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1.
Volpe Angela D’Arpa Stefania Del Moro Guido Rossetti Simona Tandoi Valter Uricchio Vito Felice 《Water, air, and soil pollution》2012,223(4):1773-1782
An environmentally friendly procedure suitable to restore a protected area was evaluated at laboratory scale. Soil contaminated
by high molecular weight (C > 10) aliphatic hydrocarbons and by chromium was withdrawn from the study site and a qualitative
study of soil hydrocarbon components was first performed in order to assess the potential source of contamination. To this
aim, a number of characteristic diagnostic ratios of hydrocarbon components were derived by processing chromatographic data,
and were used as indicators for distinguishing anthropogenic from natural hydrocarbons. Then, the efficiency of landfarming
for soil remediation was tested by comparing the effect of a few selected amendments and by monitoring the fate of chromium.
Soil microbial abundance and activity were also evaluated. Results showed that soil hydrocarbons were mainly of anthropogenic
origin and land treatment allowed effective degradation by native microbial populations even in the absence of amendments.
The investigated procedures had no effect on the mobilisation of chromium that remained in its stable form of Cr(III). Conventional
land treatment may therefore be an effective and safe procedure for the removal of hydrocarbons even in the presence of chromium,
and may be applied to areas where low-impact procedures are strictly required. 相似文献
2.
In order to assess the use of magnetic methods to study vertical migration behavior of metal pollutants in natural soils,
a controlled experiment was performed near Belle River, Ontario, Canada. The soil at the site consists primarily of clay-rich
glacial till overlain by localized alluvium. Twenty PVC tubes (16″ × 8″) were inserted vertically into the ground as test
capsules. Magnetite powder (<5 μm) was distributed on the surface of the soil inside ten tubes (10 grams/tube) to simulate
anthropogenic contamination, while the other ten were used as controls. While the surficial magnetic susceptibility (MS) remained
fairly stable in controls, decreases of 15–60% were observed in contaminated soil tubes. Post-test MS profiles from soil cores
in contaminated tubes show that the magnetic signal is strongest at depths between 4 and 6 cm. Magnetic measurements and chemical
analysis (using SEM-EDS) on soil layers with enhanced magnetic signal indicate the presence of iron containing particles,
likely magnetite. Overall, the results suggest that magnetite powder migrated vertically downwards at a rate of ∼14 cm/year
over the four month period, probably as a result of rainwater infiltration. Such magnetic methods and chemical analytical
techniques are useful in the investigation of migration of metal pollutants and the potential depth of soil contamination. 相似文献
3.
Tommaso Chiti Lorenzo Gardin Lucia Perugini Roberta Quaratino Francesco Primo Vaccari Franco Miglietta Riccardo Valentini 《Biology and Fertility of Soils》2012,48(1):9-17
The aim of this work was to quantify the soil organic C (SOC) stock in the top 30 cm of mineral soil for the whole Italian
territory, according to the different land use types of the Intergovernmental Panel on Climate Change (IPCC) cropland category
(arable land, agroforestry, vineyards, olive groves, orchards and rice fields), as a basis for future land use scenarios and
to address mitigation policy at country level. A database for SOC stock was created with the data from the national project
denominated SIAS and partly from regional map reports. All data were referred to the year 2000 since they were derived from
surveys conducted from 1995 to 2005. The data were stratified according to the Italian climatic regions, the landscape position
and the IPCC cropland subcategories. Taking into account the uncertainty in the estimate, the mean SOC stock values of the
different subcategories show significant differences (p < 0.05) among climatic regions and landscapes, ranging from 41.9 ± 15.9 Mg C ha−1 in the vineyards to 63.3 ± 27.9 Mg C ha−1 in the rice fields. Generally, a small decrease of the SOC stock from the temperate regions toward the Mediterranean ones
is observed. Taking into account the mean value of each subcategory and the country area they occupied in 2000, the total
C stored in the upper 30 cm of soil was estimated at 490.0 ± 121.7 Tg C. The resulting estimate represents the 17% of the
value reported by another study for the soil of the whole country down to 50 cm depth, suggesting the importance of preserving
this large C pool. Considering the cropland category as a whole, the estimated mean SOC stock is 52.1 ± 17.4 Mg C ha−1, similar to that reported for other European countries, 50–60 Mg C ha−1. In conclusion, the assessment of the mean SOC stock of the different cropland land uses, landscape position and climate
regions could notably help when assessing the impact of different agricultural practices and future stock change evaluation. 相似文献
4.
Simple and rapid chemical indices of soil nitrogen (N)-supplying capacity are necessary for fertilizer recommendations. In
this study, pot experiment involving rice, anaerobic incubation, and chemical analysis were conducted for paddy soils collected
from nine locations in the Taihu Lake region of China. The paddy soils showed large variability in N-supplying capacity as
indicated by the total N uptake (TNU) by rice plants in a pot experiment, which ranged from 639.7 to 1,046.2 mg N pot−1 at maturity stage, representing 5.8% of the total soil N on average. Anaerobic incubation for 3, 14, 28, and 112 days all
resulted in a significant (P < 0.01) correlation between cumulative mineral NH4+-N and TNU, but generally better correlations were obtained with increasing incubation time. Soil organic C, total soil N,
microbial C, and ultraviolet absorbance of NaHCO3 extract at 205 and 260 nm revealed no clear relationship with TNU or cumulative mineral NH4+-N. Soil C/N ratio, acid KMnO4-NH4+-N, alkaline KMnO4-NH4+-N, phosphate–borate buffer extractable NH4+-N (PB-NH4+-N), phosphate–borate buffer hydrolyzable NH4+-N (PBHYDR-NH4+-N) and hot KCl extractable NH4+-N (HKCl−NH4+-N) were all significantly (P < 0.05) related to TNU and cumulative mineral NH4+-N of long-term incubation (>28 days). However, the best chemical index of soil N-supplying capacity was the soil C/N ratio,
which showed the highest correlation with TNU at maturity stage (R = −0.929, P < 0.001) and cumulative mineral NH4+-N (R = −0.971, P < 0.001). Acid KMnO4-NH4+-N plus native soil NH4+-N produced similar, but slightly worse predictions of soil N-supplying capacity than the soil C/N ratio. 相似文献
5.
Tillage and land use effects on methane oxidation rates and their vertical profiles in soil 总被引:11,自引:0,他引:11
B. W. Hütsch 《Biology and Fertility of Soils》1998,27(3):284-292
The effect of land use and different soil tillage systems on CH4 oxidation was tested in a laboratory incubation study. Intact soil cores were collected from the topsoil (0–12 cm) of a field
site with ploughed, direct-drilled and set-aside treatments, and from an adjacent undisturbed forest site. CH4 oxidation rates were 4.5 to 11 times higher in the direct-drilled than in the continuously ploughed treatment, in the set-aside
soil they were intermediate. The oxidation rates in the forest soil were 11 times the highest rate measured at the field site,
pointing to a distinct land use effect. Vertical profiles of CH4 oxidation activity revealed a very clear zonation in all treatments. CH4 oxidation increased significantly below the plough layer (0–25 cm), and showed a subsurface maximum under direct-drilling
(5–15 cm) and under forest (5–10 cm). The vertical zonation under set-aside was comparable to that under ploughing. Generally,
the maximum CH4 oxidizing activity was in the zone nearest to the soil surface, unless various constraints prevented this.
Received: 1 December 1997 相似文献
6.
Xiao Ming Shi Xiao Gang Li Rui Jun Long Bhupinder Pal Singh Zhuo Ting Li Feng Min Li 《Biology and Fertility of Soils》2010,46(2):103-111
This study is aimed at quantifying organic carbon (C) and total nitrogen (N) dynamics associated with physically separated
soil fractions in a grassland-cultivation sequence in the Qinghai-Tibetan plateau. Concentrations of organic C and N of soil,
free and occluded particulate organic matter (OM), and aggregate- and mineral-associated OM in different land uses are increased
in the following order: 50 years cultivation < 12 years cultivation ≤ native grassland. The prolonged cropping of up to 50 years
markedly affected the concentrations of free and occluded particulate OM and mineral-associated OM. After wet-sieving, 43%
of native grassland soil mass was found in >1−10 mm water-stable aggregates that stored 40% of bulk soil organic C and N;
only 16% and 7% of soil mass containing 16% and 7% of bulk soil organic C and N was >1−10 mm water-stable aggregates of soils
cultivated for 12 years and 50 years, respectively. This indicated that losses of soil organic C and N following cultivation
of native grassland would be largely related to disruption of >1–10 mm size aggregates and exposure of intra-aggregate OM
to microbial attack. Organic C and N concentrations of soil aggregates were similar among aggregate size fractions (>0.05−10 mm)
within each land use, suggesting that soil aggregation process of these soils did not follow the hierarchy model. The increase
of the C-to-N ratio of free and occluded particulate fractions in the cultivated soils compared to the grassland soil indicated
a greater loss of N than C. 相似文献
7.
Alpine and tundra grasslands constitute 7% world terrestrial land but 13% of the total global soil carbon (C) and 10% of the
global soil nitrogen (N). Under the current climate change scenario of global warming, these grasslands will contribute significantly
to the changing global C and N cycles. It is important to understand the controlling factors on soil N cycling in these ecosystems.
To evaluate climate effects on N cycling, soil N mineralization and nitrification rates (0–15 cm) were measured using an in
situ closed-top tube incubation across altitudes and positions from 2006 to 2008 in alpine meadows. The data indicated that
soil N mineralization and nitrification rates decreased with increasing altitude, but only significantly (P < 0.05) between the lowest and the two higher altitudes. Soil N mineralization and nitrification rates of south-facing slopes
were higher than north-facing slopes at each altitude. This suggests that soil temperature and soil water content (WC) were
the controlling factors for soil N mineralization and nitrification rates across altitude with soil WC being the most important
factors over positions. Soil nitrification rate depended on soil N mineralization rate, and both rates may increase in response
to regional warming of the alpine meadow. 相似文献
8.
9.
Soil respiration, nitrogen mineralization and uptake in barley following cultivation of grazed grasslands 总被引:3,自引:0,他引:3
Soil tillage was studied as a strategy to synchronize N mineralization with plant demand following ploughing of two types
of grazed pastures [ryegrass/white clover (Lolium perenne/Trifolium repens) and pure ryegrass]. The swards were either rotovated and ploughed or ploughed only. Soil respiration, as determined by a
dynamic chamber method, was related to net N mineralization and to plant N uptake in a subsequent spring barley crop (Hordeum vulgare). Diurnal variations in temperature were important for the CO2 flux and care must be taken that temperatures during measuring periods are representative of the daily mean. Soil tillage
increased the CO2 flux considerably compared with untilled soil with total emissions of 2.6 and 1.4 t C ha–1, respectively, from start of April to end of June. Sward type or rotovation did not markedly influence accumulated emissions.
Rotovation significantly increased the content of nitrate in the soil until 43 days after rotovation, showing that net N mineralization
occurred rapidly during this period, in spite of low soil temperatures (5–10 °C). Rotovation increased barley grain yield
by 10–12% and N-uptake by 14%. For both sward types, rotovation caused an extra N-uptake in harvested plant material of about
12 kg ha–1. The availability of soil inorganic N at the early stages of barley was important for the final yield and N-uptake. The results
indicated that soil biological activity was not enhanced by rotovation and that the yield effect of rotovation was mainly
caused by quicker availability and better synchrony between N mineralization and plant uptake due to earlier start of decomposition.
Received: 3 May 2000 相似文献
10.
F. Ponder Jr Fumin Li Diann Jordan Edwin C. Berry 《Biology and Fertility of Soils》2000,32(2):166-172
The influence of compaction on Diplocardia ornata (Smith) burrowing and casting activities, soil aggregation, and nutrient changes in a forest soil were investigated using
pot microcosms. Treatments included two levels each of compaction, organic matter, and earthworms. Both burrowing and casting
activities were more abundant in uncompacted soil than in compacted soil. Bulk density decreased in microcosms of compacted
soil containing D. ornata from 1.76 g cm–3 to 1.49 g cm–3 over the study period. The overall percent of aggregates in the same size classes in compacted soil was less than the percent
of aggregates in uncompacted soil. The mean percent of aggregates in earthworm casts for size classes 0.25–1.00 mm was higher
for compacted soil than for uncompacted soil. The reverse was true for aggregates in class sizes 2.00–4.00 mm. Soil compaction
also affected soil microbial biomass carbon and soil inorganic N concentrations. These results indicate that the burrowing
and casting activities of earthworms in compacted forest soils, as in soils of agricultural and pastured lands, can help ameliorate
disturbed soils by improving aggregation, reducing bulk density, and increasing nutrient availability.
Received: 1 September 1999 相似文献
11.
Soil-released carbon dioxide from microbial biomass carbon in the cultivated soils of karst areas of southwest China 总被引:1,自引:0,他引:1
Soil microbial biomass and the emission of CO2 from the soil surface were measured in yellow soils (Ultisols) of the karst areas of southwest China. The soils are relatively
weathered, leached and impoverished, and have a low input of plant residues. The measurements were made for a 1-year period
and show a reciprocal relationship between microbial biomass and surface CO2 efflux. The highest (42.6±2.8 mg CO2-C m–2 h–1) and lowest (15.6±0.6 mg CO2-C m–2 h–1) CO2 effluxes are found in the summer and winter, respectively. The cumulative CO2 efflux is 0.24 kg CO2-C m–2 year–1. There is also a marked seasonal variation in the amount of soil microbial biomass carbon, but with the highest (644±71 μg
C g–1 soil) and lowest (270±24 μg C g–1 soil) values occurring in the winter and summer, respectively. The cumulative loss of soil microbial biomass carbon in the
top 10 cm of the soil was 608 μg C g–1 year–1 soil over 17 sampling times. The mean residence time of microbial biomass is estimated at 105 days, suggesting that the carbon
in soil microbial biomass may act as a source of the CO2 released from soils.
Received: 13 July 1999 相似文献
12.
Simple methods for the measurement of nitrogen (N) availability are needed to assess the effect of low-input, organically
based land management systems on the N supply of tropical soils. Our objectives were to determine the effect of contrasting
land-use systems (LUS) on soil N availability and to identify measures of N availability that correlated with maize (Zea mays L.) grain yield. The LUS at the two sites in Kenya involved growth of a maize crop following 17 months of either: (1) Sesbania sesban (L.) Merr. tree growth (sesbania fallow), (2) natural regrowth of vegetation without cultivation (natural fallow), (3) three
crops of unfertilized maize (maize monoculture), or (4) bare uncultivated soil (bare fallow). Soil was collected before the
post-fallow maize crop was sown. The LUS had no effect on total soil N or amount of N in the heavy fraction soil organic matter
(SOM) (>150 μm, >1.37 Mg m–3). Sesbania and natural fallows, as compared to maize monoculture, increased the N in light fraction SOM (>150 μm, <1.13Mgm–3), N in intermediate fraction SOM (>150 μm, 1.13 to 1.37 Mg m–3), ammonium-N and aerobic N mineralization at a depth of 0–15 cm. Maize yields were highest following the sesbania fallow.
Nitrate-N, inorganic-N (ammonium plus nitrate) and anaerobic N mineralization correlated with maize grain yield at both sites.
The relationship between maize yield and pre-season nitrate-N improved when the depth of soil sampling was increased to 1 m
at one site (an Alfisol), but did not improve at the site with anion adsorption in the subsoil (an Oxisol). The sesbania fallow
was more effective than the natural fallow in increasing available soil N. Maize yield was better related to pre-season nitrate
than N in size-density fractions of SOM.
Received: 5 May 1997 相似文献
13.
Richard W. Todd N. Andy Cole R. Nolan Clark William C. Rice Wen-Xuan Guo 《Biology and Fertility of Soils》2008,44(8):1099-1102
Cattle feedyards can impact local environments through emission of ammonia and dust deposited on nearby land. Impacts range
from beneficial fertilization of cropland to detrimental effects on sensitive ecosystems. Shortgrass prairie downwind from
an adjacent feedyard on the southern High Plains of Texas, USA changed from perennial grasses to annual weeds. It was hypothesized
that N enrichment from the feedyard initiated the cascade of negative ecological change. Objectives were to determine the
distribution of soil nitrogen and estimate N loading to the pasture. Soil samples were collected from 119 locations across
the pasture and soil total N (TN), nitrate-N and ammonium-N (AN) determined in the top 30 cm. Soil TN concentration decreased
with distance downwind from the feedyard from 1.6 ± 0.2 g kg−1 at 75 m to 1.2 ± 0.05 g kg−1 at 582 m. Nitrate-N concentration decreased within 200 m of the feedyard and changed little at greater distances. Ammonium-N
concentration decreased linearly (P < 0.001) with increasing distance from the feedyard from 7.9 ± 1.7 mg kg−1 within 75 m from the feedyard to 5.8 ± 1.5 mg kg−1 at more than 550 m from the feedyard; however, distance only explained 12% of the variability in AN concentration. Maximum
nitrogen loading, from 75 to 106 m from the feedyard, was 49 kg ha−1 year−1 over 34 years and decreased with distance from the feedyard. An estimate of net dry deposition of ammonia indicated that
it contributed negligibly to N loading to the pasture. Nitrogen enrichment that potentially shifted vegetation from perennial
grasses to annual weeds affected soil N up to 500 m from the feedyard; however, measured organic and inorganic N beyond that
returned to typical and expected levels for undisturbed shortgrass prairie.
相似文献
Richard W. ToddEmail: |
14.
Organic matter, microbial biomass and enzyme activity of soils under different crop rotations in the tropics 总被引:8,自引:0,他引:8
Soil organic matter level, soil microbial biomass C, ninhydrin-N, C mineralization, and dehydrogenase and alkaline phosphatase
activity were studied in soils under different crop rotations for 6 years. Inclusion of a green manure crop of Sesbania aculeata in the rotation improved soil organic matter status and led to an increase in soil microbial biomass, soil enzyme activity
and soil respiratory activity. Microbial biomass C increased from 192 mg kg–1 soil in a pearl millet-wheat-fallow rotation to 256 mg kg–1 soil in a pearl millet-wheat-green manure rotation. Inclusion of an oilseed crop such as sunflower or mustard led to a decrease
in soil microbial biomass, C mineralization and soil enzyme activity. There was a good correlation between microbial biomass
C, ninhydrin-N and dehydrogenase activity. The alkaline phosphatase activity of the soil under different crop rotations was
little affected. The results indicate the green manuring improved the organic matter status of the soil and soil microbial
activity vital for the nutrient turnover and long-term productivity of the soil.
Received: 7 January 1996 相似文献
15.
The study examined the influence of compost and mineral fertilizer application on the content and stability of soil organic
carbon (SOC). Soil samples collected from a long-term field experiment were separated into macroaggregate, microaggregate,
and silt + clay fractions by wet-sieving. The experiment involved seven treatments: compost, half-compost N plus half-fertilizer
N, fertilizer NPK, fertilizer NP, fertilizer NK, fertilizer PK, and control. The 18-year application of compost increased
SOC by 70.7–121.7%, and mineral fertilizer increased by 5.4–25.5%, with no significant difference between control soil and
initial soil. The C mineralization rate (rate per unit dry mass) in microaggregates was 1.52–2.87 mg C kg−1 day−1, significantly lower than in macroaggregate and silt + clay fractions (P < 0.05). Specific C mineralization rate (rate per unit SOC) in silt + clay fraction amounted to 0.48–0.87 mg C g−1 SOC day−1 and was higher than in macroaggregates and microaggregates. Our data indicate that SOC in microaggregates is more stable
than in macroaggregate and silt + clay fractions. Compost and mineral fertilizer application increased C mineralization rate
in all aggregates compared with control. However, compost application significantly decreased specific C mineralization rate
in microaggregate and silt + clay fractions by 2.6–28.2% and 21.9–25.0%, respectively (P < 0.05). By contrast, fertilizer NPK application did not affect specific C mineralization rate in microaggregates but significantly
increased that in silt + clay fractions. Carbon sequestration in compost-amended soil was therefore due to improving SOC stability
in microaggregate and silt + clay fractions. In contrast, fertilizer NPK application enhanced SOC with low stability in macroaggregate
and silt + clay fractions. 相似文献
16.
V. Acosta-Martínez D. Rowland R. B. Sorensen K. M. Yeater 《Biology and Fertility of Soils》2008,44(5):681-692
Little information is available on soil microbial and biochemical properties, important for understanding nutrient cycling
and organic matter dynamics, as affected by different peanut cropping systems and how they relate to soil functioning. Thus,
we studied a Tifton loamy sand (fine-loamy, kaolinitic, thermic Plinthic Kandiudults) in Georgia, which is first in peanut
production in USA, after 5 and 8 years under continuous cotton (Gossypium hirsutum, L) (CtCtCt), cotton–cotton–peanut (CtCtPt), corn (Zea mays L.)–peanut–cotton (CrPtCt), peanut–peanut–cotton (PtPtCt), and continuous peanut (PtPtPt). Soil organic carbon (OC) at 0–20 cm
was already higher under PtPtPt (average, 8.7 g C kg−1 soil), PtPtCt (average, 7.7 g C kg−1 soil), and CrPtCt (average, 7.8 g C kg−1 soil) compared with CtCtPt (average, 4.7 g C kg−1 soil) and CtCtCt (average, 3.3 g C kg−1 soil). Similarly, alkaline phosphatase, acid phosphatase, and phosphodiesterase as a group showed higher activities under
PtPtPt, PtPtCt, and CrPtCt than under CtCtPt and CtCtCt. The activities of glycosidases (α-galactosidase, β-glucosidase, and
β-glucosaminidase) as a group were more sensitive to the cropping systems than phosphastases and showed a distinctive cropping
system separation as follows: PtPtPt = CrPtCt > PtPtCt > CtCtPt > CtCtCt. Similar to OC and microbial biomass C trends, distinctive
differences were found in the microbial community structure of this sandy soil after 8 years between peanut-based cropping
systems (CrPtCt, PtPtCt, and PtPtPt) and cotton-based cropping systems (CtCtCt and CtCtPt) as indicated by the fatty acid
methyl esters profiles.
Trade names and company names are included for the benefit of the reader and do not infer any endorsement or preferential
treatment of the product by USDA-ARS. 相似文献
17.
Effects of increasing periods under intensive arable vegetable production on biological, chemical and physical indices of soil quality 总被引:6,自引:0,他引:6
The effects on soil condition of increasing periods under intensive cultivation for vegetable production on a Typic Haplohumult
were compared with those of pastoral management using soil biological, physical and chemical indices of soil quality. The
majority of the soils studied had reasonably high pH, exchangeable cation and extractable P levels reflecting the high fertilizer
rates applied to dairy pasture and more particularly vegetable-producing soils. Soil organic C (Corg) content under long-term pasture (>60 years) was in the range of 55 g C kg–1 to 65 g C kg–1. With increasing periods under vegetable production soil organic matter declined until a new equilibrium level was attained
at about 15–20 g C kg–1 after 60–80 years. The loss of soil organic matter resulted in a linear decline in microbial biomass C (Cmic) and basal respiratory rate. The microbial quotient (Cmic/Corg) decreased from 2.3% to 1.1% as soil organic matter content declined from 65 g C kg–1 to 15 g C kg–1 but the microbial metabolic quotient (basal respiration/Cmic ratio) remained unaffected. With decreasing soil organic matter content, the decline in arginine ammonification rate, fluorescein
diacetate hydrolytic activity, earthworm numbers, soil aggregate stability and total clod porosity was curvilinear and little
affected until soil organic C content fell below about 45 g C kg–1. Soils with an organic C content above 45 g C kg–1 had been under pasture for at least 30 years. At the same Corg content, soil biological activity and soil physical conditions were markedly improved when soils were under grass rather
than vegetables. It was concluded that for soils under continuous vegetable production, practices that add organic residues
to the soil should be promoted and that extending routine soil testing procedures to include key physical and biological properties
will be an important future step in promoting sustainable management practices in the area.
Received: 18 November 1997 相似文献
18.
Crop residues and fertilizer nitrogen influence residue decomposition and nitrous oxide emission from a Vertisol 总被引:2,自引:0,他引:2
Wisal Muhammad Sarah M. Vaughan Ram C. Dalal Neal W. Menzies 《Biology and Fertility of Soils》2011,47(1):15-23
Crop residues with high C/N ratio immobilize N released during decomposition in soil, thus reducing N losses through leaching,
denitrification, and nitrous oxide (N2O) emission. A laboratory incubation experiment was conducted for 84 days under controlled conditions (24°C and moisture content
55% of water-holding capacity) to study the influence of sugarcane, maize, sorghum, cotton and lucerne residues, and mineral
N addition, on N mineralization–immobilization and N2O emission. Residues were added at the rate of 3 t C ha−1 to soil with, and without, 150 kg urea N ha−1. The addition of sugarcane, maize, and sorghum residues without N fertilizer resulted in a significant immobilization of
soil N. Amended soil had significantly (P < 0.05) lower NO3−–N, which reached minimum values of 2.8 mg N kg−1 for sugarcane (at day 28), 10.3 mg N kg−1 for maize (day 7), and 5.9 mg N kg−1 for sorghum (day 7), compared to 22.7 mg N kg−1 for the unamended soil (day 7). During 84 days of incubation, the total mineral N in the residues + N treatments were decreased
by 45 mg N kg−1 in sugarcane, 34 mg kg−1 in maize, 29 mg kg−1 in sorghum, and 16 mg kg−1 in cotton amended soil compared to soil + N fertilizer, although soil NO3−–N increased by 7 mg kg−1 in lucerne amended soil. The addition of residues also significantly increased amended soil microbial biomass C and N. Maximum
emissions of N2O from crop residue amended soils occurred in the first 4–5 days of incubation. Overall, after 84 days of incubation, the
cumulative N2O emission was 25% lower with cotton + N fertilizer, compared to soil + N fertilizer. The cumulative N2O emission was significantly and positively correlated with NO3−–N (r = 0.92, P < 0.01) and total mineral N (r = 0.93, P < 0.01) after 84 days of incubation, and had a weak but significant positive correlation with cumulative CO2 in the first 3 and 5 days of incubation (r = 0.59, P < 0.05). 相似文献
19.
Spatial changes of soil fungal and bacterial biomass from a sub-alpine coniferous forest to grassland in a humid, sub-tropical region 总被引:7,自引:0,他引:7
Fungal and bacterial biomass were determined across a gradient from a forest to grassland in a sub-alpine region in central
Taiwan. The respiration-inhibition and ergosterol methods for the evaluation of the microbial biomass were compared. Soil
fungal and bacterial biomass both significantly decreased (P<0.05) with the shift of vegetation from forest to grassland. Fungal and bacterial respiration rates (evolved CO2) were, respectively, 89.1 μl CO2 g–1 soil h–1 and 55.1 μl CO2 g–1 soil h–1 in the forest and 36.7 μl CO2 g–1 soil h–1 and 35.7 μl CO2 g–1 soil h–1 in the grassland surface soils (0–10 cm). The fungal ergosterol content in the surface soil decreased from the forest zone
(108 μg g–1) to the grassland zone (15.9 μg g–1). A good correlation (R
2=0.90) was exhibited between the soil fungal ergosterol content and soil fungal CO2 production (respiration) for all sampling sites. For the forest and grassland soil profiles, microbial biomass (respiration
and ergosterol) declined dramatically with depth, ten- to 100-fold from the surface organic horizon to the deepest mineral
horizon. With respect to fungal to bacterial ratios for the surface soil (0–10 cm), the forest zone had a significantly (P<0.05) higher ratio (1.65) than the grassland zone (1.05). However, there was no fungal to bacterial ratio trend from the surface
horizon to the deeper mineral horizons of the soil profiles.
Received: 30 March 2000 相似文献
20.
Barbara Maliszewska-Kordybach Agnieszka Klimkowicz-Pawlas Bozena Smreczak Rafał Gałązka 《Water, air, and soil pollution》2012,223(2):687-697
During the intensive flood in May–June 2010, the floodplains in Little Poland Vistula Gap, used mostly for agriculture, were
waterlogged for a period of over 1 month. The aim of the study was to assess the effect of the flood on the level of contamination
of the soils in this region. The analysis included basic physicochemical soil properties, contents of ten metals, and concentrations
of 16 polycyclic aromatic hydrocarbons (PAHs). The studies cover two territories on opposite sites of the river Vistula (Wilkow
and Janowiec) differing in their areas (70 and 4.6 km2) and time of water logging (30 and 10 days). Forty soil samples were collected from both areas immediately after the flood
event from the upper (0–30 cm) soil layer together with four samples from the 30–60-cm depth layer. This was supplemented
by eight samples from the flood-deposited sediment layer (thickness, 2 cm). The concentrations of identified metals (As, Ba,
Cr, Sn, Zn, Cd, Co, Cu, Ni, Pb) at all the sampling points were below the Polish legal limits for the upper layer of soils
for agriculture use. The same regarded the median contents of nine PAHs compounds specified in the Polish regulations. In
both areas, the median contents of Σ16 PAHs (0.21–0.35 mg kg−1), Zn (10.3–10.6 mg kg−1), Pb (9.2–10.7 mg kg−1), and Cd (0.03 mg kg−1) were much below the mean concentrations of those contaminants in arable soils on the national and European levels. The results
show that this severe flooding episode in “clean” agricultural area had no immediate negative impact on the soils as regards
the basic physicochemical properties (organic matter content, acidity, nitrogen content) and did not result in excessive soil
contamination. 相似文献