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1.
段锞  胡丹  陈祉夷 《农业工程》2021,11(1):137-140
陕西作为丝绸之路的发源地,以其有利的自然生态条件和区域产业结构,形成了以茶叶为主导的产业发展格局。目前,陕西省茶叶出口规模不大,市场占有率较低。在“一带一路”倡议的推动下,陕西省茶叶出口至沿线国家的潜力较大,未来将逐步呈上升态势。研究了“一带一路”背景下陕西茶叶跨境电商市场发展现状和存在的问题,提出陕西茶叶跨境电商发展路径,通过借力跨境电商平台、开拓国际市场、稳固绿茶品牌、布局海外仓解决出口难的问题,以及完善跨境电商法律秩序,拓展陕西茶叶跨境电商发展路径。   相似文献   
2.
The microbial community structure and function under forest in tropical peatlands are poorly understood. In this study, we investigated the microbial community structure and diversity in natural peat swamp forest soil, disturbed peat soil and mineral soil in Central Kalimantan, Indonesia, using 454 pyrosequencing. The results showed that the natural peat soil had the greatest fungal species richness (Chao1), which was significantly (< .05) larger than that in the other two soils. Community structure of both fungi and bacteria in natural peat soil differed significantly from that in the disturbed peat soil (= .039 and = .045, respectively). Ascomycota (40.5%) was the most abundant phylum across the three soils followed by Basidiomycota (18.8%), Zygomycota (<0.1%) and Glomeromycota (<0.1%). The linear discriminant analysis with effect size (LEfSe) showed that Ascomycota (< .05) and genus Gliocephalotrichum (< .05) dominated in natural peat soil. Functionally, pathotrophs were more abundant in disturbed peat soil (< .05). Proteobacteria (43.8%) were the most abundant phylum followed by Acidobacteria (32.6%), Actinobacteria (9.8%), Planctomycetes (1.7%). Methylocystis, Telmatospirillum, Syntrophobacter, Sorangium and Opitutus were the more abundant genera in disturbed peat soil, whereas Nevskia and Schlesneria were more abundant in mineral soil and natural peat soil, respectively. The natural peat forest soil supported a more diverse microbiology; however, the land use of such a soil can change its microbial community structure. The results provide evidence that the disturbance of tropical peat land could lead to the introduction and spread of a large number of fungal diseases  相似文献   
3.
社会林业与五指山的自然保护   总被引:1,自引:0,他引:1  
周燕华  包焱 《热带林业》2001,29(2):73-80
五指山自然保护区是世界上现存地势最高的原始热带雨林之一,是我省目前面积最大的自然保护区,也是海南三大河流的发源地。但由于保护区横跨琼中、通什、保亭三县、市,紧邻保护区还生存着众多贫困的黎、苗族村民。因此,保护区与周边社区的联系是十分紧密的,社区的发展也直接影响到五指山热带天然林的保护。海南省林业局中德海南热带林保护和恢复项目在社会林业与五指山森林的保护上做出了有益的尝试,就在全省来说,也是首次对社会林业与森林保护上进行的探索。五指山地区社会林业的研究,对保护海南热带雨林也有着积极的意义。特对社会林业与五指山的森林保护进行了阐述、分析和设想。  相似文献   
4.
Abstract – The reproductive biology of three species of rainbowfish (Melanotaeniidae) in northeastern Australian rainforest streams was investigated. Two species, Melanotaenia eachamensis and Cairnsichthys rhombosomoides are endemic to the area, whereas the third, M. splendida splendida, is more widespread. The species were all highly fecund, producing many hundreds of eggs between 1.10 and 1.24 mm in diameter. Melanotaenia eachamensis was the most fecund, produced the largest eggs of the three species, and consequently exhibited the greatest maternal investment (as measured by gonadosomatic index). The majority of reproductive effort occurred during the dry season, although reproductively active fish were present year-round for each of the species, but particularly so for M. s. splendida and C. rhombosomoides. No evidence for a role by temperature or photoperiod as environmental cues for reproduction was found, and it was suggested that gonad development was strongly tied to somatic growth. The concentration of reproduction to the dry season ensures that larvae are produced during a period of relatively stable and benign physical conditions. Comparison of temporal changes in gonadosomatic index values suggest that the spawning season of M. eachamensis , which occurs in high-elevation streams, is more restricted and commences about 1 month earlier than either other species. A similar phenology was observed for the M. s. splendida population found at high elevation and highlights the potential for spatial differences in stream productivity to influence life history. Note  相似文献   
5.
发展红色旅游对于加强革命传统教育、保护和利用革命历史文化遗产以及带动皖北地区经济社会协调发展均具有重要的现实意义和深远的历史意义.本文以红色旅游为主题,从自然、历史和文化的角度分析了皖北红色旅游资源的现状,提出应以“四大概念”,即“大产业、大区域、大生态、大精品”作为发展皖北红色旅游的基本思路。  相似文献   
6.
为了寻求合理的节水省时畦宽,以更好地利用现有水源,在1990、1991年试验和实践的基础上,用统计回归分析方法对大城县农田畦田规格进行了分析,求出了合理畦宽,并从灌水持续时间、用电量、提水量等方面对合理畦宽的节水、节能效果进行了分析。  相似文献   
7.
北疆棉花不同品种叶绿素荧光特性的研究   总被引:8,自引:3,他引:5  
测定了北疆6个不同棉花品种田间叶片的净光合作用、荧光参数的变化。结果表明:晴天棉花叶片的光化学效率(Fv/Fm)随着光强上升而下降,到14∶00左右降到最低值,之后又随光强的减弱逐渐回升;非光化学猝灭系数(qN)则与此相反。棉叶在晴天易发生光抑制,可能会引发反应中心的降解等破坏反应。产量较高的新陆早8号和新陆早10号的Fv/Fm、光化学猝灭系数(qP)均高,且正午过后Fv/Fm恢复较快,不仅能较强地吸收光能,同时还具有较高的PSII的活性和光能转化效率,从而将所吸收的光能有效地转化为化学能,提高光合电子传递速度,形成更多的ATP和ENADPH,为光合碳同化提供充分的能量和还原能力。  相似文献   
8.
9.
我国热带牧草种质资源的收集、保存与利用现状   总被引:7,自引:5,他引:7  
介绍了牧草种质资源的作用及我国热带牧草种质资源的收集、保存与利用的现状,提出了加强我国热带牧草种质资源工作的几点建议.  相似文献   
10.
Phosphorus (P) cycles rapidly in lowland tropical forest soils, but the process have been proven difficult to quantify. Recently it was demonstrated that valuable data on soil P transformations can be derived from the natural abundance of stable oxygen isotopes in phosphate (δ18OP). Here, we measured the δ18OP of soils that had received long-term nutrient additions (P, nitrogen, and potassium) or litter manipulations in lowland tropical forest in Panama and performed controlled incubations of fresh soils amended with a single pulse of P. To detect whether δ18OP values measured in the incubations apply also for soils in the field, we examined the δ18OP values after rewetting dry soils. In the incubations, resin-P δ18OP values converged to ∼3.5‰ above the expected isotopic equilibrium with soil water. This contrasts with extra-tropical soils in which the δ18OP of resin-P matches the expected equilibrium with soil water. Identical above-equilibrium resin-P δ18OP values were also found in field soils that did not receive P additions or extra litter. We suggest that the 3.5‰ above-equilibrium δ18OP values reflect a steady state between microbial uptake of phosphate (which enriches the remaining phosphate with the heavier isotopologues) and the release of isotopically equilibrated cell internal phosphate back to the soil. We also found that soil nutrient status affected the microbial turnover rate because in soils that had received chronic P addition, the original δ18OP signature of the fertilizer was preserved for at least eight weeks, indicating that the off-equilibrium δ18OP values produced during microbial phosphate turnover was not imprinted in these soils. Overall, our results demonstrate that ongoing microbial turnover of phosphate mediates its biological availability in lowland tropical soils.  相似文献   
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