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1.
深圳市城市水土保持监督管理工作的思考 总被引：1，自引：1，他引：0
近年来,深圳市的城市化发展进程不断加快,城市规模不断扩张,同时也导致了一系列环境问题,其中比较典型的是城市水土流失问题日益突出。城市水土保持工作逐渐受到重视并逐步开展,在政府部门的支持下,深圳市的水土保持工作取得了一定的成效,但也存在诸多问题亟待解决。分析了深圳市水土保持工作中存在的主要问题,并在此基础上探究了有效的解决对策,以促进深圳市水土保持监督管理工作的有效开展,提高深圳市的环境质量。 相似文献
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通过深入贯彻落实《水土保持法》,水土保持生态环境监督管理呈现出了新的发展趋势 :社会大环境明显趋好 ;水土流失防治呈社会化、市场化、效益化发展 ;水土保持监督执法向全面性的监督管理转化 ;“预防为主”方针正在得到加强和落实 ;规范化建设成效代表了向高层次发展的趋势 ;城市水土保持监督管理工作加强等。水保监督管理好的发展趋势与问题并存 ,应采取以下对策 :依法行使归口管理职责 ;提高认识 ,加强管理 ;强化“预防为主”首要方针 ;综合发展人为水土流失防治技术 ;开展水土保持监测工作 ,提高监督管理整体水平等 ,以促进水土保持生态环境监督管理事业的顺利发展 相似文献
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深圳市水土流失面积逐年减少,并在近4年保持稳定,水土保持工作成效显著。本文在分析深圳市水土流失现状和危害的基础上,详细介绍了深圳市生产建设项目水土保持工作近年来推行的政策及采取的措施,总结了工作中的经验和目前存在的问题,为全国城市水土保持工作提供参考、借鉴。 相似文献
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以深圳为例浅谈城市建设中的水土保持管理 总被引：1，自引：1，他引：0
深圳市在城市建设中采取的水土保持管理措施主要有:从源头抓起,将水土保持方案申报审批纳入项目规划报建程序;注重行业管理,建立大水保格局的组织保障体系;国内首创政府委托水土保持监测、购买服务模式,健全水土保持监测网络;建立有效的水土保持监督管理机制,管理工作深入基层;加强取土、弃土管理,狠抓重点水土流失源管理。分析了深圳市存在的水土流失防治问题:城市建设迅速,地表扰动强度高;弃土、渣场所紧缺,弃土、渣问题难以解决;水土流失威胁市政排水设施,造成城市内涝;新增水土保持投资无从保障,水土保持措施落实难等。针对存在问题提出了相应的建议。 相似文献
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在深圳城市化快速推进过程中,大面积的土地开发、挖山填沟、采石取土等生产建设行为,给城市带来了严重的人为水土流失。通过对城市水土保持发展历程的追溯,阐述了城市水土保持与传统水土保持的区别,针对城市水土流失人为干扰剧烈、突发性强、水土流失源地点多面广等特点,结合目前水土保持监督管理中存在的水土保持方案编制深度严重滞后于主体工程、水土保持措施难以有效实施和生产建设项目各参建单位水土保持主体责任缺失等问题,从厘清水土保持监督管理责任、推进水土保持方案施工图设计和建立生产建设项目水土保持信用评价体系三个方面,提出了强化城市生产建设项目水土保持监督管理工作的思路。 相似文献
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深圳市城市水土流失现状及监督预防对策 总被引：1，自引：0，他引：1
深圳城市化的高速发展带来了严重的城市水土流失问题。经过多年的治理,城市水土流失情况有所缓解,大范围水土流失危害的发生频率较低。截止2012年深圳市水土流失面积已降至42.73km2,累计治理水土流失面积142.26km2。但还应看到,人为因素在深圳市水土流失中所起的作用越来越大。因此,治理好深圳市水土流失的有效对策是加强生产建设项目的水土保持监督监测,确保水土保持措施有效实施并发挥效用。本文重点分析了深圳市在预防生产建设项目水土流失方面所做的举措,以期为全国城市水土保持工作提供借鉴。 相似文献
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戴进福 《山西水土保持科技》2011,(3):37-39
加强水土保持监督管理能力建设,是全面提高水土保持依法行政水平,有效遏制人为水土流失危害,促进生态文明建设的需要。通过对南安市水土保持监督管理能力建设取得的成效分析,阐述了监督管理能力建设的重要性,探讨了监督管理能力建设的重点、内涵,针对基层水土保持监督管理工作存在的主要问题,提出了具体的对策措施。 相似文献
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The charge characteristics of A1 or Ap and B2 horizon samples of total 23 Ultisols, Alfisols and Oxisols in Korea and Thailand were studied by measuring the retention of NH4+ and NO3? at different pH values (4–8) and NH4NO3 concentrations (0.1–0.005 m ). The magnitude of their negative charge (σ?; meq/100g) was dependent on pH and NH4NO3 concentration (C; m ) as represented by a regression equation: log σ?=apH +blogC +c. The values of the coefficient a (0.04–0.226), b (0.03–0.264) and c (–0.676–1.262) were correlated with the kinds of the soil and horizon and with the region where the soil exists. The retention of NO3? was less than 1 and 2–3 meq/100 g for the A1 or Ap and B2 horizon samples, respectively. The sum of exchangeable base and Al (‘effective’ CEC) was close to and higher than the magnitude of permanent charge (=σ? measured at pH = 4.3 and at C = 0.005 m ) for one-third and two-thirds of samples, respectively. A σ? value of 16 meq/100 g clay at pH = 7 and C = 0.01 m was found appropriate to separate the B2 horizons of Thai Ultisols and Oxisols from those of Korean Ultisols and Alfisols. Korean Alfisols and Ultisols and Thai Ultisols were distinguished from each other on the status of exchangeable base and Al 相似文献
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Quantifying global patterns of forest soil respiration (SR), its components of heterotrophic respiration (HR) and belowground autotrophic respiration (AR), and their responses to temperature and precipitation are vital to accurately evaluate responses of the terrestrial carbon balance to future climate change. There is great uncertainty associated with responses of SR to climate change, concerning the differences in climatic controls and apparent Q10 (the factor by which respiration increases for a 10 °C increase in temperature) over HR and AR. Here, we examine available information on SR, HR, AR, the contribution of HR to SR (HR/SR), and Q10 of SR and its components from a diverse global database of forest ecosystems. The goals were to test how SR and its two components (AR and HR) respond to temperature and precipitation changes, and to test the differences in apparent Q10 between AR and HR. SR increased linearly with mean annual temperature (MAT), but responded non-linearly to mean annual precipitation (MAP) in naturally-regenerated forests. For every 1 °C increase in MAT, overall emissions from SR increased by 24.6 g C m−2 yr−1. When MAP was less than 813 mm, every 100 mm increase in MAP led to a release of 75.3 g C m−2 yr−1, but the increase rate declined to 20.3 g C m−2 yr−1 when MAP was greater than 813 mm. MAT explained less variation in AR than that in HR. The overall emissions in AR and HR for every 1 °C increase in MAT, increased by 12.9 and 16.1 g C m−2 yr−1, respectively. The AR emissions for every 100 mm increase in MAP, increased by 44.5 g C m−2 yr−1 when MAP less than 1000 mm. However, above the threshold, AR emissions stayed relatively constant. HR increased linearly by 15.0 g C m−2 yr−1 with every 100 mm increased in MAP. The Q10 value of SR increased with increasing depth at which soil temperature was measured up to 10 cm and was negatively correlated with HR/SR. Our synthesis suggests AR and HR differ in their responses to temperature and precipitation change. We also emphasized the importance of information on soil temperature measurement depth when applying field estimation of Q10 values into current terrestrial ecosystem models. Q10 values derived from field SR measurements including AR, will likely overestimate the temperature response of HR on a future warmer earth. 相似文献
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《Journal of plant nutrition》2013,36(7):1227-1242
Abstract Uptake of arsenic (As) and its distribution in Chinese Brake fern (Pteris vittata L.), an As hyperaccumulator, and Boston fern (Nephrolepis exaltata L.), a nonhyperaccumulator, in the presence of phosphorus (P), were characterized by employing a hydroponic experiment with a complete three-factorial design. Two levels of As (100 and 1000 µM) and four levels of P (0, 100, 500, and 1000 µM) were used in this study. Arsenic uptake rates on the basis of root fresh weight for the two ferns were similar at low As concentration (100 µM). At high As concentration (1000 µM), however, As uptake rates (373–987 nmol g?1 f wt h?1) of P. vittata were significantly greater than those of N. exaltata (164–459 nmol g?1 f wt h?1). In both ferns, addition of P reduced their As uptake rate as well as accumulation. Pteris vittata had a greater As TF (Translocation factor = concentration ratio of fronds to roots) than N. exaltata. On the contrary, N. exaltata displayed a greater P TF than P. vittata. As a result, high P/As ratio was observed in the roots of P. vittata, whereas high P/As ratio was observed in the fronds of N. exaltata. The study illustrated that As hyperaccumulation by P. vittata may be facilitated by its high As influx rate and its high molar P/As ratio in the roots resulting from both high As TF and low P TF. 相似文献
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Soil microbial and extractable C and N after wildfire 总被引：12，自引：0，他引：12
The effect of wildfire on soil microbes and extractable C (Cext) and N (Next) changed with respect to the time from burning and soil depth. Initially, microbial biomass C (Cmic) and N (Nmic) were drastically reduced in the soil surface layer (0–5 cm) and reduced by 50% in the subsurface (5–10 cm), whereas Cext increased by 62% in the surface layer and did not significantly change in the subsurface. These parameters were affected
for the following 4 years, during which the average reductions in the soil surface and subsurface layers were, respectively,
60% and 50% for Cmic, 70% and 45% for Nmic, 60% and 40% for the ratio Cmic: organic C (Corg) and 70% and 30% for the ratio Nmic: total N (Ntot), while for Cext the surface layer was the only zone consistently affected and Cext decreased by up to 59%. Immediately after a fire, the Cext : Corg ratio increased by 3.5-fold and 2-fold in the surface and subsurface layers, respectively; thereafter for 2 years, it decreased
in the surface layer (by up to 45%) while the effect on the subsurface layer was not consistent. The effect of burning on
Next lasted 1 year, in which Next increased by up to 7- and 3-fold in the surface and subsurface layers, respectively, while the average Next : Ntot ratio doubled in the surface layer and increased by 34% in the subsurface. During the time in which each parameter was affected
by burning, the soil factor explained a high percentage of variance in the fluctuations of Cmic, Nmic, Cmic : Corg and Nmic : Ntot, while those of Next and Next : Ntot, but not those of Cext and Cext : Corg depended on both the soil and its depth. In the burned soils similar patterns of response were found between the following
parameters listed in pairs: Cmic and Nmic; Cmic : Corg and Nmic : Ntot; Cext and Next; and Cext : Corg and Next : Ntot. However, after the fire relationships found previously between the parameters studied and many other soils properties were
either no longer evident, or were inverted. Although the addition of cellulose to the burned soil favoured fungal mycelium
development and increased Cmic and Cext contents, the negative effect of burning on the microbial biomass and the Cext was not counteracted even under incubation conditions suitable for both microbial growth and C mineralization.
Received: 28 May 1997 相似文献
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Sotiris Stasinos Marios Kostakis Nikolaos Thomaidis Ioannis Zabetakis 《Water, air, and soil pollution》2014,225(10):1-14
Tropospheric ozone (O3) has long been documented to cause an injury to plants, but a plants’ protectant, widely applicable in agronomical practice, does not exist. We evaluated the potential antiozonate efficacy of the antitranspirant di-1-p-menthene (Vapor Gard) compared with ethylenediurea (EDU) on Bel-W3 tobacco plants. Plants were treated either with water, or by EDU (10, 100, and 500 mg dm?3), or by vapor (1, 5, 10, and 50 ml dm?3) and were exposed either to O3-enriched (90 ppb) or O3-free air, for 12 days and 8 h day?1. EDU when applied at 10 mg dm?3 did not protect the plants against O3, but when applied at 100 and 500 mg dm?3 offered a significant protection to the plants. Vapor, when applied at 1 ml dm?3 did not protect the plants against O3, neither by terms of foliar visible injury nor by terms of aboveground biomass. In addition, when applied at 10 and 50 ml dm?3 caused phytotoxicity to all the plants, which it was expressed as necrotic spots on the leaves’ surface, misshaping of the leaves, or short plants' height. It is obvious that vapor does not protect Bel-W3 tobacco plants against O3. The antiozonate role of di-1-p-menthene is species-specific and probably occurs only under short-term exposures. 相似文献
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Influence of Puroindolines A and B Individually and in Combination on Wheat Milling and Bread Traits
Endosperm texture in wheat (Triticum aestivum L.) is determined by the Pina and Pinb genes located within the Hardness (Ha) locus on chromosome 5D. We have previously shown that Pina and Pinb can act alone to produce intermediate-textured grain or act together to produce soft grain. The objective here was to isolate the role of PINA and PINB individually and in combination on milling and bread traits by analyzing F3 recombinant lines created by crosses between PINA and PINB null cultivars with Pina-D1a and Pinb-D1a overexpressing transgenic lines. Homozygous lines that contained either the Pina-D1b/Pinb-D1a (Pina null) or Pina-D1a/Pinb-D1e (Pinb null) Ha locus with or lacking transgenically added Pina or Pinb were analyzed for milling and bread traits. Addition of Pina-D1a to Pina-D1b/Pinb-D1a and addition of Pinb-D1a to Pina-D1a/Pinb-D1e Ha locus genotypes gave soft grain with lower flour yield, flour ash, and a higher proportion of small flour particles. Addition of Pinb-D1a produced greater negative effects on loaf volume than addition of Pina-D1a. Grain hardness, flour protein, flour ash, and mixograph water absorption were positively correlated, which is indicative of the complex phenotype conditioned by PINs. The results demonstrate that PIN overexpression leads to a reduction in grain hardness and reduced flour yield, flour ash, and flour particle size. PIN expression also results in reduced loaf volume and flour water absorption. 相似文献
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Stefan Trapp Almut Köhler Lars C. Larsen Kim C. Zambrano Ulrich Karlson 《Journal of Soils and Sediments》2001,1(2):71-76
The toxicity of fresh and weathered gasoline and diesel fuel to willow and poplar trees was studied using a tree transpiration toxicity test. Soils were taken from an abandoned filling station. Concentrations in the samples were measured as the sum of hydrocarbons from C5 to C10 (gasoline) and C12 to C28 (diesel). Concentrations ranged from 145 to 921 mg/kg gasoline and 143 to 18231 mg/kg diesel. The correlation between log soil concentration and toxicity to willows(Salix viminalis x schwerinii) was highly significant for the diesel fraction (r2=0.81, n=19) and for the sum of hydrocarbons (r2=0.84, n=19). The EC50 (50% inhibition of transpiration) for the sum of hydrocarbons was determined at 3910 mg/kg (95% C.I., 2900 to 5270 mg/kg) and followed a log-normally distributed sigmoidal curve. The EC10 was 810 mg/kg (95% C.I., 396 to 1660 mg/kg). The results were verified with artificially mixed diesel and gasoline contaminated soils, and two willow and one poplar species(S. viminalis, S. alba and Populus nigra). Fresh diesel at about 1000 mg/kg showed no effect onS. alba, althoughP. nigra was more sensitive. 10000 mg/kg seriously affected the transpiration of all species, silver willow(S. alba) being the least sensitive. Free phase diesel killed all trees within six weeks. Fresh gasoline at 1000 mg/kg was deadly for all trees, hence was more toxic than weathered gasoline. Survival of poplars and willows planted at the abandoned filling station was compared to the laboratory findings. There was some correlation, but in the field, trees also suffered from other stress factors than fuel pollution. 相似文献
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Interactions between the N2-fixing bacterium Azospirillum brasilense and the mycorrhizal fungus Glomus mosseae were studied in relation to their effects on the growth and nutrition of Zea mays (C4) and Lolium perenne (C3) plants. Although roots from plants inoculated with Azospirillum exhibited C2H2 reduction activity no significant effect of inoculation on N concentration in the plant shoots was found. With non-mycorrhizal plants, inoculation with Azospirillum resulted in increased dry matter production at the first harvest compared to the effect achieved by supplying N as fertilizer, but this trend was reversed at the last harvest. However, with mycorrhizal maize plants, Azospirillum, which stimulated the development of VA mycorrhiza, was still effective in improving plant growth and nutrient uptake at the last harvest. Azospirillum and N behaved similarly in enhancing the growth and nutrition of mycorrhizal maize. The dual inoculation of maize by Azospirillum and Glomus produced plants of a similar size, N content, and a higher P content, than those supplied with N and P. 相似文献
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D. I. Kaplan K. S. Sajwan D. C. Adriano S. Gettier 《Water, air, and soil pollution》1990,53(3-4):203-212
Greenhouse and laboratory studies were conducted to evaluate the toxic effects of Be and V on collards (Brassica oleracea, var. acephala L.). In the laboratory germination study, incremental increases in the Be concentrations of the growing medium induced a steady decline in the radicle length of seven-day-old collard seedling. Beryllium concentrations greater than or equal to 8 mg Be L?1 totally inhibited seed germination. The presence of V in the growing medium had no effect on collard germination; however, it had a profound effect on subsequent radicle elongation. Concentrations of V less than 1 mg V L?1 stimulated radicle elongation, while concentrations greater than or equal to 3 mg V L?1 caused severe toxicity. In the greenhouse study, Be toxicity was observed in collards grown in a Blanton sand (Grossarenic Paleudult) received treatments greater than or equal to 150 mg Be kg ?1 (as BeSO4). Irrespective of treatment level, 97% of the Be taken up by the plants remained in the roots while only 3% was translocated to aboveground plant parts. Vanadium tissue concentrations and toxicity to collards varied with soil type. Additions as low as 80 mg V kg?1 to the Blanton sand significantly reduced collard biomass while additions as high as 100 mg V kg?1 to an Orangebury loamy sand (Typic Paleudult) had no effect on plant biomass. The differential response was attributed to greater accumulation of V by plants grown in the Blanton soil. 相似文献
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Rapid nitrogen（N） transformations and losses occur in the rice rhizosphere through root uptake and microbial activities. However,the relationships between rice roots and rhizosphere microbes for N utilization are still unclear. We analyzed different N forms（NH＋4,NO-3, and dissolved organic N）, microbial biomass N and C, dissolved organic C, CH4 and N2O emissions, and abundance of microbial functional genes in both rhizosphere and bulk soils after 37-d rice growth in a greenhouse pot experiment. Results showed that the dissolved organic C was significantly higher in the rhizosphere soil than in the non-rhizosphere bulk soil, but microbial biomass C showed no significant difference. The concentrations of NH＋4, dissolved organic N, and microbial biomass N in the rhizosphere soil were significantly lower than those of the bulk soil, whereas NO-3in the rhizosphere soil was comparable to that in the bulk soil. The CH4 and N2O fluxes from the rhizosphere soil were much higher than those from the bulk soil. Real-time polymerase chain reaction analysis showed that the abundance of seven selected genes, bacterial and archaeal 16 S rRNA genes, amoA genes of ammonia-oxidizing archaea and ammonia-oxidizing bacteria, nosZ gene, mcrA gene, and pmoA gene, was lower in the rhizosphere soil than in the bulk soil, which is contrary to the results of previous studies. The lower concentration of N in the rhizosphere soil indicated that the competition for N in the rhizosphere soil was very strong, thus having a negative effect on the numbers of microbes. We concluded that when N was limiting, the growth of rhizosphere microorganisms depended on their competitive abilities with rice roots for N. 相似文献