绿春县美国山核桃造林方法及效果初报

为了降低造林成本,加快造林进度,探索一种新的造林方法,2007年在绿春县进行了美国山核桃实生苗与营养袋苗嫁接造林研究.结果表明,实生苗移入营养袋定植成活率受苗木质量的影响大,营养袋中定植时间及嫁接时间对嫁接成活率的影响大,实生苗造林成活率达75.29%,嫁接苗造林成活率达52.55%.     

高酸海棠“红勋1号”苗木嫁接繁育试验初报

利用不同砧木、选择不同嫁接方式及时间,对高酸海棠“红勋1号”进行苗木繁育试验研究,结果表明,不同砧木、不同嫁接方法及时间均会对“红勋1号”成活率及生长产生影响：（1）选择不同砧木嫁接时,八棱海棠为砧木时成活率最高,黄海棠次之,野苹果为砧木时成活率最低;（2）使用不同嫁接方法对高酸海棠“红勋1号”嫁接后,成活率按顺序为双舌枝接〉插皮接〉劈接;（3）选择不同嫁接时间对高酸海棠“红勋1号”嫁接,黄海棠春季嫁接“红勋1号”成活率最高,为93%;八棱海棠的春季嫁接和秋季嫁接的成活率次之,均为92%;野苹果的秋季嫁接成活率最低,为84%。     

美国红栌的嫁接育苗技术

美国红栌属漆树科，黄栌属植物，原产美国，为美国黄栌的变种。近年来美国红栌成为彩叶树种中的新贵，我们根据近2a的生产实践，将美国红栌的特性及其嫁接育苗技术总结如下：     

美国红栌组织培养繁殖研究

对彩叶树种美国红栌试管苗的继代培养和生根培养以及试管苗移栽基质进行了研究,结果表明:在NT(1971)+BA 0.6 mg/L+NAA 0.2 mg/L 培养基上,美国红栌试管苗继代培养的丛生苗分化率最高且生长良好;最佳生根培养基为1/2 MS+IBA 0.1 mg/L+NAA 0.1 mg/L+IAA 1.5 mg/L,试管苗生根率可达90%;移栽基质为泥炭:珍珠岩=2:1混合,苗木成活率可达到90%以上.     

科尔沁沙地西伯利亚红松引种探讨

2004年辽宁省固沙造林研究所从东北林业大学引种西伯利亚红松,采用异砧嫁接方法嫁接到沙地樟子松容器苗上。现嫁接成活率为95%,圃地的栽植成活率为92%,林地的移栽成活率为95.4%,都达到了预期效果。通过12a的引种试验表明,选择优良穗条异砧嫁接育苗,并在嫁接后加强管理,注意苗木的生长情况、越冬防寒及防治病虫害,引种就能获得成功。引种西伯利亚红松对于丰富沙地地区的树种资源具有重要意义。     

两个栲属树种种间嫁接及影响因素

采用髓心形成层贴接法,对栲属的红锥与白锥2个树种种间及种内进行不同时期嫁接试验。结果表明:此嫁接方法适合2个栲属树种嫁接,本砧嫁接成活率最高达100%,异砧嫁接最高达79%;种间嫁接未见嫁接不亲和现象。在南宁3月是2个栲属树种种间嫁接最佳时期,成活率达79%,接穗生长达7 cm;2月次之,成活率达60%,接穗生长达5 cm。同时,还分析了影响嫁接成活的因素,包括气温、接穗等。     

化香作砧木嫁接山核桃育苗及造林效果

以化香、湖南山核桃、枫杨为砧木及湖南山核桃、浙江山核桃、美国山核桃为接穗,进行嫁接育苗和造林试验,结果表明：化香砧木嫁接育苗成活率最高,达90％以上,且生长快、成本低;化香砧木嫁接的山核桃苗造林后,其抗淹、耐寒及抗虫性较好,且生长快、挂果早,坚果经济性状较稳定。其中以化香砧木嫁接的浙江山核桃果重、出果率、坚果大小,仁色、味道等方面达到或超过了产区标准,出仁率、壳厚接近产区标准。     

不同嫁接方法与整地方式对红松育苗和造林效果分析

采用3种嫁接方法不同时期进行红松嫁接育苗及不同整地方式造林试验,结果表明:与劈接和单芽贴接法相比,采用舌接法嫁接成活率最高,达到了94.41%,劈接法成活率87.78%,单芽贴接法为83.52%;不同嫁接时期比较,4月25日和5月10日嫁接成活率最高,分别达到96.67%和95.33%。采用嫁接苗上山造林,各整地方式对造林成活率的效果依次为平台整地造林成活率96.67%鱼鳞坑95%竹节壕85.83%嵌缝76.67%,属平台整地造林成活率最高。     

马尾松林冠下套种红锥试验研究

对马尾松人工纯林进行不同强度的抚育间伐,开展不同郁闭度马尾松林下套种红锥试验研究。结果表明:马尾松林分林冠下套种红锥其造林成活率较高,造林成活率达90%~94%,而不同处理间造林成活率差异不显著。不同抚育间伐强度对套种红锥生长的影响差异极显著,而中度抚育间伐后林分郁闭度保持在0.5~0.6对套种的红锥生长最为有利。     

氧化石墨烯对美国红栌组培苗不定根发生的影响

为了解氧化石墨烯(Grapherie oxide,以下简称GO)对植物组培苗根系的影响,本试验研究了不同浓度GO处理对美国红栌组培苗不定根的形态、分化以及植株生长状况的影响,同时还研究了GO对美国红栌组培苗生根培养基电导率的影响。研究发现,适当浓度的氧化石墨烯能够促进美国红栌组培苗不定根的伸长,但并不能促进其根系根数的增多;各浓度的氧化石墨烯能够促进植株芽的分化,但对植株茎段的伸长没有影响;较高浓度的GO能够使培养基电导率略微下降,GO对生根培养基中有机营养物质具有较强的吸附作用,具有缓释控释效果,能够在生长的中后期促进植株生长和生根。     

A COMPARISON OF RAINFALL IN DIFFERENT WOODLANDS

At Bedgebury the rainfall in thirteen forest plots planted withdifferent tree species has been compared with that in the open.In all these forest plots the trees have closed canopy within20 years of planting and the canopies differ considerably intheir structure. From 6 to 93 per cent. of the gross rainfallmay be retained on the tree canopies and lost to the soil. Theproportion of precipitation intercepted is greatest in lightrains and least in heavy rains. During light showers considerablymore moisture is retained on the conifer than on the hardwoodcanopies. In the heavier showers rainwater flows down the stems,but stem flow represents a small proportion of the total waterreaching the forest floor. The amount of water which reachesthe ground along the trunks varies with the species and thecharacter of branching. Some raindrops penetrate directly throughthe canopy, but many are intercepted by the canopies and coalesceto fall as large drops on the forest floor. These large waterdropstend to fall continuously on the same spot so that in the plantationsthe water is distributed unevenly. In the winter months, whenthe deciduous species have shed their leaves, snow penetratesmore easily through their canopies than those of the evergreenconifers.     

土壤干旱胁迫对黄栌叶片光合性能的影响

为探索土壤干旱胁迫和光照强度对黄栌光合作用性能的影响规律,应用CIRAS-2型便携式光合作用系统,测定4种土壤水分（对照、轻度、中度和重度胁迫）处理下,3年生黄栌（Cotinuscoggygria var．cinerea）苗木叶片光合作用的光响应过程。结果表明：1）土壤干旱胁迫对黄栌叶片的光合性能参数具有明显影响,随着土壤水分胁迫的加剧,黄栌叶片的光合速率、蒸腾速率、光量子效率明显降低,光补偿点增高,叶片水分利用效率在轻度水分胁迫（土壤相对含水量60-65％）下的水平最高;2）黄栌叶片光合作用对强光胁迫的适应性较强,在较大幅度的强光（有效辐射强度1000-1800μmol·m^-1·s^-1）范围内,均能获得较高的光合速率和水分利用效率;3）黄栌光舍作用对弱光的光能吸收、转换和利用效率（光合量子效率）较低,并随土壤水分胁迫加剧而明显下降。     

不同造林措施对岩质海岸防护林造林成活率及其生长的影响

以 1年生南酸枣和湿地松为试验材料 ,于沿海岩质典型岸段分别就种植穴大小和磷肥蘸根、ABT生根粉沾根、选用容器苗、覆草、集团造林等共 12个技术组合进行了选择试验。结果表明 ,有利于提高湿地松造林成活率和促进幼树树高、胸径生长的技术措施分别是集团造林、选用容器苗及磷肥蘸根 ;而有利于提高南酸枣造林成活率和促进其幼树树高、胸径生长的技术措施为截干和ABT生根粉沾根处理。试验结果同时表明 ,种植穴大小对南酸枣和湿地松的成活率及其 3年生幼树生长影响不显著。     

美国红栌组培苗嫩枝扦插育苗试验

对引进的美国红栌组培苗进行了嫩枝扦插试验,以正交试验方法分析了不同激素种类、浓度、浸泡时间、扦插基质等对扦插生根的影响,结果表明：美国红栌嫩枝扦插的插穗用100×10^-6～250×10^-6浓度的生根激素（ABT,NAA,IBA）浸泡0．5h,以河沙为扦插基质,生根率可达95％。对美国红栌组培苗截顶促萌,并且加强水、肥管理,可常年剪取嫩枝插穗,便于推广。     

Soil water dynamics, growth of Dendrocalamus strictus and herbage productivity influenced by rainwater harvesting in Aravalli hills of Rajasthan

Degraded Aravalli hills in western India require rehabilitation through resource conservation and afforestation for meeting the biomass needs of resource-poor tribes of the region. Rainwater harvesting treatments i.e., control, Contour trench (CT), Gradonie (G), Box trench (BT) and V-ditch (VD) were prepared in <10%, 10–20% and >20% slopes categories and Dendrocalamus strictus L. seedlings were planted in August 2005 with a view to conserve soil and water and increase the productivity of the hills. Soil water content (SWC), survival and height of D. strictus plants were highest (P < 0.05) in <10% slope and all these variables decreased with increase in slope. SWC increased by 27.45% and 25.68% in <10% and >20% slopes, respectively than in 10–20% slope. From lowest in control SWC increased by 11.95%, 20.21%, 17.61% and 11.49% in CT, G, BT and VD treatments, respectively. Growth variables were highest in VD plots but the increase in shoot number was highest (2.9-fold) in CT plots. Increase in effects of rainwater harvesting with time indicated by a change in production pattern from highest (P < 0.05) fresh and dry herbage in <10% slope in 2005 to 10–20% slope (24.66% and 26.09%) in 2006 and >20% slope (42.42% and 48.35%, respectively) in 2007. The increase in herbage was 1.17–2.40-fold in fresh and 1.20–2.52-fold in dry herbage over control. Highest (P < 0.01) production was in V-ditch plots. The treatments order for herbage production was C < CT < G < BT < VD. But the production was highest in BT in <10% and in V-ditch plots in 10–20 and >20% slopes. Conclusively, soil water status is affected by natural slope, stony soil surface and rainwater harvesting structures influencing seedling growth and herbage production. Box trench and V-ditch enhanced surface soil water facilitating herbage growth, whereas contour trench facilitated deep soil water storage, which was made available to the plants after monsoon. Thus rainwater harvesting practices enhanced vegetation cover and productivity of the degraded hills and can be replicated to conserve soil resource and increase biomass for rural poor of the region.     

不同土壤水分下黄栌光合作用CO2响应过程

测定了不同土壤水分条件下黄栌光合作用的CO2响应过程,采用直角双曲线修正模型对其响应过程进行拟合。结果表明:黄栌的净光合速率(Pn)对土壤水分的变化具有显著的阈值响应。维持黄栌较高光合速率的RWC在42.1%-73.6%(MWC在11.0%-19.2%)之间时,最适宜的RWC为61.7%(MWC为16.1%)左右。黄栌的羧化效率(CE)、光合能力(Pnmax)、光呼吸速率(Rp)表现为对土壤水分具有明显的阈值响应,当RWC为61.7%(MWC为16.1%)时CE、Pnmax达到最大值,当RWC为73.6%(MWC为19.2%)时Rp达到最大值。黄栌的CO2补偿点(Γ)、CO2饱和点CSP随着土壤含水量的增加表现出先下降后上升的规律。     

城市绿地空间分布对雨水径流量的影响

文章针对不同城市绿地空间分布方案,构建相应的一维管网排水模型,对比不同降雨重现期下的地表径流和管网动态存储量模拟结果,分析不同绿化占地比率和绿地空间格局对雨水地表径流及排放的影响。结果表明,雨水径流与地块的绿化占地比率呈现高度相关,绿地的空间格局对雨水径流的影响并不显著,绿地空间布局和管网的匹配程度会影响管道内的动态储水量。该研究可为城市绿地的空间布局规划提供支撑。     

杉木人工复层林试验初报

本研究探讨杉木人工复层林营造技术。通过对４０年生杉木林不同程度的疏伐，采用１年生杉木实生苗在其林冠下营造复层林，３ａ的试验结果表明：不同疏伐区内的下层木平均树高为对照区的４２．４％～５１．１％，平均地径为对照区的３９．６％～４９．６％，成活率为对照区的６４．７％～９８．１％；不同处理区间的栽植木生长具有极显著差异，在复层林中以Ｂ区的下层木成活与生长为最佳，初步认为维持杉木人工复层林的下层木正常生长，林内相对照度必须达到５０％以上。     

Effects of rainwater harvesting on herbage diversity and productivity in degraded Aravalli hills in western India

Over-exploitation and rural growth have severely damaged native vegetations of Aravalli hills in Rajasthan, India. This study was conducted to evaluate the effects of different restoration practices (i.e., rainwater harvesting (RWH) and planting of tree seedlings) on improve- ment in soil water and nutrients and growth and biomass of herbaceous vegetation. Contour trench (CT), Gradonie (G), Box trench (BT), V-ditch (VD) and a control were imposed on 75 plots (each of 700 m 2 ) in natural slope gradient defined as <10%, 10% 20% and >20% slopes in 2005. Each plot had three micro-sites of 1-m 2 at up (USP), middle (MSP) and lower (LSP) part of the plot for observation in 2008. The existed gradient (due to soil texture and topographic features) of soil pH, EC, SOC, NH 4 - N, NO 3 -N and PO 4 -P in June 2005 between >20% to <10% slopes were decreased in 2008 after applying RWH techniques. Such improvement in soil status promoted vegetation growth and biomass in higher slope gra- dients. Soil water, species diversity and herbage biomass increased from USP to LSP, and RWH techniques had positive role in improving SOC, nutrients, vegetation population, evenness and growth at MSP. Despite of lowest SWC, regular rain and greater soil water usage enhanced green and dry herbage biomasses in 10% 20% and >20% slopes, compared with <10% slope. The highest diversity in CT treatment was related to herbage biomass, which was enhanced further by highest concentrations of SOC and PO 4 -P. Further, CT treatment was found to be the best treat- ment in minimizing biomass variance in different slopes. Conclusively, soil texture and topographic features controlled soil water and nutrients availability. Rainwater harvesting techniques increased soil water storage and nutrient retention and also enhanced vegetation status and biomass by minimizing the effects of hillslopes. Thus depending upon the site conditions, suitable RWH technique could be adopted to increase herb- age biomass while rehabilitating the degraded hills.     

Establishing royal paulownia on the Virginia Piedmont

A study was established in the Virginia Piedmont to investigate theeffects of site preparation treatments (subsoiling and trenching) and the useofweed mats on royal paulownia survival and growth. Seedlings were monitored inthree study blocks for seven years. Following the seventh growing season,survival was low, ranging from 11% in the control plots to 27% in the trenchedplots. Plot volume index averaged 28,633 for the subsoil plots, while controlplots had an average plot volume index of 12,685. Weed mats significantlyincreased soil moisture from 18.7 to 20.4%. Likewise, weed mats significantlyimproved seedling survival after seven years, from 9% to 30%.