雨豆树播种前预处理对种子发芽和种苗发育的影响

播种前对雨豆树(Albizia saman (Jacq.) F. Muell.)的种子进行了5 种预先处理,研究种子预先处理对种子发芽和苗圃种苗发育的影响。实验是在孟加拉吉大港大学林业与环境研究所的苗圃进行。研究结果表明,在种子末端修剪(处理4)提高种子发芽率50%,在冷水中浸泡24 小时(处理1)提高种子发芽率42%,在开水中浸30 秒后再在冷水中浸泡24 小时(处理2),种子发芽完全被抑制。处理4 和处理1 的种子发芽率、种苗初期形态生长和生物量都明显高于对照组。因此,这2 种播种前的种子预处理方法,可用于提高雨豆树种子发芽率和促进早期壮苗生长。图2 表3 参30。     

A review of measurement options for multipurpose trees

There is an urgent need to standardize the methods used to assess the growth of multipurpose trees. Most of the standard methods so far described have been developed specifically for use in multilocational trial networks. This paper was prepared for the F/FRED/ICRAF Workshop on MPTS Assessment Methods, held in Thailand in May 1991 to develop internationally-recognised standards for assessment methodology. It critically reviews the methods prescribed by different networks for height and diameter measurement, and for biomass estimation, giving researchers a range of methodological options to consider and re-emphasizing the need, all too often neglected, to define assessment methods clearly and unambiguously.     

土壤含水率对I—69杨苗木生长和生物量的影响

在3种土壤含水率条件下,研究了I-69杨插条苗的苗高、叶面积等生长进程和生物量。不同供水条件下苗木的生长进程相似,低供水处理封顶期提早10～15d.生物量测定表明,I-69杨十分喜水,高供水处理(土壤含水率保持在田间持水量的96％)的生物量为低供水处理(土壤含水率为田间持水量的55％)的2.74倍。     

26种乡土树种苗木生长规律及育苗技术的系统研究

通过对省沽油科圆齿野鸦椿、壳斗科8种、木兰科2种、冬青科2种、山茶科4种、蔷微科2种、桃金娘科的赤楠、八角科的莽草、槭树科的五裂槭、交让木科1种、金缕梅科3种等26种亚热带乡土树种的种子预处理、种子主要播种品质参数测定、对苗木的苗高、地径、主根长、大于5cmI级侧根数、根幅、冠幅、鲜叶重、鲜干枝重、鲜根重的测定,以及对苗木物候、苗木生长节律进行研究,从而得出上述树种的较为系统的育苗技术。     

Observations on the rooting patterns of some agroforestry trees in an arid region of north-western India

The present study deals with root architecture of 6-year-old trees of 9 indigenous and 3 exotic species growing in arid climate of north-western India. Observations, made on excavated root systems (3 tree replicates of each species) showed large variation in horizontal and vertical spread of roots. In Morus alba, Melia azedarach and Populus deltoides, the roots were confined to 80 cm, while in Prosopis cineraria, Acacia nilotica and Eucalyptus tereticornis, roots penetrated more deeply to 233 cm. The number of total roots ranged from 103 in Acacia catechu to 1932 in Eucalyptus tereticornis, and 62 to 80% of the roots were less than 2 mm in diameter. The primary roots were more horizontal than the secondary roots. The total root biomass varied from 2.2 kg in Acacia catechu to 30.6 kg^–1 tree in Populus deltoides, and top 30 cm soil contained 42 to 78% of the total biomass. The implications of the results are discussed in the context of the ecological niche of the species, and its usefulness in agroforestry systems.     

Effect of pruning intensities of three woody leguminous species grown in alley cropping with maize and cowpea on an alfisol

Field trials were carried out on an Oxic Paleustalf in the humid zone of southwestern Nigeria withLeucaena leucocephala (Lam.) de Wit,Gliricidia sepium (Jacq.) Steud. andSesbania grandiflora (L.) Pers. alley cropped with maize and cowpea. The three leguminous woody species were grown in hedgerows spaced at 2 m. Trials were carried out one year after establishment of the hedgerows using a split-plot design with four replications. TheLeucaena trial had twenty pruning combinations consisting of five pruning heights (25, 50, 75, 100 and 150 cm) and four pruning frequencies (monthly, bi-, tri- and six-monthly). TheGliricidia andSesbania hedgerows were subjected to nine pruning intensities consisting of three pruning heights (25, 50 and 100 cm) and three pruning intensities (monthly, tri- and six-monthly). For the three woody species, biomass, dry wood and nitrogen yield from the hedgerow prunings increased with decreasing pruning frequency and increasing pruning height. Biomass, dry wood and nitrogen yields were in the following orderLeucaena >Gliricidia >Sesbania. The various pruning intensities had no effect on survival ofLeucaena plants. Pruning frequency had a larger effect than pruning height on survival ofGliricidia andSesbania plants. With monthly pruning, about 25 percent of theGliricidia and all of theSesbania plants died within six months of repeated pruning. Even with lower pruning frequencySesbania plants showed lower survival rates thanGliricidia orLeucaena. The various pruning intensities of all the hedgerow species had more pronounced effects on the grain yield of the alley cropped cowpea than on maize grain yield. Higher maize and cowpea yields were obtained with increasing pruning frequency and decreasing pruning height. IITA Journal paper number 335     

生物质能源的利用技术与开发对策

生物质能源是十分重要的可再生能源,高效转化利用生物质能源对解决能源、生态环境问题将起到十分积极的作用。世界各国尤其是发达国家都很重视生物质能源的研究与开发。本文概述了生物质能资源的类型和特点以及国内外研究和开发进展,并从我国实际情况出发,提出研究开发前景和建议。     

修枝对杨粮间作系统中光照及作物产量和生物量的影响

实验选取株行距 1m× 10m的毛白杨和花生间作田 ,研究修枝对间作田不同水平位置的光照及花生产量和生物量的影响。结果表明 :随修枝强度的增大 ,不同处理间作田相应位置的光照强度增强 ,花生的产量和生物量也随之增加。修一层枝和修两层枝的间作田 ,东林冠下测点日均光照强度分别比不修枝的提高 2 6 0 %和 5 5 1% ;西林冠下提高 19 0 %和 38 4 % ;行中提高 2 0 7%和 38 6 %。修一层枝、修两层枝的间作田花生产量分别比不修枝的提高17 1%和 4 7 6 % ,花生果生物量提高 17 6 %和 4 7 8% ,秸秆提高 12 0 %和 31 5 %。修枝对花生根生物量影响不显著     

Tree growth and stand development of four Populus clones in large monoclonal plots

Four clones of Populus were planted in replicated monoclonal plots near Olympia, WA, to evaluate their suitability for use in short-rotation culture. All clones were easily established and had minimal problems from damaging agents during the first five years. Observed differences among clones in pattern and amount of growth appeared to be associated with differences in number and density of buds, sylleptic branching, and phenology. In addition, differences in drought tolerance and stockability may also have influenced clonal differences in annual growth and stand productivity. Individual tree growth was limited by the dense 1.0-m spacing, but the best-growing clones averaged 13 to 16 m tall, 7 to 9 cm in breast-high diameter (1.3 m), and produced stand basal areas exceeding 38 m²ha^-1at 8 years. Mortality was negligible for 7 years, after which various combined effects of competition, stem borer damage (Cryptorhyncus lapathi), and a severe windstorm caused mortality ranging from 18 to 36% in the three fastest growing clones.     

生物质材料生物技术研究进展及展望

介绍国内外采用酶活化木材纤维生产无甲醛释放人造板的技术及生物技术在生物质材料生物防治、生物制浆和防腐废弃木材的净化等方面的研究进展,并阐述了我国今后的研发方向.