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101.
Meat goat production in the eastern USA is increasing as a result of growing demand from various ethnic groups. Because goats naturally prefer a high proportion of browse in their diets, research was initiated to investigate various silvopastoral production systems. The genus Paulownia contains several species which exhibit rapid juvenile growth and other characteristics that justify research into their potential use in meat goat feeding systems. In May 1997, six Paulownia genotypes were planted in a randomized complete block experiment with six replications. Trees were between 6 and 12 cm in height at planting. Genotypes included: P. fortunei seedlings, P. tomentosa seedlings, P. elongata seedlings and three P. elongata clones. Each 4-m wide plot contained a single row of 12 trees with an intra-row spacing of 1 m. Plant measurements included height, root collar diameter (RCD) at 3 cm above soil surface, and the number of main branches. Leaf samples were collected from all six replications for estimates of herbage quality. During 1998, trees were browsed with goats on two occasions to assess palatability of the herbage and to determine any preference for specific genotypes by the animals. Compared with seedling trees of all three species, the three P. elongata clones were taller (clones: 79.7 cm, seedlings: 55.9 cm; P < 0.01), had larger RCDs (clones: 18.4 mm, seedlings: 13.9 mm; P < 0.01) and had a higher branching frequency (clones: 4.9, seedlings: 1.5; P < 0.01) by the end of the first growing season. Mortality averaged 4.8% across all treatments and ranged between 0 and 8%. Early in the 1998 growing season before trees were browsed, P. elongata clones grew more rapidly than seedlings (clones: 116.4 cm, seedlings: 84.1 cm; P < 0.01). Estimates of herbage quality indicated favorable concentrations of energy and protein for lamina. In vitro true dry matter disappearance ranged from 85.4 (blades) to 71.5% (petioles) and crude protein from 25.1 (blades) to 4.9% (petioles). Animals readily browsed the lamina during two separate sessions, but no clear preference trends were observed among the different Paulownia genotypes.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
102.
P. A. Durr 《Agroforestry Systems》2001,51(3):223-237
Samanea saman (Jacq.) Merr. (syn. Albizia saman (Jacq.) F. v. Muell.) is a large tree, native to tropical America, which has now become widespread throughout the humid and
subhumid tropics. Although noted as a promising agroforestry species, there is little specific research that substantiates
this potential. On the basis of a review of its biology, ecology and recorded uses, it is concluded that the most appropriate
use for S. saman would be in an extensive silvopastoral system for cattle production. The tree provides excellent protective shade, and produces
highly palatable pods that are suitable as a dry season feed supplement. Additionally, there are reports of enhanced grass
production beneath its canopy indicating a potential role in maintaining or improving the productivity of tropical grasslands.
It is concluded that the tree should receive more research attention, focusing particularly on its interaction with the herbaceous
understorey and the identification of provenances adapted to a variety of environmental conditions.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
103.
Nitrogen fixing and non-N2 fixing legumes such as Gliricidia speium and Senna siamea have been used in alley cropping systems for soil improvement and source of N for food crops. However their
establishments could be limited by P and moisture deficiencies in degraded soils. Vesicular-arbuscular mycorrhizal fungi can
help to overcome these deficiencies. We examined the effects of a vesicular-arbuscular mycorrhizal (VAM) fungus, Glomus deserticola, on the performance of sole hedgerow trees of Gliricidia sepium and Senna siamea and their mixtures (interplanted) in a fallowed alley cropping experiment on a degraded Alfisol in southwestern Nigeria.
Percentage root infection by VAM fungi was higher in inoculated plants than in uninoculated ones irrespective of whether they
were interplanted or non-interplanted. Inoculation with G. deserticola increased dry matter accumulation and nutrient uptake (N. P, Mg and K) but there was no significant interaction between mycorrhizal
inoculation and interplanting for growth and nutrient uptake except for the uptake of P, Mg and K in G. sepium. Inoculation with G. deserticola reduced leaf shedding of G. sepium by 50% but did not have the same effect for S. siamea. For both tree species inoculated plants extracted more water from 0–30 cm depth than the uninoculated ones. 相似文献
104.
Evaluation of existing on-farm agroforestry plots should provide useful supplementary information for the design of improved agroforestry systems, in both research and development projects. Such evaluation has been little used, however, largely due to the methodological difficulties of surveying highly variable on-farm plots, and difficulties in identifying key variables for measurement. This paper describes a set of methods and tools used in evaluating plots of alley-cropping and tree borders around crop fields established by farmers working with the CARE Agroforestry Extension Project in western Kenya. Details of survey design, sampling, and implementation are discussed, and suggestions made for carrying out agroforestry surveys in other projects. A condensed version of the questionnaire is appended. 相似文献
105.
论云南名木古树的保护价值 总被引:4,自引:0,他引:4
在研究分析了云南省1604株古树名木的基础上,认为古树名木具有如下保护价值:①模式标本的采集树,植物群落类型区划的重要依据;②引种栽培的科学依据,生物资料的贮藏库,生物的基因库;③历史与社会学的活文物,革命斗争的见证人;④自然历史的真实记录,赏心悦目的旅游景观。 相似文献
106.
107.
大树引入城市是改变城市生态环境、提高城市绿化绿地质量、生态效益和景观的有效途径。本文分析了进城大树成活率低的原因,提出了提高大树成活率的对策。 相似文献
108.
广西乡土阔叶树种资源现状及其发展对策 总被引:2,自引:0,他引:2
通过对广西乡土阔叶树种资源现状、主要功能分析及红锥(Castanopsis hystrix)、大叶栎(Castanopsisfissa)、木周木(Lithocarpus thalassica)、红楠(Machilus thunbergii)、西南桦(Betula alnoides)等最具前途乡土树种的介绍,提出应加快乡土阔叶树种遗传改良技术研究,提高乡土阔叶人工造林良种化率;重视乡土阔叶树种造林技术研究,提高阔叶树种经济效益;制定配套政策措施,鼓励发展乡土阔叶树种种植与林产品加工的策略。 相似文献
109.
110.
GU WanchunResearch Institute of Forestry. Chinese Academy of Forestry. Beijing China 《中国林业科技(英文版)》2002,(1)
The present situation of forest tree genetic germplasm resources research and conservation in China is introduced which including the background, decision-making of conservation strategies and principles, the plan of area division and tree species classification, the sample strategy of germplasm conservation, the advances in conservation pattern and related technologies research, the achievements of germplasm conservation and utilization in China, and the problems to be solved. The recent achievements and data related are listed. 相似文献