沼液对莴笋和生菜硝酸盐含量及营养品质的影响

采用盆栽试验 ,研究了不同沼液用量对莴笋、生菜硝酸盐含量和营养品质的影响。结果表明 ,施用沼液提高了莴笋、生菜株高和产量 ,降低了莴笋茎和生菜硝酸盐含量 ,有利于增加莴笋茎、叶及生菜含水量和氨基酸含量 ,生菜维生素C含量略高于对照。在施用氮磷钾化肥 (N 12 0mg·kg-1、P2 O580mg·kg-1、K2 O 10 0mg·kg-1)基础上 ,每钵增施沼液 5 0 0ml,可改善蔬菜营养品质 ,使莴笋叶和生菜硝酸盐含量分别降低 5 3.5 %和 4 5 .5 % ,同时还可使 2种蔬菜分别增产 5 1.0 %和 5 6 .7% ,为本试验条件下莴笋、生菜最佳施肥组合。     

菠菜（Spinacia oleracea）硝酸盐含量的控制和预测的研究

建立了菜园系统中施氮量ρＡ（Ｎ）土壤水分ｗ（Ｈ２Ｏ）（以占田间最大持水量的百分数表示）土壤肥力ｗ（ＲＡＨＮ）（以土壤还原碱解Ｎ（ＲＡＨＮ）水平表示）３因素影响菠菜植株ＮＯ３－Ｎ含量（ｗ（ＮＯ３－Ｎ）的三元二次数学模型，模型分析和盆栽，微区及大田验证试验结果表明：３因素对菠菜植株ｗ（ＮＯ３－Ｎ）影响的顺序是：ρＡ（Ｎ）〉ｗ（ＲＡＨＮ）〉ｗ（Ｈ２Ｏ），既能使菠菜高产，又能使植株ｗ（ＮＯ３－Ｎ）达到国颁     

Logistic Regression在我国河流水系氮污染研究中的应用

对四川省岷江、沱江及嘉陵江流域和江西省的赣江流域及鄱阳湖地区共170多个水文站的数据进行了相关分析和多元回归分析。结果表明，河流水中硝态氮浓度与年降雨量、人口密度、氮肥施用量、牲畜饲养量、农作物及粮食作物种植面积等因素有较好的相关性。以以上数据资料为基础，将河流水NO3^--N的浓度划分为背景浓度（＜0．7mg/L)、受人类活动的显著影响的NO3^--N浓度（＞3．0mg/L)以及中间类（0．7－3．0mg/L)进行Logistic Regression分析，两个Logistic模型的准确度分别达82．46％和89．19％。运用Logistic模型对整个长江流域河流水中NO3^--N浓度进行估计，结果与实测值基本相符合。     

珠江三角洲典型地区蔬菜硝酸盐与亚硝酸盐污染评价

研究了珠江三角洲典型地区中山市大型蔬菜生产基地中9种蔬菜30个样品中硝酸盐与亚硝酸盐的污染现状,初步摸清了蔬菜中硝酸盐及亚硝酸盐的污染状况。并以WHO/FAO规定的日允许摄入量换算得到的标准评价了其主要蔬菜品种的硝酸盐污染状况。结果表明:在被调查的蔬菜中,硝酸盐含量由高到低依次为菜心→白菜>芥菜→空心菜→生菜→瓜果类,菜心、芥菜和白菜为严重污染,生菜与空心菜为重污染,瓜果类蔬菜为轻污染;亚硝酸盐含量普遍较低,均未超标。因而有必要采取有效的污染防治措施控制该地区蔬菜中的硝酸盐污染状况。     

Effects of allelochemicals on activity of nitrate reductase

ＩｎｔｒｏｄｕｃｔｉｏｎＰｌａｎｔｓｔｒａｗａｓａｉｍｐｏｒｔａｎｔｍｅａｓｕｒｅｆｏｒｉｎｃｒｅａｓｉｎｇｔｈｅｆｅｒｔｉｌｉｔｙａｎｄｉｍｐｒｏｖｉｎｇｔｈｅｓｔｒｕｃｔｕｒｅｏｆｓｏｉｌ,ｈａｓｂｅｅｎｗｉｄｅｌｙａｐｐｌｉｅｄｉｎａｇｒｉｃｕ?..     

长江中下游浅水湖泊中总氮及其形态的时空分布

分析和比较了长江中下游 3个浅水湖泊———太湖、巢湖和龙感湖夏、秋和冬季沉积物和上覆水中的总氮及其氮形态 ,描述了氮及其各形态在 3个湖泊中的时空分布特征 .结果表明 :空间上 ,无论是在表层沉积物还是在上覆水中 ,太湖中总氮的含量均高于其他 2个湖泊 ,且在太湖和巢湖都呈现西高东低的分布特征 .氨氮在沉积物和上覆水及溶解态硝态氮在上覆水中的分布与总氮分布趋势基本相同 .巢湖沉积物中氨氮浓度所占的比例稍高于太湖和龙感湖 .在不同季节 ,表层沉积物和上覆水中的总氮含量冬季高于秋季和夏季 ,表层沉积物中氨氮浓度在秋季最高 .巢湖和龙感湖上覆水中的溶解态硝态氮在冬季浓度较高 ,而在太湖西北部这种季节差异几乎没有 ,氨氮的浓度季节性差异也不十分明显     

矿山炸药污染防治

大多数工业炸药含70％～94％硝酸铵（重量比）铵油炸药是最为普遍使用的且比其他炸药价廉的一种炸药，但它易溶于水，并析出氮和硝酸盐。文中论述启用严密的炸药管理程序可以降低炸药的损失。另外，在贮存、爆破设计、装药等方面采取措施，也可控制炸药损失，并可降低水中氮和硝酸盐的含量，减少环境污染量。     

REGIONAL ASSESSMENT OF NLEAP NO3-N LEACHING INDICES1

ABSTRACT: Nonpoint source ground water contamination by nitrate nitrogen (NO₃-N) leached from agricultural lands can be substantial and increase health risks to humans and animals. Accurate and rapid methods are needed to identify and map localities that have a high potential for contamination of shallow aquifers with NO₃-N leached from agriculture. Evaluation of Nitrate Leaching and Economic Analysis Package (NLEAP) indices and input variables across an irrigated agricultural area on an alluvial aquifer in Colorado indicated that all leaching indices tested were more strongly correlated with aquifer NO₃-N concentration than with aquifer N mass. Of the indices and variables tested, the NO₃-N Leached (NL) index was the NLEAP index most strongly associated with groundwater NO₃-N concentration (r² values from 0.37 to 0.39). NO₃-N concentration of the leachate was less well correlated with ground water NO₃-N concentration (r² values from 0.21 to 0.22). Stepwise regression analysis indicated that, although inorganic and organic/inorganic fertilizer scenarios had similar r² values, the Feedlot Indicator (proximity) variable was significant over and above the NO₃-N Leached index for the inorganic scenario. The analysis also showed that combination of either Movement Risk Index (MIRI) or NO₃-N concentration of the leachate with the NO₃-N Leached index leads to an improved regression, which provides insight into area-wide associations between agricultural activities and ground water NO₃-N concentration.     

DISTRIBUTION OF NITRATE AND ORTHOPHOSPHATE IN SELECTED STREAMS IN CENTRAL NEBRASKA1

ABSTRACT: The Central Nebraska Basins is one of 60 study units in the National Water-Quality Assessment Program of the U.S. Geological Survey. The study unit includes the Platte River and two major tributaries, the Loup and Elkhorn Rivers. Agriculture is the predominant land use in the study unit, with only eight urbanized communities exceeding a population of 10,000. Water samples were collected from selected streams in the study unit during 1993–1995. The data were used to assess the distribution of nitrogen compounds and phosphorus in the streams and to relate the concentrations of these constituents to environmental settings. This article focuses on dissolved nitrate and orthophosphate. Dissolved nitrate concentrations were highest (90th percentiles were less than 7.0 milligrams per liter as nitrogen) in areas with extensive cropland and pasture, where chemical fertilizers are intensively applied. Synoptic measurements conducted in March and August 1994 indicate that relatively little residual fertilizer, as nitrate, applied during a single crop-growing season enters streams. Dissolved nitrate concentrations showed a seasonal pattern, being highest during winter months and lowest during the late spring and summer. Dissolved orthophosphate concentrations tended to be low across the study unit, 90 percent of all analyses did not exceed 1.7 milligrams per liter as phosphorus.     

AGRICULTURAL LAND USE EFFECTS ON NITRATE CONCENTRATIONS IN A MATURE KARST AQUIFER1

ABSTRACT: The impact on water quality by agricultural activity in karst terrain is an important consideration for resource management within the Appalachian Region. Karst areas comprise about 18 percent of the Region's land area. An estimated one-third of the Region's farms, cattle, and agricultural market value are on karst terrain. Nitrate concentrations were measured in cave streams draining two primary land management areas. The first area was pasture serving a beef cow-calf operation. The second area was a dairy. Nitrate-N concentrations were highest in cave streams draining the dairy and a cave stream draining an area of pasture where cattle congregate for shade and water. The dairy contributed about 60 to 70 percent of the nitrogen load increase in the study section of the cave system. It was concluded that agriculture was significantly affecting nitrate concentrations in the karst aquifer. Best management practices may be one way to protect the ground water resource.