缺能山区不同树草种、畜粪和秸秆的燃烧值比较

在黄土高原半干旱缺能山区,主要靠生物质资源做燃料,在农村生活用生物质能源中,畜粪占生物质总能量的41.7%,居首位;草类占26%,居第2位;农作物秸秆占19.2%,居第3位;薪柴的产量最少,可利用量居末位。据《西吉县农村能源区划研究》调查,一般年景。

北川大熊猫栖息地植被恢复主要树草种选择初步研究

通过调查分析"5·12"汶川地震后小寨子沟和片口两自然保护区大熊猫栖息地的受损情况和立地条件,结合现有植被恢复技术手段,本研究选择了18种植物作为北川保护区大熊猫栖息地植被恢复的主要树草种,设计20个恢复模型用于地震受损恢复工程,提出了大熊猫栖息地恢复过程中采取多部门协作、项目整合、重点走廊建设、加强施工管理、加大主食竹研究等措施。

湘中红壤丘陵水土保持生态修复树草种生长量初步研究

文章通过对湘中红壤丘陵水土保持生态修复树草种生长量进行对比试验研究,初步筛选了桤木、马尾松、枫香、杉木、板栗、金银花、葛藤、萱草、苏丹草等树草种;桤木、马尾松和枫香等树种在疏林、纯林地补植中适应性较强;试验初期生长量较大的退耕还林模式依次为杉木水保林模式、马尾松水保林模式和板栗经果林模式;萱草和苏丹草在本区具有一定的适应能力。

Effect of Seed Sizes on the Growth and Establishment of Seedlings of Sheanut Tree （Vitellaria paradoxa）

Seed size can influence germination, emergence and further development of plants to produce high yield. Therefore, pot trial was conducted to assess the effects of seed sizes on growth and establishment of sheanut tree seedlings （Vitellaria paradoxa） in tlae southern Guinea savanna of Nigeria. Seedlings produced from large sized seed had higher germination （80%） than those from medium （70%） and small （65%） sized seeds. Number of days to emergence of seedling from large-sized seed planting was 30 days, 49 days for small- and medium-sized seeds. Large sized seeds had higher N, P, K, Ca and Mg contents compared with small and medium sized seeds. Generally, seedlings from large sized seeds had about 1.5 times more leaves than medium sized seeds and about 2 times more leaves than small sized seeds at 8, 10, 12, 14 and 16 weeks after planting （WAP）. Seedlings from large sized seeds were taller and had larger stem girth （at 16WAP） than those from medium sized seeds. Variations in seedling growth from seed sizes could be of operational importance in nursery management as seeds can be sown according to size to improve uniformity. However, further studies to ascertain if the superior growth of seedlings from large sized seeds will lead to higher yield is recommended.

Contribution of Promiscuous Soybean （Glycine max L.） to Upland Rice-based Cropping Systems in West Africa

A two-year on-farm study was carried out at Eglime in the moist savanna （MS） and Ouake in the dry savanna （DS） of Benin to evaluate the contribution of inoculation of dual-purpose soybean varieties to grain yield of upland NERICA rice fertilized with low N level. In 2005, four dual-purpose, promiscuous soybean varieties （cv. TGx1440-IE; TG×1448-2E; TG×1019-2EB; and TG×1844-18E）, and a popular improved variety （cv. Jupiter） were sown in 12 farmer fields with and without Bradyrhizobium japonicum inoculation. There was also land which was left fallow that acted as the control. In 2006, upland interspecific rice （NERICA 1） was sown in all the plots and supplied with 15 kg N haL. Dry matter yield, N accumulation, and net N-balance were significantly enhanced by over 40% with inoculation of cv. TG× 1844-18E than non-inoculation in the DS in comparison to other cultivars. There were no significant effects of inoculation of previous soybean cultivars on soybean grain yield and on the succeeding NERICA rice yield. Averaged over inoculation, previous cv. TG× 1019-2EB plots supplied with only 15 kg N hal gave the highest grain yield, more than twice the yield of control plots in the DS, possibly because of significant production of higher tillers, panicles and harvest index than the other cultivars; and it could be recommended for upland rice-based system for NERICA production.

Effects of tsaoko (Fructus tsaoko) cultivating on tree diversity and canopy structure in the habitats of eastern hoolock gibbon (Hoolock leuconedys)

In this study, the quadrat method was used to study the effects of tsaoko （Fructus tsaoko） plantation on tree diversity and canopy structure of two natural habitats of eastern hoolock gibbon （Hoolock leuconedys）： Nankang （characterized by extensive tsaoko plantation） and Banchang （relatively well reserved and without tsaoko plantation）. Totally, 102 tree species from 25 families and 16 woody liana species from 10 families were recorded in Nankang, whereas 108 tree species from 30 families and 17 woody liana species from 12 families were recorded in Banchang. Although the tree species between two habitats is different, both habitats are characterized by enriched food resources for eastern hoolock gibbons, sharing similar dominant plant families. Due to tsaoko plantation, tree density proportion and diversity of forest layer I （〉20 m） in Nankang were both significantly decreased, but the tree density of layerH （10-20 m） increased. Likewise, in conjunction with these behavioral observations, we also address potential impacts of tsaoko plantation on the behavior of eastern hoolock gibbon.

Consumption and species preference for house construction wood in central highlands of Ethiopia–implications for enhancing tree growing

A study was conducted in central Ethiopian highland in 2008 to investigate the consumption of house construction wood, the tree species preference for construction wood and the forthcoming conditions of this forest product and possible strategies for future availability. Twenty-four iron-roofed houses and twenty-eight thatch-roofed houses belonging to thirty-six farm households were investigated for types, volumes and sources of construction wood used. It was found that an average farmhouse with a floor space of 57 m^2 consumed about 13.7 m^3 of wood. Both floor space and wood consumptions vary with house types An average iron-roofed house with floor space of 51.9 m^2 consumed 16.8 m^3 of wood and an average thatch-roofed house with mean floor space of 28.6 m^2 consumed 3.2 m^3 of wood. Family size and floor space were the major factors influencing construction wood consumption. An average living house was composed of woods of 39.3% ,luniperus procera, 5.6% Cupressus lusitanica, 29.2% Eucalyptus globulus and 26% Eucalyptus camaldulensis. The wood volume from the first two species and half that of the third species were obtained from state forest which is currently banned from any construction wood extraction and hence there is a shortage of around 59.5% of woods. We suggest the promotion of various tree planting approaches to increase the wood supply and the use of alternative local materials like soil bricks for house construction.

Stable isotope evidence for trophic niche partitioning in a South African savanna rodent community

Species＇ partitioning of resources remains one of the most integral components for understanding community assem- bly. Analysis of stable carbon and nitrogen isotopes in animal tissues has the potential to help resolve patterns of partitioning be- cause these proxies represent the individual＇s diet and trophic niche, respectively. Using free-ranging rodents in a southern Afri- can savanna as a model community, we find that syntopic species within habitats occupy distinct isotope niches. Moreover, spe- cies with strongly overlapping isotope niches did not overlap in their spatial distribution patterns, suggesting an underlying effect of competitive exclusion. Niche conservatism appears to characterize the behaviour of most species in our sample - with little or no observed changes across habitats - with the exception of one species, Mastomys coucha. This species displayed a generalist distribution, being found in similar abundances across a variety of habitats. This spatial pattern was coupled with a generalist isotope niche that shifted across habitats, likely in response to changes in species composition over the same spatial gradient. The case for M. coucha supports contentions that past competition effects played a significant evolutionary role in shaping community structures of today, including the absence of strong interspecific niche overlaps within particular habitats. Our study highlights the value of stable isotope approaches to help resolve key questions in community ecology, and moreover introduces novel ana- lytical approaches to quantifying isotope niche breadths and niche overlaps that are easily comparable with traditional metrices