%和3.94%,土壤细菌、真菌、放线菌数量分别提高19.01%、28.89%和16.32%,土壤过氧化氢酶、脲酶、蔗糖酶、磷酸酶活性分别提高17.02%、12.63%、17.57%和7.98%,单果质量和单位面积产量分别提高7.14%和7.68%,维生素C、干物质、可溶性固形物、可溶性总糖和可滴定酸含量分别提高7.97%、18.29%、2.09%、12.37%和14.18%。相关性分析结果表明,套种蕺菜后猕猴桃根际土壤速效钾含量与土壤中细菌数量、真菌数量、放线菌数量、脲酶活性、蔗糖酶活性、磷酸酶活性极显著正相关。土壤细菌数量与蔗糖酶活性显著正相关,与磷酸酶活性极显著正相关。土壤真菌数量与蔗糖酶活性极显著正相关。土壤放线菌数量与蔗糖酶活性、磷酸酶活性显著正相关。土壤速效磷含量与维生素C含量、可滴定酸含量极显著负相关,与干物质含量、可溶性固形物含量和可溶性总糖含量极显著正相关。土壤细菌数量、放线菌数量与维生素C含量极显著负相关。土壤真菌数量与维生素C含量显著负相关。土壤脲酶活性与干物质含量显著正相关,与可滴定酸含量显著负相关。维生素C含量与土壤蔗糖酶活性极显著负相关,与土壤磷酸酶活性显著负相关。套种蕺菜有利于提高猕猴桃根际土壤养分含量、微生物数量和酶活性,增加猕猴桃果实产量,改善猕猴桃果实品质。     

中度火灾一年后马尾松林土壤碳库特征

【目的】分析不同林龄马尾松次生林在森林火灾前后土壤理化性质、土壤活性有机碳组分(LOC)的动态特征及变化趋势,定量评价中度林火强度对土壤碳库稳定性的影响,可为定量研究中度林火对土壤碳平衡与碳循环的影响提供参考。【方法】选择成熟林、中龄林和幼龄林的马尾松次生林,采集火烧迹地及相邻未烧林分0～60 cm土壤,测定其土壤理化性质、细根生物量和土壤LOC组分含量,通过计算土壤碳库管理指数(CPMI)分析土壤碳库变化特征,采用通径分析探讨土壤CPMI的直接影响和间接影响因素。【结果】与对照样地相比,森林火灾后各林龄0～60 cm土层的土壤密度提高3.80%～4.85%、土壤pH值提高4.21%～5.78%、土壤全磷含量提高7.97%～12.44%,土壤含水率降低3.41%～3.97%、土壤全氮含量降低15.09%～17.45%、土壤有机碳含量降低10.07%～14.31%,幼龄林、中龄林和成熟林的土壤活性有机碳(LOC)分别降低22.70%、19.48%和17.48%。不同林龄马尾松次生林土壤CPMI对森林火灾的响应有差异,幼龄林、中龄林和成熟林的土壤CPMI分别为26.15、30.57和32....     

香榧-大豆复合经营对土壤化学性质的影响

于2012-2015年在浙江省松阳县开展香榧幼林下套种大豆试验(以不套种大豆为对照),探讨香榧幼林下套种大豆对林地土壤pH值和主要养分含量的影响。连续3 a的试验结果表明:与对照相比,套种3 a后土壤pH值提高1.0,土壤有机质含量提高29.4%,速效氮、磷、钾含量分别提高27.2%、12.2%、5.5%。说明香榧幼林下套种大豆能改善林地土壤的酸碱度,并有效提高土壤有机质和土壤氮、磷、钾速效养分含量。     

吉林省西部苏打盐碱土区林草植被恢复技术研究

笔者阐述了在苏打盐碱土区种植不同的树、草植被进行试验研究,对比选出适宜盐碱土区种植生长的树、草品种,治理吉林省西部苏打盐碱土区的脆弱的生态现状,研究表明:西伯利亚白刺、吉生四号羊草抗盐碱能力强,模式(羊草0.5 m ×白刺0.5 m ×羊草)×1.0 m最适合迅速提高植被盖度.     

Biomass production of trees and grasses in a silvopasture system on marginal lands of Doon Valley of north-west India 2. Performance of grass species

In a long-term study (1980 to 1993), the survival, growth performance and biomass production of two grass species viz. Chrysopogon fulvus (Spreng.) Chiov. and Eulaliopsis binata (Retz.) C.E. Hubb. were assessed when intercropped with four tree species viz. Albizia lebbek (L.) Benth., Grewia optiva Drumm., Bauhinia purpurea L. and Leucaena leucocephala (Lamk.) de Wit. on the bouldery riverbed lands of Doon Valley of north-west India. The survival of grass clumps was higher under the canopy of B. purpurea (48.3% in 1993 of the initial planting density of 20,000 clumps ha⁻¹ in 1980) and G. optiva (47.4%) than of L. leucocephala (31.1%) and A. lebbek (29.4%), and at 75% intensity of tree lopping (40.9%) than at 50% (37.1%). The effect of tree species on different growth parameters of grasses was not uniform, with G. optiva and B. purpurea causing comparatively more synergistic effect on clump height and clump diameter respectively. Although the performance of grasses was good under A. lebbek and L. leucocephala in the early years (1980--1987), these tree species resulted in the lowest grass dry weight in the later years up to 1993. The beneficial effect of higher lopping intensity of 75% was observed on the growth and biomass production of grasses over 50% lopping, presumably due to increased light penetration into the under-storey. The biomass production of grasses reached a maximum at four years of growth in 1983, after which, it decreased gradually to less than half in 1993. Eulaliopsis binata showed higher survival, growth and biomass production than C. fulvus throughout the period of study. The total biomass production was highest in association with B. purpurea followed by G. optiva, which appeared to be the most suitable tree species along with E. binata for sustainable silvopasture development on the marginal lands of Doon Valley of north-west India. This revised version was published online in June 2006 with corrections to the Cover Date.     

Acacia nilotica-based silvipastoral systems for resource conservation and improved productivity from degraded lands of the Lower Himalayas

High population density and unscientific land use practices have induced severe land degradation in the fragile Lower Himalayan ecosystem of India. Land cover management has been an effective strategy in managing land degradation through the reduction of water, soil and nutrient losses and improvement in soil fertility and quality. Acacia nilotica (Acacia)-based silvipastoral systems with five intercrops, viz., Eulaliopsis binata (bhabbar), Saccharum munja (munj), Vetiveria zizanioides (vetiver), natural grasses and no grass, were evaluated in a long-term study in degraded bouldery lands in Haryana state of India. All grasses resulted in a reduction of soil, water and nutrient losses and improved microbial properties. However, their association adversely affected the growth of Acacia, and the decline varied with grass species. After 11 years of establishment, sole Acacia plantation had the maximum height (7.58 m), diameter at breast height (dbh) (21.32 cm) and crown spread (7.41 m). Munj produced the highest biomass under Acacia, but most adversely affected its growth, resulting in minimum survival (48 %), height (7.07 m), dbh (16.23 cm) and crown spread (6.57 m). Yield of all the grasses increased during the initial 5–6 years, but declined sharply thereafter, with the maximum decline in bhabbar. Detailed investigations established that the sharp decline in survival and growth of bhabbar was due to shade and not because of nutrient competition or allelopathy. Acacia + V. zizanioides proved the most effective silvipastoral system for resource conservation and biomass production. It also provided the highest NPV (Rs 1.88 lakhs ha^?1), B:C (2.37) and IRR (24.70 %) as compared to Rs 6,998 ha^?1, 1.05 and 8.76 % under pure Acacia plantation, respectively.     

Biomass production of trees and grasses in a silvopasture system on marginal lands of Doon Valley of north-west India. 1. Performance of tree species

Bouldery riverbed lands occupy about one-third of the geographical area in Doon Valley of north-west India. These marginal lands need rehabilitation through establishment of silvopasture system for meeting the biomass requirements of resource-poor farmers. A study was carried out for 14 years (1980 to 1993) at Dehradun, involving four multi-purpose tree species viz. Albizia lebbek (L.) Benth., Grewia optiva Drumm., Bauhinia purpurea L. and Leucaena leucocephala (Lamk.) de Wit.; and two grass species viz. Chrysopogon fulvus (Spreng.) Chiov. and Eulaliopsis binata (Retz.) C.E. Hubb. Fifty and 75% of the tree crown was lopped once a year after four years of age. Tree survival decreased with age, and was highest with L. leucocephala (86.9% in 1993 of initial density of 625 trees ha⁻¹) and lowest with B. purpurea (49.3%). Canopy parameters of trees progressed differently, presumably due to their varying growth habits. The trees of A. lebbek were taller with more crown spread, whereas G. optiva had more crown height with lesser crown spread. Stem diameter growth of A. lebbek was highest followed by B. purpurea. Lopping intensity did not affect tree survival and also canopy growth in most years, but collar diameter and diameter at breast height (dbh) decreased significantly at the higher intensity of lopping. Intercropped grass species E. binata caused a greater adverse effect on the tree survival and growth parameters than C. fulvus. The biomass production (leaf and branch wood weight of lopped material) was highest at eight years of age in 1987 but showed no definite trend over the study period. Bauhinia purpurea produced the highest biomass and L. leucocephala the lowest, despite opposite trends in their survival. The performance of A. lebbek was on par with B. purpurea in the later years (1990--1993), but G. optiva was inferior despite its superiority in the early years (1984--1985). The effects of lopping intensity were not appreciable, but intercropping with E. binata decreased leaf and branch wood production significantly compared with C. fulvus throughout. However, the adverse effect was comparatively less pronounced on B. purpurea and A. lebbek than on G. optiva and L. leucocephala. The fibre yield of G. optiva also decreased due to intercropped E. binata compared with C. fulvus. This revised version was published online in June 2006 with corrections to the Cover Date.     

松花坝水源区不同林分土壤特性及其水源涵养功能

通过对松花坝水源区4种主要林分样地的土壤物理性质和贮水量进行测定,同时与裸地进行对比分析,结果表明：4种林分平均土壤的自然含水量比裸荒地高15％,土壤容重、孔隙度、有机质含量和土壤粒度都优于裸荒地;林分的水源涵养功能高于裸荒地,其中圣诞林水源涵养功能最好,华山松林次之,云南松林和滇石栎林稍差。说明培植林分对水源涵养有巨大作用,对水源区生态发展意义重大。     

祁连山北坡退化水源涵养林生态修复模式研究

祁连山水源涵养林对西北干旱区降水调节、涵养水源、保持水土、改善气候发挥着重要作用。通过对祁连山北坡不同类型林地进行调查研究,结果表明:毁林耕种致使中山区的90%水源涵养林林缘都受到破坏,10%的森林中有面积超过30m×30m的较大林窗。采用坡地鱼鳞坑和坡脚水平沟营造青海云杉和祁连圆柏,形成坡面流水收集,坡底沟缘"锁"边的水源涵养林恢复体系。鱼鳞坑增加表层土壤蓄水力,水平沟则增加了20~40cm土层含水量,而林窗的土壤受干扰则增加了40cm土层含水量。人工造林增加了植被盖度,提高了土壤蓄水量,减少水土流失,增加水源涵养能力。根据立地类型,将封山育林、造林和水土保持工程结合是有效的退化涵养林恢复措施。     

湖南西毛里湖湖滨毛竹林水源涵养能力及其价值评估

竹林具有重要的水源涵养功能，为科学认识毛竹林的水源涵养能力、充分发挥竹林在西毛里湖的水源涵养功能，利用综合蓄水能力法研究了西毛里湖湖滨毛竹林的水源涵养能力及其服务价值。结果表明：毛竹林生态系统每年水源涵养量为3 353.97 m³/hm²，其服务价值为2 247.16元/hm²。其中，林冠层、灌草层、枯枝落叶层和土壤层的水源涵养服务价值分别为1 082.05、0.51、11.66和1 152.94元/hm²，分别约占生态系统水源涵养服务价值的48.15%、0.02%、0.52%和51.31%。林冠层水源涵养能力仅次于土壤层，在生态系统水源涵养价值评估中不宜忽视。     

密度对毛竹林水源涵养能力的影响

以崇阳县毛竹为研究对象,在4种密度(D1)1 300±100、(D2)1 900±100、(D3)2 500±100及(D4)3 100±100株·hm~(-2)毛竹林分内通过标准地设置与调查对毛竹林分水源涵养能力进行了研究。结果表明,虽然不同毛竹林密度林冠层截留率之间的差异不显著,但截留量之间的差异极显著。半分解以及未分解凋落物持水量与浸泡时间之间均为对数方程,半分解以及未分解凋落物吸水速率与浸泡时间之间均为幂函数方程。不同密度凋落物最大持水量0.81~1.21 mm,并随林分密度增加而增加。凋落物总最大持水率380.39%~402.13%。林分有效拦蓄量0.75~0.92 mm,有效拦蓄率292.92%~311.31%,并密度增大而增大。毛竹林土壤土壤含水率11.21%~13.70%,土壤容重1.19~1.34 g/cm~3,毛管总孔隙度52.89%~54.77%,土壤毛管总孔隙度随土层深度的增加而减小,土壤非毛管孔隙度9.39%~10.22%。林分密度对土壤物理性状及其土壤渗透性能影响均不显著。毛竹林土壤饱和蓄水量3 173.35~3286.11 t·hm~(-2),不同密度毛竹林分土壤层饱和蓄水量之间的差异不显著。虽然不同密度毛竹林分土壤毛管蓄水量之间的差异不显著,但非毛管蓄水量差异显著。毛竹林水源涵养总量584.15~626.58 t·hm~(-2),土壤蓄水量、林冠截留量及凋落物持水量分别占96.41%~97.91%、0.79%~1.51%及1.30%~2.07%。     

太行山阳坡樟子松的生长表现及发展前景

对太行山石灰岩区干旱阳坡引种了11a的樟子松的生长、开花结实及其对土壤的改良效果、水保效益进行了分析,结果表明,引种的樟子松比相同立地条件下同龄油松的树高平均提高了28.60%,地径平均提高了8.20%,林地持水量提高了23.9%。实践证明,樟子松是适宜在太行山阳坡生长的优良水土保持树种。