氮肥施用对砖红壤硝态氮和盐基离子淋失特征的影响

氮肥品种的合理选用对作物增产增收、 土壤酸化改良有重要的影响。本文以海南省海口市观澜湖采集的砖红壤为研究对象,采用室内土柱模拟试验,对尿素、 硝酸铵和硫酸铵3种氮肥处理下砖红壤硝态氮及盐基离子（Ca2+、 Mg2+、 K+、 Na+）淋失特征进行了研究。结果表明, 1）硝态氮累积淋溶量表现为硫酸铵硝酸铵尿素N0,且硝态氮的淋溶量与施肥量呈正相关关系,整个淋溶过程中硝态氮累积淋溶量（y kg/hm2）与施肥量（x kg/hm2）之间满足线性方程 y=3.3064x+315.74（R2=0.8848）; 2）尿素、 硝酸铵、 硫酸铵处理整个淋溶过程的盐基离子淋溶量均表现为 Ca2+Mg2+K+Na+,且盐基离子淋溶总量（kg/hm2）表现为硫酸铵（1821.12）硝酸铵（1080.27）尿素（872.24）N0（417.23）; 3）砖红壤盐基离子迁移速率表现为硫酸铵（26.28%）硝酸铵（13.37%）尿素（11.78%）,尿素、 硝酸铵和硫酸铵处理分别以线性方程 y=0.1178x+123.18（R2=0.9121）、 乘幂方程 y=15.634x0.4423（R2=0.9259）和对数方程 y=128.38e0.0007x（R2= 0.9244）的拟合度最高。     

Deterioration of copper and bronze caused by acidifying air pollutants

The ‘ICP on effects on materials’ was launched in 1985, within the framework of the Convention on Long-range Transboundary Air Pollution with the aim to find an approach for clearing the main gaps in the knowledge about material degradation caused by environmental impacts. The project was organized as a staggered8 year's material exposure programme accompanied by an extensive measuring programme for environmental parameters. During the evaluation of the 4 years data set it took shape that the most efficient parameters for quantifying the material degradation are the mass loss and especially for copper the corrosion volumes. Bronze already reacts extremely sensitive on low SO₂ concentrations. The starting corrosion rate for copper is suprisingly high. A strong impact of chloride on the formation of pin holes for sheltered copper could be detected without showing high mass loss. At simultanous presence of ozone the corrosive action is catalysed by it's oxidation power and leads to severe mass loss. Based upon the 4 years data set for most of the materials preliminary dose-response-functions have been prepared. For the first time a synergetic effect of SO₂ and ozone has been demonstrated in a field exposure.     

Sources,Rates and Time of Nitrogen Application on Maize Crops under No-Tillage System

Quantitatively, nitrogen (N) is the foremost nutrient for maize crops (Zea mays L.), but the N source to increase the grain productivity still needs more investigation. Thus, the aim of this experiment was to study sources, rates and time of N application on the crop yield and agronomic characteristics of the maize under no-tillage system. The experiment was carried out during two growing seasons on an Oxisol under the factorial 5 × 3 × 3 scheme with five N rates (0, 50, 100, 150, and 200 kg ha^?1) and three sources (ammonium-sulfate-nitrate as inhibitor of the nitrification (ASN+I), ammonium sulfate (AS) and urea); we applied them two times with four replicates: first time at the sowing or later under side dressing when the plants had the six leaves stage. In the first year, the sources of N had no influence on the number of grain line /ear (NGLE), grain number/line (GNL), total number of grain/ear (TNFE), biomass of 100 grain, plant height (PH), height of the first ear insertion (AFEI) and stalk diameter, in contrast with the foliar N content and the crop yield. Early fertilization with N at the sowing time can afford applications as well as the total side dressing. The increase of the rates had positive influence on the N foliar content, plant height and 100 grains biomass. The highest productivities were found with rates above the threshold of 150 kg ha^?1, no matter the sources and the fertilization time.     

Nitrogen transport in plants,with an emphasis on the regulation of fluxes to match plant demand

Physiological methods, especially the use of isotopes of N, have allowed for the detailed characterizations of the several putative transport systems for nitrate and ammonium in roots of higher plants. In the last decade, the cloning of genes that appear to encode both high- and low-affinity transporters represent major advances, as well as substantiating the inferences based on earlier physiological methods. Nevertheless, the unexpected plethora of genes that have been identified now presents even greater challenges, to resolve their individual functions and to attempt to place these functions in a whole plant/environmental context.     

Emissions of acidifying air pollutants in the North West region of England

Most estimates of emission are concerned with the nation state level. This paper will discuss methods utilised in the estimates of emissions to the atmosphere of sulphur dioxide, volatile organic compounds and oxides of nitrogen from a densely populated and heavily industrialised region of the United Kingdom. Data on power generation, industrial plant, fuel usage, air, sea and road transportation, and human population statistics have been integrated into a method to provide regional emission estimates. The resulting emission patterns are described in terms of sources and emission density. Spatial and temporal patterns are identified and major sources of emissions discussed in terms of national control programmes. Transportation is the dominant source of oxides of nitrogen emissions whilst power generation is the dominant source of sulphur dioxide. The relative importance of the North West as an emission source within the UK is assessed. The change in the strengths of acidifying emissions between 1987 and 1992 is discussed and the rate of change in emission magnitudes between the North West region and the UK as a whole compared.     

Estimate of health impacts of acidifying air pollutants and tropospheric ozone in Europe

Based on combined information available from air quality monitoring data and long-range transport models, European population exposure to SO₂, NO₂ and O₃ has been estimated. This information has been combined with the results of epidemiological studies assessing strength of association between the exposure and health effects to estimate an impact of the pollution on health in Europe. The analysis indicates that a considerable number of health problems, ranging from mild irritation of the respiratory system to increased mortality, can be attributed to short-term peaks of pollution observed in Europe. Chronic impacts of prolonged elevated SO₂ levels on lung function are estimated to occur in close to10 million people in Europe.     

Precipitation chemistry in Japan 1989–1993

Precipitation chemistry in Japan was discussed on a wet-only sample database obtained in a nationwide survey from April 1989 to March 1993. Wet-only samples were collected at 29 stations over Japan on a biweekly basis. Commonly determined chemical parameters were measured in laboratories. The volume-weighted annual mean pH at each site ranged from 4.50 to 5.83 with a mean of 4.76. Concentration ranges and means (parenthesized) on an equivalent basis for major ions were as follows: nss-SO₄ ^2–; 5.2–58.9 (38.6), NO₃ ^–; 1.8–25.0 (14.1), NH₄ ⁺; 0.55–29.8 (18.3), nss-Ca²⁺; 2.0–34.5(14.2), Na⁺; 6.4–275.3 (49.1), Cl^–; 13.7–322.4 (63.5) eq L^–1. Acid-base relationships for Phase-II records were quantitatively discussed in terms of three measures: pH, fractional acidity, and our proposed pA_i.     

Effect of sulfate on nitrate transport in volcanic ash soils sampled from the A and the B horizons

Intensive cultivation of crop fields using agricultural chemicals and fertilizers has led to changes in ecological systems, resulting in a high possibility of environmental pollution by contamination, or occasional reactions not only in the soil but also in the water and the atmosphere. Some substances are known to be very toxic to human beings at low concentrations. For example, nitrosamines are believed to be carcinogenic and mutagenic.     

Colorimetric interference and recovery of adsorbed ions from ion exchange resins

Abstract

Analytical interference in the colorimetric determinations of ammonium and nitrate was examined in various KCl extracts of several ion exchange resins. No analytical interference was found in the colorimetric NO₃ ^‐‐N determination in any extract of any resin. However, a mixed‐bed (cation + anion) exchange resin extract substantially affected the colorimetric determination of NH₄ ^‐ ‐N. Recovery of adsorbed ammonium and nitrate from ion exchange resins was also studied as a function of KCl extractant strength and number of extractions. The recovery of adsorbed NO₃ ^‐‐N in the first extraction increased with increasing KCl concentration, with a 2 M solution recovering about 80%. However, a 1 M KCl solution gave the greatest recovery of ammonium‐N, recovering about 75–80% of the adsorbed ammonium. The second extraction with the same concentration of KCl solution was greater with the 0.5 and 2.0 M than with the 1 M solution so that total NH₄ ⁺‐N recovery after two extractions was about the same for all three KCl concentrations. The recovery of resin‐adsorbed NH₄ ⁺‐N and NO₃ ^‐‐N appeared independent of their concentrations on the resins.     

杨梅硝酸还原酶活力研究

用改进的活体法测定了杨梅幼树体内硝酸还原酶(NR)的分布状况。杨梅叶片,枝条、根和根瘤的NR活力分别为404.59,226.40,135.87和45.05 n mol NO_2/30min/gFW。品种、枝梢种类及叶片成熟度不同,其NR活力也不同。介质中氮源的种类和浓度对杨梅叶片的NR活力也有明显影响。对未结瘤的幼苗和离体幼树枝条,硝态氮能提高叶片的NR活力和叶片中的硝态氮含量,两者随硝酸盐浓度的增高而提高;铵态氮抑制叶片的NR活力,浓度愈高,抑制作用愈强。     

A regional scale model for the calculation of episodic concentrations and depositions of acidifying components

An eulerian long-range transport model for the calculation of concentrations of SO₂, SO₄, NO _x , and NO₃ and wet and dry depositions of SO _x (sum of SO₂ and SO₄) and NO _y (sum of NO, NO₂ and NO₃) over Europe is presented. The model is developed in such a way that only routinely available, analyzed or prognostic meteorological fields are required as input data. In this way it is possible to obtain a forecast of the air quality during smog episodes. For evaluation of smog episodes the model provides a way to estimate the contributions of different sources and the effect of emission scenarios. The model has been evaluated for four winter and three summer episodes. The modeled concentrations of SO₂ and SO, are in agreement with the available measurements. A less good agreement is found for NO₂ and NO _x (sum of NO and NO₂) concentrations. For these components the model tends to underpredict the measured values.     

Nitrogen Source and Concentration Affect Growth and Performance of Bedding-Plant Impatiens

ABSTRACT

Impatiens (Impatiens wallerana Hook. f.) is the most important annual bedding plant in the United States, based on wholesale dollar volume. Production of high-quality plants requires optimization of the nutrition regimen during growth, especially the total nitrogen (N) concentration and the ratio of N sources. The objective was to determine the N concentration and the nitrate (NO₃ ^??N):ammonium (NH₄ ⁺?N) ratio of N source that optimized bedding-plant impatiens growth and flower development. Four N concentrations (3.5, 7, 10.5, and 14 mmol N · L^?1) were used in factorial combination with four ratios of NO₃ ^??N:NH₄ ⁺?N (4:0, 3:1, 1:1, and 1:3). Application of treatments was made for 30 d. Then for 10 d only deionized water was applied to reduce salt buildup. Substrate pH was lowest (4.9) with the NH₄ ⁺?N source and electrical conductivity (EC) highest, but never > 2.4 dS m^?1. Nitrogen concentration and N source displayed an interaction for most growth parameters. Shoot fresh and dry weights and flower bud number were maximized at the 1:3 NO₃ ^??N:NH₄ ⁺?N ratio with a N concentration of 10.5 mmol L^?1. However, plant diameter, leaf number, and leaf chlorophyll content responded quadratically to N form ratio, with the 1:1 ratio optimum at a concentration of 10.5 mmol N· L^?1.     

地表水NH4和NO3随水体入渗在土壤和地下水中输送过程的土槽试验研究

The infiltration of water contaminants into soil and groundwater systems can greatly affect the quality of groundwater. A laboratory-designed large soil tank with periodic and continuous infiltration models, respectively, was used to simulate the migration of the contaminants NH4 and NO3 in a soil and groundwater system, including unsaturated and saturated zones. The unsaturated soil zone had a significant effect on removing NH4 and NO3 infiltrated from the surface water. The patterns of breakthrough curves of NH4 and NO3 in the unsaturated zone were related to the infiltration time. A short infiltration time resulted in a single sharp peak in the breakthrough curve, while a long infiltration time led to a plateau curve. When NH4 and NO3 migrated from the unsaturated zone to the saturated zone, an interracial retardation was formed, resulting in an increased contaminant concentration on the interface. Under the influence of horizontal groundwater movement, the infiltrated contaminants formed a contamination-prone area downstream. As the contaminants migrated downstream, their concentrations were significantly reduced. Under the same infiltration concentration, the concentration of NO3 was greater than that of NH4 at every corresponding cross-section in the soil and groundwater tank, suggesting that the removal efficiency of NH4 was greater than that of NO3 in the soil and groundwater system.     

氮素形态对菠菜可食部分硝酸盐和草酸累积的影响

采用溶液培养试验研究了营养液中硝态氮/铵态氮比例对菠菜地上部可食部分不同器官硝酸盐以及不同形态草酸累积的影响。结果表明,菠菜地上部生物量随供铵比例从0%提高到50%呈增加趋势而后显著下降。叶片和地上部可食部分的硝酸盐含量和累积量均随供铵比例增加而显著下降;叶柄的硝酸盐含量随供铵比例提高而降低,而硝酸盐积累量则先升高后显著下降。叶片是菠菜积累草酸的主要器官,可溶态草酸与草酸总量分别占地上部的56.3%～89.8%和76.6%～87.4%。可溶态草酸是菠菜体内草酸的主要形态,在叶片、叶柄及地上部中所占草酸总量的比例分别在36.7%～83.5%,79.0%～93.3%以及50.0%～83.0%之间。地上部各器官的可溶态草酸含量、难溶态草酸含量和草酸总量以及积累量均随着供铵比例的增加而显著下降,叶片和地上部的草酸含量和积累量的下降幅度均高于叶柄。可见,调节营养液中硝态氮/铵态氮比例可以有效降低菠菜地上部可食部分硝酸盐和草酸的含量和积累量,50/50是营养液中适宜的硝态氮/铵态氮比例,不仅菠菜的生物量最高,而且硝酸盐和各形态草酸的含量以及累积量较低,从而大大减轻了硝酸盐和草酸对人体健康产生的负面影响。     

硝酸磷肥中氮含量测定方法的研究

研究了硝酸磷肥中总氮量的测定，在测定过程中，在浓硫酸的存在下，硝酸根与过量尿素发生反应，过量尿素水解成铵根离子，加入一定量的中性甲醛，生成定量的酸，用碱标准溶液滴定，所得结果和国标法（真值）比较，相对误差在0．4％以内，具有较高的准确度和精密度。文章还对测定条件做了正交实验，选择了最佳实验条件，通过试验，说明了这种方法的可行性。     

Nitrogen rates in strawberry (Fragaria ananasa) nursery on growth and yield in the field

Strawberry (Fragaria ananassa cv. Aliso) plants were grown under three N‐rates in the nursery: 80, 320 and 640 kg N/ha, and then transplanted to the fruiting field. Plants from each nursery treatment were given 150, 300 and 450 kg N/ha. The fertilizer was given as ammonium sulfate in the nursery and as ammonium nitrate in the field, a part broadcasted before planting and the other part applied as top dressings. Biomass production, plantlets size distribution and N content were restricted by the lowest level of N given in the nursery. Plants grown at 320 kg N/ha in the nursery gave significantly earlier and higher total yields than those grown at the other rates. Fruit yields were not significantly influenced by the N‐application in the field. N fertilization in the early stages of strawberry plant development in the nursery is more important than later field application.

The influence of N fertilization on the growth and yield of strawberry plants has been studied by several workers. In some reports yields were increased when the rate of N applied was increased (1, 2, 3). In other studies no influence was found (4, 5, 6), or even a decrease in yield was reported as the rate of applied N was increased (7). While in some studies detrimental effects of N‐fertilizer on fruit yield were observed at 200–300 kg N/ha (8, 9), in other studies (6, 7) N applications up to 400 kg/ha did not affect yield. In Spain (3), adding up to 680 kg/ha caused an increase in fruit yield.

Even at relatively low applied‐N levels, up to 150 kg N/ha, strawberry response reports are not consistent. Some workers found that increasing N in this range caused an increase in fruit yield (8, 9, 3, 7, 10), while no effect was observed (4, 5, 6, 11) in several other studies. Most of the reported experiments with N‐fertilizer were carried out after plants were transplanted from the nursery to the field. To the best of our knowledge no attempt was made to evaluate the effect of fertilizer applied in the nursery.

The objective of this work was to evaluate the influence of different levels of N‐fertilizer, in both the nursery and the field, on strawberry plant development and composition, earliness, yield level and yield distribution.     

Concentration and deposition of acidifying air pollutants over Sweden: Estimates for 1991 based on the match model and observations

The MATCH (Mesoscale Atmospheric Transport and CHemistry) model has been developed as a tool for air pollution assessment studies on different geographical scales. MATCH is an Eulerian atmospheric dispersion model, including physical and chemical processes governing sources, atmospheric transport and sinks of oxidized sulfur and oxidized and reduced nitrogen. Using a combination of air and precipitation chemistry measurements and the MATCH model, the national and long-range transport contributions to air pollution and deposition can be quantified in the model region. The calculations for the year 1991 show that the Swedish import was about 4.5 times larger than the export for sulfur and about six times larger for reduced nitrogen, while the Swedish import of oxidized nitrogen only exceeded the export by 10%. Using the MATCH system we estimate the long-range transport in an independent way compared to EMEP. Comparison between the EMEP and MATCH calculations for 1991 show that the total deposition of oxidized nitrogen over Sweden is similar, while the EMEP-values for total deposition of oxidized sulfur and reduced nitrogen are 25% respectively 40% smaller than what is obtained from MATCH.     

Corn (Zea mays L.) Grain and Stover Yield as Affected by Soil Residual Mineral Nitrogen

Evaluation of nitrogen (N) dynamic in soil using regression equations is important for proper determination of N fertilization. A 3-year field experiment was conducted to (1) develop the best-fitted regression model relating corn grain and stover yield to soil residual ammonium (NH₄)-N and nitrate (NO₃)-N for corn yield prediction and (2) evaluate how such a model can be beneficial to the health of ecosystem by predicting the appropriate rates of N fertilization for corn production. Soil NH₄-N and NO₃-N were determined at corn harvest at the depths of 0–30 and 30–60 cm. Nitrogen fertilizer rates and soil mineral N accounted for a maximum of 93% variation in corn grain yield. Soil mineral N enhanced corn yield more than N fertilizer. Totals of 63.1 and 14.1 kg/ha of soil residual NO₃-N and NH₄-N were found in the 0- to 60-cm depth, indicating the importance of performing soil N tests.     

四川省不同区域地表太阳总辐射模型适用性评价

选用1994−2016年四川省7个辐射站气象数据,在3个辐射区（川西高原I区、川东盆地II区和川西南山地III区）中评价了6种地表太阳总辐射（Rs）估算模型在3种天气类型（晴、多云、阴）下的适用性,并分析基于天气类型的组合模型在不同区域的模拟效果,以探寻最适宜全省不同区域的Rs估算方法。结果表明：（1）各经验模型在四川省整体表现良好（决定系数R2介于0.554～0.934,P <0. 001）,I区（甘孜和红原站）模拟效果最好的为日照时数模型A−P（平均绝对误差MAE为2.210±0.714MJ∙m⁻²∙d⁻¹）,II区（成都、绵阳和泸州站）、III区（峨眉山和攀枝花站）模拟效果最佳的均为混合模型Chen（II区MAE为1.510±0.027MJ∙m⁻²∙d⁻¹,III区为1.930±0.006MJ∙m⁻²∙d⁻¹）;（2）6个模型在四川省3种天气类型下的模拟效果呈晴天>多云>阴天的规律,日照时数模型（A−P和Ba模型）能更好地模拟晴天时的Rs,混合模型（Chen和Ab模型）则在多云和阴天时模拟效果更佳,I区在晴天、多云、阴天3种天气下模拟效果最好的模型分别是A−P（整体评价指标GPI为0.850）、Ab（1.294）、Ba（0.862）,II区分别为A−P（0.381）、Chen（1.358）、Chen（1.742）,III区分别为Chen（0.204）、Chen（0.857）、Chen（0.526）;（3）基于天气类型的组合模型（M新）模拟各区Rs的效果均比未组合前各模型的效果好（3个区GPI分别为0.558、0.582、0.134）。因此,推荐使用基于天气类型的组合模型来估算四川省Rs。