几种介质对土壤的改良及彩叶树种的生理响应

采用沸石、草炭、食用菌下脚料及液体土壤调节剂4种土壤改良介质按照一定重量比组合为5种配方对土壤进行施肥处理,通过测定处理后土壤理化性质的相关指标和苗木叶绿素含量,研究改良剂对土壤理化性质及苗木生理的影响,同时筛选出相对理想的处理配方。结果表明,5种处理对土壤状况和苗木生长均有不同程度的改善和促进作用,表现为土壤容重、pH值降低,孔隙度、有机质及水解氮含量增加,叶片叶绿素含量增加。其中以40％沸石＋60％草炭处理的改良效果最优。     

榆林沙区针叶树苗木繁育的影响因素及其综合效益分析——以樟子松为例

针叶树种是耐寒、抗旱优良树种,它对增加固沙植物的多样性、改变沙地景观、促进沙地生态环境的逆转等具有重要意义。针对近年来榆林沙区不同规格樟子松苗木繁育面积逐年扩大现象,本文从影响樟子松育苗的气候、环境等因素和苗木繁育所产生的综合效益进行了分析,以期为北方沙区樟子松育苗提供参考。     

地膜覆盖技术对土壤温湿条件及苗木生长的影响

干旱缺水是新世纪面临的全球性环境问题,我国也是缺水严重国家之一,节约用水成为共识。而在苗圃生产中,用水量较大,因此,开展节水抗旱苗木培育技术的研究,既节约水资源,又可降低育苗成本,在今后的苗圃以及林业生产中将具有广阔的应用前景。本实验选用辽育1号杨和荷兰64号杨作为育苗试验树种,采用覆黑色膜、覆V型黑膜、覆白色膜和未覆膜四种不同处理,测定不同杨树幼苗在不同处理条件下的土壤含水量、土壤温度、苗木生长等指标。结果表明:覆膜区比未覆膜区地温增高0.5-7.5℃,土壤含水量增高2.84%-13.28%,高生长和地径生长分别提高9.02cm和1.28mm。由此可见,覆膜不仅具有增温、保墒的作用,同时可提高苗木生长量,覆膜对杂草的生长也有明显的抑制作用。     

亚高山半干旱地带植被恢复保水剂试验研究

在亚高山半干旱地带采用四种不同类型的保水剂材料对油松、岷江柏、刺槐、山桃进行了持续三年的田间试验。试验结果表明，采用CMS吸水材料、植物生长调节剂、生长素等配制的复合保水剂对亚高山半干旱地带造林树种进行处理，可提高苗木成活率、保存率并促进幼苗生长。造林第二年针叶树和阔叶树的平均成活率提高5．9％，造林第三年针叶树和阔叶树的平均保存率提高5．2％，针叶树和阔叶树的苗木高生长量平均增加61．7％。经统计检验，确认了复合保水剂的不同剂型对苗木成活和生长的影响之差异。     

抗旱保水剂对干旱荒漠区沙棘造林的影响

通过5种不同类型抗旱保水剂对沙棘造林效果的对比试验,结果表明:5种保水剂对沙棘造林成活率、苗木生长量、造林地土壤含水率影响与对照相比差异极显著,不同类型的产品之间差异显著.由此可见,抗旱保水剂在干旱荒漠区造林中具有较大的推广应用价值.     

沙质土蓄水保肥栽培措施及其效果研究

采用掺壤土、施秸秆、根下铺塑料膜、置塑料袋和聚水抗旱栽植等措施，营造了毛白杨节水灌溉栽培试验林。造林后连续５ａ的试验结果表明：掺壤土和施秸秆使土壤蓄水性和保肥性明显提高；在根下铺塑料膜可截留下渗的水分和营养物质，使土壤剖面局部水分、养分含量显著增加，聚水抗旱栽培调节了地表水聚集动态，增加了根系周围土层水分的入渗，在一定程度上提高了土壤含水量。各项措施不同程度地改善了土壤蓄水性能；使降水利用率和灌溉效率明显提高。     

清香木对不同土壤水分胁迫的生长和光合响应

以1年生清香木实生苗为试验材料,通过设置2种土壤极端水分条件与5种不同程度土壤水分胁迫处理,研究不同土壤水分胁迫对苗木地径、株高、生物量、净光合速率、胞间CO2浓度、蒸腾速率等光合指标变化。结果表明,（1）苗木的成活率、地径、苗高等指标随着水分胁迫（干旱）的加深而呈现递减趋势;（2）苗木净光合速率、气孔导度、蒸腾速率及瞬时羧化效率与胁迫程度成反比,而胞间CO2浓度和瞬时水分利用效率与胁迫程度成正比;（3）清香木幼苗具有一定程度的抗旱能力,恢复能力较强,可作为喀斯特山区植被恢复和群落构建的先锋树种。     

果尔在苗圃针叶树育苗除草中的应用

果尔作为一种应用较多的化学除草剂,已经在苗圃中广泛应用。通过试验得出结论:一年生针叶树出苗前采用果尔土壤处理除草,对红松效果最好,其次是红皮云杉和樟子松。二年生针叶苗木生长期采用果尔土壤处理除草,对红皮云杉效果最好,其次是红松和樟子松。因此说果尔是林区比较理想的除草剂。     

抗旱保水长效新型复混肥料

抗旱保水长效新型复混肥料是将材料科学、农业栽培、土壤、植物营养和肥料科学融为一体的新型高徽产品。它具有一定的抗旱节水作用,能以水带肥、以水促肥,起到节水节肥的双重效益,提高肥料的利用率,能够满足作物正常生育期内对养分的需求,提高作物产量,改善农产品品质,增加农民收入,同时减少肥料对土壤和水质等环境的污染。     

不同土壤含水量下黄连木苗木生长及耗水特性研究

研究不同土壤供水条件下黄连木幼苗生长及其耗水规律,可为北方干旱缺水地区黄连木能源林节水育苗工作提供重要参考。采用盆栽试验法,设置了4种不同土壤含水量梯度,分析各供水梯度下苗木生长变化及其耗水特征。结果表明:苗高、地径、生物量等指标在不同水分梯度下差异显著,过高或过低土壤水分含量会降低苗木的茎根比;苗木耗水日进程在生长季各月多呈单峰曲线,4种土壤含水量条件下最大耗水月均在8月份,苗木的月耗水量、总耗水量、平均日耗水量均随着土壤含水量的下降而下降,并且差异显著。综合考虑苗木生长及耗水特性认为:在土壤含水量为田间持水量的60%±5%时,能够实现能源林苗木壮苗的定向培育目标,同时又能实现水分的高效利用。     

樟子松母树林疏伐密度研究

通过对孟家岗林场40年生樟子松母树林不同密度疏伐处理后14个主要性状的统计分析,结果表明,疏伐处理对樟子松母树多个性状造成了显著影响,而且不同性状之间存在极为复杂的相关性;利用聚类分析和主分量分析法将存在显著差异性和相关性的8个性状分成3类,分别代表了生长、树冠和结实性状;通过这3类性状在各主成分上得分值的加权和比较表明,孟家岗林场40年生樟子松母树林疏伐抚育最佳密度是150株·hm-2。     

4个国外引进树种扦插试验初报

采用全光自动喷雾扦插育苗设备,进行欧洲云杉、白云杉、黑云杉、东部白松４个 国外引进成功树种半木质化嫩枝扦插试验,探讨了这４个树种的扦插育苗技术。沙质插壤上各树种生根率分别达欧洲云杉７７．５％、白云杉５２％、黑云杉４４．５％,东部白松在锯末插壤上扦插生根率为３５％。为进一步扩大栽培,加速林木良种化,走有性选择、无性繁育的无性系林业发展道路,提供了新的可行的无性繁殖方法。     

章古台固沙林更新造林中天然更新的结合与利用

辽宁省章古台固沙林经过经营疏伐与块状采伐以后,通风透光条件改善,促进了天然下种更新。天然更新强度,在采伐迹地为690株·hm^-2,人工更新造林地为575株·hm^-2,油松和赤松林下松树为181株·hm^-2,其他树种295株·hm^-2。通过采取保护1年生樟子松幼树越冬,抚育油松、赤松幼树等措施,促进针叶树天然更新。在更新造林中,沙丘下部与丘间低地营造杨树,利用行间天然更新树木形成阔叶树混交林,沙丘中上部营造针叶树,利用行间天然更新灌木,形成乔灌混交林。     

施肥对红松无性系种子园母树结实效应研究

通过在红松无性系幼龄种子园进行的氮肥、磷肥和钾肥3种肥料,每种肥料设置4个水平的施肥试验,研究分析了氮肥、磷肥和钾肥3种肥料,以及每种肥料的不同施用数量,对促进红松无性系种子园幼龄母树结实的效果,提出促进红松无性系幼龄植株结实的适宜施肥数量。     

章古台固沙林几种更新造林模式的初步研究

在章古台樟子松固沙林采伐迹地上,按照不同沙丘部位,选择不同造林树种进行了杨树用材林模式、樟子松杨树针阔混交造林模式、阔叶树混交造林模式、乔灌混交造林模式、针针混交造林模式等5种更新模式造林,通过调查分析可知,樟子松混交林的生长量与生态效益显著高于樟子松纯林.在沙丘下部与丘间低地杨树的生长量明显高于樟子松.降低造林密度,...     

The effect of release cutting on the growth and external quality of the dominant trees in a Pinus sylvestris stand established by spot sowing

The effect of the number of Pinus sylvestris trees in seed spots on the growth and external quality of the dominant trees was studied. The trees were monitored during the period between release cutting and the first commercial thinning. The treatments were one, two and four of the tallest seedlings retained per seed spot, and a control. The mean height of the dominant trees was highest in the one‐tree and two‐tree treatments. Diameter at breast height (DBH) increased with increasing spacing. On average, the stump diameter was 1.5–4.7 cm greater in the one‐tree treatment than in the control. Slenderness (height/DBH) was highest in the control treatments. The average living crown limit of the dominant trees was 4.6 m, and was at its highest in the two‐tree treatment. The results indicate that the competition in seed spots decreases the height growth of the dominant trees.     

Higher resistance of the offspring of Scots pine trees resulting from natural regeneration in old foci of Heterobasidion annosum root rot

Abstract

Heterobasidion annosum (Fr.) Bref. is a fungal pathogen causing annosum root rot – one of the most economically important diseases in coniferous stands. The major aim of this study was to compare the resistance of the offspring of Scots pine trees (Pinus sylvestris L.) from seed orchards and the offspring of trees that were naturally reproduced in old foci of the disease. In experiments conducted in vitro, we used 960 seedlings which were grown from seeds collected from 60 trees in 6 old foci of the disease and 640 seedlings grown from seeds collected in 4 seed orchards. The offspring of trees from seed orchards after inoculation with H. annosum had nearly twofold higher mortality rate than the seedlings developed from the seeds collected in old foci of the disease. This suggests that the offspring of self-sown trees in old foci of the disease has a greater, genetically conditioned resistance to annosum root rot.     

Role of weeds in the management of nitrogen in a young Pinus radiata plantation

Pinus radiata trees were grown on a podzolized sandy soil at a second rotation site under the following treatments: total weed control, total weed control plus ammonium nitrate, strip weed control and no weed control. During the first two summers after planting the differences in needle water potential between trees under no, strip or total weed control were very small. Despite similar rates of net N-mineralization in strip and total weed control treatments, which averaged 64 kg ha^–1 yr^–1 in the 0–15 cm soil depth, weeds in the strip weed control treatment reduced soil mineral-N concentrations by 50–80%, leaching of N by the end of the first growing season by 45%, foliar-N concentrations by 4–14% and stem biomass at 20 months after planting by 46%. Although N-uptake by above-ground vegetation (trees plus weeds) was 49% higher in the strip weed control treatment, the amount of N apportioned to trees during the first 20 months after planting was reduced from 15.5 to 9.0 kg ha^–1. These effects of weeds were even more pronounced in the no weed control treatment. Since weeds had little effect on the needle water potential of trees and the annual rates of N-mineralization, but adversely affected N-uptake by trees, results indicate that weeds directly competed with trees for N, and thereby aggravated N-deficiency in trees. Application of ammonium nitrate after complete weed control increased foliar-N concentrations, and N-uptake and growth of trees, but also induced severe stem deformation.     

沙地樟子松人工林冠下人工更新研究

在渐伐后郁闭度不足0.4的沙地樟子松人工林冠下进行人工更新试验,10年后观测各树种的生长状况,并对林下的土壤进行调查.结果表明:利用这种冠下人工更新方式使樟子松纯林转变为多树种混交的复层林;色木槭等4个树种可以作为冠下更新的主培树种;冠下人工更新可以逐渐改良土壤,延缓樟子松人工林林地土壤的衰退.     

沙地樟子松人工林合理经营密度的研究

通过调查不同密度的沙地樟子松人工林胸径、树高、蓄积、干形等生长指标和松枯梢病的发病情况等健康指标,分析了密度对樟子松人工林生长与健康的影响。综合分析得出:亚湿润干旱区樟子松人工林的造林密度可以控制在1 250~2 500株·hm-2;当樟子松人工林林龄达到21 a时保留密度1 000株·hm-2左右;当林龄31 a时,密度控制为500株·hm-2左右。