信阳市园林树种资源调查及评价

对河南省信阳市园林树种现状进行调查,得知该市常见园林树种共208种(含变种),初步分析了园林树种的应用现状,为信阳市园林树种的合理使用提供理论依据。     

树型金银花与蔬菜套种栽培模式的研究

[目的]研究树型金银花中银一号与不同蔬菜套种的立体栽培模式。[方法]树型金银花中银一号与萝卜、辣椒和甘蓝进行金银花+萝卜+甘蓝、金银花+辣椒+甘蓝2种不同模式套种,每种套种作物设计1.0、1.4、1.8和2.2 m4种种植幅宽,分为4个区组,每区组2个小区。[结果]套种萝卜以幅宽2.2 m效果最好,产值159 940.48元/hm2,收益为97 901.79元/hm2。金银花+萝卜+甘蓝种植模式,产值和收益随幅宽的增加而增加,幅宽2.2和1.8 m的最终效益分别为106 845.24和105 595.24元/hm2。金银花的产量随套种辣椒的幅宽增加而减小。套种幅宽1.0、1.4、1.8和2.2 m的分别减产863.39、1 077.53、1 102.23和1 273.66 kg/hm2,减幅达7.3%、9.1%、9.3%和10.8%。[结论]江汉平原种植金银花中银一号套种萝卜比辣椒更适宜。金银花+萝卜+甘蓝种植模式以在金银花行间套种1.8 m幅宽萝卜为宜,金银花与萝卜之间的间距以50～80 cm为宜,其效益可达105 595.24元/hm2。     

金银花的药用价值与产业化发展——以湖南隆回县为例

本文介绍了金银花的成分、疾病治疗和健康保健等药用价值;分析了隆回县发展金银花产业的优越自然生态环境条件;阐述了隆回县采取政府支持,进行农村土地互换,农村土地入股发展金银花产业的成功经验,在整合公司、农户、政府各主体的优势资源、实现现代农业的规模经营等方面做出了重要探索。提出以龙头企业控股的股份有限公司和农民合作社为核心的一体化经营,构建生产、加工、仓储、销售于一体的产业链,进行农村土地产权制度的改革等促进农村产业化发展的对策。     

覆盖对山地甜柿园土壤性状及树体生长结果的影响

研究了秸秆覆盖和薄膜覆盖对山地甜柿园土壤水热变化规律、土壤理化性状和树体生长结果的影响。3年定位试验结果表明,覆盖提高了果园各层土壤含水量和土壤养分的有效性,改善了果园土壤的结构和性状、增加了植株根系数量,对叶片数量、质量、叶片大小以及枝条抽生数量、质量和树冠大小、叶面积系数等指标均有良好的优化作用。秸秆覆盖有降低生长季节土温和提高冬季土温的作用,薄膜覆盖有增加土温的作用。     

Methane emissions from stems of Fraxinus mandshurica var. japonica trees in a floodplain forest

We measured methane (CH₄) emissions from the stem surfaces of mature Fraxinus mandshurica var. japonica trees in a floodplain forest. Flux measurements were conducted almost monthly from May to October 2005, and positive CH₄ fluxes were detected throughout the study period, including the leafless season. The mean CH₄ flux was 176 and 97 μg CH₄ m⁻² h⁻¹ at the lower (15 cm above the ground) and upper (70 cm above the ground) stem positions, respectively. The CH₄ concentration was lower in soil gas than in ambient air to a depth of at least 40 cm. One possible source of CH₄ emitted from the stems might be the dissolved CH₄ in groundwater; maximum concentrations were 10,000 times higher than atmospheric CH₄ concentrations. Our results suggest that CH₄ transport from the submerged soil layer to the atmosphere may occur through internal air spaces in tree bodies.     

Methane fluxes from three ecosystems in tropical peatland of Sarawak, Malaysia

Methane fluxes were measured monthly over a year from tropical peatland of Sarawak, Malaysia using a closed-chamber technique. The CH₄ fluxes in forest ecosystem ranged from −4.53 to 8.40 μg C m⁻² h⁻¹, in the oil palm ecosystem from −32.78 to 4.17 μg C m⁻² h⁻¹ and in the sago ecosystem from −7.44 to 102.06 μg C m⁻² h⁻¹. A regression tree approach showed that CH₄ fluxes in each ecosystem were related to different underlying environmental factors. They were relative humidity for forest and water table for both sago and oil palm ecosystems. On an annual basis, both forest and sago were CH₄ source with an emission of 18.34 mg C m⁻² yr⁻¹ for forest and 180 mg C m⁻² yr⁻¹ for sago. Only oil palm ecosystem was a CH₄ sink with an uptake rate of −15.14 mg C m⁻² yr⁻¹. These results suggest that different dominant underlying environmental factors among the studied ecosystems affected the exchange of CH₄ between tropical peatland and the atmosphere.     

The effect of forest clearcutting in Norway on the community of saproxylic beetles on aspen

In a study of the effect of forest clear-cutting on the saproxylic beetle fauna in aspen in Norwegian boreonemoral forest, we find that both sun exposure and substrate are important structuring factors for the community of saproxylic beetles. Even though the species number and abundance is rather similar across the gradient of sun exposure, there is a major turnover in species composition in decaying aspen from mature forest to clear-cuttings. Our results confirm that aspen is an important element for beetle biodiversity both because of a generally species-rich community and a high number of rare and threatened (red-listed) beetles. There is a higher probability of presence of red-listed beetle species in snags than in logs. Sun exposure increases the probability of presence of red-listed species, but this was largely an effect of one dominating species. We conclude that retention of trees when clear-cutting is an important means for safeguarding the fauna of saproxylic beetles in aspen.     

Fluxes of CO2, CH4 and N2O from drained organic soils in deciduous forests

We examined net greenhouse gas exchange at the soil surface in deciduous forests on soils with high organic contents. Fluxes of CO₂, CH₄ and N₂O were measured using dark static chambers for two consecutive years in three different forest types; (i) a drained and medium productivity site dominated by birch, (ii) a drained and highly productive site dominated by alder and (iii) an undrained and highly productive site dominated by alder. Although the drained sites had shallow mean groundwater tables (15 and 18 cm, respectively) their average annual rates of forest floor CO₂ release were almost twice as high compared to the undrained site (1.9±0.4 and 1.7±0.3, compared to 1.0±0.2 kg CO₂ m⁻² yr⁻¹). The average annual CH₄ emission was almost 10 times larger at the undrained site (7.6±3.1 compared to 0.9±0.5 g CH₄ m⁻² yr⁻¹ for the two drained sites). The average annual N₂O emissions at the undrained site (0.1±0.05 g N₂O m⁻² yr⁻¹) were lower than at the drained sites, and the emissions were almost five times higher at the drained alder site than at the drained birch site (0.9±0.35 compared to 0.2±0.11 g N₂O m⁻² yr⁻¹). The temporal variation in forest floor CO₂ release could be explained to a large extent by differences in groundwater table and air temperature, but little of the variation in the CH₄ and N₂O fluxes could be explained by these variables. The measured soil variables were only significant to explain for the within-site spatial variation in CH₄ and N₂O fluxes at the undrained swamp, and dark forest floor CO₂ release was not explained by these variables at any site. The between-site spatial variation was attributed to variations in drainage, groundwater level position, productivity and tree species for all three gases. The results indicate that N₂O emissions are of greater importance for the net greenhouse gas exchange at deciduous drained forest sites than at coniferous drained forest sites.     

低丘红壤花生南酸枣间作系统研究 IV.光能竞争与剪枝作用

农林间作导致间作花生区域光合有效辐射和花生产量的下降,而且花生产量与光合有效辐射呈极显著正相关,表明了光能竞争是导致农林间作花生产量下降的主要原因。2001年6月初剪枝后,5龄和9龄南酸枣间作系统花生相对光合有效辐射分别从5月份的79.2%和63.4%增加到88.7%和67.5%; 但随着南酸枣生长,5龄和9龄南酸枣间作系统中7月份的花生相对光合有效辐射又下降到80.8%和65.7%。2001年剪枝以后,5龄南酸枣和9龄南酸枣间作系统花生相对产量分别由2000年的64.1%和55.4%提高到68.2%和58.1%。这表明剪枝在短期内能在一定程度上减轻光能竞争,但仍然不能满足花生生长需要。