Influence of a grass layer on vineyard soil temperature

Vineyard grass cover can modify soil variables such as temperature and water content, which in turn influence berry quality at harvest. Such effects require further documentation and this study was conducted to determine how a grass layer could change soil thermal behaviour compared to bare soil. Soil temperature, soil water content and net radiation were measured in a Médoc vineyard, Château Talbot (France). The field used for the experiment was divided into two parts, one with a bare ploughed soil and the other with a partial grass cover. The same measurements were taken on both parts. Bare soil temperatures were generally higher, and the difference between the two treatments was greater in the middle of the inter-row, just under the grass layer. Nevertheless, net radiation above the vegetation, which represents the radiative available energy, was the same for the two plots. Soil conduction heat flux (G) was calculated from temperature measurements. Under the grass layer, the horizontal component of G was barely detectable, whereas under bare soil, G was essentially vertical. The grass layer was therefore acting as an insulating layer, preventing exchanges between soil and atmosphere. Soil temperature and thermal behaviour are heavily influenced by soil surface management practices. The field experiment provided a large data set of measurements which will be used to calibrate a heat and mass transfer model.     

堤防工程的植被防护措施

通过试验工程，阐述了在江河堤防工程中，除采用传统工程防护措施外，还可结合植被防护措施，诸如营造固滩防浪林，采取三维网垫植草护坡及水力喷播等植被防护措施，既能提高堤坝的行洪安全性，又能改善生态环境。     

黑麦小孢子母细胞核基质的超显微结构观察

把黑麦的幼穗剪下插入含5％二甲基亚砜(DMSO)的Banner's盐溶液中。室温下培养24小时后,解剖出花药,按常规的超薄切片法制片。透射电子显微镜下观察发现小孢子母细胞核内出现类似微丝的微纤丝结构。这种结构粗约6-7nm,集合成微纤丝束,特异性地出现在凝线期的小孢子母细胞核中。在凝线期,染色质向核的一极集中,靠近核膜的区域由于染色质的转移变为透明区。微纤丝束通常分布在这种透明区。微纤丝束位于染色质附近,并与细胞核的长轴和染色质向极端运动的方向平行。在未经DMSO处理的小孢子母细胞中偶尔也可看到这种结构。文章讨论了黑麦小孢子母细胞核中微纤丝结构的生化本质和可能的作用。     

基于ASP技术的动态网站组件的研发及应用

作为一种典型的服务器端网页制作技术,利用ASP(Active Server Pages)可以创建动态交互的Web服务器应用程序。根据油田生产、科研和日常办公的应用需求,以面向对象的思想和ASP技术开发出3类25种动态网站组件。应用结果表明,基于ASP技术的网站组件有利于快速、高效地开发动态网站,增强网站的实用性,降低网站的管理和维护成本。     

草地资源利用浅谈

草资源对防治土壤流失、水和空气的污染 ,对保护环境有重要作用。随着经济发展和科技进步 ,这种资源在某种程度上遭到破坏 ,应采取相应的措施加以保护 ,如实施正确的激励政策 ;转变农地结构和耕作方式、转变工程方式等。     

海州露天矿排土场植被重建技术研究

由于农业用地对环境要求相对较高,且需要大量的人力、物力进行管理,多数矿山企业在土地复垦时一般不将种植作物作为其土地用途,而是以管理工作及费用相对较少的林、草种植为主.林草种植在矿山复垦种植中占有相当重要的地位,着重探讨海州露天矿排土场牧草种植的技术途径.     

Hydrothermal Transformation of Dried Grass into Graphitic Carbon‐Based High Performance Electrocatalyst for Oxygen Reduction Reaction

In this work, we present a low cost and environmentally benign hydrothermal method using dried grass as the sole starting material without any synthetic chemicals to directly produce high quality nitrogen‐doped carbon nanodot/nanosheet aggregates (N‐CNAs), achieving a high yield of 25.2%. The fabricated N‐CNAs possess an N/C atomic ratio of 3.41%, consist of three typed of doped N at a ratio of 2.6 (pyridinic):1.7 (pyrrolic):1 (graphitic). The experimental results reveal that for oxygen reduction reaction (ORR), the performance of N‐CNAs, in terms of electrocatalytic activity, stability and resistance to crossover effects, is better or comparable to the commercial Pt/C electrocatalyst. The theoretical studies further indicate that the doped pyridinic‐N plays a key role for N‐CNAs' excellent four‐electron ORR electrocatalytic activity.     

Light interception, use-efficiency and energy yield of switchgrass (Panicum virgatum L.) grown in a short season area

Switchgrass (Panicum virgatum L.) has been identified as a potential biomass crop in North America. A two-year study was conducted to characterize leaf area development and estimate radiation-use efficiency (RUE) of switchgrass in eastern Canada. Three cultivars, Cave-in-Rock (CIR), Pathfinder (PF) and Sunburst (SB) were grown in solid stands in a randomized complete block design. Dry matter (DM) yield, leaf area development and light interception were monitored bi-weekly throughout the growing season. Herbage subsamples were hand separated into leaf and sheath-stem fractions. Mean seasonal maximum leaf area indices (LAI) were 6.1, 5.3 and 5.1 for CIR, PF and SB, respectively. By early July of each season the canopies were intercepting about 90% of the incoming light. End of season DM yields were 12.2, 11.5 and 10.6 Mg ha⁻¹ for CIR, PF and SB, respectively. The stem plus leaf sheaths constituted the major component of DM and its accumulation trend parallelled that of total DM. End of season stem-sheath components averaged 764, 714 and 691 of the total g kg⁻¹ DM for CIR, PF and SB, respectively. Energy contents of the switchgrasses averaged 17.4 MJ g⁻¹ DM and did not vary among cultivars or during the season. This translated into total energy yields ha⁻¹ of 216 GJ for CIR, 197 for PF and 186 for SB. Radiation-use efficiencies computed using total incoming solar radiation, for the near linear growth phases, averaged 1.07 g DM MJ⁻¹ for CIR, 0.90 for PF and 0.89 for SB. The respective values based on photosynthetically active radiation were 2.20, 2.00 and 1.96 g DM MJ⁻¹. Changes in LAI, relationships between LAI and light interception and DM yield could all be described by predictive regression equations. These results indicate the potential of switchgrass as a biomass crop in short season areas.     

推广"牛-沼-草"生态农业是实现农民增收的有效途径

本文简要介绍了“牛－沼－草”生态农业的内容、主要做法和推广措施,并通过实践证明推广“牛－沼－草”生态模式是实现农民增收的有效途径。     

Reed canary grass yield and fuel quality in Estonian farmers’ fields

Reed canary grass (Phalaris arundinacea) is one of the possible raw materials for bioenergy production in northern Europe. Its cultivation is favoured because its high productivity and local origin. However, problems with the biomass quality for combustion have been reported. Usually delayed harvest in spring is suggested to improve the quality and decrease the moisture content of biomass. On the other hand, the feasibility of spring harvest depends on local climatic conditions and may cause yield losses. In current paper we studied reed canary grass fields in Estonia locating on different soil types and cultivated with various varieties. The influence of several fertilisation schemes on biomass yield was analysed. Our results indicated that production was higher on mineral soils than on the organic soil of abandoned peat extraction sites. Even different types of fertilisation did not increase the production on organic soils to the level comparable to those on mineral soils. Among studied varieties ‘Venture’ had the highest production. The highest yield per area was obtained late in the autumn (12.7 t d.w. per ha and 7.2 t d.w. per ha on mineral and organic soils, respectively). By spring the amount of biomass had decreased in all studied sites. Due to wet soil some of the fields remained unharvested, the others had high yield losses during practical harvesting. The chemical analyses did not reveal significant differences in the composition of biomass between late autumn and spring. Therefore we conclude that late autumn harvest should be preferred in local climatic conditions.