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1.
Boreal lands have long been considered unsuitable for agriculture. Climate change projections support a shift towards increased agricultural production in boreal ecosystems via land use conversion. Depending on the conversion protocol, the new plough layer may variably reflect the properties of different soil depths. This study assessed how adding mineral or organic fertilizer sources to distinct soil layers within ploughing depth (0–15 cm [topsoil] or 15–30 cm [subsoil]) affects nutrient uptake and crop productivity. Locally relevant organic waste fertilizers (dairy manure [DMN], recirculating aquaculture system supernatant [SUP] and slurry [RAS]), were compared against mineral fertilizer. Tall fescue was used to verify agronomic responses. Starting available nutrient concentrations were balanced as necessary with mineral N and P fertilizers. Except for NH4-nitrogen, both soils were of apparent similar fertility (total C < 1%); unfertilized, neither could support significant plant growth. Subsoil-based growth was fast but limited in time reflecting immediately available nutrients. Topsoil led to delayed, extended growth. This might be due to dichotomous priming effects: during the duration of the experiment up to 36% of subsoil carbon was lost, while the topsoil gained up to 49% carbon, most apparent for DMN. While RAS led to the greatest N and P acquisition efficiencies for topsoil, it had no such effect for subsoil, suggesting distinct fixation and mineralization processes. Dissimilar C cycling and nutrient acquisition for the two soil depths indicates that site-specific considerations that include soil health parameters with commonly tested available nutrients are needed where podzols are farmed after land-use conversion. 相似文献
2.
An incubation experiment （Exp. 1） with three soils, two from Australia and one from Norway, was carried out to investigate the fate of dissolved BorreGro （a lignosulfonate, produced by Borregaard LignoTech Company, Norway） at different concentrations （0, 10 and 100 mg C L-1） in soil solutions. A rhizobox experiment （Exp. 2） was also done in a Norwegian clay soil, mixed with four levels of BorreGro-carbon （BG-C） added （0, 2, 20 and 200 mg BG-C kg-1） to test the impact of BorreGro on root growth, rhizosphere chemistry （pH, metals and dissolved organic carbon （DOC）） and the composition of phospholipid fatty acids （PLFAs）. The BorreGro addition increased the concentration of Mn due to the high concentrations in BorreGro. The BorreGro addition to soil had an indirect but significant impact on the rhizosphere chemistry and PLFAs. The lowest amounts of added BorreGro facilitated the DOC excretion at plant roots, and thereby increased the bacterial and fungal biomass, likely as an effect of increased Mn solubility from BorreGro in the root zone. 相似文献
3.
We used the soil‐core translocation method to investigate the effect of increased temperature on above‐ and below‐ground phytomass and organic matter in cool alpine areas. The translocation of undisturbed soil cores from a high alpine site (2525 m a.s.l.) to an alpine site near the timberline (1895 m a.s.l.) achieved an effective artificial warming of 3.3 K. From a methodological point of view, the translocation of soil cores was performed successfully. Soil cores moved to a new site at the same altitude showed no change in above‐ and below‐ground vegetation, bulk density, and soil skeleton. At both sites, soils were Haplic Podzols with a similar chemistry and clay mineralogy. At the lower elevation site, however, podzolization processes seemed to be more pronounced. As a consequence, the translocation of the soil cores probably led to a disturbance of the actual steady state that had been established after about 10,000–13,000 years of soil formation. This might have affected the adaptability of the vegetation system. Therefore, it cannot be fully excluded that the experimental design influenced the results. Translocation of soil cores from a very cool to a warmer site led to a distinct decrease in above‐ground phytomass (about –45%) over the experimental period of two years. Below‐ground phytomass significantly decreased (up to –50%) in the topsoil (0–5 cm) after artificial warming. Possible mechanisms are that roots reduced photosynthesis and hence C flow below‐ground, a reduction of soil moisture that would have led to root death (not a very probable cause, however) or an abrupt change in the radiation duration and flux which affected root growth (also not very probable). Fast climate change exceeded the ability of the above‐ground and below‐ground phytomass to adapt quickly. Whether the decrease in phytomass was a short‐term or a long‐term response to climate warming remains uncertain. Based on a gradient study (climosequence at the same locality), we hypothesize that the decreased plant productivity might be a short‐term effect. 相似文献
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Traditional models of soil organic matter (SOM) decomposition are all based on first order kinetics in which the decomposition rate of a particular C pool is proportional to the size of the pool and a simple decomposition constant (dC/dt=kC). In fact, SOM decomposition is catalyzed by extracellular enzymes that are produced by microorganisms. We built a simple theoretical model to explore the behavior of the decomposition-microbial growth system when the fundamental kinetic assumption is changed from first order kinetics to exoenzymes catalyzed decomposition (dC/dt=KC×Enzymes). An analysis of the enzyme kinetics showed that there must be some mechanism to produce a non-linear response of decomposition rates to enzyme concentration—the most likely is competition for enzyme binding on solid substrates as predicted by Langmuir adsorption isotherm theory. This non-linearity also induces C limitation, regardless of the potential supply of C. The linked C and N version of the model showed that actual polymer breakdown and microbial use of the released monomers can be disconnected, and that it requires relatively little N to maintain the maximal rate of decomposition, regardless of the microbial biomass’ ability to use the breakdown products. In this model, adding a pulse of C to an N limited system increases respiration, while adding N actually decreases respiration (as C is redirected from waste respiration to microbial growth). For many years, researchers have argued that the lack of a respiratory response by soil microbes to added N indicates that they are not N limited. This model suggests that conclusion may be wrong. While total C flow may be limited by the functioning of the exoenzyme system, actual microbial growth may be N limited. 相似文献
6.
Quantitative soil organic carbon (SOC) models are required for a better understanding of C sequestration in soils and for prognoses at different scenarios. However, it is unclear whether the major C‐stabilization mechanisms are included adequately. Objectives were (1) to test the performance of the CIPS (Carbon turnover In Pore Space) model and the Rothamsted Carbon (RothC) Model for a prediction of the SOC dynamics at the long‐term experiments at Halle (Germany) and (2) to compare the model structures of the quantitative models and a conceptual model in order to identify shortcomings of the quantitative models. Both quantitative models had a similar prediction performance: the C dynamics was predicted satisfactorily for the Halle sites under continuous rye with NPK fertilization or without any fertilization (1878–1953), but larger deviations between modeled and measured C contents were observed for the continuous rye and maize in the entire period from 1878 to 1996. The comparison of the conceptual model with the quantitative models revealed that the neglect of the black C dynamics and the interactions of SOC with mineral surfaces are not included explicitly. Site‐specific calibrations are required where these processes have a significant impact on soil organic matter dynamics. Furthermore, the number of pools and mechanisms in the conceptual model is higher than in the quantitative models independent of their level of abstraction. Despite the neglect of some important mechanisms in the quantitative models, it has to be noted that they reproduce the SOC data generally well in agricultural surface soils. Moreover, they need only few inputs which are generally easily obtainable. 相似文献
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O. Popovic Å.R. Almås M. Manojlovic S. Muratović 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(8):730-738
Abstract Three thermal power plants in Serbia, Croatia and Bosnia of the Western Balkan region were expected to be metal polluting sources, and this study was performed to investigate the bioavailability and chemical speciation of trace metals in soils and soil water extracts, respectively. Surface (0–15 cm) soil samples along with maize and grass samples were collected at a gradient from the pollution source. The chemical speciation of metals was conducted using the Windereme Humic Aqueous Model (WHAM)/Model VI for water, whereas the Diffusion Gradient in Thin Films (DGT) technique was used to estimate plant availability. The chemical speciation indicated that more than 99% of all four metals in soil water extracts were complexed to fulvic acid. This is connected to relatively high soil pH (> 6.5) and high contents of soil organic matter in these soils. The accumulation of trace metals by DGT was not correlated to plant uptake. This is connected to the very low partitioning of free ions in solution, but also to the low variation in metal solubility and metal concentration in plant tissue between sites. In spite of active thermal power plants located in the areas, hardly any differences in concentration of soil metals between sites were seen and the partition of metals in soil waters was insignificant. The latter indicates that these soils have a large metal-retaining capacity. The only significant soil chemical variable affecting the variation in metal solubility was the soil pH. In a time with large infrastructure and industrial expansion in these areas, this investigation indicates the importance of protecting these high-quality soils from industrial use and degradation. High industrial activity has so far had insignificant effect on soil quality with respect to bioavailability of trace metals in these soils. 相似文献
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《Communications in Soil Science and Plant Analysis》2012,43(1-2):158-167
Abstract Speciation of cadmium (Cd) was studied in four spiked agricultural soils at moisture content corresponding to 1.2 times field moisture capacity (FMC) and in the range from 1.2 FMC to soil–water 1∶10. Cadmium desorption isotherms were nonlinear in all soils, resulting in the decrease in Cd partition coefficient with loading. The Windermere Humic Aqueous Model (WHAM VI) was applied to predict Cd concentration in the solutions, and predicted values were compared with the measured ones. Based on total Cd content in soils, with concentrations of dissolved organic carbon (DOC), calcium (Ca), magnesium (Mg), and sodium (Na) and soil solution pH as the input variables, WHAM VI predicted Cd concentration in soil solutions with the root‐mean‐square error (RMSE) of log[Cd] RMSElog[Cd]=0.54 (n=37). Using total Cd content in soils, average concentrations of Ca and DOC in soil solutions, and soil pH instead of soil solution pH enabled prediction of Cd concentration in soil solution with RMSElog[Cd]=0.56. Calculation of Cd concentration as a function of moisture content resulted in RMSElog[Cd]=0.25 (n=20). 相似文献
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依托10 a定位试验研究了秸秆还田对典型砂姜黑土有机矿质复合体中有机质稳定性的影响机制。田间试验设置5个处理:氮磷钾配施下的小麦和玉米秸秆双季还田(WMS+F)、小麦秸秆还田(WS+F)、玉米秸秆还田(MS+F)、非秸秆还田(F)处理,以不施肥模式下的非秸秆还田为对照(CK)。结果显示,铁铝键合态和紧密结合态有机质含量累计占土壤总有机质的88.70%,且三者变化趋势一致,均呈现WS+F≈WMS+F≈MS+FFCK,并与土壤短程有序、有机结合态铁铝氧化物呈显著正相关,但与非晶型铁铝氧化物呈负相关性。秸秆还田显著促进了土壤有机质累积,并受到土壤铁铝键合态有机质的影响,但由于非晶型铁铝氧化物生成速度较慢,限制了土壤有机质的进一步累积。土壤紧密结合态有机质对其全量的贡献明显高于铁铝键合态有机质,相关机制值得进一步研究。 相似文献
11.
Soil density fractionation is a common tool to separate organic matter of different function and turnover. But it has not been tested so far how much soil material is necessary to obtain reproducible results. A reduction of chemicals like polytungstate would further save valuable resources. Here, we show that soil weight reduction from 25 to 5 g was not significantly affecting fractionation results. Compared to the commonly used 10–25 g, this corresponds to a saving of resources of up to 80%. 相似文献
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Cícero Célio de Figueiredo Walda Monteiro Farias Bruno Araújo de Melo Jhon Kenedy Moura Chagas Ailton Teixeira Vale Thais Rodrigues Coser 《Archives of Agronomy and Soil Science》2019,65(6):770-781
One of the main advantages of using biochar for agricultural purposes is its ability to store carbon (C) in soil for a long-term. Studies of labile and stable fractions of soil organic matter (SOM) may be a good indicator of the dynamics of biochar in soils. This study evaluated the effects of applying sewage sludge biochar (SSB) in combination with mineral fertilizer on fractions of SOM. To conduct this evaluation, 15 Mg ha?1 of SSB combined or not with mineral fertilizer (NPK) was applied to the soil in two cropping seasons. Apart from total organic C (TOC), the labile and stable fractions of SOM were also determined. The combined use of SSB and NPK resulted in higher TOC, a 22% to 40% increase compared to the control and to the NPK treatments, respectively. The SSB produced at a lower temperature increased the labile fractions of SOM, especially the microbial biomass C, showing its capacity to supply nutrients in the short-term. The stable pools of SOM are increased after adding SSB produced at a higher temperature. It was concluded that pyrolysis temperature is a key-factor that determines the potential of SSB to accumulate C in labile and stable fractions of SOM. 相似文献
13.
Corn straw is an important source of carbon (C),and when applied to soil,it alters the accumulation and distribution of organic C.However,the mechanistic pathways by which newly added C is stored and stabilized in soil remain a subject of interest and debate among scholars.In this study,we investigated the chemistry of organic matter in different density fractions of Haplic Cambisol (sandy clay loam) in a field experiment with corn straw at8 900 kg ha-1year-1under no tillag... 相似文献
14.
B. L. M. Leroy H. M. S. K. Herath S. Sleutel S. De Neve D. Gabriels D. Reheul & M. Moens 《Soil Use and Management》2008,24(2):139-147
We examined the short-term effect of five organic amendments and compared them to plots fertilized with inorganic fertilizer and unfertilized plots on aggregate stability and hydraulic conductivity, and on the OC and ON distribution in physically separated SOM fractions. After less than 1 year, the addition of organic amendments significantly increased ( P < 0.01) the aggregate stability and hydraulic conductivity. The stability index ranged between 0.97 and 1.76 and the hydraulic conductivity between 1.23 and 2.80 × 10−3 m/s for the plots receiving organic amendments, compared with 0.34–0.43, and 0.42–0.64 × 10−3 m/s, respectively, for the unamended plots. There were significant differences between the organic amendments (P < 0.01), although these results were not unequivocal for both soil physical parameters. The total OC and ON content were significantly increased ( P < 0.05) by only two applications of organic fertilizers: between 1.10 and 1.51% OC for the amended plots versus 0.98–1.08% for the unamended and between 0.092 and 0.131% ON versus 0.092–0.098% respectively. The amount of OC and ON in the free particulate organic matter fraction was also significantly increased ( P < 0.05), but there were no significant differences ( P < 0.05) in the OC and ON content in the POM occluded in micro-aggregates and in the silt + clay-sized organic matter fraction. The results showed that even in less than 1 year pronounced effects on soil physical properties and on the distribution of OC and ON in the SOM fractions occurred. 相似文献
15.
土壤团聚体的形成与分散及其在农业生产上的应用 总被引：8，自引：2，他引：8
土壤团聚体是保持土壤水分和土壤透性的基本单元.本综述的目的是通过围绕团聚体理论的讨论,明确影响团聚体形成的因素,为农田维护提出可靠的理论依据.首先总结了团聚体形成的主要理论,即Emerson的粘团理论、Edwards和Bremner的微团聚体理论和Oades 及Waters的团聚体分级构建理论,然后讨论了土壤有机质、可溶性阳离子和氧化铁、铝3个影响团聚体形成的主要因素,最后分析了团聚体破坏的机理和评价团聚体稳定性的主要方法,指出保持土壤颗粒的凝聚状态、增加各种形态的土壤有机质是增加土壤团聚性的主要措施. 相似文献
16.
Vesicles enriched in right‐side‐out plasma membranes were isolated from corn roots by a modified two‐phase partition method. Using reduced nicotinamide adenine dinucleotide as electron donor, isolated vesicles were capable of reducing both ferricyanide and oxygen. At pH 6.0, the presence of Al inhibited both reduction processes to a similar extent. This result indicates that these two reduction processes share at least one common step that is sensitive to Al. Inhibition was not associated with a change in the structure of the membrane domain, as revealed by fluorescence polarization of membrane incorporated probes. These results are the first indications that the electron transfer processes of plasma membranes are sensitive to the presence of Al. 相似文献
17.
采集了全国不同类型的土壤40个,分析了土壤全氮、有机质、固定态铵、剩余有机质（KOBr处理后的土壤有机质）、残渣有机质（KOBr-HF处理后的土壤有机质）含量.结果表明,以2∶1型粘粒矿物为主土壤的残渣有机质含量与固定态铵含量之间呈极显著正相关（r=0.831^＊＊）,晶格之间存在的有机质（即残渣有机质与剩余有机质之差值）含量则与固定态铵含量之间也呈极显著正相关（r=0.832^＊＊）,而以1∶1型粘粒矿物为主土壤的残渣有机质含量和晶格有机质含量与固定态铵含量不相关;土壤剩余有机质、残渣有机质的含量分别为2.59 g kg^-1、3.70 g kg^-1,分别占土壤有机质的10%和16%.土壤残渣C/N比（平均值为16.69）明显高于原土壤（平均值为5.37）. 相似文献
18.
Sarah V. Novais Mariana D. O. Zenero Elizio F. Frade Junior Roberto F. Novais 《Communications in Soil Science and Plant Analysis》2018,49(10):1208-1217
Plants with different photosynthetic cycles (C3 and C4) and different plant parts (root or shoot) contribute in different ways to soil organic carbon (SOC). In addition, phosphate and nitrogen fertilization also act differently on the SOC stock. In this study, roots or shoots of corn (C3) and soybean (C4) plants were incorporated into samples of an Oxisol, with or without the addition of nitrogen (N) and phosphorus (P) and had the emission of carbon (C)- carbon dioxide (CO2) measured during 45 days. Subsequently, soil organic matter fractionation, carbon and nitrogen microbial biomass and 13C isotopic discrimination were performed. The greatest increment in SOC was observed by adding corn plant material rather than soybean material. For both crops, the greatest contribution to SOC was achieved by adding roots as compared to shoots. Phosphorus addition produced greater microbial activity, followed by the addition of NP and then the addition of only N. 相似文献
19.
不同耕作制度对紫色水稻土活性有机质及碳库管理指数的影响 总被引：13，自引：1，他引：13
以长期定位试验点的紫色水稻土为研究对象,研究了耕作制度对紫色水稻土活性有机质和碳库管理指数的影响。结果表明：稻田长期垄作免耕0～10cm土层有机质含量比常规平作高,10～60cm土层有机质含量则比常规平作低;表明稻田长期垄作免耕土壤有机质具有表层富集现象;水旱轮作各土层有机质含量均比常规平作低。垄作免耕各土层活性有机质含量普遍增加,水旱轮作表层（0～10cm）活性有机质含量减少,其余土层变化不大。对活性有机质组分含量的研究表明：与常规平作相比,垄作免耕增加了土壤表层活性有机质各个组分的含量,在其余土层增加了低活性有机质含量,而减少了高活性有机质含量;水旱轮作增加了各土层低活性有机质含量而减少了中活性和高活性有机质含量。垄作免耕所有土层的碳库管理指数都在100以上,水旱轮作除表层（0～10cm）小于100以外,其余土层都在100以上。由此可见,农业管理措施对土壤有机质、活性有机质及碳库管理指数有较大影响。 相似文献
20.
Kenneth Miller Brenna J. Aegerter Nicholas E. Clark Michelle Leinfelder-Miles Eugene M. Miyao Richard Smith 《Communications in Soil Science and Plant Analysis》2019,50(1):77-92
Soil nitrogen (N) mineralization rates from different agricultural regions in California were determined and related to soil properties. Undisturbed soil cores were sampled in spring from 57 fields under annual crop rotations and incubated at 25℃ for 10 weeks. Soil properties varied across and within regions, most notably those related to soil organic matter (SOM), with total soil carbon ranging from 6 to 198 g kg?1. Multivariate linear regression was used to select soil properties that best predicted N mineralization rates. Regression models with a good fit differed between soils with high and low SOM contents, but generally included a measure of SOM quantity, its quality as well as soil texture or mineralogy. Adjusted R2 values were 0.95 and 0.60 for high and low SOM soils, respectively. This study has shown that information on soil properties can contribute to better estimates of N mineralization in soils of contrasting characteristics. 相似文献