Insectivorous birds consume an estimated 400–500 million tons of prey annually

In this paper, we present an estimate of the predation impact of the global population of insectivorous birds based on 103 (for the most part) published studies of prey consumption (kg ha^?1 season^?1) of insectivorous birds in seven biome types. By extrapolation—taking into account the global land cover of the various biomes—an estimate of the annual prey consumption of the world’s insectivorous birds was obtained. We estimate the prey biomass consumed by the world’s insectivorous birds to be somewhere between 400 and 500 million metric tons year^?1, but most likely at the lower end of this range (corresponding to an energy consumption of ≈?2.7?×?10¹⁸ J year^?1 or ≈?0.15% of the global terrestrial net primary production). Birds in forests account for >?70% of the global annual prey consumption of insectivorous birds (≥?300 million tons year^?1), whereas birds in other biomes (savannas and grasslands, croplands, deserts, and Arctic tundra) are less significant contributors (≥?100 million tons year^?1). Especially during the breeding season, when adult birds feed their nestlings protein-rich prey, large numbers of herbivorous insects (i.e., primarily in the orders Coleoptera, Diptera, Hemiptera, Hymenoptera, Lepidoptera, and Orthoptera) supplemented by spiders are captured. The estimates presented in this paper emphasize the ecological and economic importance of insectivorous birds in suppressing potentially harmful insect pests on a global scale—especially in forested areas.     

Nutrient cycling within the developing oil palm-legume ecosystem

Oil palms (Elaeis guineensis Jacq.) are normally planted in fields stripped of all other vegetation. Leguminous cover crops are planted simultaneously to protect the soil surface and to provide other, less tangible benefits. Nutrient cycling, especially of nitrogen, was followed in a commercial oil palm plantation and showed that: (a) legumes contribute about 150 kg nitrogen ha^?1 year^?1 to the system through nitrogen fixation; (b) during the early stages of oil palm growth the legumes absorb 149 kg nitrogen ha^?1 year^?1 from the soil; (c) with a loss of nitrogen through litter fall of 123 kg nitrogen ha^?1 year^?1, legumes accumulate a net amount of 176 kg nitrogen ha^?1 year^?1 in their foliage; (d) in comparison with “natural” covers, leguminous covers reduce leaching losses by 63 kg nitrogen ha^?1 year ^?1 so that the total benefits of leguminous covers amount to 239 kg nitrogen ha^?1 year^?1; (e) the combined inputs from fertilization and oil palm debris in plots without legumes is 208 kg nitrogen ha^?1 year^?1; and (f) during the initial growth phase, oil palms need only 175 kg nitrogen ha^?1 year^?1. Since legumes fix nitrogen and thoroughly scavenge the soil for minerals they eventually provide more nitrogen to the oil palms than is needed for growth. This surplus nitrogen is “banked” in the legume foliage. Then, when the rooting system of the oil palms has grown under the inter-rows, competition for nutrients causes a gradual decline in the cover-crop. Nutrients “deposited” in the legumes are thus slowly re-released stimulating root-growth and general development of the oil palm.     

Effect of age and disturbance on decadal changes in carbon stocks in managed forest landscapes in central Canada

Forests have the potential to be a sink in the global carbon (C) budget and thus play an important role in mitigating climate change. However, large-scale management of forests to their sink potential requires understanding of factors responsible for changes in forest C stocks. In this paper, we quantify the effects of initial forest landscape condition and disturbance rates on landscape-level changes in forest C stocks using predictions for managed forests in Ontario, Canada. Ten-year changes in C stocks in public forests managed for wood fibre production were simulated under four scenarios reflecting the range of volume harvested between 1998 and 2007. Changes in forest C stocks varied across Ontario and with harvest rate, resulting in the forest ranging from being a source of 0.767 tC ha^-1 year^?1 to a sink of 0.656 tC ha^?1 year^?1. Simulation results were used to develop a predictive equation explaining over 93 % of the variation in forest C stocks. Variables included in the equation, in descending order of their effect on changes in forest C stocks, were relative harvest rate, forest growth rate, natural disturbance rate, and initial forest C stocks. A reduced equation, including only the first three variables, explained nearly 89 % of the variation in forest C stocks. The results indicate that short-term changes in C stocks depend on initial forest condition and that there are limits to how much these changes can be manipulated by altering harvest and disturbance rates.     

Managing crop residues, fertilizers and leaf litters to improve soil C, nutrient balances, and the grain yield of rice and wheat cropping systems in Thailand and Australia

This paper reports on the influence that residue and fertilizer management have on nutrient balances, soil organic matter (SOM) dynamics, and crop yields of a flooded rice system in northeast Thailand (1992–1997) and a wheat–forage legume rotation in eastern Australia (1992–1998). Both soils had been subject to at least 18 years of cultivation and had lost up to 90% of the original labile (C_L) and 85% of the total carbon (C_T).For the rainfed rice cropping systems of northeast Thailand, a system is described in which small applications of leaf litter from locally grown trees are applied annually to rice paddy soils prior to transplanting. Annual applications of 1500 kg ha⁻¹ of leaf litter from different locally grown shrubs for five seasons resulted in increases in rice grain yield in 1997 of between 20 and 26% above the no-leaf litter control. Nutrient balances, determined by the difference between the inputs (fertilizer and added leaf litters) and outputs (grain and straw), indicated net positive balances of up to 457 kg N ha⁻¹, and 60 kg P ha⁻¹, after five seasons of leaf litter applications. Sulfur and potassium balances resulted in net deficits of up to −13 kg S ha⁻¹ and −52 kg P ha⁻¹, where no leaf litter was applied and rice straw was removed following harvest. Soil carbon (C) concentrations increased significantly only where higher fertilizer rate and rice stubble retention were combined.The poor management of fertilizers and crop residues, and excessive cultivation has also resulted in large soil fertility losses in the grain growing areas of Eastern Australia. After five wheat and two legume/fallow crops, negative N balances of up to −303 kg ha⁻¹ were calculated for the treatments where wheat stubble was not retained and bare fallow leys were used. The balance of nutrients such as K, which are contained in larger proportions in stubble, were found to be up to −362 kg ha⁻¹ on the straw-removed treatments and up to +29 kg ha⁻¹ on the straw-retained treatments. Forage legume leys resulted in short term increases in C_L and the carbon management index (CMI).Sustainable farming systems require that crop yields are stable through the maintenance of soil fertility and the balance of nutrients in the system. Increases in soil C levels require sustained periods of balanced fertilization and residue retention.     

Mediterranean shrublands carbon sequestration: environmental and economic benefits

To date, only a few attempts have been done to estimate the contribution of Mediterranean ecosystems to the global carbon cycle. Within this context, shrub species, composition and structure of the Mediterranean shrublands developing along the Latium coast (Italy) were analyzed in order to evaluate their contribution to carbon (C) sequestration, also taking into consideration the economic benefits at a national level. The considered shrublands had a shrub density of 1,200?±?500 shrubs ha^?1. Shrubs were classified into small (S), medium (M) and large (L), according to their volume (V) and leaf area index (LAI). The total yearly carbon dioxide (CO₂) sequestration per species (SC_y) was calculated multiplying the total photosynthetic leaf surface area (spt) of each species by the mean yearly photosynthetic rate and the total yearly photosynthetic activity time (in hours). Q. ilex and A. unedo had the highest SC_y (46.2?±?15.8 kg CO₂ year^?1, mean value), followed by P. latifolia (17.5?±?6.2 kg CO₂ year^?1), E. arborea, E. multiflora, C. incanus, P. lentiscus, R. officinalis, and S. aspera (6.8?±?4.2 kg CO₂ year^?1, mean value). The total yearly CO₂ sequestration per shrub (SC_shy) was 149?±?5 kg CO₂ year^?1 in L, decreasing 30 % in M and 80 % in S shrubs. Taking into account the frequency of S, M and L and their SC_shy, the total CO₂ sequestration of the Mediterranean maquis was quantified in 80 Mg CO₂ ha^?1?year^?1, corresponding to 22 Mg C ha^?1?year^?1. From a monetary viewpoint, this quantity could be valued to more than 500 US$ ha^?1?year^?1. Extending this benefit to the Mediterranean shrublands throughout the whole country, we obtained a nationwide estimated annual benefit in the order of $500 million.     

Net Ecosystem Production of Boreal Larch Ecosystems on the Yenisei Transect

The study was carried out in the Turukhansk Research Station of Yenisei Transect (65^°46^′N, 89^°25^′E). Larch (Larix gmelinii (Rupr.) Rupr.) is the dominant overstory tree species. The research has been conducted on four permanent test plots in same-age mature (110-year old) and overmature (380-year old) post-fire larch stands of green moss and lichen groups of forest type. Carbon cycle parameters were assessed based on a biometric method. Quantitative analysis of carbon pools and fluxes shows that net ecosystem production of north taiga larch stands averages 32% of net primary production. Sink of atmospheric CO₂ makes 1.22 and 0.74 t C ha^{− 1} year^{− 1} for mature and overmature green moss larch stands, and 0.65 and 0.35 t C ha^{− 1} year^{− 1} for lichen type. Net carbon sink in the tree layer make up 9% of net primary production carbon, ground vegetation – 15%, and dead plant residues accumulation – 8% of atmospheric carbon uptake via photosynthesis.     

CO2 emissions from tropical drained peat in Sumatra,Indonesia

With the increasing use of tropical peatland for agricultural development, documentation of the rate of carbon dioxide (CO₂) emissions is becoming important for national greenhouse gas inventories. The objective of this study was to evaluate soil-surface CO₂ fluxes from drained peat under different land-use systems in Riau and Jambi Provinces, Sumatra, Indonesia. Increase of CO₂ concentration was tracked in measurement chambers using an Infrared Gas Analyzer (IRGA, LI-COR 820 model). The results showed that CO₂ flux under oil palm (Elaeis guineensis) plantations ranged from 34?±?16 and 45?±?25 Mg CO₂ ha^–1 year^–1 in two locations in Jambi province to 66?±?25 Mg CO₂ ha^–1 year^–1 for a site in Riau. For adjacent plots within 3.2 km in the Kampar Peninsula, Riau, CO₂ fluxes from an oil palm plantation, an Acacia plantation, a secondary forest and a rubber plantation were 66?±?25, 59?±?19, 61?±?25, 52?±?17 Mg ha^–1 year^–1, respectively, while on bare land sites it was between 56?±?30 and 67?±?24 Mg CO₂ ha^–1 year^–1, indicating no significant differences among the different land-use systems in the same landscape. Unexplained site variation seems to dominate over land use in influencing CO₂ flux. CO₂ fluxes varied with time of day (p?<?0.001) with the noon flux as the highest, suggesting an overestimate of the mean flux values with the absence of night-time measurements. In general, CO₂ flux increased with the depth of water table, suggesting the importance of keeping the peat as wet as possible.     

Greenhouse gas emissions in restored secondary tropical peat swamp forests

Restoration of deforested and drained tropical peat swamp forests is globally relevant in the context of reducing emissions from deforestation and forest degradation. The seasonal flux of carbon dioxide (CO₂), methane (CH₄), and nitrous oxide (N₂O) in a restoration concession in Central Kalimantan, Indonesia, was measured in the two contrasting land covers: shrubs and secondary forests growing on peatlands. We found that land covers had high, but insignificantly different, soil carbon stocks of 949?+?56 and 1126?+?147 Mg ha^?1, respectively. The mean annual CO₂ flux from the soil of shrub areas was 52.4?±?4.1 Mg ha^?1 year^?1, and from secondary peat swamp forests was 42.9?±?3.6 Mg ha^?1 year^?1. The significant difference in mean soil temperature in the shrubs (31.2 °C) and secondary peat swamp forests (26.3 °C) was responsible for the difference in total CO₂ fluxes of these sites. We also found the mean annual total soil respiration was almost equally partitioned between heterotrophic respiration (20.8?+?1.3 Mg ha^?1 year^?1) and autotrophic respiration (22.6?+?1.5 Mg ha^?1 year^?1). Lowered ground water level up to ??40 cm in both land covers caused the increase of CO₂ fluxes to 40–75%. These numbers contribute to the provision of emission factors for rewetted organic soils required in the national reporting using the 2013 Supplement of the 2006 Intergovernmental Panel on Climate Change (IPCC) Guidelines for wetlands as part of the obligation under the United Nations Framework Convention on Climate Change (UNFCCC).

     

Greenhouse gas emission factors for land use and land-use change in Southeast Asian peatlands

Tropical peat swamp forests, which are predominantly located in Southeast Asia (SEA) and play a prominent role as a global carbon store, are being intensively degraded and converted to agricultural lands and tree plantations. For national inventories, updated estimates of peat emissions of greenhouse gases (GHG) from land use (LU) and land-use change in the tropics are required. In this context, we reviewed the scientific literature and calculated emission factors of peat net emissions of carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O) in seven representative LU categories for SEA i.e. intact peat swamp forest, degraded forest (logged, drained and affected by fire), mixed croplands and shrublands, rice fields, oil palm, Acacia crassicarpa and sago palm plantations. Peat net CO₂ uptake from or emissions to the atmosphere were assessed using a mass balance approach. The balance included main peat C inputs through litterfall and root mortality and outputs via organic matter mineralization and dissolved organic carbon. Peat net CO₂ loss rate from degraded forest, croplands and shrublands, rice fields, oil palm, A. crassicarpa and sago palm plantations amounted to 19.4?±?9.4, 41.0?±?6.7, 25.6?±?11.5, 29.9?±?10.6, 71.8?±?12.7 and 5.2?±?5.1 Mg CO₂ ha^?1 y^?1, respectively. Total peat GHG losses amounted to 20.9?±?9.4, 43.8?±?6.8, 36.1?±?12.9, 30.4?±?10.6, 72?±?12.8 and 8.6?±?5.3 Mg CO₂-equivalent ha^?1 y^?1 in the same LU categories, respectively. A single land-clearing fire would result in additional emissions of 493.6?±?156.0 Mg CO₂-equivalent ha^?1.     

Carbon storage and sequestration potential of selected tree species in India

A dynamic growth model (CO2FIX) was used for estimating the carbon sequestration potential of sal (Shorea Robusta Gaertn. f.), Eucalyptus (Eucalyptus Tereticornis Sm.), poplar (Populus Deltoides Marsh), and teak (Tectona Grandis Linn. f.) forests in India. The results indicate that long-term total carbon storage ranges from 101 to 156 Mg C?ha^?1, with the largest carbon stock in the living biomass of long rotation sal forests (82 Mg C?ha^?1). The net annual carbon sequestration rates were achieved for fast growing short rotation poplar (8 Mg C?ha^?1?yr^?1) and Eucalyptus (6 Mg C?ha^?1?yr^?1) plantations followed by moderate growing teak forests (2 Mg C?ha^?1?yr^?1) and slow growing long rotation sal forests (1 Mg C?ha^?1?yr^?1). Due to fast growth rate and adaptability to a range of environments, short rotation plantations, in addition to carbon storage rapidly produce biomass for energy and contribute to reduced greenhouse gas emissions. We also used the model to evaluate the effect of changing rotation length and thinning regime on carbon stocks of forest ecosystem (trees?+?soil) and wood products, respectively for sal and teak forests. The carbon stock in soil and products was less sensitive than carbon stock of trees to the change in rotation length. Extending rotation length from the recommended 120 to 150 years increased the average carbon stock of forest ecosystem (trees?+?soil) by 12%. The net primary productivity was highest (3.7 Mg ha^?1?yr^?1) when a 60-year rotation length was applied but decreased with increasing rotation length (e.g., 1.7 Mg ha^?1?yr^?1) at 150 years. Goal of maximum carbon storage and production of more valuable saw logs can be achieved from longer rotation lengths. ‘No thinning’ has the largest biomass, but from an economical perspective, there will be no wood available from thinning operations to replace fossil fuel for bioenergy and to the pulp industry and such patches have high risks of forest fires, insects etc. Extended rotation lengths and reduced thinning intensity could enhance the long-term capacity of forest ecosystems to sequester carbon. While accounting for effects of climate change, a combination of bioenergy and carbon sequestration will be best to mitigation of CO₂ emission in the long term.     

Linking spatio-temporal variation of crop response with sediment deposition along paddy rice terraces

In tropical mountainous regions of South East Asia, intensive cultivation of annual crops on steep slopes makes the area prone to erosion resulting in decreasing soil fertility. Sediment deposition in the valleys, however, can enhance soil fertility, depending on the quality of the sediments, and influence crop productivity. The aim of the study was to assess (i) the spatio-temporal variation in grain yield along two rice terrace cascades in the uplands of northern Viet Nam, (ii) possible linkage of sediment deposition with the observed variation in grain yield, and (iii) whether spatial variation in soil water or nitrogen availability influenced the obtained yields masking the effect of inherent soil fertility using carbon isotope (¹³C) discrimination and ¹⁵N natural abundance techniques. In order to evaluate the impact of seasonal conditions, fertilizer use and sediment quality on rice performance, ¹⁵N and ¹³C stable isotope compositions of rice leaves and grains taken after harvest were examined and combined with soil fertility information and rice performance using multivariate statistics. The observed grain yields for the non-fertilized fields, averaged over both cascades, accounted for 4.0 ± 1.4 Mg ha^?1 and 6.6 ± 2.5 Mg ha^?1 in the spring and summer crop, respectively, while for the fertilized fields, grain yields of 6.5 ± 2.1 Mg ha^?1 and 6.9 ± 2.1 Mg ha^?1 were obtained. In general, the spatial variation of rice grain yield was strongly and significantly linked to sediment induced soil fertility and textural changes, such as soil organic carbon (r 0.34/0.77 for Cascades 1 and 2, respectively) and sand fraction (r ?0.88/?0.34). However, the observed seasonal alteration in topsoil quality, due to sediment deposition over two cropping cycles, was not sufficient to fully account for spatial variability in rice productivity. Spatial variability in soil water availability, assessed through ¹³C discrimination, was mainly present in the spring crop and was linearly related to the distance from the irrigation channel, and overshadowed in Cascade 2 the expected yield trends based on sediment deposition. Although δ¹⁵N signatures in plants indicated sufficient N uptake, grain yields were not found to be always significantly influenced by fertilizer application. These results showed the importance of integrating sediment enrichment in paddy fields within soil fertility analysis. Furthermore, where the effect of inherent soil fertility on rice productivity is masked by soil water or nitrogen availability, the use of ¹³C and ¹⁵N stable isotopes and its integration with conventional techniques showed potential to enhance the understanding of the influence of erosion – sedimentation and nutrient fluxes on crop productivity, at toposequence level.     

Spatial and long-term variability of soil loss due to crop harvesting and the importance relative to water erosion: A case study from Belgium

The harvest of crops such as sugar beet (Beta vulgaris L.), potato (Solanum tuberosum L.), leek (Allium porrum L.) and carrot (Daucus carota L.) causes soil loss from arable land because soil adhering to the crop and soil clods that failed to be separated by the harvesting machine, are exported from the field together with these harvested crops. These soil losses can be of the same order of magnitude as soil losses caused by water erosion processes, but are often neglected in soil erosion research. In this article we developed a methodology to investigate the spatial and long-term (1846–2004) variability of soil loss due to crop harvesting (SLCH) in Belgium and the spatial distribution of the importance of SLCH relative to soil losses caused by water erosion processes in Flanders. The study is based on long-term time series of soil tare data of crop processing factories and area and crop yield statistics. Until the middle of the 20th century, potato and roots and tubers grown as second crop, had the largest share in the SLCH-crop growing area in Belgium. Sugar beet gained importance from the end of the 19th century onwards and has now, of all SLCH crops, the largest growing area. We could estimate that, partly due to increasing crop yields and the mechanisation of the harvesting process, SLCH per hectare of cropland increased from 0.4 Mg ha⁻¹ year⁻¹ in 1846 to 2.4 Mg ha⁻¹ year⁻¹ in the 1970s and early 1980s. Since then mean annual soil losses decreased again to 1.8 Mg ha⁻¹ year⁻¹ in 2004. It was assessed that total yearly SLCH in Belgium rose from more than 575,000 Mg in the middle of the 19th century to more than 1.7 × 10⁶ Mg in the 1970s and early 1980s, while current SLCH values are 1.4 × 10⁶ Mg. We estimated that since 1846, more than 163 × 10⁶ Mg soil was exported from cropland in Belgium through this erosion process, which corresponds to 109 hm³ or an average soil profile truncation of 1.15 cm. Average sediment export from cropland in Flanders was 3.7 Mg ha⁻¹ year⁻¹ in 2002, of which 46% was due to SLCH and 54% was due to water erosion processes. The relative importance of SLCH varied, depending on the agricultural region, between 38% and 94%.     

长三角地区秸秆焚烧污染物排放清单及其在重霾污染天气模拟中的应用

根据2008年长三角地区江苏、安徽、浙江3省各地级市及上海市水稻、小麦、玉米、油菜4种农作物的年产量,结合谷草比、秸秆焚烧比例及排放因子建立了长三角地区秸秆焚烧大气污染物排放清单.结果表明：长三角地区秸秆焚烧产生的PM10、PM2.5、SO2、NOx、CO、EC、OC分别为36.8×104、14.4×104、1.5×104、9.2×104、20.8×104、2.6×104、12.2×104t.秸秆焚烧污染物排放量较大的区域主要集中在江苏中北部和安徽北部.在区域大气环境模拟系统RegAEMS中考虑秸秆焚烧源的影响,针对2008年10月底江苏一次重霾污染天气事件进行模拟,发现考虑秸秆焚烧源后模拟结果有较大的改善.秸秆焚烧可以导致区域PM10、CO浓度上升30%以上,黑碳和有机物的消光贡献明显增强.区域输送研究表明,苏中地区、外省秸秆焚烧排放源对此次重霾污染的贡献分别达到32.4%、33.3%.     

‘Carbon stocks in a Scots pine afforestation under different thinning intensities management’

Thinning, as a forest management strategy, may contribute towards mitigating climate change, depending on its net effect on forest carbon (C) stocks. Although thinning provides off-site C storage (in the form of wood products) it is still not clear whether it results in an increase, a reduction or no change in on-site C storage. In this study we analyze the effect of thinning on C stocks in a long-term experiment. Different thinning intensities (moderate, heavy and unthinned) have been applied over the last 30 years in a Scots pine (Pinus sylvestris L.) stand, with a thinning rotation period of 10 years. The main C compartments were analyzed: above and belowground tree biomass, deadwood, forest floor and upper 30-cm of the mineral soil and tree biomass removed in thinning treatments. The results revealed that unthinned stands had the highest C stocks with 315 Mg C ha^?1, moderate thinning presented 304 Mg C ha^?1 and heavy thinning 296 Mg C ha^?1, with significant differences between unthinned and heavily thinned stands. These differences were mainly due to C stock in live biomass, which decreased with thinning intensity. However, soil C stocks, forest floor and mineral soil, were not influenced by thinning, all of the stands displaying very similar values 102–107 Mg C ha^?1 for total soil; 15–19 Mg C ha^?1 for forest floor; 87–88 Mg C ha^?1 for mineral soil). These results highlight the sustainability of thinning treatments in terms of C stocks in this pinewood afforestation, and provide valuable information for forest management aimed at mitigating climate change.     

Soluble phosphorus release from organic soils

Soluble P release during soil organic matter decomposition was measured under fluctuating seasonal temperatures in several of Florida's organic soils. Natural soil profiles obtained from seven locations in central and south Florida were used in the study. Soil columns were leached once every 25 days, followed by applying a suction of 100 cm. Soil columns were flooded for 25 days in the months of July and August (between 14 and 21 weeks after initiation of the study for central Florida organic soils and between 11 and 18 weeks for south Florida organic soils) to simulate normal agronomic practice.The amounts of P released into effluent from Florida's organic soils were in the range of 2.9–26.2 μg P/cm³ of soil per year (16–168 kg P ha^?1 year^?1). This represents 2.2–20% of the total soil P for central Florida organic soils and 0.75–1.1% of total soil P for south Florida organic soils. Soluble ortho-P accounted for about 70–89% of total effluent P for central Florida organic soils and 54–57% of effluent P for south Florida organic soils. Estimated soil P mineralization during organic matter decomposition was about 38–185 kg P ha^?1 year^?1 for central Florida organic soils and 16–23 kg P ha^?1 year^?1 for south Florida organic soils. Seasonal temperature fluctuations had minimal influence on the P release into effluent. Flooding the organic soils, however, increased P release into drainage effluent by about 4–8 times, compared with drained conditions.     

基于调查的中国秸秆露天焚烧污染物排放清单

基于2010年初农村能源消费情况的问卷调查,获得全国分省秸秆露天焚烧比例,在此基础上确定秸秆露天焚烧的活动水平,采用排放因子法建立中国秸秆露天焚烧的污染物排放清单. 结果表明,中国农村秸秆露天焚烧平均比例为20.8%. 2009年全国28个省区(不包括西藏自治区、天津市、上海市、港澳台地区,下同)秸秆露天焚烧的PM_2.5、BC、OC、SO₂、NO_x、CO、NMVOC、NH₃、CH₄和CO₂排放量分别138.1×104、6.4×104、41.1×104、8.7×104、41.8×104、594.6×104、94.4×104、8.0×104、44.2×104和14 355.4×104 t. 稻谷、玉米和小麦是露天焚烧的三大作物秸秆,其对污染物排放的贡献合计约为87%. 秸秆露天焚烧排放量最高的前3位分别为湖南省、河南省和安徽省, 秸秆露天焚烧比例分别43.1%、20.8%和39.7%. 污染排放的高值区主要集中在华北和华中地区. 95%置信区间下的不确定性分析结果显示,PM_2.5、BC、OC、SO₂、NO_x、CO和NMVOC排放的不确定性范围分别为-60%~83%、-78%~147%、-73%~135%、-48%~75%、-49%~78%、-91%~155%和-67%~94%. 2015年初对六省(湖南省、广东省、江苏省、河南省、黑龙江省和辽宁省)农村能源消费调查的结果显示,2014年江苏省、湖南省和广东省的秸秆露天焚烧比例较2009年均有下降,而辽宁省、黑龙江省和河南省则相对上升. 研究显示,秸秆禁烧政策已取得初步成效,建议国家有关部门进一步加大秸秆禁烧政策的推行力度,完善相关政策措施.      

基于电生理信息的两种桑科植物叶片细胞代谢能比较

植物的细胞代谢能可以表征植物的生理活性和源库状况,而植物的细胞代谢能可由细胞的生理电容、生理电阻和生理阻抗来表征.本研究以桑科植物构树(Broussonetia papyrifera)和桑树(Morus alba)为例研究了不同夹持力下生理电阻、生理阻抗和生理电容的特征.先依据吉布斯自由能方程和Nernst方程构建模型...     

The impact of climate change under different thinning regimes on carbon sequestration in a German forest district

The objective of this paper is to assess how much carbon (C) is currently stored in a forest district in Thuringia, Germany, and how the carbon stocks will develop up to the year 2099 with a changing climate and under various management regimes (including no management), with different assumptions about carbon dioxide (CO₂) fertilization effects. We applied the process-based model 4C and a wood product model to a forest district in Germany and evaluated both models for the period from 2002 to 2010, based on forest inventory data for the stands in the district. Then, we simulated the growth of the stands in the forest district under three different realizations of a climate change scenario, combined with different management regimes. Our simulations show that in 2099, between 630 and 1149 t C ha^?1 will be stored in this district. The simulations also showed that climate change affects carbon sequestration. The no management strategy sequestered the highest amount of carbon (8.7 t C ha^?1 year^?1), which was greater than the management regimes. In the model, the possible fertilization effect of CO₂ is an important factor. However, forest management remains the determining factor in this forest district.     

Global warming potential of emissions from rice paddies in Northeastern China

In this study, paddy fields in Jilin province which are flooded parcel of arable lands used for growing rice (Oryza sativa Linn.) were selected as the object. Long-term exploitation of paddy fields led to variations of soil organic carbon (SOC) and green house gases (GHGs) emissions which might contribute to global warming. In order to calculate the amount of global warming potentials (GWPs) of emissions from ricepaddies and find the correlations among rice yield, SOC storage and GWP, DeNitrification-DeComposition (DNDC) model was used to simulate SOC densities and fluxes of main GHGs emitted from paddy fields. After verification, simulation results were used to calculate SOC storages and 100-year GWPs from 1949 to 2009. Results indicated that SOC densities in depths of 0–10 cm, 10–20 cm and 20–30 cm all kept increasing. Average methane (CH₄) and nitrous oxide (N₂O) fluxes were 278.55 kg carbon (kgC) ha⁻¹ a⁻¹ and 2.22 kg nitrogen (kgN) ha⁻¹ a⁻¹. The SOC storage (0–30 cm) had increased from 3.96 × 10⁹kgC in 1949 to 47.85 × 10⁹kgC in 2009. In addition, GWP emission was increasing exponentially in the past 61 years, from 0.16 × 10⁶ Mg carbon dioxide equivalents (CO₂-equivalents) to 66.36 × 10⁶ Mg CO₂-equivalents. Both SOC storage and GWP presented obviously linear relation to rice yields. Overall, the research suggested that long-term rice yields could be used to estimate the SOC storage and GWP variations.     

Assessment of the Risks for Human Health of Adenoviruses,Hepatitis A Virus,Rotaviruses and Enteroviruses in the Buffalo River and Three Source Water Dams in the Eastern Cape

Buffalo River is an important water resource in the Eastern Cape Province of South Africa. The potential risks of infection constituted by exposure to human enteric viruses in the Buffalo River and three source water dams along its course were assessed using mean values and static quantitative microbial risk assessment (QMRA). The daily risks of infection determined by the exponential model [for human adenovirus (HAdV) and enterovirus (EnV)] and the beta-Poisson model (for hepatitis A virus (HAV) and rotavirus (RoV)) varied with sites and exposure scenario. The estimated daily risks of infection values at the sites where the respective viruses were detected, ranged from 7.31 × 10^?3 to 1 (for HAdV), 4.23 × 10^?2 to 6.54 × 10^?1 (RoV), 2.32 × 10^?4 to 1.73 × 10^?1 (HAV) and 1.32 × 10^?4 to 5.70 × 10^?2 (EnV). The yearly risks of infection in individuals exposed to the river/dam water via drinking, recreational, domestic or irrigational activities were unacceptably high, exceeding the acceptable risk of 0.01 % (10^?4 infection/person/year), and the guideline value used as by several nations for drinking water. The risks of illness and death from infection ranged from 6.58 × 10^?5 to 5.0 × 10^?1 and 6.58 × 10^?9 to 5.0 × 10^?5, respectively. The threats here are heightened by the high mortality rates for HAV, and its endemicity in South Africa. Therefore, we conclude that the Buffalo River and its source water dams are a public health hazard. The QMRA presented here is the first of its kinds in the Eastern Cape Province and provides the building block for a quantitatively oriented local guideline for water quality management in the Province.