山西省永定河上游和湫水河流域重点治理进展

至 2 0 0 0年底止 ,山西省湫水河流域和永定河上游国家重点治理区 ,二期工程第二阶段治理共完成水土流失初步治理面积 989km2 ,占规划治理任务的 75 %。治理中以沙棘、柠条为主的灌木林建设得到长足发展 ,退耕还林还草迈出了扎实的步伐 ;以高标准的精品小流域建设为示范样板 ,辐射和带动全省小流域治理向纵深发展 ;组建专业队 ,实行招标制 ,确保了治理质量和效益。介绍了水保生态建设的特点和创新机制的做法     

The Pollution Load by Nitrogen and Phosphorus in the Cetina River

The objective of the investigations of the Cetina River, located in southern Croatia, was to record specific characteristics and properties of the Cetina waters at nine stations. In addition to measurements undertaken in the Cetina River, the water quality of its most significant springs and tributaries, such as Kosinac, ?ilovka, Studenci and Mala Ruda, Velika Ruda and Grab, has also been measured. The water quality in the Cetina watershed has been evaluated in the following storage reservoirs: Peru?a, Bu?ko Blato and Pran?evi?i. The nitrogen compounds and phosphorus concentrations have been estimated at all these sampling sites over a 3-year period (2005–2008). Concentration levels at the Cetina-Vinali? sampling site for total N (from August 2005 to December 2008) ranged from 0 to 1.759 mg/L, for NH₃–N from 0 to 0.374 mg/L, for NO₃–N from 0.063 to 0.916 mg/L and for PO₄–P from 0 to 0.099 mg/L. The results prove that the Cetina-Vinali? sampling site is not polluted by nitrogen and phosphorus compounds. The river section from Trilj to the Pran?evi?i dam, where the water is used for the water supply of Omi?, Makarska and Dalmatian islands, has been polluted by wastewater because the majority of agricultural area, roads, industry and settlements are located upstream of it. The highest concentration for total N of 1.128 mg/L and of 1,527 total coliforms in 100 mL, expressed as a mean value for a 3-year period of investigations, was found at the sampling site Trilj. The results of concentration changes at the ?ikotina La?a and Cetina Radmanove Mlinice sampling sites show no regularities. The highest concentration for total N of 0.941 mg/L was measured at the Cetina Radmanove Mlinice during 2007. The highest concentration for NO₃–N of 0.916 mg/L was measured at the same sampling site. According to the investigations of the water quality of the Cetina springs and tributaries, the bacteriological most polluted river spring is Kosinac, and the bacteriological most polluted river tributary is Grab. With reference to the water quality in the Cetina storage reservoirs, it may be concluded that the lowest quality standard has been found within the Pran?evi?i storage reservoir regarding nitrogen compounds and phosphorus concentration levels.     

树木枯落叶在河流水体中的分解及氮、磷释放动态

以郑州市东风渠为试验点,选择法国梧桐枯落叶为对象,利用分解袋法,在为期39d的分解试验中,研究了落叶分解及氮、磷的动态变化。结果表明:分解过程中,样品质量变化呈现持续减少的趋势,试验期间质量损失约11.6%,理论完全分解时间约8.21a。在生物和非生物因素共同作用下,落叶中的氮、磷含量变化波动较大。试验初期(0-9d),氮含量快速降低;然后又表现为逐渐升高,在分解后期(29-39d)又呈现下降趋势。落叶中磷含量在分解初期呈下降趋势,随后又逐渐升高,到分解中期,磷含量又表现为先下降后升高的趋势,至分解末期,再次出现下降。落叶中氮素的累积指数NAI和磷素累积指数PAI整体上表现出以释放为主。随分解时间,大体上呈现释放-积累-再释放的规律。     

Residues of 2,3,7,8-tetrachlorodibenzo-p-dioxin in the Spring River,Missouri

Contamination of the Spring River in southwest Missouri by 2,3,7,8-tetrachlorodibenzo-p -dioxin (TCDD) is believed to result from several well-defined point source waste disposal sites. Analyses of 31 fish samples and samples of crayfish, mussels, other aquatic invertebrates, and sediments collected in 1981-1983 demonstrated a rapid decline in TCDD levels in biota both upstream and downstream of the area of contamination and are believed to indicate a continuing, long term input of TCDD into the river. Mean concentrations of TCDD 0.5 km downstream from the area of contamination were 38 parts per trillion (pptr) in whole fish and 20 pptr in fish fillet; mean concentrations beyond 14 km downstream were below 4 pptr in both whole fish and fillets. Caged mussels (65 day exposure) did not accumulate TCDD (detection limit, 10 pptr). High fish consumption by local sportsmen may indicate maximum permissible concentrations of less than 5 pptr. in fish fillets.     

Nitrogen and Phosphorus Storage in Contrasting Reaches of a Sub-tropical River System

This study investigated the storage of nitrogen (N) and phosphorus (P) in the biomass, bed sediments and water column of representative reaches of a sub-tropical river, the upper Brisbane River (UBR), Queensland, Australia, and contrasted instream storage with total wet season exports. In reaches which contained accumulated fine sediments, more than 87% of total P and between 50% and 92% of total N were stored in the surface sediments. The lower proportion of N in sediment at some sites was attributed to substantial differences in the N/P ratios of sediments and macrophytes. At one site, the riverbed was dominated by cobbles and boulders and total nutrient stocks were comparatively low and dominated by the biomass. In reaches with a narrow channel and intact riparian cover, biomass N and P were stored predominately in leaf litter, while in wider unshaded reaches, macrophytes dominated. Total instream storage in the mid to lower reaches of the UBR was ??50.9 T for N and ??18.1 T for P. This was considerably higher than total wet season N (??15.6 T) and P (??2.7 T) exports from the UBR. The first flow event in the river after a prolonged period of no flow resulted in the export of free-floating, emergent species Azolla. The estimated biomass of Azolla in the mid to lower reaches of the river was equivalent to approximately 24% and 9% of the total N and P flux, indicating that this may be a significant, previously unaccounted for, source at peak flow.     

长江上游及西南诸河泥石流滑坡及其减灾对策

长江上游及西南诸河区地形高差悬殊,地质构造复杂,降雨丰沛且多暴雨,是我国泥石流、滑坡最为发育的地区。区内发育降雨型泥石流、溃决型泥石流和冰雪消融型泥石流,以及地震滑坡、工程滑坡和降雨滑坡。泥石流和滑坡主要沿断裂带、河流和交通线成线状密集分布,在地震区成群分布,其活动具有突发性、准周期性、群发性、季节性和夜发性、灾害链生效应等特征,对城镇、道路、矿山、农田、水利水电工程、景观资源和风景名胜、生态环境等造成危害。考虑到灾害活动特点和现有的减灾基础,提出如下减灾对策:开展全区灾害普查,建立灾害信息共享平台;全面考虑减灾需求,合理部署减灾工作;重视基础研究,研发减灾技术,规范减灾行为;健全灾害监测体系,提高灾害监测预警精度;加大重点灾害的治理力度,建立不同类型灾害治理模式;进行灾害风险分析,加强灾害风险管理;探索新时期减灾规律,建立灾害持续治理和减灾长效运行机制;加强能力建设,进行减灾教育和科普宣传。     

海河流域水稻田氮磷地表径流流失特征初探

选取海河流域水稻田作为研究对象,在自然降雨条件下通过田间实测方法研究其氮磷元素地表径流流失特征。结果表明,氮磷元素流失率分别为0.7%和0.6%,流失负荷分别为4.77kg.hm-2和2.08kg.hm-2。在详细分析试验结果后,找出影响氮磷地表径流流失量的因素,其中颗粒态氮是农田径流流失的主要形式,并与径流量成明显正向相关,而磷素流失量则受施肥量和径流量双重影响,影响规律较氮素更为复杂,尚需进一步研究。进而得出结论：在北方干旱少雨的气候影响下,地表径流并非海河流域农田种植作物氮磷元素流失的首要途径。     

黄河口新生湿地土壤氮磷分布特征研究

研究了黄河口新生湿地土壤中氮磷的分布特征,并进行了初步环境效应评价。结果表明,黄河口新生湿地土壤氮含量比较低,磷含量相对丰富;全氮分布水平变异系数较大,全磷变异系数较小;除裸滩外,土壤中氮含量垂直变异规律比较明显,土壤磷含量与土壤层次相关性普遍较差,只有滩涂碱蓬表现为异常。湿地土壤中氮磷含量均具有明显的季节动态特征。研究表明,黄河口新生湿地土壤中氮磷含量水平尚不会对近海环境产生富营养污染威胁。     

A retrospective analysis on changes in sediment flux in the Mississippi River system: trends,driving forces,and implications

Journal of Soils and Sediments - The Mississippi River is the largest river in the USA and one of the most regulated rivers in the world. Understanding fluvial sediment flux changes in the...     

A Study of Surface Water Quality in Macedonia,Greece: Speciation of Nitrogen and Phosphorus

A 2-yr (1997–1998) survey aiming at the establishment of national data bases concerning the quality of surface waters has been conducted in the major river systems of Macedonia, N. Greece. This paper presents the physicochemical parameters(pH, conductivity, total suspended solids, temperature and DO),the organic pollution parameters (BOD₅, COD) and the major N and P species (NO₃ ^-, NO₂ ^-,NH₄ ⁺,organic N, orthophosphates and total P) determined at 25 sampling sites located on main rivers, tributaries, streams andditches that drain the major rural, agricultural, urban and industrial areas of N. Greece. Use of multivariate statistics is also made to identify the principal factors which influencethe chemistry of the water in individual river systems.The eutrophication status of the examined systems was evaluatedby means of N/P ratios. Mean N/P ratios showed large variationsamong sampling sites ranging from potential N- to P-limitationconditions. N/P ratios at particular sampling sites showed also great temporal variability thus suggesting temporary states of N- or P- limitation. Most frequently, highest ratio values wereobserved during winter and early spring. Comparisons are made between data from this study region and literature on rivers elsewhere.     

甘肃农田土壤氮磷钾养分变化特征

自1983年全国第二次土壤普查以来,由于经过多年的地力培肥,农田土壤养分发生了变化。1998年土壤养分调查结果揭示了甘肃省不同地域的主要耕种土类及耕地类型的土壤氮磷钾养分变化特征,为今后土壤养分资源的综合评价和科学施肥管理提供了基础资料。     

江河源区高寒嵩草草甸土壤氨基酸成分和含量特征分析

通过高效液相色谱技术分析了青海省果洛州达日县窝赛乡原生嵩草草甸、严重退化草地及人工草地三类植被土壤中各种氨基酸成分及含量。结果表明:(1)三种类型土壤中都检测出19种常见氨基酸:精氨酸、天冬氨酸、丝氨酸、谷氨酸、苏氨酸、丙氨酸、甘氨酸、氨基丁酸、脯氨酸、蛋氨酸、缬氨酸、苯丙氨酸、异亮氨酸、亮氨酸、胱氨酸、组氨酸、鸟氨酸、赖氨酸、酪氨酸;(2)测定结果表明原生嵩草草甸土壤的氨基酸总量显著高于人工恢复重建草地和严重退化土壤氨基酸,而后两者之间差异不显著。原生高寒草地的土壤(6316.28μgg-1)严重退化草地土壤(2977.10μgg-1)人工恢复重建草地土壤(2975.90μgg-1)。(3)原生高寒草地土壤氨基酸总体呈现下降趋势:5月氨基酸含量最高,随后6月7月的显著下降,8月稍微有所回升,9月氨基酸含量到达最低;严重退化草地土壤与人工恢复重建草地土壤氨基酸含量季节变化相似,氨基酸总量在6月份到达最高点,随后7月8月显著下降,9月份稍微有所回升。     

太湖地区河蟹“养殖-净化”复合系统氮磷循环模拟模型研究

以"养殖-净化"复合系统为对象,探讨河蟹养殖尾水达标排放(地表Ⅲ类水)的工程与技术措施。通过构建系统动力学模型,模拟河蟹养殖尾水达标排放的最佳养殖塘与净化塘的面积比,及不同饵料替代比例、水质调控技术与净化效率对养殖塘和净化塘水体TN和TP浓度的影响。模拟结果显示,在常规养殖条件下,要使净化尾水达到地表Ⅲ类水标准,养殖塘与净化塘的最佳面积比为20.5∶1。商品饲料代替5%、10%和15%时,养殖塘TN浓度分别降低3.1%、6.3%和10.0%,TP浓度分别降低4.2%、8.3%和8.3%;净化塘TN浓度分别降低4.5%、10.1%和14.6%。养殖塘水质调控技术对养殖塘和净化塘水体的TN和TP浓度无显著影响。与水葫芦收获1次相比,收获2次和3次的养殖塘TN浓度分别显著降低10.0%和10.0%,TP浓度降低11.1%和11.1%;净化塘TN浓度分别降低16.1%和17.2%。水葫芦收获2次与3次对养殖塘和净化塘水体TN、TP浓度变化无显著影响。以上结果表明,河蟹养殖工程可以按照养殖塘与净化塘的面积比为20.5∶1进行构建,二塘水体的TN、TP浓度随商品饲料替代比例增加而降低;净化塘水葫芦只需收获2次,净化水质即可达标地表Ⅲ类水。     

沼液中氮磷钾化学形态组成及其生物有效性评价

为了解沼液主要养分的组成特点,从长三角地区的养猪场、养牛场和一般农户的沼气池中收集了39个沼液原样,测定了氮、磷、钾的含量及其形态组成,统计分析了各养分组分之间的关系,分析了沼液中氮、磷、钾的生物有效性。结果表明,沼液中氮、磷、钾含量与组分变化很大,养猪场、养牛场与一般农户来源的沼液之间氮、磷、钾含量在统计上差异不明显。氮、磷、钾的各组分含量与它们的全量呈正相关。NH4-N含量、有机氮含量、固相磷占全磷比例、有机磷占水溶性磷比例、颗粒态磷占液相磷比例及Na OH-P占固相磷比例随有机质含量增加而增加,而液相磷占全磷比例、水溶性磷占液相磷比例、PO4-P占水溶性磷比例、残余磷占固相磷比例及液相钾占全钾比例均随有机质含量增加而减少。沼液中氮、磷、钾元素有较高的生物有效性,生物有效态氮、磷、钾占其全量的平均比例分别为75.58%、49.62%和80.98%。     

河南省淮河流域不同土地利用类型氮磷流失的特征分析

为了解河南省淮河流域农业面源污染特征,根据河南省淮河流域的地形地貌、降雨量、土地利用类型等因素,选择区域内有代表性的土地类型和试验点位,建立径流小区,通过测试连续2年的氮磷流失,分析不同土地利用类型径流水中氮磷浓度差异、氮磷流失量差异,并分析氮磷流失量与径流量和径流泥沙量的相关性。结果表明:土地利用类型不同氮磷流失存在明显差异,5种土地类型中种植蔬菜的土地氮的流失量最大,达10.21kg/hm2,种植花卉的土地磷的流失量最大,达3.98kg/hm2;地表径流中氮流失以溶解态氮为主要形式,磷的流失以吸附态磷为主要形式;氮磷流失量与径流量和径流泥沙量存在明显相关性。     

Determination of Optimal Nitrogen,Phosphorus, and Zinc Doses in a Multifactoral Pot Experiment

The effects of nitrogen (N), phosphorus (P), and zinc (Zn) fertilization on the yield of ryegrass was studied in a greenhouse experiment. The treatment combination was set according to the Box–Wilson method. By performing multiple regression analysis, the yield was described as a function of fertilizer doses by a polynomial of the second degree. The R² value of the regression was 0.863. Based on the regression equation, we calculated the optimal fertilizer doses and evaluated the effects of fertilizers by means of three-dimensional graphs. According to the graphs, it can be stated that the yield-increasing effect of N is dominant, but P and Zn doses also influenced yield. The optimum concentrations of the doses were N, 120; P₂O₅, 89; and Zn, 2.8 mg kg^?1. Optimal dry matter (12–14 g pot^?1) can be produced with a large range of Zn and P concentrations and a relatively large N range. At doses more than the optimal dose for each element, a slight depression can be observed.     

The influence of hydrological conditions on dissolved and suspended constituents in the Missouri River

Physical and chemical constituents of the Missouri River near Brownville, Neb. U.S.A. were studied during the period May, 1970 through December, 1972. Considerable variation in river discharge was observed. The changing hydrological conditions affected the concentrations of both the dissolved and suspended constituents in the river. Rain and snowmelt runoff increased the river discharge and also contributed to increased turbidity and total suspended solids. A number of parameters including total phosphorus, total organic nitrogen, oxygen demand and certain metals correlated with increased suspended solids. However, most of the major anions and cations measured showed decreased concentrations as a result of increased river discharge.     

生态工程人工土壤氮磷钾径流损失模型研究

以生态工程人工土壤为研究对象,开展室内人工模拟降雨试验,应用幂函数模型拟合生态工程人工土壤中3种大量元素氮、磷、钾的径流损失与降雨量间的关系,结果显示:磷和钾元素的径流损失量与降雨量的关系呈现相同变化趋势,即在产流初始阶段其单位时间径流损失量较大,随着降雨时间的延长,其单位时间损失量逐渐衰减,最后均趋于稳定,而氮元素的变化趋势与其他元素不同,其单位时间损失量较稳定;钾元素累积径流损失量最大,氮元素累积径流损失量次之,磷元素累积径流损失量相对最小;幂函数模型相关性系数均达0.85以上,能较好地拟合人工降雨后大量元素损失量随降雨量的变化过程。因此,利用该模型可初步描述氮磷钾元素径流损失与降雨量间的耦合关系,为生态工程水土保持与人工土壤养分设计提供理论基础。     

重庆市农田氮磷流失系数初探

结合重庆市农业生产的实际情况,在全市设置监测点12个,以一个种植季为监测周期,采集每次降雨后产生的径流和淋溶水,测定其产生量和氮、磷浓度,测算出氮磷流失系数。结果表明,氮主要以地下淋溶途径流失进入水体,磷主要是以地表径流途径流失进入水体。各监测点总氮流失系数在0.011%~10.82%之间,总磷流失系数在0.013%~0.894%之间。氮的流失以硝态氮为主,最高占总氮流失的61.214%。从地表径流看,氮磷流失系数与地面坡度、施肥量成正相关,坡度越高、施肥量越大,氮磷流失系数就越大。从地下淋溶看,养分流失主要受土壤性质的影响,砂质土壤在灌溉或者降雨后,更容易造成养分的流失。     

Biomass Accumulation and its Relationship with the Demand and Concentration of Nitrogen,Phosphorus, and Potassium in Lettuce

Lettuce (Lactuca sativa L.) has a short cultivation cycle and a rare growth pattern. The nutritional management program of this species must be designed before its establishment in field or greenhouse. There are two scientifically based methods to design its fertilization management: the simplified rational model and the dynamics of nutritional accumulation. There is not much information to input into these methods. The present study reports about the biomass accumulation pattern of lettuce, cv. Coolward, and its relationship with the demand and concentration of nitrogen (N), phosphorus (P), and potassium (K). The study was conducted in a greenhouse with a slightly acidic sandy-loam substrate (pH 6.5) and a medium/high content of organic matter and nutrients. Twenty-one replicates were set in pots with increasing amounts of soil, depending on the time of harvest. Nine samplings were conducted from emergence up to commercial maturity (MC) (0–65 days after emergence, DDE). The plants collected were divided into two parts, aboveground (PA) and root (PR), and their dry weights and concentrations of N, P, and K were measured. With these data, biomass relative accumulation and nutrients were calculated. Total biomass association (BT) with the demand and concentrations of N, P, and K was estimated. The growth of lettuce during the first 35 DDE was slow and only represented 10% of the total accumulation of biomass, N, P, and K, mainly in PA. From the beginning of the rosette formation (IFRO) up to MC, the linear accumulation stage of MS, N, P, and K emerged. Over the last 22 days of its cycle, the crop acquired more than 60% of MS and nutrients measured at harvest. The PA accumulated nearly 90% of MS, N, P, and K, and the remaining 10% was found in PR. A close linear association was established between BT and the demand of N, P, and K in lettuce (R² = 0.99), which leads us to assume that the simplified rational model might be employed to estimate the dose of fertilization in this crop. The concentrations of N, P, and K in BT at MC were 4.0, 0.46, and 4.3%, respectively. These values are similar to those reported as internal requirements for this crop in other countries; on this account, they could be used tentatively to feed the models proposed.