Highest Annual Yield Research Articles

Sediment yield during typhoon events in relation to landslides, rainfall, and catchment areas in Taiwan

Debris sourced from landslides will result in environmental problems such as increased sediment discharge in rivers. This study analyzed the sediment discharge of 17 main rivers in Taiwan during 14 typhoon events, selected from the catchment area and river length, that caused landslides according to government reports. The measured suspended sediment and water discharge, collected from hydrometric stations of the Water Resources Agency of Taiwan, were used to establish rating-curve relationships, a power-law relation between them. Then sediment discharge during typhoon events was estimated using the rating-curve method and the measured data of daily water discharge. Positive correlations between sediment discharge and rainfall conditions for each river indicate that sediment discharge increases when a greater amount of rainfall or a higher intensity of rainfall falls during a typhoon event. In addition, the amount of sediment discharge during a typhoon event is mainly controlled by the total amount of rainfall, not by peak rainfall. Differences in correlation equations among the rivers suggest that catchments with larger areas produce more sediment. Catchments with relatively low sediment discharge show more distinct increases in sediment discharge in response to increases in rainfall, owing to the little opportunity for deposition in small catchments with high connectivity to rivers and the transportation of the majority of landslide debris to rivers during typhoon events. Also, differences in geomorphic and geologic conditions among catchments around Taiwan lead to a variety of suspended sediment dynamics and the sediment budget. Positive correlation between average sediment discharge and average area of landslides during typhoon events indicates that when larger landslides are caused by heavier rainfall during a typhoon event, more loose materials from the most recent landslide debris are flushed into rivers, resulting in higher sediment discharge. The high proportion of large landslides in Taiwan contributes significantly to the high annual sediment yield, which is among the world's highest despite the small area of Taiwan.

Bagasse composites

This study provides a bibliographic review for future reference in the broad field of bagasse composites by looking for factors that influence their attributes. As an abundant agriculture resource, sugarcane bagasse has attracted extensive research interests because of its high annual yields, low costs, and environmental-friendly characters. During these research, various parameters have been tested to identify their effects; however, these studies are carried out dispersedly. This review provides a summary of these factors, their impacts, and mechanisms. Three factors are used to explain the attributes of bagasse composites followed by the factors involved in preparation, modification, and additives and also their influences. Then the best mechanical properties of different bagasse composites and their achieving condition are summarized. Durability is also reviewed. Additionally, competitive application of bagasse composites is defined by comparing their attributes with other natural fiber composites.

Landfill Leachate Effects on Germination and Seedling Growth of Hemp Cultivars (Cannabis Sativa L.)

Landfill leachate is one of the major sources of pollutions discharged into the environment. It is composed from a complex mixture of chemicals and handling typically involves treatment either on-site or at a wastewater treatment plants but phytoremediation is a promising method. The aim of this work was to evaluate the potential of agronomic plant species with high annual biomass yield (Cannabis sativa L.) for toxicity removal from landfill leachate. Raw leachate collected from the pond of untreated leachate at sanitary landfill in Czech Republic was used in the study. The hemp cultivation experiments were performed in the beginning of 2017 under laboratory conditions using three hemp cultivars registered in the European Union: Tiborszallasi (Hungary), Bialobrzeska (Poland) and Monoica (Hungary). The seeds were used for modified standard mustard germination test. The germination of hemp cultivars was tested using the hydroponics medium supplemented with leachate 25, 50, 75, 90 and 100%. The control seeds were growing on untreated nutrient medium under the same condition. The nature of germination of seeds was studied. Based on the obtained results, it can be concluded that the tested samples of leachate were toxic for hemp cultivars (C. sativa L.). Growth inhibition (%) at the studied samples ranged from −6.48 to 75.78%.

A new bioenergy crop based on oil-rich seeds from the legume tree <em>Pongamia pinnata</em>

A new bioenergy crop based on oil-rich seeds from the legume tree Pongamia pinnata Peter M Gresshoff,1 Latha Rangan,2 Arief Indrasumunar,1 Paul T Scott11Centre for Integrative Legume Research, School of Agriculture and Food Sciences, The University of Queensland, St Lucia, Brisbane, QLD, Australia; 2Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Assam, India Abstract: Any informed discussion on the future sources of energy in our world requires the consideration of renewable biofuels. These are produced by biological processes, such as plant growth based on photosynthesis and microbes using waste products from diverse origins. Many biofuels, such as ethanol produced from plants like sugarcane, are seen as sustainable, such paradigms should be critically analyzed in terms of total inputs. The legume tree Pongamia pinnata (also called Millettia pinnata) offers a substantiated opportunity for a sustainable biofuel feedstock. It is characterized by fast plant growth, broad tropical and subtropical growth habitat, and high annual yields of oil-rich seed. Annual yield of the seed-extracted oil, rich in the monounsaturated fatty acid oleic acid (C18:1), is between 1,000 and 5,000 L/ha, depending on local conditions, including rainfall, temperature, and soil. It can be burnt in bioenergy generators to yield electrical output. It can also be converted to biodiesel by transesterification for transportation and industrial use. Conversion to aviation jet fuel by hydrogenation and subsequent purification is also possible. The legume nature of the plant allows it to harbor nitrogen-fixing soil bacteria (broadly called “rhizobia”) in newly induced root organs called nodules. This symbiosis makes the energy inputs considerably less than those seen with nitrate fertilizer – requiring biofuel feedstocks, such as corn, sugarcane, and canola. Combined with general characteristics of plant, such as abundant seed set and large oil-rich seed, secondary products, such as seed meal and vigorous growth characteristics, make this tree an excellent candidate for sustainable bioenergy production in many parts of the globe. Keywords: biofuel, biotechnology, legume, plant growth, renewables, sustainability

The effectiveness and efficiency of phytoremediation of a multicontaminated industrial site: Porto Marghera (Venice Lagoon, Italy)

The Venice Lagoon is worldwide considered as a typical example of the human impact on the surrounding ecosystem. The development of the industrial zone of Porto Marghera begun in 1917 as an extension of the Venice Port, in order to sustain activities related to oil and coal, as well as to exploit the railway system. Despite the recent decrease in the number of employees, Porto Marghera is still one of the most important chemical districts in Italy. This study reports early results from the ongoing in-situ phytoextraction of potentially toxic elements (Cd, Hg, Zn) within the industrial area of Porto Marghera. Two agronomic plant species with high annual biomass yield (Helianthus annuus L., Brassica juncea (L.) Czern.) were used. This paper also reports the microcosms and mesocosms tests to evaluate the efficacy of the treatments to be applied to the in-situ phytoextraction process of the polluted site. The combined use of EDTA and Ammonium Thiosulfate during phytoextraction increases the efficiency of Cd, Hg, Zn removal from contaminated soil.

Temporal Dynamics of Standardized Precipitation Evapotranspiration Index and Its Influence to Summer Maize Yield from Kaifeng Region in He’nan Province

Many quantitative studies get more and more attention on drought occurrence and monitoring trends of drought change using different methods; however few studies involve correlation between drought and crop yield especially drought index. This study analyzed the climate change about annual mean SPEI-3, SPEI-6 and SPEI-12, of Kaifeng region in the period of 1961-2013. The SPEI-3 and SPEI-6 seasonal short timescales showed a decreasing tendency, especially rapidly a decline since 2004, and high-frequency alternate dry/wet periods occurred during 1961-2013. However, the annual timescale SPEI-12 showed almost no evidently rise/decline tendency but severity events of dry/wet episode aggravated in terms of duration and magnitude and remarkable low-frequency change. Correlation analysis results between maize yield from Kaifeng region and multi-month scale annual SPEI showed a high negative significant correlation with -0.689 (ρ < 0.001) in SPEI-3 and only a negative significant correlation (-0.663, ρ < 0.001) in June SPEI-3. Further analysis between maize yield and temperature, precipitation and light during June-September found that precipitation in June and August was the main limiting factor to maize yield and their correlation values were well below the correlation of SPEI-3 of June. Finally, the reconstruction equation found that there was a better change consistency between the maize yield reconstruction and actual production but more error in extremely high and low annual yield. This study provides a reliable analysis of climate change to corn yield and basic data support for services of grain production and food security in the future.

Performance of legume–grass mixtures in the West Balkan region

ABSTRACTThree perennial legumes (alfalfa, red clover and birdsfoot trefoil) and four cool-season perennial grasses (orchardgrass, tall fescue, Italian ryegrass and red fescue) were grown in legume–grass combinations and in pure stands of individual species, at three locations in the West Balkan region (Novi Sad, Banja Luka and Pristina) in the period from 2012 to 2015. The study evaluated dry matter yield, legume–grass–weed proportion and forage quality. High annual forage yield of legume–grass mixtures can be obtained with proper selection of species and an appropriate legume–grass ratio. However, high and stable yield, particularly in the case of grasses, depends on the amount and schedule of precipitation as well as the cutting time. The mixtures and legume pure stands achieved better forage production both per cutting and on the annual basis and had better forage quality than grass pure stands.

Pressure influence on pyrolysis product properties of raw and torrefied Miscanthus: Role of particle structure

Compared to coal, few studies were performed on biomass pyrolysis at elevated pressures, high heating rates, and moderate temperatures, the conditions usually prevailing in commercial fluidized bed gasifiers. In this work, Miscanthus is selected as one of the most promising biomass energy crops which is characterized by high annual yield and energy ratio. The effect of pressure on the product yields, gas composition, and char structure for pyrolysis of pulverized raw and torrefied Miscanthus was investigated in a drop tube reactor. Torrefaction was carried out at 250°C for 30min, while pyrolysis of raw and torrefied Miscanthus was performed at 800°C in a pressure range of 1–30bar. The gases were analyzed using a micro-GC, while the chars were characterized using proximate and ultimate analysis, porosity and BET surface area measurements, and Scanning Electron Microscopy (SEM). It was found that the pyrolysis pressure significantly affects the yields and properties of products, and that torrefaction significantly changes properties and pyrolysis behavior of Miscanthus. The torrefied Miscanthus was found to have higher char yields and char porosities at all the investigated pressures, while the raw Miscanthus was found to have higher gas yields, and higher liquid yields at high pressures. The char yield of both raw and torrefied Miscanthus increases till 10bar and did not show any further changes at higher pyrolysis pressures. The yield of CO2 increased with pyrolysis pressure for both raw and torrefied Miscanthus, while the yield of the high molecular weight gases like C2H4 and C2H6 decrease with increasing pyrolysis pressure and totally disappear at 30bar. Hydrogen represented the major difference in the gas yield trend for raw and torrefied Miscanthus. A non-monotonous trend with pressure was observed for the liquid product yield of raw Miscanthus, while a decreasing trend with asymptote-like nature took place for torrefied Miscanthus. The different pyrolysis behavior of raw and torrefied Miscanthus evidenced in the liquid product yield trend, char porosity and SEM images might be attributed to the force balance on the particles’ structure which led to extensive fragmentation occurrence in the 10–15bar range for raw Miscanthus chars, and its absence in the whole pressure range for torrefied Miscanthus chars, a hypothesis that is to be confirmed in future research work. The results obtained in this study are important inputs for modeling industrial fluidized bed gasifiers working on Miscanthus.

Three decades of monitoring in the Rio Cordon instrumented basin: Sediment budget and temporal trend of sediment yield

This paper investigates nearly 30years of monitoring of sediment fluxes in an instrumented Alpine basin (Rio Cordon, Italy). The collected bedload and suspended sediment transport data allows sediment dynamics to be analyzed at different time scales, ranging from short- (single event) to long-term (three decades). The Rio Cordon monitoring station has been operating since 1986, continuously recording water discharge, bedload and suspended load. At the flood event scale, a good relationship was found between peak discharges (Qpeak) and sediment load (bedload and suspended load). The inter-annual sediment yields were analyzed, also assessing the contribution of the single floods to the total sediment budget. The annual suspended load ranges from 10 to 2524tyr−1, while the bedload varies from 0 to 1543tyr−1. The higher annual yields were recorded in the years when large floods occurred, highlighting that the sediment budget in the Rio Cordon is strongly controlled by the occurrence of high magnitude events. Investigation of the seasonal suspended load contribution demonstrated that from 1986 to 1993 most fine sediments were transported during the snowmelt/summer seasons, while autumn and snowmelt were the dominant seasons contributing to sediment yield in the periods 1994–2002 and 2003–2014, respectively. The mean annual sediment yield from 1986 to 2014 is equal to 103tkm−2yr−1, and overall, bedload accounts for 21% of the total sediment yield. The ratio between the sediment transport and the effective runoff of the events allowed the temporal trends of transport efficiency to be inferred, highlighting the existence of periods characterized by different sediment availability. In particular, despite no significant changes in the hydrological variables (i.e. rainfall), nearly a decade (1994–2002) with high transport efficiency appears to have occurred after an exceptional event (recurrence interval >100years). This event affected the sediment availability at the basin and channel bed scales, and provided a legacy influencing the sediment dynamics in the basin over the long-term by increasing the transport efficiency for approximately a decade. This work benefits from the long-lasting monitoring program undertaken in the Rio Cordon and is the product of long-term data series. The quasi-unique dataset has provided detailed evidence of sediment dynamics over about three decades in a small Alpine basin, also enabling the effects triggered by an exceptional event to be analyzed.

两种农业种植模式对重金属土壤的修复潜力

PDF HTML阅读 XML下载 导出引用 引用提醒 两种农业种植模式对重金属土壤的修复潜力 DOI: 10.5846/stxb201405040883 作者: 作者单位: 湖南农业大学生物科学与技术学院,湖南农业大学资源与环境学院,湖南农业大学资源与环境学院,湖南农业大学生物科学与技术学院,湖南农业大学生物科学与技术学院 作者简介: 通讯作者: 中图分类号: 基金项目: 环境保护部公益性行业科研专项(201009047) The potential of two agricultural cropping patterns for remediating heavy metals from soils Author: Affiliation: College of Resources and Environment,Hunan Agricultural University,,,, Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:植物修复农田土壤重金属污染需要经历一个长期的过程,而大部分用来修复的植物都不具备利用价值,不能给当地农民带来经济收入。因此,一些农作物由于其较大的生物量和一定的经济价值,在植物修复土壤重金属污染的应用中受到广泛关注。是在重金属(Cu、Zn、Pb、Cd、As、Hg)复合污染的郴州矿区废弃农田种植油菜、玉米和油葵,研究油菜-玉米和油-油葵两种种植模式对土壤重金属污染的修复潜力。实验结果表明:三种作物在复合污染土壤中对重金属都表现出一定的耐性及吸收积累能力。向日葵的根和叶中重金属Cd、Cu的含量都很高,其中Cd在向日葵的各个部位的富集系数(BCF)及Cu在向日葵的根和叶的富集系数(BCF)都大于1。两种轮作模式对作物的产量没有明显的影响,收获得到的干物质量都很高,每年每公顷分别为油菜16.6t、玉米25.29t、油葵22.5t。两种种植模式都可以对土壤中的重金属进行有效的提取,油菜-油葵种植模式下提取重金属Cu、Pb、Cd、As的量较高,分别为:Cu 2408g hm-2 a-1,Pb 2027g hm-2 a-1,Cd 658.5g hm-2 a-1,As 250g hm-2 a-1,油菜-玉米模式下Zn和Hg的提取量较高,分别为Zn 4987g hm-2 a-1和Hg 7.92g hm-2 a-1;对于多种重金属复合污染的土壤来说,油菜-油葵的种植模式要优于油菜-玉米的种植模式。总的来说,利用3种作物两两轮作的种植模式,在不影响作物产量的前提下大大的提高了作物对重金属的提取总量。3种作物在收获以后又可以用做工业原料,这就使得当地农民充分利用矿区废弃农田修复污染的同时又能从中获得一定经济效益。 Abstract:Plants needs cost many years to remediateheavy metal-contaminated croplands, and because some plants lack economic value, farmers often have no income during this period.Therefore, selecting suitable plants tolerant to heavy metals and producing products ofeconomicvalue may be a key factor in promoting the practical application of phytoremediation polluted soils. Many studies have demonstrated that some cash crops, which have the ability to attain large biomasses and accumulate metals, are highly tolerant to metal pollution.In order to fully utilize farmland contaminated with heavy metalsfrom mine tailings in Chenzhou, three cash crops (rape, corn, and sunflower) wereinvestigated as candidate phytoextraction plants with the potential to overcome these disadvantages of phytoremediation. To identify the potential of two seasonal cropping patterns (rape and corn, rape and sunflower) to remediate heavy metal contaminated land in Chenzhou, field experiments were conducted using rape, corn, and sunflower at a site highly contaminated with heavy metals(Cu, Zn, Pb, Cd, As, and Hg) from mine tailings.The three cash crops demonstrated the potential to tolerate and accumulate heavy metals. Significant accumulations of Cu and Cd were found in leaves and roots of sunflower. The bioconcentration factors (BCF) of Cd in all sunflower parts (roots, stems, leaves, flower heads, and seeds) and the BCF of Cu in sunflower leaves and roots were more than 1. Both cropping patterns (rape-corn, rape-sunflower) performed well and had no significant effect on yield. Three cash crops produced high annual yields of dry biomass (rape: 16.6t/hm2, corn: 25.29t/hm2, sunflower: 25.25t/hm2)after one year rotations. Both cropping patterns absorbed a wide range of heavy metals from thesoil due to their highbiomass yields.Data obtained from the field experiment were used to estimate the amounts of heavy metals (g hm-2 a-1) extracted by the three cash crops grown in each of the two cropping patterns. The rape-sunflower cropping system extracted large amounts of Cu (2408g hm-2 a-1), Pb (2027g hm-2 a-1), Cd (658.5g hm-2 a-1), As (250g hm-2 a-1), while Zn (4987g hm-2 a-1) and Hg (7.92g hm-2 a-1) were extracted by the rape-corn cropping system. The rape-sunflower system performed better than rape-corn at remediating the heavy metal contaminated soil. Overall, the three cash crops tested are more suitable for phytoextraction than most conventional hyperaccumulator plants due to their larger biomass, although they have low bioconcentration factors. Cropping pattern had no effect on crop yield, but increased annual extraction of heavy metals from soil comparedsingle crop systems. Furthermore, rape, corn and sunflower are widely used as biofuel crops, so their seed oil could be for this purpose and the stems have great commercial value in ethanol and paper production. Using these crops and cropping systems for phytoextraction offers thepossibility of producing some economic returns for farmers during the remediationprocess. 参考文献 相似文献 引证文献

Biomass of invasive plant species as a potential feedstock for bioenergy production

AbstractInvasive alien species (IAS) are one of the most important drivers of species loss. A series of recent (inter)national policies and guidelines however did not prevent new introductions and further spread of non‐indigenous species. But instead of considering invasive plant species as a burden, the biomass production of IAS can be considered and used as an ecosystem service. To assess the possibilities for bioenergy production of four invasive alien plant species in Europe, Fallopia japonica, Heracleum mantegazzianum, Impatiens glandulifera and Solidago gigantea, we determined their biomass production, gross calorific value and biogas yield. The viability of the propagules after digestion was also tested to assess the dispersal risk related to the bioenergy chain. Fallopia japonica and S. gigantea achieved a high annual biomass yield of 8.6 ton DM per hectare. Impatiens glandulifera and H. mantegazzianum had a lower biomass production (5.8 and 6.0 ton DM ha−1). Without extra inputs or agronomic optimization of the crops, the anaerobic digestion of the studied invasive plant species achieved comparable energy outputs per hectare (28–88 GJ ha−1) as some of the current bioenergy systems. All propagules lost their viability after digestion. The risk of further invasion is thus minimized during the digestion process. However, caution during harvest and transport is required to prevent the spread of new propagules. The energetic valorization of the biomass of IAS can create an economic incentive for habitat restoration of invaded sites and offers the opportunity to reconcile the restoration of the invaded habitats with renewable energy goals. © 2015 Society of Chemical Industry and John Wiley &amp; Sons, Ltd

Lifecycle assessment of microalgae to biofuel: Comparison of thermochemical processing pathways

Abstract Microalgae is being investigated as a renewable transportation fuel feedstock based on various advantages that include high annual yields, utilization of poor quality land, does not compete with food, and can be integrated with various waste streams. This study focuses on directly assessing the environmental impact of two different thermochemical conversion technologies for the microalgae-to-biofuel process through life cycle assessment. A system boundary of “well to pump” (WTP) is defined and includes sub-process models of the growth, dewatering, thermochemical bio-oil recovery, bio-oil stabilization, conversion to renewable diesel, and transport to the pump. Models were validated with experimental and literature data and are representative of an industrial-scale microalgae-to-biofuel process. Two different thermochemical bio-oil conversion systems are modeled and compared on a systems level, hydrothermal liquefaction (HTL) and pyrolysis. The environmental impact of the two pathways were quantified on the metrics of net energy ratio (NER), defined here as energy consumed over energy produced, and greenhouse gas (GHG) emissions. Results for WTP biofuel production through the HTL pathway were determined to be 1.23 for the NER and GHG emissions of −11.4 g CO 2-eq (MJ renewable diesel) − 1 . Biofuel production through the pyrolysis pathway results in a NER of 2.27 and GHG emissions of 210 g CO 2-eq (MJ renewable diesel) − 1 . The large environmental impact associated with the pyrolysis pathway is attributed to feedstock drying requirements and combustion of co-products to improve system energetics. Discussion focuses on a detailed breakdown of the overall process energetics and GHGs, impact of modeling at laboratory-scale compared to industrial-scale, environmental impact sensitivity to systems engineering input parameters for future focused research and development, and a comparison of results to literature.

Influence of rootstocks on growth, yield, fruit quality and leaf mineral element contents of pear cv. 'Santa Maria' in semi-arid conditions.

BackgroundRootstocks play an essential role to determining orchard performance of fruit trees. Pyrus communis and Cydonia oblonga are widely used rootstocks for European pear cultivars. The lack of rootstocks adapted to different soil conditions and different grafted cultivars is widely acknowledged in pear culture. Cydonia rootstocks (clonal) and Pyrus rootstocks (seedling or clonal) have their advantages and disadvantages. In each case, site-specific environmental characteristics, specific cultivar response and production objectives must be considered before choosing the best rootstock. In this study, the influence of three Quince (BA 29, Quince A = MA, Quince C = MC) and a local European pear seedling rootstocks on the scion yield, some fruit quality characteristics and leaf macro (N, P, K, Ca and Mg) and micro element (Fe, Zn, Cu, Mn and B) content of ‘Santa Maria’ pear (Pyrus communis L.) were investigated.ResultsTrees on seedling rootstock had the highest annual yield, highest cumulative yield (kg tree−1), largest trunk cross-sectional area (TCSA), lowest yield efficiency and lowest cumulative yield (ton ha−1) in the 10th year after planting. The rootstocks had no significant effect on average fruit weight and fruit volume. Significantly higher fruit firmness was obtained on BA 29 and Quince A. The effect of rootstocks on the mineral element accumulation (N, K, Ca, Mg, Fe, Zn, Cu, Mn and B) was significant. Leaf analysis showed that rootstocks used had different mineral uptake efficiencies throughout the early season.ConclusionThe results showed that the rootstocks strongly affected fruit yield, fruit quality and leaf mineral element uptake of ‘Santa Maria’ pear cultivar. Pear seedling and BA 29 rootstock found to be more prominent in terms of several characteristics for ‘Santa Maria’ pear cultivar that is grown in highly calcareous soil in semi-arid climate conditions. We determined the highest N, P (although insignificant), K, Ca, Mg, Fe and Cu mineral element concentrations on the pear seedling and BA 29 rootstocks. According to the results, we recommend the seedling rootstock for normal density plantings (400 trees ha−1) and BA 29 rootstock for high-density plantings (800 trees ha−1) for ‘Santa Maria’ pear cultivar in semi-arid conditions.

Sediment yield of a forest river basin in Ghana

The Pra River Basin, located in south central Ghana is a forest basin that has been engulfed by certain anthropogenic activities particularly illegal small scale mining (popularly called galamsey) and serious concerns have been raised by stakeholders within the basin of the level of pollution due to the release of sediments into the water bodies. This study was undertaken to assess sediment yield levels within the Pra Basin through field data collection to ascertain stakeholder's perceptions and suggest remedial measures to the land degradation problem in the basin.Suspended sediment concentration measurements were undertaken for 10months in selected stream discharge measuring stations within the basin by coupling dip and integrated sampling approaches. Samples were analyzed using the evaporation method. Daily mean suspended sediment concentration was calculated from which monthly and annual suspended sediment yields were derived. Suspended sediment concentration (mg/l) and sediment yield (tyr−1) of the Pra Basin were found to be very high resulting in a high annual specific suspended sediment yield (tkm−2yr−1). Illegal small scale gold mining along the rivers and alluvial gold mining within the basin were found to be the probable cause for the high sediment levels of the rivers. To promote coordinated development and sustainable management of the resources of the basin, there is the need to resource agencies in charge of regulating natural resource utilization to control land use activities particularly galamsey. This will reduce fluvial sediment concentration and sustain good water quality of the rivers and promote socio-economic development in the basin.

Financial Markets in May 2014

In May 2014, Russia’s stock market continued its steady recovery. As of 26 May, the MICEX Index stood at 1,449.3 points, having grown since the beginning of that month by more than 11%. The growth leader among highly liquid shares were VTB Bank’s securities – over the period from 2 May through 26 May they rose 24.25%. However, the highest annual yield on shares – more than 40% per annum – was shown by Norilsk Nickel. As of 26 May, the stock market’s capitalized on amounted to Rb 22.9 trillion (or 35.3% of GDP).

Ecological-Economic Values of Lignocellulosic Herbaceous Plant on Contaminated Land

Lignocellulosic herbaceous plant is a high-quality kind of biomass resource. In China, large-scale cultivation of lignocellulosic herbaceous plant on marginal land is a crucial method to resolve sustainable supplement of biomass feedstock. In order to analyse its potential, this research conducted large-scale cultivation of four species of lignocellulosic herbaceous plant, switchgrass, silver reed, giant reed and hybrid pennisetum on a contaminated land in Beijing suburb. And a quantitative analysis of their biomass yields and ecological-economic values were performed in the sequential four growing seasons. With high annual biomass yields, 21.37 ton·hm-2, 26.21 ton·hm-2, 44.48 ton·hm-2 and 57.61 ton·hm-2, respectively, these four species of lignocellulosic herbaceous plant had enormous ecological values, including carbon fixation, oxygen release, sulfur dioxide absorption and dust retardment, and considerable economic values, according to standard coal conversion and cellulosic ethanol production. Of these four species, hybrid pennisetum is optimal in ecological value on contaminated land in the future, while giant reed in economic value.

Comparison of Energy Yield of Small Wind Turbines in Low Wind Speed Areas

The objective of this paper is to compare the energy yield and generated electricity cost of several commercially available small wind turbines under low wind speed condition. Many small wind turbines were not able to generate the amount of electricity promised by the manufacturers. The predicted annual energy yield simulated using manufacturers' power curve were sometimes higher than actual measured values by up to a factor of two. Furthermore, above a rotor size of 3 m, large diameter turbines performed better, having both low generated electricity cost ( € /kWh) and high annual energy yield per swept area (kWh/m 2).

Seasonal dynamics of above‐ and below‐ground biomass and nitrogen partitioning in Miscanthus × giganteus and Panicum virgatum across three growing seasons

AbstractThe first replicated productivity trials of the C4 perennial grass Miscanthus × giganteus in the United States showed this emerging ligno‐cellulosic bioenergy feedstock to provide remarkably high annual yields. This covered the 5 years after planting, leaving it uncertain if this high productivity could be maintained in the absence of N fertilization. An expected, but until now unsubstantiated, benefit of both species was investment in roots and perennating rhizomes. This study examines for years 5–7 yields, biomass, C and N in shoots, roots, and rhizomes. The mean peak shoot biomass for M. × giganteus in years 5–7 was 46.5 t ha−1 in October, declining to 38.1 t ha−1 on completion of senescence and at harvest in December, and 20.7 t ha−1 declining to 11.3 t ha−1 for Panicum virgatum. There was no evidence of decline in annual yield with age. Mean rhizome biomass was significantly higher in M. × giganteus at 21.5 t ha−1 compared to 7.2 t ha−1 for P. virgatum, whereas root biomass was similar at 5.6–5.9 t ha−1. M. × giganteus shoots contained 339 kg ha−1 N in August, declining to 193 kg ha−1 in December, compared to 168 and 58 kg ha−1 for P. virgatum. The results suggest substantial remobilization of N to roots and rhizomes, yet still a substantial loss with December harvests. The shoot and rhizome biomass increase of 33.6 t ha−1 during the 2‐month period between June and August for M. × giganteus corresponds to a solar energy conversion of 4.4% of solar energy into biomass, one of the highest recorded and confirming the remarkable productivity potential of this plant.

Production of high-starch duckweed and its conversion to bioethanol

Growing high-starch duckweed for its conversion to bioethanol was investigated as a novel technology to supplement maize-based ethanol production. Under the fall (autumn) climate conditions of North Carolina, the biomass accumulation rate of Spirodela polyrrhiza grown in a pilot-scale culture pond using diluted pig effluent was 12.4 g dry weight m−2 day−1. Through simple transfer of duckweed plants into well water for 10 days, the duckweed starch content increased by 64.9%, resulting in a high annual starch yield of 9.42 × 103 kg ha−1. After enzymatic hydrolysis and yeast fermentation of high-starch duckweed biomass in a 14-l fermentor, 94.7% of the theoretical starch conversion was achieved. The ethanol yield of duckweed reached 6.42 × 103 l ha−1, about 50% higher than that of maize-based ethanol production, which makes duckweed a competitive starch source for fuel ethanol production.

Yield Performance and Resource Efficiency of Double-Cropping Maize in Yellow-Huai-Hai River Valleys Region

The winter wheat (Triticum aestivum L.)-summer maize (Zea mays L.) relay system (W-M system) is the main cropping pattern in the Yellow-Huai-Hai River Valleys region of China. In recent years, winter freezing and drought stress occur frequently in this area, which causes great loss of wheat yield. In this study, the double-cropping maize system (M-M system) was tested in Xinxiang, Henan Province in 2009 and 2010 growing seasons to compare grain yield and resource efficiency between M-M and W-M systems. Compared to the W-M system, the M-M system produced 2.3% higher annual yield and increased 26.1% annual light energy efficiency and 6.5% annual temperature production efficiency. Besides, the economic benefit in the M-M system was 1628 RMB ha−1 higher than that in the W-M system, and the total growth duration was reduced 140 d in the M-M system. This result suggests that the M-M system not only facilitates land fallow and avoids winter freezing and drought stress, but also obtains high light and temperature efficiencies and economic benefit.