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1.
N mineralization in sandy soils of the ‘Fuhrberg well field’ (Hannover) during winter Net N mineralization was measured under field conditions during winter and spring 1991/92 in sandy arable soils (Gleyic Podzols, Mollic Gleysols, Gleyic Arenosols) of the ‘Fuhrberg well field’, a drinking water catchment north-east of Hannover. The aim was to assess leaching losses of nitrate from mineralization processes during the winter on soils formerly used as grassland. Two field procedures were used: the incubation of soil material in polyethylene bags at its original location and rain sheltered fallow plots. Between 6 and 40 (100) kg N ha?1 were mineralized during 73 days from Dec., 17th to March, 2nd. Mineralisation rates were closely correlated to the organic N and C contents of the soils (r2 ± 0.9). In the uncovered soils, the NO3 was completely leached out. On five out of seven fields the process ‘N-mineralization during winter’ alone was sufficient to exceed the official limit for drinking water (50 mg 1?1 NO3? ) in the uppermost groundwater. It is concluded that even 15 years after converting grassland into arable land the Norg and Corg levels in the soils had not reached a new equilibrium. 相似文献
2.
Günther Springob Sven Brinkmann Nicole Engel Holger Kirchmann Jürgen Bttcher 《植物养料与土壤学杂志》2001,164(6):681-690
We evaluated the contents of organic carbon (Corg) of Ap horizons from 11 North German study areas along a Southeast to Northwest precipitation gradient with respect to their general levels and as related to C : N ratio, soil texture (clay content), bulk soil density, climate, and historical land‐use since 1780. The focus was on sandy soils, with the largest group of samples originating from 308 km2 of the Fuhrberg catchment north of Hannover/Lower Saxony. Data from loess areas were used for comparisons. Major aims were (1) to quantify current Corg stocks, (2) to provide data on site‐specific, steady‐state Corg levels in old arable soils, and (3) to identify the main controls of Corg levels in the studied sands. The mean Corg content in sandy, well‐drained, old Ap horizons (uplands, > 200 years under cultivation, near steady‐state) increased with precipitation from < 8 g kg—1 in the dry eastern parts of the study area (530 mm year—1, 8.3°C) to 25 g kg—1 in the moist Northwest (825 mm year—1, 8.4°C). The Corg levels in lowlands which have been drained for more than 40 years were approximately 3 g kg—1 higher than those of uplands under a similar climate. The factor clay content had no predictive value because low contents were associated with high Corg levels. Large proportions of refractory organic matter in sands resulting from specific features of historical land‐use and soil development (calluna heathland, heath plaggen fertilization, podzolization) appeared to be the most probable reason for such high Corg levels. However, the high Corg levels of these old arable sites were still exceeded by those of younger arable areas formerly under continuos grassland. A chrono‐sequence suggested that a period of about 100 years is necessary until a new steady‐state Corg level is established after conversion of grassland into arable land. Elevated Corg levels in current Ap horizons were also found for former woodland and heathland soils. The main conclusion is that sands can contain a lot of stable organic matter, sometimes more than finer textured soils. 相似文献
3.
This study aims to elucidate the significance of compost and soil characteristics for the biological activity of compost‐amended soils. Two agricultural soils (Ap horizon, loamy arable Orthic Luvisol and Ah horizon, sandy meadow Dystric Cambisol) and a humus‐free sandy mineral substrate were amended with two biowaste composts of different maturity in a controlled microcosm system for 18 months at 5 °C and 14 °C, respectively. Compost application increased the organic matter mineralization, the Cmic : Corg ratio, and the metabolic quotients significantly in all treatments. The total amount of Corg mineralized ranged from < 1 % (control plots) to 20 % (compost amended Dystric Cambisol). Incubation at 14 °C resulted in 2.7‐ to 4‐fold higher cumulative Corg mineralization compared to 5 °C. The Cmic : Corg ratios of the compost‐amended plots declined rapidly during the first 6 months and reached a similar range as the control plots at the end of the experiment. This effect may identify the compost‐derived microbial biomass as an easily degradable C source. Decreasing mineralization rates and metabolic quotients indicated a shift from a compost‐derived to a soil‐adapted microbial community. The Corg mineralization of the compost amended soils was mainly regulated by the compost maturity and the soil texture (higher activity in the sandy textured soils). The pattern of biological activity in the compost‐amended mineral substrate did not differ markedly from that of the compost‐amended agricultural soils, showing that the turnover of compost‐derived organic matter dominated the overall decay process in each soil. However, a priming effect occurring for the Dystric Cambisol indicated, that the effect of compost application may be soil specific. 相似文献
4.
Th. Beck 《植物养料与土壤学杂志》1983,146(2):243-252
N mineralization in soils under laboratory incubation conditions The potential rate of release of nitrogen by the organic matter in agriculturally used soils was determined under laboratory conditions by means of incubation. Mineralization of the more resistant soil organic matter proceeded linearly with time during an incubation period of 2–3 weeks, when field-moist and air-dried samples were used and at the beginning of the incubation experiment sufficient water was added to bring them to saturation. Mineralization was taking an exponential course in soils with additions of easily decomposable organic matter or in soils with a higher proportion of organic residues from crops. For the 14 investigated arable and grassland soils great variations in the average daily rate of mineralization were found ranging from 5–60 μg Nmin/10 g DM. The data correlated very well with the biomass (r = 0.96) and the cell-free protease activity (r = 0.98) of the soils. Different measures of soil management (preceding crops, application of sewage sludge, addition of heavy metals) had a more or less pronounced influence on the rate of mineralization. The optimum temperature was 50°C for N mineralization and 26°C for nitrification. Contrary to nitrification, the soil reaction had only little influence on mineralization and proved also independent of the Nmin content of soils. The results indicate that ammonification of organic N compounds may largely proceed via the microbial biomass. 相似文献
5.
V. M. Semenov B. M. Kogut N. B. Zinyakova N. P. Masyutenko L. S. Malyukova T. N. Lebedeva A. S. Tulina 《Eurasian Soil Science》2018,51(4):434-447
Experimental and literature data on the contents and stocks of active organic matter in 200 soil samples from the forest-tundra, southern-taiga, deciduous-forest, forest-steppe, dry-steppe, semidesert, and subtropical zones have been generalized. Natural lands, agrocenoses, treatments of long-term field experiments (bare fallow, unfertilized and fertilized crop rotations, perennial plantations), and different layers of soil profile are presented. Sphagnum peat and humus–peat soil in the tundra and forest-tundra zones are characterized by a very high content of active organic matter (300–600 mg C/100 g). Among the zonal soils, the content of active organic matter increases from the medium (75–150 mg C/100 g) to the high (150–300 mg C/100 g) level when going from soddy-podzolic soil to gray forest and dark-gray forest soils and then to leached chernozem. In the series from typical chernozem to ordinary and southern chernozem and chestnut and brown semidesert soils, a decrease in the content of active organic matter to the low (35–75 mg C/100 g) and very low (<35 mg C/100 g) levels is observed. Acid brown forest soil in the subtropical zone is characterized by a medium supply with active organic matter. Most arable soils are mainly characterized by low or very low contents of active organic matter. In the upper layers of soils, active organic matter makes up 1.2–11.1% of total Corg. The profile distribution of active organic matter in the studied soils coincides with that of Corg: their contents appreciably decrease with depth, except for brown semidesert soil. The stocks of active organic matter vary from 0.4 to 5.4 t/ha in the layer of 0–20 cm and from 1.0 to 12.4/ha in the layer of 0–50 cm of different soil types. 相似文献
6.
Leaching of plant nutrients from vineyard soils Leaching of plant nutrients particularly of nitrate from vineyard, arable, and forest soils of the Middle-Mosel have been investigated over a two-year period. Nitrate concentration in the leachate of vineyards amounted to an average of 326 mg NO3/l and was about 10 to 20 times higher than the nitrate concentration in the leachate of arable and forest soils. According to the hydro-dynamic model assumptions on groundwater flow in the slates of the Rhenish Massif, the data obtained for the groundwater recharge (158-180 mm/year as gained in spring) and leaching of nitrate (144 kg N/ha/year) must be considered as minimum values. Hydrodynamic model assumptions suggest nitrate leaching rates of about 200 kg N/ha. Main reasons for the high leaching of nutrients are heavy fertilizer application and high mineralization rates in the vineyard soils favoured by relatively high soil temperatures and a high soil permeability. 相似文献
7.
Interactions between microbial communities and organic matter were analyzed for soils from the project regions ’︁Ecosystem Research in the Agricultural Landscape/FAM, Munich’ in southern Germany and ’︁Ecosystem Research in the Bornhöved Lake district’ from northern Germany using ratios between microbial biomass content (Cmic), microbial metabolic quotient (qCO2) and organic carbon content (Corg). In the agricultural soils in southern Germany, the qCO2/Corg ratio differed significantly with respect to agricultural management in contrast to ecophysiological Cmic/Corg ratio. In addition, Cmic/Corg ratio decreased from 39 to 21 mg Cmic g—1 Corg and qCO2/Corg ratio increased from 72 to 180 mg CO2‐C g—1 Cmic h—1 (g Corg g—1 soil)—1 with increasing soil depth. For the upper soil horizons from the landscape in northern Germany the two quotients differed significantly with reference to land use showing highest microbial colonization under grassland and lowest under beech forest. In contrast, C use efficiency was lowest in arable field under maize monoculture and highest in a wet grassland having a high organic C content. 相似文献
8.
Dissolved organic matter (DOM) has been recognised as a key carbon and nitrogen (N) pool involved with soil-plant-microbe interactions. Yet few studies have quantified this contribution in agricultural soils. In this study we leached DOM from a sandy loam and sandy clay loam soil under either grassland or arable cropping. Two weeks after DOM removal microbial respiration from soils was not altered. However, a significant (P<0.05) decline in microbial biomass-N, potentially mineralizable-N, gross N mineralization and gross nitrification occurred after leaching. This data illustrate that whilst DOM is a small component of the soil OM it contributed up to 25% of microbial N supply within these agricultural soils. 相似文献
9.
Using data from long-term experiments at the Loess-Chernozem site, Bad Lauchstädt und 12 other European sites, the carbon (C) and nitrogen (N) dynamics in soils, the determination of decomposable soil organic matter (SOM), the effect on yield of SOM as well as carbon and nitrogen balances are discussed. Both C and N in SOM have to be divided into an inert and a decomposable fraction. The inert C is strongly correlated with clay content, while most changes in both C and N occur in the readily decomposable fraction. In the experiments considered the latter ranges between 0.2 to 0.6% C and 0.02 to 0.06% N. The annual changes of the Corg content amount only to about 0.01% Corg corresponding to 500 kg/ha, even under extreme changes of the fertilizing system. Hot water extractable C (Chwe) has proved to be an appropriate criterion for the calculation of the decomposable C and thus for the N release from soil. Different methods to maintain a SOM balance are compared and first guideline values for an agronomically and ecologically justified SOM content of arable soils are recommended. In arable soils the exceeding of an upper Corg value influences neither crop yield nor the C and N balance in a positive way. In terms of ecology and environment, set-aside-programmes or fallows in a crop rotation affect the balances negatively. Atmospheric N deposition can amount to about 50 kg/ha·yr. 相似文献
10.
Enrichment of C and N in soils of southeastern Niedersachsen after deepening of top soil In a comprehensive study, the effects of deepening of top soil during the last 20 years on C-organic-and N-total-masses of some selected arable land sites have been analyzed. The sampling sites represent soil groups predominating in southeastern Niedersachsen. In 145 plots of 22 agricultural farms with the rotation sugar beets/winter wheat/winter barley, sugar beets/winter wheat/winter wheat respectively, the actual depth of plow horizon varies from 32 to 38 cm in summer. Organic matter has been analyzed in 125 soils. A C-org.- and N-total-balance sheet has been prepared for the time after deepening of the top soils. In luvisols with a top soil deepening of about 10 cm a period of 15 years has been necessary for aquirement of the C-content before deepening. A C-enrichment up to 15 t/ha was recorded with incorporation of plant residues in the last 15 years. During this period up to 1,5t of N/ha accumulated assuming constant C/N-ratios. For chernosems, a similar rate has been determined. In sandy cambisols, the short period of observation of 10 years and less after top soil deepening did not permit a complete reenrichment with organic matter. The ”?potentially”? possible enrichment with organic C amounts to 14–17 t/ha (= 1,4–1,7 t N). Furthermore, luvisols gave a significant correlation between clay- and C-amounts of non deepened soils. A weak interrelation has also been found between clay content and the enrichment potential of organic matter in these soils. 相似文献
11.
D. S. POWLSON 《European Journal of Soil Science》1980,31(1):77-85
Grinding more than doubled the respiration rate of two silt loam soils, one arable and one grassland. The increases were smaller when the grinding treatment was given to portions of soils that had previously been fumigated with CHCI3and incubated, a treatment that greatly decreased microbial biomass. The results indicate that the flush of decomposition caused by grinding was in part derived from killed organisms and in part from enhanced decomposition of non-biomass sections of the soil organic matter. Grinding killed about a quarter of the biomass in both soils. Carbon from killed organisms accounted for a quarter of the extra CO2–C evolved after grinding in the arable soil and almost half in the grassland soil. The extra non-biomass organic matter decomposing after grinding amounted to about 0.5% of the soil organic carbon in both soils. This non-biomass material rendered decomposable by grinding had a higher C/N ratio than the organic matter decomposing in unground soil. 相似文献
12.
The major aim of this study was to evaluate how the pool size of slowly mineralizable, ‘old’ soil organic N can be derived from more easily accessible soil and site information via pedotransfer functions (PTF). Besides modeling, this pool size might be of great importance for the identification of soils with high mineralization potential in drinking‐water catchments. From long‐term laboratory incubations (ca. 200 days) at 35 °C, the pool sizes of easily mineralizable organic N (Nfast), mainly in fresh residues, and slowly mineralizable, ‘old’ soil organic N (Nslow) as well as their first‐order rate coefficients were obtained. 90 sandy arable soils from NW Germany served to derive PTFs for Nslow that were evaluated using another 20 soils from the same region. Information on former land‐use and soil type was obtained from topographical, historical, and soil maps (partly from 1780). Pool size Nslow very strongly depends on soil type and former land‐use. Mean pool sizes of Nslow were much lower in old arable lowland (105 mg N kg–1) than upland soils (175 mg N kg–1) possibly due to lower clay contents. Within lowlands, mean pool sizes in former grassland soils (245 mg N kg–1) were 2 to 3 times larger than in old arable soils due to accumulation of mineralizable N. In contrast, mean pool sizes of Nslow were lowest in recently cleared, former heath‐ and woodland (31 mg N kg–1) as a result of the input of hardly decomposable organic matter. Neither N nor C in the light fraction (density < 1.8 g cm–3) was adequate to derive pool size Nslow in the studied soils (r2 < 0.03). Instead, Nslow can be accurately (r2 = 0.55 – 0.83) derived from one or two basic soil characteristics (e.g. organic C, total N, C : N, mineral fraction < 20 μm), provided that sites were grouped by former land‐use. Field mineralization from Nslow during winter (independent data set) can be predicted as well on the basis of Nslow‐values calculated from PTFs that were derived after grouping the soils by former land‐use (r2 = 0.51***). In contrast, using the PTF without soil grouping strongly reduced the reliability (r2 = 0.16). 相似文献
13.
The aim of the study was to evaluate the spatial variability pattern of some soil quality parameters at landscape‐scale, particularly soil microbial biomass‐C (Cmic) and ‐N (Nmic), and soil microbial activity (respiration) as well as soil organic carbon (Corg), and hot water extractable carbon (Chwe) by multivariate analyses of variance and canonical discriminant analyses (CDA). The study area was the Trier region, Rhineland‐Palatinate, which is characterized by a wide range of soil types developed from various parent materials. Additionally, the investigated fields differed in soil management intensity (conventional, integrated, organic farming) and crops grown. Within the whole study area CDA revealed a separation into three sub‐areas. Within the sub‐areas the soil quality parameters were significantly influenced by the soil management systems and the crops grown. Despite the spatial variability and the relationship to soil management, the contents of Cmic could be predicted by stepwise multiple linear regression models, both for arable and grassland soils. The explained variance for the regression models were 72 % for arable soils and 63 % for grassland soils, respectively. Regression models for predicting Nmic and microbial activity revealed an explained variance between 30 and 58 %. 相似文献
14.
Upper limits for soil nitrate in late fall as function of soil properties, climate and soil use: Model considerations Strategies and measures to reduce the leaching of nitrate from agricultural soils can only be successful if possibilities of control are available. In temperate regions measurement of soil mineral nitrogen (predominantly nitrate) in late fall, together with appropriate upper limits for tolerable soil nitrate, can be considered as an efficient control instrument. With assumptions about the mineralization of crop residues and the input of nitrate from the atmosphere, a procedure is developed with which the nitrate leaching in winter can be estimated if the amount of soil nitrate in late fall is known. With the procedure sample calculations for the crop rotation sugarbeets-summer wheat-winter barley are carried out for a variety of site conditions. The calculations show, that when no residual nitrate is left in the soil at the time of harvest, the cumulative amount of leached nitrate for the crop rotation (due to mineralization of residues) is 63.7 kg/ha NO3? N. However, when each year an amount of soil mineral nitrogen of 45 kg/ha in late fall is allowed for, the leached amount of soil nitrate can, for average site conditions, be as high as 133.6 kg/ha. It is shown how with the model in a rational way late fall site- and crop-specific upper limits for soil nitrate can be derived. However, the stipulation of such upper limits is not a matter of soil science only. 相似文献
15.
Influence of long-term slurry application on soil nutrients. 1. N accumulation and N mineralization potential The influence of longterm slurry applications on the total N content, N fractions and N mobilization potential of the soil was investigated. The following results were obtained:
- – Application of high amounts of slurry over a long period of time resulted in higher total N contents not only in the upper soil layers but also in the layer 60–90 cm.
- – In two sites the higher total N contents are mainly resulting from higher contents of hydrolyzable organic N compounds and in one site of higher contents of non hydrolyzable organic N compounds.
- – The influence of the slurry application on the content of non exchangeable NH4+ is depending on the K saturation of the clay minerals.
- – In incubation experiments N mobilization of the soils supplied with slurry was higher as compared to soils supplied with mineral fertilizer.
- – A highly significant correlation is existing between N mobilization and the content of hydrolyzable organic N compounds and the Norg fraction, determined by means of EUF, respectively.
- – The Nmin content of the soils supplied with slurry was higher during the whole growing season.
16.
A balsam poplar clone (Populus trichocarpa cv. Weser 6) was inoculated by two ectomycorrhizal strains (Laccaria bicolor MW 158 and Paxillus involutus 1444) in Kick‐Brauckmann‐pots. The substrates were two arable sandy soils (Cambisols) with different organic matter content and nutrient supply. One soil (WIL) was rich in organic matter (Corg = 1.6%) and total nitrogen (Nt = 0.14%), whereas the other soil (RIE) had low contents of Corg (0.8%) and Nt (0.08%). Leaf nutrient concentrations, shoot lengths, root and shoot biomass production and nitrogen accumulation in the biomass were determined to discover possible inoculation effects. Mycorrhization indices (% colonized fine roots) of 36% with Laccaria bicolor and 40% with Paxillus involutus were observed on the Corg rich soil (WIL) in contrast to 16% and 14% on the Corg poor soil (RIE), respectively. Inoculation of poplar on the soil WIL increased shoot length, biomass production, shoot:root ratio and total N uptake of the cuttings, whereas on the soil RIE only the shoot:root ratio increased and the N nutrition was improved. We conclude that interactions between soil and fungus should be tested when choosing ectomycorrhizal strains for inoculation. 相似文献
17.
A significant fraction of soil organic carbon, named stable organic carbon (C) pool, has residence times longer than centuries and its vulnerability to land use or climatic changes is virtually unknown. Long-term bare fallows offer a unique opportunity to isolate the stable organic pool of soils and study its properties. We investigated the vulnerability of the stable organic C pool to fresh organic matter inputs by comparing the mineralization in a long-term bare fallow soil with that of an adjacent arable soil, containing stable C as well as more labile C. For this, we amended or not the soil samples with two different 13C-labelled fresh organic matter (straw or cellulose). In all cases we found a positive priming effect (i.e. an increased mineralization of soil organic carbon) when fresh organic matter was added. By comparing the results obtained on both soils, we estimated that half of the “primed” C in the arable soil due to straw addition as fresh organic matter, originated from the stable C pool. Our results suggest that under such conditions, which frequently occur, the stable pool of soil organic matter may largely contribute to soil extra-CO2 emissions due to priming effect. Consequently, the C storage potential of this pool may be modified by changes in land use and/or biomass production that might change the priming of the mineralization of the stable pool of soil organic carbon. 相似文献
18.
Short-time pH buffering of soils Changes in pH of 60 soils after HCl addition were related to reaction time and soil characteristis. Between 80 and 100% of the added protons were taken up by the soils within a few seconds, resulting in the release of exchangeable Ca, Mg and Al in strongly acid soils. The decrease of proton activity between 0.25 and 30-70 h can be formally described as a diffusion process. pH buffering depended on soil pH and organic C content but not on clay content. Buffering decreased from pH 3.5 to about 6 and increased again up to pH 7. Increase of Corg increased buffering mainly from pH 6-7. 相似文献
19.
A. A. Romanovskaya 《Eurasian Soil Science》2006,39(1):44-52
The dynamics of organic carbon upon natural overgrowing of abandoned croplands transferred into the category of long-fallow
lands is analyzed for the period from 1990 to 2002. The total area of long-fallow lands in Russia reaches 21.6 million ha.
The dynamics of organic carbon in fallowed soils has been simulated using the ROTHC model. For this purpose, the territory
of Russia was subdivided into 40 regions, for which the major soil characteristics, climatic data, and the input of organic
matter into the soils have been averaged. The results of calculations show that the long-fallow lands of Russia have lost
9.9 million tons Corg (36.4 million tons CO2) in 13 years with the average loss rate of 0.46 t C/ha. It is expected that the accumulation of organic carbon will take
place in the fallowed soils in the future.
The Editorial Board publishes this paper with a comment that it does not contain experimental data confirming the loss of
organic carbon from abandoned plowlands in comparison with cultivated lands. 相似文献
20.
Sewage sludge is a valuable source of organic matter, N, P and certain micronutrients that have beneficial effects on plant growth and biomass production. However, sanitary regulations often require the stabilization of sewage materials prior to applying them to soils as biosolids. Environmental regulations also demand appropriate management of biosolid‐N to avoid groundwater contamination. Because stabilization processes usually make sewage sludge less putrescible, we hypothesized that the mineralization rates of organic‐N from stabilized biosolids would be affected. Therefore, this study aimed to evaluate the mineralization of five biosolids in two soils – a sandy Spodosol and a clayey Oxisol. Digested sludge, composted sludge, limed sludge, heat‐dried sludge and solar‐irradiated sludge were mixed with soil samples at a concentration of 32.6 mg N/kg soil (1.0 dry t/ha of digested sludge) and incubated at 25 °C in a humidity chamber for 23 weeks. Results showed that the stabilization processes generally slowed the release of mineral‐N in soils relative to the digested sludge from which the biosolids originated. However, increments in the levels of mineral‐N were more influenced by soil type than by the type of stabilization process applied to the sewage sludge. Mineralization rates were up to 5‐fold higher in the Oxisol than in the Spodosol soil, and as a result, organic‐N in biosolids mineralized 10–24% in Spodosol and 23–52% in Oxisol. Any appropriate plan for the management of biosolid‐N for plant use should consider the interaction between soil type and biosolid type. 相似文献