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41.
太子山马尾松种子园营建技术研究   总被引:5,自引:1,他引:5  
本文从建园材料选择和收集、嫁接技术、建植方式及定植密度、种子园营建和激素对促进球花形成的研究等方面总结了太子山马尾松种子园建设的技术及经验。太子山种子园的建成不但加速了我省马尾松良种化的进程 ,而且为今后我省马尾松种子园营建和育种提供了理论依据和材料。  相似文献   
42.
在分析宁波建设生态屏障必要性和有利条件的基础上,提出今后一段时期宁波生态屏障建设的目标、重点及应采取的对策。  相似文献   
43.
In the Yucatan peninsula of Mexico, Maya natives have been propagating important species for centuries. However, little documentation exists of these methods, and traditional knowledge is fading as younger generations seek work in urban centers. With growing interest in using some of these species for plantation-scale production, this knowledge should be captured to aid in propagation and cultural methods of selected species. One such species, Ramón (Brosimum alicastrum Sw.), is grown in Mayan homegardens primarily as a source of dry season forage. We conducted a survey of Mayan families in several municipalities to determine basic propagation habits and procedures for cultivating Ramón, and used this information to conduct some controlled-environment studies of reproductive ecology of the species. Our survey showed that all or most Maya grow the Ramón tree in homegardens for forage and that the tree is both cultivated from wild seedlings as well as planted on a small scale. Propagation is by seed and young seedlings are irrigated until they are established. We examined the effects of temperature on seed germination and found that maximum germination occurred between 27° and 38 °C, with best germination and growth of healthy seedlings at 33 °C. No germination occurred below 21° or above 44 °C. Simulated Maya irrigation gave a four-fold increase in growth rate of seedlings, aiding early establishment. Watering gave seedlings of greater biomass, greater stem and root length, and greater numbers and size of leaves. This magnitude of response may provide an economic return for plantation culture of Ramón for forage production.  相似文献   
44.
Tree and windbreak species considered for the Southern Sahelian Zone (SSZ) of West Africa have to be evaluated following multiple criteria such as fast establishment, shelter efficiency, production of feed for livestock, and firewood. An on-station experiment was conducted on a sandy soil in southwest Niger between 1988 and 1993 to assess the establishment, growth, nutritive, and calorific values of seven species considered for windbreaks:Andropogon gayanus, Bauhinia rufescens, Acacia holosericea, Acacia nilotica, Acacia senegal, Faidherbia albida, andAzadirachta indica. Mortality and stem diameter were monitored twice a year. From 20 months after planting (MAP) onwards, species were annually trimmed to 2 m height and to 1 m sidewards of the main stem. Fresh and dry weight of leaves, twigs, wood, and fruits were recorded. Leaves were analyzed for crude protein (CP) and metabolizable energy (ME) content. Wood was analyzed for its gross calorific value and its ash content. At 56 MAP, all species had less than 5% morality, except forA. holosericea, which had a mortality rate of 15.9%.A. indica andA. holosericea showed the highest stem diameter among species with 12.2 and 11.8 cm, respectively, at 56 MAP.A. senegal had the highest dry matter production with 22.3 t ha–1 at 56 MAP, followed byA. indica (12.0 t ha–1),A. holosericea (11.7 t ha–1) andB. rufescens (11.2 t ha–1), butA. holosericea was most productive at earlier harvests. OnlyA. senegal (6.4 t ha–1) andA. indica (5.1 t ha–1) had a significant wood production, whereasA. holosericea (5.7 t ha–1) had the highest phyllodes production. Leaves ofA. senegal andA. indica had highest CP contents of 258 and 214 g kg–1, respectively. The leaves of all species exceptA. gayanus had a higher CP:ME ratio than natural pasture in the region. The calorific values of firewood did not differ significantly among the species.A. nilotica, the species with one of the lowest firewood production, had the highest Fuelwood Value Index of 6.6. The choice of species for planting trees and windbreaks in the SSZ must be oriented along these criteria. Further research should be directed towards cost-benefit analyses, land tenure and property rights in combination with surveys on local knowledge of rural people.  相似文献   
45.
台州市沿海围涂果园防护林效益调查研究   总被引:1,自引:0,他引:1  
沿海围涂果园,采用“窄带小网型”防护林营建技术,能降低风速36.8%-70.%,减少落果38.2%-60.5%,提高空气湿度1%-3%,减少蒸发量13.7%〉改善果园生态环境,促进果树生长,从而提高产量,该技术宜于南方滨海果园推广。  相似文献   
46.
马尾松速生丰产林营建技术的研究   总被引:2,自引:0,他引:2  
根据立地、遗传、密度3大因素控制的原则,营建马尾松速生丰产林,着重采取了选用良好的造林地、优良种源、合理整地、适当密植与培育容器苗造林5项主要技术措施,并在造林后3~4年内进行及时合理的幼林抚育。从幼龄林生长量测试结果表明:与国家速生丰产林专业标准相比较,1~5年生高生长量超标达31.8%~60.0%4~5年生胸径生长量超标达21.1%~24.0%,5年生材积生长量超标达368.0%,达到了预期的速丰林幼林期的培养目标。  相似文献   
47.
Green roofs provide a number of valuable ecosystem services compared to conventional roofs, but may require yearly maintenance. Trees and other woody plants that persist on the roof may damage or overload shallow-substrate green roofs and their removal is a standard maintenance procedure. The germination potential of colonizing species may differ depending on the vegetation surrounding them. The aim of this study was to determine whether the germination of colonizing tree species (Picea glauca and Ulmus glabra) will vary depending on which plant species form the established vegetation seeds land in. To determine germination success, survival, and seed capture ability of the plant canopy, tree seeds were added either directly to the growing medium or atop the plant canopy, in replicated monocultures of 14 species native to Nova Scotia. When seeds were added directly to the soil, no significant difference was detected between the monocultures for germination success or survival for U. glabra or P. glauca. However, when the seeds were added atop the plant canopy, percent germination of U. glabra was significantly higher in Carex argyrantha green roof modules. Overall, sod forming graminoids showed higher germination of U. glabra. The number of seeds reaching the soil was typically lower in vegetation with a denser canopy. This study demonstrates that some vegetation repels colonizing tree species by reducing ground contact. Although these effects differed according to tree species, non-vegetated substrates enhanced seedling persistence. Additionally, the majority of tree seeds that germinated failed to survive a single growing-season on shallow-substrate green roofs.  相似文献   
48.
In recent years, conventional rice production technologies have been leading to deterioration of soil health and declining farm profitability due to high inputs of water and labor. Conservation agriculture(CA) based resource-conserving technologies i.e. zero-tillage(ZT), raised-bed planting and direct-seeded rice(DSR) have shown promise as alternatives to conventional production technologies to overcome these problems. Present study was undertaken during 2009–2012 to establish an understanding of how permanent raised bed cropping system could be practiced to save water at the field application level to improve water productivity and also have the capability to enhance productivity, profitability and soil physical quality. The results showed that among different crop establishment techniques, conventional-tilled puddle transplanted rice(CT-TPR) required 14%-25% more water than other techniques. Compared with the CT-TPR system, zero till direct-seeded rice(ZT-DSR) consumed 6%–10% less water with almost equal system productivity and demonstrated higher water productivity. Wide raised beds saved about 15%–24% water and grain yield decrease of about 8%. Direct-seeded rice after ZT or reduced tillage or on unpuddled soil provided more net income than CT-TPR. The CTTPR system had higher bulk density and penetration resistance due to compaction caused by the repeated wet tillage in rice. The steady-state infiltration rate and soil aggregation( 0.25 mm) were higher under permanent beds and ZT and lower in the CT-TPR system. Under CT-TPR, soil aggregation was static across seasons, whereas it improved under no-till and permanent beds. Similarly, mean weight diameter of aggregates was higher under ZT and permanent beds and increased over time. The study reveals that to sustain the rice productivity, CA-based planting techniques can be more viable options. However, the long-term effects of these alternative technologies need to be studied under varying agro-ecologies in western Uttar Pradesh, India.  相似文献   
49.
试验通过施肥处地对公路护被土壤进行改良和植被建植,观察其植被密度、盖度、株高、生物景的变化,探讨快速形成边坡植被方法的理论依据,结果表明,大风坝地区紫色岩石土壤的最佳改良肥料配方为:24g/m2有机肥十90g/m2N、P、K复合肥十20g/m2钙磷肥作基肥施用。  相似文献   
50.
阐述了农业科研立题,成果鉴定的情报查新的必然性及重要意义,并对查新工作提出了几点建议。  相似文献   
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