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1.
An open incubation technique was used to measure S mineralization in a range of upland soils of north China. Six mineralization
patterns were examined, and a soil S-exhaustion experiment with ryegrass (Lolium multiflorum L.) was conducted to investigate the availability of various organic S pools to plants. For all of the 12 soils tested, the
release of S as SO4
2– was curvilinear with time, and during a 28-week incubation at 30 °C the amount of S mineralized ranged from 14.0 mg S kg–1 soil to 37.4 mg S kg–1 soil. A first-order model and Gompertz model appeared to best describe S mineralization. Examination of the soils after incubation
revealed the bulk of the mineralized S was mainly derived from the C-bonded S pool, while the majority of mineralized S under
soil S exhaustion by ryegrass was derived from the HI-reducible S pool.
Received: 9 July 1998 相似文献
2.
This study examines the effects of atrazine on both microbial biomass C and C mineralization dynamics in two contrasting agricultural
soils (organic C, texture, and atrazine application history) located at Galicia (NW Spain). Atrazine was added to soils, a
Humic Cambisol (H) and a Gleyic Cambisol (G), at a recommended agronomic dose and C mineralization (CO2 evolved), and microbial biomass measurements were made in non-treated and atrazine-treated samples at different time intervals
during a 12-week aerobic incubation. The cumulative curves of CO2–C evolved over time fit the simple first-order kinetic model [Ct = Co (1 − e
−kt
)], whose kinetic parameters were quantified. Differences in these parameters were observed between the two soils studied;
the G soil, with a higher content in organic matter and microbial biomass C and lower atrazine application history, exhibited
higher values of the total C mineralization and the potentially mineralizable labile C pool than those for the H soil. The
addition of atrazine modified the kinetic parameters and increased notably the C mineralized; by the end of the incubation
the cumulative CO2–C values were 33–41% higher than those in the corresponding non-added soils. In contrast, a variable effect or even no effect
was observed on the soil microbial biomass following atrazine addition. The data clearly showed that atrazine application
at normal agricultural rates may have important implications in the C cycling of these two contrasting acid soils. 相似文献
3.
H. Niknahad Gharmakher J. M. Machet N. Beaudoin S. Recous 《Biology and Fertility of Soils》2009,45(3):297-304
A 25-week laboratory study was carried out to determine sulfur, carbon, and nitrogen mineralization rates in soil samples
obtained from representative soils in France. Their relationship with some of the soil properties was investigated to find
a predictor of mineralized S in soils. At 20°C and 80% water-holding capacity, the S mineralization rate ranged from 0.02
to 0.16 mg kg−1 day−1. It was significantly positively related to soil organic C and N and to C and N mineralization rates. It was weakly related
to total soil S. The results suggest that the S mineralization is predominantly driven by heterotrophic microbial activity.
A predictive equation for S mineralization based on soil C content, soil pH, and clay content is proposed. 相似文献
4.
David Fangueiro Henrique Ribeiro João Coutinho Laura Cardenas Henrique Trindade Cristina Cunha-Queda Ernesto Vasconcelos Fernanda Cabral 《Biology and Fertility of Soils》2010,46(4):383-391
The following six pig slurries obtained after acidification and/or solid/liquid separation were used in the research: original
(S) and acidified (AS) pig slurry, nonacidified (LF) and acidified (ALF) pig slurry liquid fraction, and nonacidified (SF)
and acidified (ASF) pig slurry solid fraction. Laboratory incubations were performed to assess the effect of the application
of these slurries on N mineralization and CO2 and N2O emissions from a sandy soil. Acidification maintained higher NH4
+-N contents in soil particularly in the ALF-treated soil where NH4
+-N contents were two times higher than in LF-treated soil during the 55–171-day interval. At the end of the incubation (171 days),
32.9 and 24.2 mg N kg−1 dry soil were mineralized in the ASF- and SF-treated soils, respectively, but no mineralization occurred in LF- and S-treated
soils, although acidification decreased N immobilization in ALF- (−25.3 mg N kg−1 soil) and AS- (−12.7 mg N kg−1 soil) compared to LF- (−34.4 mg N kg−1 soil) and S-treated (−18.6 mg N kg−1 soil) soils, respectively. Most of the dissolved CO2 was lost during the acidification process. More than 90% of the applied C in the LF-treated soil was lost during the incubation,
indicating a high availability of the added organic compounds. Nitrous oxide emissions occurred only after day 12 and at a
lower rate in soils treated with acidified than nonacidified slurries. However, during the first 61 days of incubation, 1,157 μg N
kg−1 soil was lost as N2O in the AS-treated soil and only 937 in the S-treated soil. 相似文献
5.
A study was conducted to investigate the effects of cow manure and sewage sludge application on the activity and kinetics
of soil l-glutaminase. Soil samples were collected from a farm experiment in which 0, 25, and 100 Mg ha−1 of either cow manure or sewage sludge had been applied annually for 4 consecutive years to a clay loam soil (Typic Haplargid).
A chemical fertilizer treatment had also been applied. Results indicated that the effects of chemical fertilizer and the solid
waste application on pH in the 18 surface soil (0–15 cm) samples were not significant. The organic C content, however, was
affected significantly by the different treatments, being the greatest in soils treated with 100 Mg ha−1 cow manure, and the least in the control treatment. l-Glutaminase activity was generally greater in solid-waste applied soils and was significantly correlated (r = 0.939, P < 0.001) with organic C content of soils. The values of l-glutaminase maximum velocity (Vmax) ranged from 331 to 1,389 mg NH4
+–N kg−1 2 h−1. Values of the Michaelis constant (K
m) ranged from 35.1 to 71.7 mM. Organic C content of the soils were significantly correlated with V
max (r = 0.919, P < 0.001) and K
m (r = 0.763, P < 0.001) values. These results demonstrate the considerable influence that solid waste application has on this enzymatic
reaction involved in N mineralization in soil. 相似文献
6.
Jinbo Zhang Christoph Müller Tongbin Zhu Yi Cheng Zucong Cai 《Biology and Fertility of Soils》2011,47(5):533-542
A study was carried out to investigate the potential gross nitrogen (N) transformations in natural secondary coniferous and
evergreen broad-leaf forest soils in subtropical China. The simultaneously occurring gross N transformations in soil were
quantified by a 15N tracing study. The results showed that N dynamics were dominated by NH4+ turnover in both soils. The total mineralization (from labile and recalcitrant organic N) in the broad-leaf forest was more
than twice the rate in the coniferous forest soil. The total rate of mineral N production (NH4+ + NO3−) from the large recalcitrant organic N pool was similar in the two forest soils. However, appreciable NO3− production was only observed in the coniferous forest soil due to heterotrophic nitrification (i.e. direct oxidation of organic
N to NO3−), whereas nitrification in broad-leaf forest was little (or negligible). Thus, a distinct shift occurred from predominantly
NH4+ production in the broad-leaf forest soil to a balanced production of NH4+ and NO3− in the coniferous forest soil. This may be a mechanism to ensure an adequate supply of available mineral N in the coniferous
forest soil and most likely reflects differences in microbial community patterns (possibly saprophytic, fungal, activities
in coniferous soils). We show for the first time that the high nitrification rate in these soils may be of heterotrophic rather
than autotrophic nature. Furthermore, high NO3− production was only apparent in the coniferous but not in broad-leaf forest soil. This highlights the association of vegetation
type with the size and the activity of the SOM pools that ultimately determines whether only NH4+ or also a high NO3− turnover is present. 相似文献
7.
Does long-term farmyard manure fertilization affect short-term nitrogen mineralization from farmyard manure? 总被引:2,自引:0,他引:2
Leif Nett Sven Averesch Silke Ruppel Jörg Rühlmann Carmen Feller Eckhard George Matthias Fink 《Biology and Fertility of Soils》2010,46(2):159-167
One of the challenges in organic farming systems is to match nitrogen (N) mineralization from organic fertilizers and crop
demand for N. The mineralization rate of organic N is mainly determined by the chemical composition of the organic matter
being decomposed and the activity of the soil microflora. It has been shown that long-term organic fertilization can affect
soil microbial biomass (MB), the microbial community structure, and the activity of enzymes involved in the decomposition
of organic matter, but whether this has an impact on short-term N mineralization from recently applied organic substances
is not yet clear. Here, we sampled soils from a long-term field experiment, which had either not been fertilized, or fertilized
with 30 or 60 t ha−1 year−1 of farmyard manure (FYM) since 1989. These soil samples were used in a 10-week pot experiment with or without addition of
FYM before starting (recent fertilization). At the start and end of this experiment, soil MB, microbial basal respiration,
total plant N, and mineral soil N content were measured, and a simplified N balance was calculated. Although the different
treatments used in the long-term experiment induced significant differences in soil MB, as well as total soil C and N contents,
the total N mineralization from FYM was not significantly affected by soil fertilization history. The amount of N released
from FYM and not immobilized by soil microflora was about twice as high in the soil that had been fertilized with 60 t ha−1 year−1 of FYM as compared with the non-fertilized soil (p < 0.05). 相似文献
8.
Carbon mineralization kinetics as influenced by soil properties 总被引:3,自引:0,他引:3
In a short-term laboratory study C mineralization potentials were determined on soil samples obtained from some representative agricultural soils in Tuscany, Italy. All the kinetic models tested to describe the mineralization process provided a good fit to the experimental data. A modified first-order model best described C mineralization in the soil. Both potentially mineralizable C and the mineralization rate (k) varied considerably among soils, reflecting the differences in soil properties. Potentially mineralizable C was positively related to C evolved as CO2 and to the exchange capacity. Normalized values (potentially mineralizable C divided by organic C), representing on average about 2% of the total soil C, was positively correlated to soil pH and negatively to the soil C pool, the soil N pool, and total microbial activity. Values for k ranged between 0.050 and 0.104 day-1, being higher in fine-textured soils and in soils with a large free Fe content. A low C:N ratio was indicative of a high k value. Turnover times for mineralized C were relatively rapid, ranging from 10 to 20 days. 相似文献
9.
Previous studies have shown that carbon (C) mineralization in saline or sodic soils is affected by various factors including
organic C content, salt concentration and water content in saline soils and soil structure in sodic soils, but there is little
information about which soil properties control carbon dioxide (CO2) emission from saline-sodic soils. In this study, eight field-collected saline–sodic soils, varying in electrical conductivity
(ECe, a measure of salinity, ranging from 3 to 262 dS m−1) and sodium adsorption ratio (SARe, a measure of sodicity, ranging from 11 to 62), were left unamended or amended with mature wheat or vetch residues (2% w/w). Carbon dioxide release was measured over 42 days at constant temperature and soil water content. Cumulative respiration
expressed per gram SOC increased in the following order: unamended soil<soil amended with wheat residues (C/N ratio 122)<soil
with vetch residue (C/N ratio 18). Cumulative respiration was significantly (p < 0.05) negatively correlated with ECe but not with SARe. Our results show that the response to ECe and SARe of the microbial community activated by addition of organic C does not differ from that of the less active microbial community
in unamended soils and that salinity is the main influential factor for C mineralization in saline–sodic soils. 相似文献
10.
Kotha Sammi Reddy Muneshwar Singh Anand Swarup Annangi Subba Rao Kamlesh Narain Singh 《植物养料与土壤学杂志》2002,165(2):167-171
The mineralization of sulfur (S) was investigated in a Vertisol and an Inceptisol amended with organic manures, green manures, and crop residues. Field‐moist soils amended with 10 g kg—1 of organic materials were mixed with glass beads, placed in pyrex leaching tubes, leached with 0.01 M CaCl2 to remove the mineral S and incubated at 30 °C. The leachates were collected every fortnight for 16 weeks and analyzed for SO4‐S. The amount of S mineralized in control and in manure‐amended soils was highest in the first week and decreased steadily thereafter. The total S mineralized in amended soils varied considerably depending on the type of organic materials incorporated and soil used. The cumulative amounts of S mineralized in amended soils ranged from 6.98 mg S (kg soil)—1 in Inceptisol amended with wheat straw to 34.38 mg S (kg soil)—1 in Vertisol amended with farmyard manure (FYM). Expressed as a percentage of the S added to soils, the S mineralized was higher in FYM treated soils (63.5 to 67.3 %) as compared to poultry manure amended soils (60.5 to 62.3 %). Similarly the percentage of S mineralization from subabul (Leucaena leucocephala) loppings was higher (53.6 to 55.5 %) than that from gliricidia (Gliricidia sepium) loppings (50.3 to 51.1 %). Regression analysis clearly indicated the dependence of S mineralization on the C : S ratio of the organic materials added to soil. The addition of organic amendments resulted in net immobilization of S when the C : S ratio was above 290:1 in Vertisol and 349:1 in Inceptisol. The mineralizable S pool (So) and first‐order rate constant (k) varied considerably among the different types of organic materials added and soil. The So values of FYM treated soils were higher than in subabul, gliricidia, and poultry manure treated soils. 相似文献
11.
A 15N dilution experiment was carried out to investigate effects of cultivation on the gross N transformation rate in coastal
wetland zone. Microbial community composition was estimated by phospholipid fatty acid (PLFA) analysis and abundance of soil
ammonia-oxidizing bacteria (AOB) was quantified by real-time polymerase chain reaction (PCR). Soil salinity decreased significantly,
while total N increased after coastal wetland was cultivated. Microbial biomass (total PLFA), bacterial biomass, fungal biomass,
and actinomycete biomass of the native coastal wetland soils were significantly (p < 0.05) lower than those of the cultivated soils whereas AOB population size also significantly increased after coastal wetland
cultivation. Multiple regression analysis showed that total PLFA biomass and soil total N (TN) explained 97% of the variation
of gross N mineralization rate in the studied soils (gross mineralization rate = 0.179 total PLFA biomass + 5.828TN − 2.505,
n = 16, p < 0.01). Gross nitrification rate increased by increasing the soil AOB population size and gross mineralization rate (M) (gross nitrification rate = 3.39AOB + 0.18 M − 0.075, R
2 = 0.98, n = 16, p < 0.01). Management of salt discharge and mineral N fertilization during the cultivation of wetland soils might have changed
composition of soil microflora and AOB population size, thus influencing mineralization and nitrification. Probably, the cultivation
of coastal wetland soils increased the risk of N losses from soil through nitrate leaching and gas emission (e.g., N2O and NO). 相似文献
12.
Influence of soil compaction on carbon and nitrogen mineralization of soil organic matter and crop residues 总被引:18,自引:0,他引:18
We studied the influence of soil compaction in a loamy sand soil on C and N mineralization and nitrification of soil organic
matter and added crop residues. Samples of unamended soil, and soil amended with leek residues, at six bulk densities ranging
from 1.2 to 1.6 Mg m–3 and 75% field capacity, were incubated. In the unamended soil, bulk density within the range studied did not influence any
measure of microbial activity significantly. A small (but insignificant) decrease in nitrification rate at the highest bulk
density was the only evidence for possible effects of compaction on microbial activity. In the amended soil the amounts of
mineralized N at the end of the incubation were equal at all bulk densities, but first-order N mineralization rates tended
to increase with increasing compaction, although the increase was not significant. Nitrification in the amended soils was
more affected by compaction, and NO3
–-N contents after 3 weeks of incubation at bulk densities of 1.5 and 1.6 Mg m–3 were significantly lower (by about 8% and 16% of total added N, respectively), than those of the less compacted treatments.
The C mineralization rate was strongly depressed at a bulk density of 1.6 Mg m–3, compared with the other treatments. The depression of C mineralization in compacted soils can lead to higher organic matter
accumulation. Since N mineralization was not affected by compaction (within the range used here) the accumulated organic matter
would have had higher C : N ratios than in the uncompacted soils, and hence would have been of a lower quality. In general,
increasing soil compaction in this soil, starting at a bulk density of 1.5 Mg m–3, will affect some microbially driven processes.
Received: 10 June 1999 相似文献
13.
Summary Topsoils (0–75 mm) from four soil types with different sulphate retention capacities were collected from stock camp and non-camp (main grazing area) sites of grazed pastures in New Zealand which had been annually fertilized with superphosphate for more than 15 years. These soils were analysed for different S fractions and incubated at 30°C for 10 weeks using an open incubation technique in order to assess the extent of S mineralization and the release of soluble soil organic S from camp and non-camp soils during incubation. The soils were preleached with 0.01 M KCl, followed by 0.04 M Ca(H2PO4)2 before being incubated. Pre-incubation leachates and weekly 0.01 M KCl leachates were analysed for mineralized S (i.e., hydriodic acid-reducible S) and total S. Soluble organic S was estimated as the difference between these two S fractions. Results obtained show higher cumulative amounts of all three S fractions in leachates over a 10-week incubation period in camp than in non-camp soils, suggesting that higher mineralization occurred in camp soils. Cumulative amounts of mineralized S from camp and non-camp soils showed a linear relationship with duration of incubation (R
20.985***), while the cumulative release of soluble organic S followed a quadratic relationship (R
20.975***). A significant proportion (14.6%–40.8%) of total S release in KCl leachates was soluble organic S, indcating that organic S should be taken into account when assessing S mineralization. Mineralized S and soluble organic S were best correlated with 0.01 M CaCl2-extractable soil inorganic S (R
2=0.767***) and 0.04 M Ca(H2PO4)2-extractable soil inorganic S(R
2=0.823***), respectively. Soil sulphate retention capacity was found to influence amounts of mineralized S and soluble organic S, and thus periodic leaching with KCl to remove mineralized S from soils may not adequately reflect the extent of soil S mineralization in high sulphate-retentive soils. In low (<10%) sulphateretentive soils, increasing the superphosphate applications from 188 to 376 kg ha–1 year–1 increased S mineralization but not amounts of C-bonded and hydriodic acid-reducible soil S fractions. 相似文献
14.
Long-term effects of mineral fertilization on microbial biomass C (MBC), basal respiration (R
B), substrate-induced respiration (R
S), β-glucosidase activity, and the r–K-growth strategy of soil microflora were investigated using a field trial on grassland established in 1969. The experimental
plots were fertilized at three rates of mineral N (0, 80, and 160 kg ha−1 year−1) with 32 kg P ha−1 year−1 and 100 kg K ha−1 year−1. No fertilizer was applied on the control plots (C). The application of a mineral fertilizer led to lower values of the MBC
and R
B, probably as a result of fast mineralization of available substrate after an input of the mineral fertilizer. The application
of mineral N decreased the content of C extracted by 0.5 M K2SO4 (C
ex). A positive correlation was found between pH and the proportion of active microflora (R
S/MBC). The specific growth rate (μ) of soil heterotrophs was higher in the fertilized than in unfertilized soils, suggesting the stimulation of r-strategists, probably as the result of the presence of available P and rhizodepositions. The cessation of fertilization with
320 kg N ha−1 year−1 (NF) in 1989 also stimulated r-strategists compared to C soil, probably as the result of the higher content of available P in the NF soil than in the C
soil. 相似文献
15.
We developed a model for plant available sulfur (S) in Ohio soils to predict potential crop plant S deficiency. The model
includes inputs of plant available S due to atmospheric deposition and mineralization of soil organic S and output due to
leaching. A leaching index was computed using data on annual precipitation; soil pH and clay content that influence sulfate
adsorption; and pore water velocity based upon percent sand, silt, and clay. There are five categories of S status ranging
from highly deficient to highly sufficient, and the categories are defined based on whether the crop S requirement was 15
or 30kg S ha−1 year−1. The final database derived from the model includes 1,473 soil samples representing 443 of the 475 soil series in Ohio. For
a crop requiring 15kg S ha−1 year−1, most soils (68.6%) were classified as variably deficient, which implies that the response to S fertilization will be variable
but often positive depending on specific crop conditions. For a crop requiring 30kg S ha−1 year−1, 43.2% of soils were classified as variably deficient, but 49.7% were classified as moderately or highly deficient, implying
that a response to S fertilization will usually or always occur. The model predicts crop S status for a single state in the
USA, but with proper inputs, it should be applicable to other areas. 相似文献
16.
Girma Abera Endalkachew Wolde-meskel Lars R. Bakken 《Biology and Fertility of Soils》2012,48(1):51-66
Seasonal drought in tropical agroecosystems may affect C and N mineralization of organic residues. To understand this effect,
C and N mineralization dynamics in three tropical soils (Af, An1, and An2) amended with haricot bean (HB; Phaseolus vulgaris L.) and pigeon pea (PP; Cajanus cajan L.) residues (each at 5 mg g−1 dry soil) at two contrasting soil moisture contents (pF2.5 and pF3.9) were investigated under laboratory incubation for 100–135 days.
The legume residues markedly enhanced the net cumulative CO2–C flux and its rate throughout the incubation period. The cumulative CO2–C fluxes and their rates were lower at pF3.9 than at pF2.5 with control soils and also relatively lower with HB-treated than
PP-treated soil samples. After 100 days of incubation, 32–42% of the amended C of residues was recovered as CO2–C. In one of the three soils (An1), the results revealed that the decomposition of the recalcitrant fraction was more inhibited by drought stress than easily
degradable fraction, suggesting further studies of moisture stress and litter quality interactions. Significantly (p < 0.05) greater NH4+–N and NO3−–N were produced with PP-treated (C/N ratio, 20.4) than HB-treated (C/N ratio, 40.6) soil samples. Greater net N mineralization
or lower immobilization was displayed at pF2.5 than at pF3.9 with all soil samples. Strikingly, N was immobilized equivocally
in both NH4+–N and NO3−–N forms, challenging the paradigm that ammonium is the preferred N source for microorganisms. The results strongly exhibited
altered C/N stoichiometry due to drought stress substantially affecting the active microbial functional groups, fungi being
dominant over bacteria. Interestingly, the results showed that legume residues can be potential fertilizer sources for nutrient-depleted
tropical soils. In addition, application of plant residue can help to counter the N loss caused by leaching. It can also synchronize
crop N uptake and N release from soil by utilizing microbes as an ephemeral nutrient pool during the early crop growth period. 相似文献
17.
The long-term treatment effect (since 1957–1966) of farmyard manure (FYM) application compared with crop residue incorporation
was investigated in five soils (sandy loam to silty clay) with regards to the net sulfur (S) mineralization potential. An
open incubation technique was used to determine accumulated net S mineralization (SAccMin) and a number of soil physical and chemical properties were determined. Treatments and soil differences in SAccMin, as well as correlations with soil variables, were tested with single and multivariate analyses. Long-term FYM application
resulted in a significantly (p = 0.012) higher net S mineralization potential, although total amounts of C, N, and S were not significantly (p < 0.05) increased. The accumulated S mineralization differed significantly (p < 0.05) between soils within this treatment. The measured soil variables were not significantly correlated to SAccMin. Conclusively, different treatment histories influenced the quality (e.g., chemical composition) and cycling rate of the
organic S pool, rather than its size. 相似文献
18.
Microbial and soil parameters in relation to N mineralization in soils of diverse genesis under differing management systems 总被引:4,自引:1,他引:3
Oregon soils from various management and genetic histories were used in a greenhouse study to determine the relationships
between soil chemical and biological parameters and the uptake of soil mineralized nitrogen (N) by ryegrass (Lolium perenne L.). The soils were tested for asparaginase, amidase, urease, β-glucosidase, and dipeptidase activities and fluorescein diacetate
hydrolysis. Microbial biomass carbon (C) and N as well as metabolic diversity using Biolog GN plates were measured, as were
total soil N and C, pH, and absorbance of soil extracts at 270 nm and 210 nm. Potentially mineralizable N (N0) and the mineralization rate constant (k) were calculated using a first order nonlinear regression model and these coefficients were used to calculate the initial
potential rate of N mineralization (N0
k). Except for Biolog GN plates, the other parameters were highly correlated to mineralized N uptake and each other. A model
using total soil N and β-glucosidase as parameters provided the best predictor of mineralized N uptake by ryegrass (R
2
=0.83). Chemical and biological parameters of soils with the same history of formation but under different management systems
differed significantly from each other in most cases. The calculated values of the initial potential rate of mineralization
in some cases revealed management differences within the same soil types. The results showed that management of soils is readily
reflected in certain soil chemical and biological indicators and that some biological tests may be useful in predicting N
mineralization in soils.
Received: 31 January 1997 相似文献
19.
Robert M. Zablotowicz L. Jason Krutz Mark A. Weaver Cesare Accinelli Krishna N. Reddy 《Biology and Fertility of Soils》2008,45(1):19-26
The co-application of glufosinate with nitrogen fertilizers may alter atrazine cometabolism, thereby extending the herbicide’s
residual weed control in adapted soils. The objective of this study was to assess the effects of glufosinate, ammonium sulfate,
and the combination of glufosinate and ammonium sulfate on atrazine mineralization in a Dundee silt loam exhibiting enhanced
atrazine degradation. Application of glufosinate at rates of 10 to 40 mg kg−1 soil extended the lag phase 1 to 2 days and reduced the maximum degradation rate by 15% to 30%. However, cumulative atrazine
mineralization averaged 85% 21 days after treatment and was independent of treatment. Maximum daily rates of atrazine mineralization
were reduced from 41% to 55% by application of 1 to 8 g kg−1 of ammonium sulfate. Similarly, cumulative atrazine mineralization was inversely correlated with ammonium sulfate rates ranging
from 1.0 to 8 g kg−1 soil. Under the conditions of this laboratory study, atrazine degradation was relatively insensitive to exogenous mineral
nitrogen, in that 8 g (NH4)2SO4 per kilogram soil repressed but did not completely inhibit atrazine mineralization. Moreover, an additive effect on reducing
atrazine mineralization was observed when glufosinate was co-applied with ammonium sulfate. In addition, ammonium fertilization
alters the partitioning of 14C-atrazine metabolite accumulation and nonextractable residues, indicating that ammonium represses cleavage of the triazine
ring. Consequently, results indicate that the co-application of glufosinate with N may increase atrazine persistence under
field conditions thereby extending atrazine residual weed control in adapted soils. 相似文献
20.
Seth Nii-Annang Holger Grünewald Dirk Freese Reinhard F. Hüttl Oliver Dilly 《Biology and Fertility of Soils》2009,45(5):531-538
The impact of alley cropping on post-lignite mine soils developing from quaternary deposits after 9 years of recultivation
was evaluated on the basis of microbial indicators, organic C and total N contents, and the isotope characteristics of soil
C. Soils were sampled at the 0 to 3, 3 to 10, and 10 to 30 cm depths under black locust (Robinia pseudoacacia L.), poplar (Populus spp.), the transition zone and in the middle of alley under rye (Secale cereale). There was no significant effect of vegetation on microbial properties presumably, due to the high variability, whereas organic
C and total N contents at the 0- to 3-cm layer were significantly higher under black locust and poplar than in the transition
zone and rye field. Organic C total N contents, and basal respiration, microbial biomass, and microbial quotient decreased
with soil depth. Soil organic C and total N contents were more than doubled after 9 years of recultivation, with annual C
and N accretion rate of 162 g C
org m−2 year−1 and 6 g N
t m−2 year−1. Microbial properties indicated that the soils are in early stages of development; the C isotope characteristics confirmed
that the sequestered C was predominantly from C3 plants of the alley cropping. 相似文献