连南县杉木幼林抚育比较试验

采用5种不同类型的抚育管理方式，对立地条件和造林质量均相同的新造杉木幼林进行抚育，并对8年生杉木林各项生长指标进行了测定。结果表明，与对照清除杂草抚育方式相比，林农间作、松土埋青、树盘覆草3种抚育方式的杉木高生长与径生长均存在显著或极显著差异。结合投资净现值考虑，树盘覆草抚育方式投资小，又能显著促进杉木高、径和材积生长，达到了“省工节资增效”的目的。     

不同幼林抚育方式对马尾松林分生长的影响

分析不同幼林抚育措施对10年生马尾松林分的平均胸径、平均树高、造林保存率、单株材积及样地蓄积量生长的影响,结果表明不同的幼林抚育管理措施对马尾松造林成林及林分生长具有显著的影响。高标准的幼林抚育措施能显著促进马尾松的生长,提高林地生产力。     

岷江上游干旱河谷辐射松引种造林研究

经过连续14 a的辐射松(Pinus radiata D.Don)引种造林研究,结果表明(1)采用1.5 m×2.0 m造林密度,短册状或水平沟整地,采用石块、塑料薄膜覆盖,造林成活率达96%,保存率达90%.(2)抚育压青6 a的辐射松幼树树高生长量为对照的2.02倍,地径生长量为对照的2.19倍;每株幼树施20 g(N)+100g(P)施肥量的树高生长量比对照提高65.7 cm～120.2 cm,地径生长量比对照提高1.74 cm～3.83 cm;1/3修枝强度比对照树高生长量提高295.7 cm,地径生长量提高3.0 cm,1/4修枝强度比对照树高提高198.1 cm、地径生长量提高2.54 cm;(3)辐射松1 a中有2次高生长高峰期、3次径生长高峰期,高、径速生期在4～6龄年出现,幼林的根系、枝干、叶的生物量在5 a生时也急剧增加.     

不同经营措施对南方退耕山地杨树生长影响

为了提高退耕还林地经营杨树人工林的经济和生态效益,比较了两种经营措施对南方退耕还林地杨树人工林生长的影响,结果表明:杨树人工林林农间作显著促进杨树的生长,连续间作2 a后,其胸径、树高和蓄积量比对照分别增加5.8%、56.1%、130.7%。密度对南方退耕还林地3 a生杨树蓄积量有显著的影响,蓄积量最大值是最小值的4.15倍。     

杉木一般产区幼林抚育管理研究

采取 6种不同类型的抚育管理方式 ,对立地条件和造林质量标准均相同的新造杉幼林进行抚育。并对 8年生林木各生长指标进行了较为系统的测定与研究 ,结果表明 ,在杉木高粗生长均有明显或极显著差异的林农间作、松土埋青和树盘覆草管理中 ,树盘覆草抚育达到了省工节资增效的目的     

杉木幼林抚育技术的综合评价和决策

本文在全面分析不同抚育技术对杉木生长、群体结构、林地植被物种多样性、生物量、水土流失和抚育成本的影响基础上，运用灰色局势决策理论对不同抚育技术进行多目标决策，结果表明：块状抚育和全垦抚育可提高杉木的保存率，并促进杉木幼林的生长；抚育技术对杉木群体树高和地径结构有一定的影响，尤其是对地径结构；全垦抚育的成本最大，不抚育最小，块状抚育居中；块状抚育有利于形成多层次的林分结构和林地植被物种多样性的提高。综合评价结果表明块状抚育是南方林区较好的杉木幼林抚育方式，它既能有效地减少林地植被对杉木的竞争，保持杉木的正常生长，又能降低抚育成本和保持地力及物种多样性。这对今后指导杉木幼林抚育具有重要的实践意义。     

杉木一般产区幼林抚育管理研究

采取6种不同类型的抚育管理方式，对立地条件和造林质量标准均相同的新造杉幼林进行抚育。并对8年生林木各生长指标进行了较为系统的测定与研究，结果表明，在杉木高粗生长均有明显或极显著差异的林农间作、松土埋青和树盘覆草管理中，树盘覆草抚育达到了省工节资增效的目的。     

不同抚育技术对杉木幼林生长及群体结构的影响

对不同幼林抚育技术对杉木幼林生长和群体结构的影响进行定位研究 ,结果表明 :抚育技术对杉木保存率和生长有较大的影响。块状抚育和全垦抚育可提高杉木的保存率 ,而不抚育的杉木保存率则最低。树高和抽梢高基本上表现出块状抚育 >全垦抚育 >带状抚育 >劈草抚育 >不抚育 ,并且在后期更为明显 ;地径则基本上表现出全垦抚育 >块状抚育 >带状抚育 >劈草抚育 >不抚育。方差分析的结果表明抚育技术对地径的影响大于树高。多重比较表明 :除了不抚育外 ,其他 4种抚育技术均能有效地促进杉木生长 ,它们之间并没有多大的差异。块状抚育、全垦抚育、带状抚育和劈草抚育的总单株生物量分别为不抚育的 3 4 6、3 4 0、3 15和 1 11倍 ;块状抚育、全垦抚育、带状抚育、劈草抚育和不抚育的根 茎比分别为 0 1992、0 193 1、0 1673、0 3 5 75和 0 2 680。这可能是劈草抚育和不抚育的杉木对地下营养空间激烈竞争的一种适应现象。抚育技术对杉木群体树高和地径结构有一定的影响 ,尤其是对地径结构     

思茅松种子与农作物种子混合撒播造林试验研究

思茅松种子与农作物种子混合撒播造林，其发芽率（播种2个月）为75．70％，与直播造林没有显著差异；幼苗成活率（0．5a）和保存率（1．5a）明显低于直播造林。但是随着林龄的增长，差异越来越小，到幼树阶段（2．5a）时保存率为3．82％．只比同期直播造林的保存率低0.29％，到3a以后，保存率几乎一样。同时思茅松种子与4种农作物种子混合撒播造林的发芽率几乎一样。与4种农作物种子混合撒播造林对思茅松幼苗成活率和幼树保存率影响较大，其中与旱稻、玉米种子混合撒播造林时幼苗成活率明显高于与黄豆和花生混合撒播。混合撒播造林有利于思茅松生长，其树高和地径的生长量都高于直播造林。其中与旱稻混合撒播造林的思茅松生长最快。进行抚育管理的林地恩茅松的保存率和幼树的生长量都明显高于未进行抚育管理的林地，特别是到林龄为2．5a时，其差异更为显著。此外，混合撒播造林不但有利于思茅松幼树生长和提高其成活率，而且有较好的经济效益。     

兴安落叶松林农间作效果研究

为了探索兴安落叶松幼林合理间作模式,连续2年对造林当年和第2年的林地进行间作。结果表明:不同模式间兴安落叶松幼林树高和地径生长量差异均极显著,显著水平为0.0001。造林当年,生长量最大的间作模式是间作红小豆,树高和地径生长量分别达到59.49 cm和0.70 cm;造林第2年,生长量最大的间作模式是间作大豆,树高和地径生长量分别达到109.35 cm和1.77 cm。间作后净收入最大的作物是籽角瓜,造林当年为235.19元/667 m2,造林第2年为290.62元/667 m2。     

Crop yield and tree-leaf production in three planting patterns of temperate-zone alley cropping in Oregon, USA

The objective of this study was to determine crop and tree productivity in several alley cropping planting patterns. The four- year study was conducted in western Oregon, United States and involved irrigated sweet corn (Zea mays) intercropped between hedgerows of red alder (Alnus rubra) and black locust (Robina pseudoacacia). Three alley cropping planting patterns with variable plant populations and tree-crop proximity were tested with each tree species in a randomized block design. Space available to trees and crops determined yield of both plant components. High crop yield coincided with low pruning yield, and vice versa. Compared to monocropping, yield reductions in traditional alley cropping planting patterns with widely spaced, double tree rows ranged from 5% to 15%. A. rubra and R. pseudoacacia coppiced readily and produced 0.9 to 4.7 tons of dry matter pruning biomass per growing season, depending on planting pattern and year. A. rubra yield continually increased during the trial, while the ability of R. pseudoacacia to produce green manure after frequent coppicing appeared to weaken. After four years, soil organic matter was 4 to 7% higher in the topsoil of an alley cropping system compared to a monocropping system. However, continuous growing of sweet corn resulted in decreased soil organic matter levels in both cropping systems compared to original levels. Crop yield reductions and the need for additional management inputs constrain the implementation of alley cropping in temperate climates. Only if benefits other than minor soil fertility improvements are realized is alley cropping a feasible alternative in temperate climate regions. This revised version was published online in June 2006 with corrections to the Cover Date.     

退耕还林地造林树种选择研究

为了探索退耕还林适宜的造林树种,在福建省福安市进行了黄底、青底、白底灰泥田的退耕还林造林树种选择试验,应用回归分析研究。结果表明,3种土壤的农田退耕还林造林的适应树种有香椿、深山含笑、邓恩桉、拟赤杨、马尾松等12种,其造林成活率均在86%以上。退耕还林造林的选择应根据立地条件、经济条件、造林目的选择最佳的造林树种,才能发挥最好的生态效益和社会效益。     

Effects of alley cropped Calliandra calothyrsus and Cliricidia sipium hedges on weed growth,soil properties,and taro yields in Western Samoa

Field experiments were conducted on a tropical Inceptisol at Apia, Western Samoa to evaluate the effects of alley cropping on soil characteristics, weed populations, and taro yield. Taro yields were compared from Calliandra calothyrsus and Gliricidia sipium alleys, spaced at 4 m, 5 m, and 6 m, and a no tree control. Measurements were made for soil moisture and temperature, weed growth, hedge biomass production, and taro growth and yield. Data was analyzed over 4 consecutive years from 1988 to 1991.Hedge biomass yields ranged from 5.1 to 16.1 t/ha/yr dry weight over the 4 years of the trial, with Calliandra and Gliricidia performing equally well. Biomass yields decreased by about 2 mt/ha with increasing alley width from 4 to 6 m alleys. Weed populations were significantly lower in the 4 m alleys compared to the 5 m, 6 m, and control plots. The 6 m alleys supported the significantly highest weed populations. Soil from alley plots held significantly more water in the 0.3 to 1 bar range than soils from the controls. Four years of mulch application measurably improved soil water holding capacity and bulk density. However, no improvement was seen in nitrogen, phosphorus, potassium, calcium, magnesium and organic carbon content in the alley plots compared to the controls. There was no positive yield effect of alley cropping on taro yield. Yields in the 5 m and 6 m alleys were not significantly different from the control, while the 4 m alleys produce significantly lower yields than the control. Thus, alley cropping did not prove a viable alternative to traditional shifting cultivation after 4 years of continuous cropping, in this trial.     

Microbial community diversity in a 21-year-old temperate alley cropping system

Soil physical and chemical properties in the crop alleys and tree rows in alley cropping systems vary greatly due to differences in litter quality and microclimate under trees compared to the alleys. Variations in soil properties influence microbial diversity and function, and thus, in alley cropping systems, bacterial diversity could be different between soils in tree rows and crop alleys. The objective of this study was to compare and contrast soil bacterial diversity in the crop alleys and tree rows in a 21-year-old alley cropping system in Northeast Missouri, USA. Soil samples were taken in three parallel transects to a depth of 10 cm in the tree row and at the middle of the alley in a silver maple (Acer saccharinum) alley cropping system with a companion maize (Zea mays)—soybean (Glycine max) rotation. Soil bulk density, C and N concentrations were similar between the different transects while minor differences were observed between crop alleys and tree rows. No significant difference in bacterial diversity was observed between the tree rows and alley soil based the denaturing gradient gel electrophoresis profiles, band richness (19.6 and 22.8 for tree row and alley, respectively) and Shannon–Weiner diversity (2.958 and 3.099 for tree row and alley, respectively). Identification of bacterial genera revealed dominance of gram +ve as well as gram ?ve bacteria in both soil types. Ordination plot revealed no clustering effect based on location (transect) or on the cropping system in the different samples. Bacterial diversity in crop alleys most likely was influenced not only by the maize-soybean rotation, but also by the tree rows contributing both above and belowground litter for the past 21 years.     

中德合作造林项目防护林混交造林技术与效果评价

介绍了中德合作陕西（二期）延安造林项目造林地立地类型划分、树种选择、混交造林技术、造林方法和幼林抚育管理,并对项目实施10年后的造林成效进行了评价.     

油杉属树种人工造林的试验研究

长期以来,油杉属树种,只开发利用而未人工造林,资源濒于枯竭。国内仅少数植物园引种作观察或观赏,国外也仅英、美、意等国零星引种于公园庭院,尚无系统的作为用材树种造林的研究。广西林业科学研究所从1957年开始油杉人工引种驯化试验,在完成广西油杉属物种资源调查和采种育苗试验基础上,对油杉属中的4个主要树种进行造林试验,至1989年止,已推广造林700ha,并总结了一整套人工造林的技术措施。一、试验内容自1978年以来,先后在全区设试验点8个,试验林80多公顷,进行了造林地选择、物种比较、密度、混交造林、抚育等试验,各试点的试验内容有所不同。1989年5月至9月对各点的试验林及推广林进行了全面的调查、总结。     

A comparison of alley cropping and block planting systems in sub-humid Bénin

Alley cropping would be acceptable to farmers in West Africa, if the amount of tree-crop competition could be reduced and crop yields increased and stabilized. The importance of overall tree-crop competition in alley cropping was therefore quantified at three locations in the Republic of Bénin, by comparing the performance of a maize-cassava intercrop and mixed hedges of Gliricidia sepium and Flemingia macrophylla in an alley cropping system, where the tree-crop interaction was high, and in a cut and carry system with block plantings, where the interface was restricted to one face. The establishment and productivity of trees in both agroforestry systems depended strongly on the natural soil fertility of the site, K and Ca being critical for both species. Alley hedges produced progressively more cut dry matter with higher leaf proportions than tree blocks and hence yielded significantly higher nutrient masses. Overall, the cut dry matter from five cuttings per cropping season ranged among locations from 855 to 1651 kg ha^–1 yr^–1 for alley hedges and from 777 to 869 kg ha^–1 yr^–1 for tree blocks. Differences in yields of maize and cassava between both systems were insignificant in all three environments and all cropping years under observation. The results of this study suggest that the overall effect of tree-crop competition was unimportant, but that tree-tree competition was the decisive factor in determining the total system productivity.     

Stepwise approach to alley cropping technology development and transfer in the forest zone of Cameroon

Two projects on alley cropping research and development have been implemented in the Forest zone of Cameroon (FZC) since 1988. Their goal was to identify the main agricultural constraints in the FZC and to introduce alley cropping in the farming systems to improve soil fertility and crop yields. The first step in the implementation process was the participatory surveys which revealed that (a) the main agricultural constraint in the FZC is low soil fertility; (b) alley cropping is an agroforestry technology which may solve the problem; (c) alley cropping should be first targetted to farmers who own inherited or purchased lands. The second step was the on-station tree screening activity from which Leucaena leucocephala, Gliricidia sepium, Calliandra calothyrsus and Paraserianthes falcataria were identified as promising tree species. The third activity was to test alley cropping with three promising tree species (Leucaena, Gliricidia and Calliandra) on farmers' fields. Results from the first year testing on farmers' fields showed that: (1) the direct seeding method used was ineffective: seedling emergence rate was 45% for Leucaena and 52% for Gliricidia; (2) Cassava suppressed the growth of Leucaena and Gliricidia by 57 and 45%, respectively; (3) three-month-old Calliandra seedlings planted 1 m away from cassava plants had 96% survival rate. Based on these third step findings, all new farms were established with Calliandra seedlings using maize as a test-crop in the year of establishment and the subsequent year. After two years of cropping, maize grain yield in alley plots was 52% higher than maize grown on no-tree plots. In 1993, 52 farmers who had witnessed the alley farm maize growth in 1992 requested to join the project. This sudden interest of farmers to start their own alley farms was considered as a positive sign for adoption and therefore a success in alley cropping (AC) introduction in the zone.     

滇东南岩溶区4种松树的生长量比较研究

2001—2003年,在建水县半干旱暖热岩溶区具有代表性的石漠化和非石漠化2种立地类型上,采用云南松、湿地松、加勒比松和马尾松4个针叶树种造林,通过10余年的生长量观On,0,研究其对滇东南岩溶区的生长适应性。结果表明,4个树种对滇东南非石漠化土地和石漠化土地均有较强的适应性,其中以马尾松和湿地松的总体表现较优;云南松前3年生长较慢,其后生长加快,总体表现较好;加勒比松表现最差,不适宜滇东南半干旱暖热岩溶区作造林树种。     

大果紫檀的育苗栽培技术

大果紫檀是珍贵的红木类树种,原产东南亚热带地区,引种到云南西双版纳热带植物园生长迅速,心材形成千,并大量结果,是优良的珍贵造林树种.文章对其种子特性、生态习性、育苗及造林技术作了较详细的介绍.建议在云南、海南岛、台湾、广东、广西、福建等省区条件适宜地区进行试种并发展造林.