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土壤盐渍化对尿素与磷酸脲氨挥发的影响 总被引:5,自引:0,他引:5
氨挥发是肥料氮素损失的重要途径之一,肥料类型、土壤类型、肥料用量以及土壤全盐量均影响氨挥发损失率及挥发特征。本文采用通气法测定了磷酸脲和尿素两种肥料六个施肥量处理分别施入六个不同盐渍化程度(1.7、9.9、16.4、23.2、29.1、37.9 g/kg)的土壤后氨挥发累积状况和动力学特性,以及土壤氨挥发累积量与土壤电导值之间的相关性。结果表明:(1)在土壤总盐介于1.66 -37.9 g/kg的范围内,随着土壤含盐量增加,尿素与磷酸脲处理的氨挥发累积量显著增加;土壤含盐量对氨挥发速率有显著的促进作用。(2)各处理二次线性函数拟合的二项式系数a均为负值,表明:在不同盐渍化条件下肥料的挥发速率是随着时间增长而降低的;一次线性函数和Elovich 方程的斜率a随土壤含盐量增加而增大,表明:土壤盐渍化将加剧土壤的氨挥发速率。(3)土壤氨挥发累积量与电导值拟合结果符合logistic方程(︱R︱分别为0.9732,0.9815,0.965,0.9182,0.9817,0.9971︱R︱>r0.01=0.9172, n=6),氨挥发累积量随土壤电导值呈“S”型增长。 相似文献
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Plants, by influencing water fluxes across the ecosystem–vadose zone–aquifer continuum, can leave an imprint on salt accumulation
and distribution patterns. We explored how the conversion of native grasslands to oak plantations affected the abundance and
distribution of salts on soils and groundwater through changes in the water balance in naturally salt-affected landscapes
of Hortobagy (Hungary), a region where artificial drainage performed ∼150 years ago lowered the water table (from −2 to −5 m)
decoupling it from the surface ecosystem. Paired soil sampling and detailed soil conductivity transects revealed consistently
different salt distribution patterns between grasslands and plantations, with shallow salinity losses and deep salinity gains
accompanying tree establishment. Salts accumulated in the upper soil layers during pre-drainage times have remained in drained
grasslands but have been flushed away under tree plantations (65 and 83% loss of chloride and sodium, respectively, in the
0 to −0.5 m depth range) as a result of a five- to 25-fold increase in infiltration rates detected under plantations. At greater
depth, closer to the current water table level, the salt balance was reversed, with tree plantations gaining 2.5 kg sodium
chloride m−2 down to 6 m depth, resulting from groundwater uptake and salt exclusion by tree roots in the capillary fringe. Diurnal water
table fluctuations, detected in a plantation stand but not in the neighbouring grasslands, together with salt mass balances
suggest that trees consumed ∼380 mm groundwater per year, re-establishing the discharge regime and leading to higher salt
accumulation rates than those interrupted by regional drainage practices more than a century ago. The strong influences of
vegetation changes on water dynamics can have cascading consequences on salt accumulation and distribution, and a broad ecohydrological
perspective that explicitly considers vegetation–groundwater links is needed to anticipate and manage them. 相似文献
4.
With the aim to specify the microhabitats of annual plants at arid sites, five different sites within an Acacietum tortilis in the Wadi Araba were investigated. During one vegetation period, plants and soil conditions were analyzed simultaneously and the results were correlated. The water regime is one of the most important facts influencing vegetation pattern: On the one hand, additional lateral water favours the conditions of some microhabitats, on the other hand, the plant available water is strongly limited by salinization leading to osmotic stress. Additionally, ion specific effects of salinization influence the vegetation pattern. The different supply of nitrogen scarcely influences plant growth. The character of the surface can be important for the plant establishment and therefore for the species composition at the different sites. 相似文献
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The development of irrigated agriculture is necessary for fulfilling the rising food requirements of the burgeoning global population. However, the intensification of irrigated agriculture causes the twin menace of waterlogging and soil salinization in arid and semiarid regions where more than 75% of the world's population lives. Waterlogging and salinization have direct and indirect effects on plant growth and yield. The damage to plant growth and yield is much serious when these processes occur simultaneously and generally yield reduction is linearly correlated with the salinity level. The control of shallow watertable with irrigation management and installation of drainage systems are suggestible to control the waterlogging and salinization problems of irrigated agriculture. This paper presents an overview of the different aspects of waterlogging and soil salinization and its impact on the food production and sustainability of irrigated agriculture. Conclusions are provided which could be useful for all the stakeholders. 相似文献
7.
Monitoring wetlands in a salinizing landscape: case studies from the Wheatbelt region of Western Australia 总被引:1,自引:1,他引:0
M. N. Lyons S. A. Halse N. Gibson D. J. Cale J. A. K. Lane C. D. Walker D. A. Mickle R. H. Froend 《Hydrobiologia》2007,591(1):147-164
Three elements of wetland biodiversity (aquatic invertebrates, waterbirds and overstorey vegetation of the wetland edge) have
been monitored since 1998 at Lake Eganu and Paperbark Swamp in the Western Australian Wheatbelt to provide information about
the changes occurring in wetland biodiversity in a landscape that is severely affected by dryland salinization. Changes in
extent of wetland vegetation since the 1960s were examined using historical aerial photographs and waterbird use of Lake Eganu
during the early 1980s was compared with recent waterbird survey results. Lake Eganu, which is within a major drainage line,
started to become salinized in the mid-1960s, about 70 years after land clearing began in the catchment, and its salinity
has increased an order of magnitude. The extent of wetland overstorey vegetation and the richness of freshwater aquatic invertebrates
have both declined about 80%. Waterbird richness has also declined over the past 20 years, with changes in species composition.
Salinization has not occurred at Paperbark Swamp, which is in a small catchment off the main drainage line, and there has
been no consistent change in the biodiversity elements monitored. 相似文献
8.
Marc Estiarte Josep Peñuelas Constancia López-Martínez Ramon Pérez-Obiol 《Vegetation History and Archaeobotany》2008,17(6):667-674
The palaeoenvironment of a former coastal lagoon in the south eastern Iberian Peninsula (San Rafael, Almeria, Spain) were
inferred from one core analyzed for particulate organic matter content (POM) together with its C/N, δ13C, δ15N to depict the biogeochemical record from the Late Glacial to the Holocene. The results, complemented by previously reported
pollen assemblages, indicate the appearance of a freshwater lagoon at 7300 b.p. (uncalibrated 14C age), its salinization at 6200 b.p. and its disappearance at 4400 b.p. The period of existence of the lagoon coincided with a period of wetter conditions as inferred from terrestrial vegetation.
The lagoon’s salinization was not related to a decrease in precipitation but to a stronger maritime influence since there
were no parallel changes in terrestrial vegetation. Salinization caused an increase in δ13C, associated with a higher relative presence of C4 plants, and an increase in δ15N, due to a decrease in plant N demand. The late period of the lagoon, from about 5100 to 4400 b.p., shows a progressive drying and salinization not detected in isotopes but reflected in a decrease in POM, and in the pollen
records. Increases in δ15N were related to increases in salinity within the lagoon, and are indicative of a more open N cycle, because the absence
of changes in terrestrial vegetation rules out changes in the catchment area as the cause for changes in δ15N. 相似文献
9.
Accumulation and toxicity of chloride in bean plants 总被引:1,自引:0,他引:1
S. Hajrasuliha 《Plant and Soil》1980,55(1):133-138
Summary Chloride tends to accumulate in tissues, particularly leaves, of some plants to toxic levels. Chloride accumulation in plants is closely related to Cl concentration in the external solution and the genotype.An experiment was conducted to study the rate of Cl accumulation in bean plants under greenhouse conditions and to determine the toxic levels of this anion in the leaves of red kidney beans. Plants were grown in large tanks containing a basal nutrient solution, salinized with either NaCl or Na2SO4 to produce 80 meq/l solutions of these two salts. Control plants were grown in nonsalinized nutrient solutiosn. Salt-treated plants were harvested at different time intervals and analyzed. Chemical analysis of leaves showed that accumulation of chloride was different from that of other ions derived from salines. The leaf-Cl accumulation was shown to be dependent on Cl concentration of the culture solution as well as the duration of the experiment. The data also revealed two processes of rapid Cl accumulation in the leaves of bean plants when a relatively high concentration of this ion is present in the external solution. These are: (a) a rapid Cl accumulation occurring between transplanting and the first harvest; (b) a second rapid Cl accumulation occurring after the fourth harvest to the end of the experiment leading to a toxic concentration of Cl in the leaves. The second rapid absorption period was absent for the other ions derived from salines. 相似文献
10.
Increasing degradation of the water quality, caused by overuse and salinization, leads to considerable changes of the phytoplankton
composition in Kenyan Rift Valley lakes. Exemplarily, the phytoplankton communities and biomasses of deteriorating freshwater
Lake Naivasha and salinizing Lake Oloidien were studied between 2001 and 2005, accompanied by physico-chemical measurements
(pH, total phosphorus and nitrogen, alkalinity, conductivity). Over the last three decades, the ecology of these two water
basins has been subjected to dramatic changes, caused by excessive use of water and catchment area by man. In L. Naivasha
a shift in the dominance of coccoid cyanobacteria towards dominance of Chlorophyceae (Botryococcus terribilis) was observed. Lake Oloidien exhibited a shift in the dominance of coccoid Chlorophyceae towards dominance of cyanobacteria
(Arthrospira fusiformis, Anabaenopsis elenkinii). Phytoplankton findings and chemical data demonstrate that L. Naivasha has developed towards a eutrophic freshwater lake
while L. Oloidien has progressed towards a hypereutrophic alkaline-saline lake.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.
Handling editor: J. Padisak 相似文献