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Modeling aggregate size distribution of eroded sediment resulting from rain-splash and raindrop impacted flow processes

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International Journal of Sediment Research 2019年第2期34卷 166-177页

作者： Selen Deviren Saygin Gunay Erpul department of soil science and plant nutrition Faculty of AgricultureUniversity of Ankara

soil susceptibility to detachment and transport sub-processes of erosion is generally controled by the aggregate breakdown *** particle size and aggregation to the estimate erodibility potential of soils is important under erosive rainfall *** Aggregate Size Distribution（ASD）is one of the most important determinants of soil structure along with soil organic matter content for describing the efficiency of applied,sustainable management *** study aimed to compare the performances of three different aggregate size distribution models to predict the characteristic aggregate size parameter(median diameter,D50)for eroded sediment from interrill erosion processes of RainSplash Transport（RST）and Raindrop Impacted Flow Transport（RIFT）.The ASDs of 1143 collected sediment samples from the RST and RIFT processes were measured and modeled by the Log-normal,Fractal,and Weibull *** D50value,as a characteristic parameter for aggregate size distributions,derived from the cumulative ASD curve was compared for soils from different land use types and different slope and rainfall intensity *** performance of each model was evaluated using the Mean Square Error（MSE）and Coefficient of Determination（R2）.The Weibull approach was the most accurate model showing the best fit with the lowest MSE values（0.0002≤MSE≤0.0048）and having the greatest R2values（0.936≤R2≤0.998）when compared with the Log-normal and Fractal ***,for semi-arid land use and soil,specific shape and scale parameters for the Weibull distribution,the respective ASDs were successfully re-generated for modeling the eroded sediment of the simulated RST and RIFT interill processes.

关键词： Aggregate size distribution Eroded sediment Log-normal model Fractal model Weibull model

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soil chronosequence and biosequence on old lake sediments of the Burdur Lake in Turkey

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Pedosphere 2021年第6期31卷 882-891页

作者： Gafur GOZUKARA Yakun ZHANG Alfred EHARTEMINK Sevda ALTUNBAS Mustafa SARI department of soil science and plant nutrition Eskisehir Osmangazi UniversityEskisehir 26160(Turkey) department of soil science FD Hole Soils Lab1525 Observatory DriveUniversity of Wisconsin-MadisonMadison 53706(USA) department of soil science and plant nutrition Akdeniz UniversityAntalya 07059(Turkey)

The Burdur Lake is located in the southwest of Turkey,and its area has decreased by 40% from 211 km^(2) in 1975 to 126 km^(2) in *** this study,we investigated how the soil has changed in the lacustrine *** soil profiles were sampled from the former lakebed(chronosequence profiles:P1,2007;P2,1994;and P3,1975),and three soil profiles under different land use types(biosequence profiles:P4,native forest vegetation;P5,agriculture;and P6,lakebed)were *** chronosequence and biosequence soil profiles represented various distances from the Burdur Lake and showed different stages of lacustrine *** electrical conductivity(EC;18.1 to 0.4 dS m^(-1)),exchangeable Na^(+)(34.7 to 1.4 cmol kg^(-1))and K^(+)(0.61 to 0.56 cmol kg^(-1)),and water-soluble Cl^(-)(70.3 to 2.1 cmol L^(-1))and SO_(4)^(2-)(275.9 to 25.0 cmol L^(-1))decreased with increasing distance from the Burdur Lake,whereas the A horizon thickness(10 to 48 cm),structure formation(0 to 48 cm),gleization-oxidation depth(0 to 79 cm),and montmorillonite and organic matter(OM;25.9 to 46.0 g kg^(-1))contents increased in the chronosequence soil *** formation of P3 in the chronosequence and P5 in the biosequence soil profiles increased due to longer exposure to pedogenic processes(time,land use,vegetation,etc.).Changes in EC,exchangeable cation(Na^(+) and K^(+))and water-soluble anion(Cl^(-) and SO_(4)^(2-))concentrations of the salt-enriched horizon,OM,gleization-oxidation depth,A horizon thickness,and structure formation of the chronosequence and biosequence soil profiles(especially the topsoil horizon)were highly related to the distance from the Burdur Lake,time,and land use.

关键词： biosequence soil profile chronosequence soil profile lacustrine material lakebed soil formation

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soil Wettability as Affected by soil Characteristics and Land Use

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Pedosphere 2010年第1期20卷 43-54页

作者： R. HORN Institute of plant nutrition and soil science Christian-Albrechts-University zu Kiel

Depth distribution of soil wettability and its correlations with vegetation type, soil texture, and pH were investigated under various land use (cropland, grassland, and forestland) and soil management systems. Wettability was evaluated by contact angle with the Wilhelmy plate method. Water repellency was likely to be present under permanently vegetated land, but less common on tilled agricultural land. It was mostly prevalent in the topsoil, especially in coarse-textured soils, and decreased in the subsoil. However, the depth dependency of wettability could not be derived from the investigated wide range of soils. The correlation and multiple regression analysis revealed that the wettability in repellent soils was affected more by soil organic carbon (SOC) than by soil texture and pH, whereas in wettable soils, soil texture and pH were more effective than SOC. Furthermore, the quality of SOC seemed to be more important in determining wettability than its quantity, as proofed by stronger hydrophobicity under coniferous than under deciduous forestland. soil management had a minor effect on wettability if conventional and conservation tillage or different grazing intensities were considered.

关键词： soil management soil organic carbon soil pH soil texture

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Determining the Zn Content of Cherry in Field Using VNIR Spectroscopy

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光谱学与光谱分析 2015年第2期35卷 355-361页

作者： Mert Dedeoglu Levent Basayigit Selcuk University Agriculture FacultySoil Science and Plant Nutrition Department Suleyman Demirel University Agriculture FacultySoil Science and Plant Nutrition Department

Visible and near-infrared(VNIR)spectroscopy is an eco-friendly method used for estimating plant nutrient *** aim of this study was to investigate the possibility of using VNIR method for estimating Zn content in cherry orchard leaves under field *** study was conducted in 3different locations in Isparta region of *** cherry orchards containing normal and Zn deficient plants were chosen,and 60 leaf samples were collected from each *** reflectance spectra of the leaves were measured with an ASD FieldSpec HandHeld spectroradiometer and a plant *** Zn contents of leaf samples were predicted through laboratory *** spectral reflectance measurements were used to estimate the Zn levels using stepwise multiple linear regression analysis *** models were created using the highest coefficient of determination *** results show that Zn content of cherry trees can be estimated using the VNIR spectroscopic method(87.5plant nutrient contents can be estimated without using ***,further research is necessary to develop a standard method for field *** spectral reflectance is affected by ecological conditions,agricultural applications and nutrient interactions,more effective models must be developed depending on the geographical location,period and plant type.

关键词： Cherry Spectroradiometer Stepwise Regression Visible and Near Infrared(VNIR) Zn content

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Retention and Mobility of Copper and Lead in soils as Influenced by soil Horizon Properties

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Pedosphere 2011年第5期21卷 603-614页

作者： B.CERQUEIRA E.F.COVELO M.L.ANDRADE F.A.VEGA department of plant Biology and soil science University of Vigo

The mobility and bioavailability of heavy metals in soils is largely governed by sorption and desorption ***2+ and Pb2+ are among the most potentially toxic heavy metals and they are present,often concomitantly,in many polluting spills and in *** objective was to assess and compare the competitive sorption and desorption capacities and sorption hysteresis of Cu2+ and Pb2+,as well as their migration through the profiles of four natural soils:a Humic Umbrisol,an Umbric Cambisol,an Endoleptic Luvisol and a Humic *** all horizons Pb2+ was invariably sorbed and retained to a greater extent than Cu2+.The sorption and retention of Cu2+ were most in?uenced by pH,e?ective cation exchange capacity(CECe) and Mn oxide *** the other hand,the fixation capacity of Pb2+ was most in?uenced by pH,CECe,and Mn oxide and organic matter *** and CECe were the individual soil properties most markedly in?uencing Cu2+ and Pb2+ sorption and *** all the horizons Pb2+ exhibited greater hysteresis than Cu2+.In each soil the hysteresis in the A horizon was greater than that in the B horizon,except in the Bt horizon of the Endoleptic Luvisol,due to its high pH and vermiculite *** on migration indices,Pb2+ was less mobile than Cu2+ in the studied soils.

关键词： desorption heavy metal hysteresis migration sorption

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Interactive effects of phosphorus deficiency and exogenous auxin on root morphological and physiological traits in white lupin (Lupinus albus L.)

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science China(Life sciences) 2013年第4期56卷 313-323页

作者： TANG HongLiang SHEN JianBo ZHANG FuSuo RENGEL Zed Centre for Resources Environment and Food Security Department of Plant Nutrition Key Laboratory of Plant-Soil Interactions Ministry of Education China Agricultural University College of Life science Hebei University soil science & plant nutrition School of Earth and Environment The University of Western Australia

White lupin （Lupinus albus） exhibits strong root morphological and physiological responses to phosphorus （P） deficiency and auxin treatments, but the interactive effects of P and auxin in regulating root morphological and physiological traits are not fully understood. This study aimed to assess white lupin root traits as influenced by P （0 or 250 ~tmol L-1） and auxin （10=8 mol L-1 NAA） in nutrient solution. Both P deficiency and auxin treatments significantly altered root morphological traits, as evi- denced by reduced taproot length, increased number and density of first-order lateral roots, and enhanced cluster-root for- marion. Changes in root physiological traits were also observed, i.e., increased proton, citrate, and acid phosphatase exudation. Exogenous auxin enhanced root responses and sensitivity to P deficiency. A significant interplay exists between P and auxin in the regulation of root morphological and physiological traits. Principal component analysis showed that P availability ex- plained 64.8% and auxin addition 21.3% of the total variation in root trait parameters, indicating that P availability is much more important than auxin in modifying root responses of white lupin. This suggests that white lupin can coordinate root mor- phological and physiological responses to enhance acquisition of P resources, with an optimal trade-off between root morpho- logical and physiological traits regulated by external stimuli such as P availability and auxin.

关键词： cluster root carboxylate exudation proton auxin phosphorus deficiency Lupinus albus

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Shoot Apex Demand Determines Assimilate and Nutrients Partitioning and Nutrient-uptake Rate in Tobacco plants

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Journal of Integrative plant Biology 2007年第11期49卷 1654-1661页

作者： Huai-Yu Yang Chun-Jian Li Fu-Suo Zhang The Key Laboratory of plant nutrition Ministry of Agriculture Key Laboratory of Plant-Soil Interactions Ministry of Education Department of Plant Nutrition China Agricultural University Beijing 100094 China

Our previous experiment revealed that apex-removed plants have larger root systems but a lower K＋-uptake rates than intact tobacco plants. Since the apex is not only a center of growth and metabolism, but also an important place of auxin synthesis and export, the aims of this study were to distinguish whether the apex demand or auxin synthesized in the apex regulates assimilate and nutrients partitioning within plant, and to explain the reason for the lower K＋-uptake rate of the apex-removed plant. In comparison with the control plant, covering the shoot apex with a black transparent plastic bag reduced net increases in dry matter and nutrients; however, the distribution of the dry matter and nutrients between shoot and roots and nutrient-uptake rates were not changed. Removal of the shoot apex shifted the dry mass and nutrients distributions to roots, and reduced the rate of nutrient uptake. Application of 1-naphthylacetic acid （NAA） could partly replace the role of the removed apex, stimulated assimilate and nutrient deposition into the treated tissue, and enhanced the reduced plasma membrane ATPase activity of roots to the control level. However, treatment of the apex-removed plants with NAA could not rescue the reduced nutrient uptake rate and the shifted assimilates and nutrients partitioning caused by excision of the apex. Higher nutrient uptake rate of the intact plants could not be explained by root growth parameters, such as total root surface area and number of root tips. The results from the present study indicate that strong apex demand determined assimilates and nutrients partitioning and nutrient-uptake rate in tobacco （Nicotiana tabacum） plants.

关键词： assimilate and nutrient partitioning auxin nutrient uptake removal of the shoot apex shoot apex demand tobacco (Nicotiana tabacum).

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Heterogeneity of Physico-Chemical Properties in Structured soils and Its Consequences

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Pedosphere 2006年第3期16卷 284-296页

作者： E.JASINSKA H.WETZEL T.BAUMGARTL R.HORN Institute for plant nutrition and soil science Christian-Albrechts University Kiel(Germany) Earth sciences/Centre for Mined Land RehabilitationThe University of Queensland/Brisbane Brisbane (Australia) Institute for plant nutrition and soil science Christian-Albrechts University Kiel (Germany)

Structured soils are characterized by the presence of inter- and intra-aggregate pore systems and aggregates, which show varying chemical, physical, and biological properties depending on the aggregate type and land use system. How far these aspects also affect the ion exchange processes and to what extent the interaction between the carbon distribution and kind of organic substances affect the internal soil strength as well as hydraulic properties like wettability are still under discussion. Thus, the objective of this research was to clarify the effect of soil aggregation on physical and chemical properties of structured soils at two scales: homogenized material and single aggregates. Data obtained by sequentially peeling off soil aggregates layers revealed gradients in the chemical composition from the aggregate surface to the aggregate core. In aggregates from long term untreated forest soils we found lower amounts of carbon in the external layer, while in arable soils the differentiation was not pronounced. However, soil aggregates originating from these sites exhibited a higher concentration of microbial activity in the outer aggregate layer and declined towards the interior. Furthermore, soil depth and the vegetation type affected the wettability. Aggregate strength depended on water suction and differences in tillage treatments.

关键词： aggregate peeling aggregation chemical disequilibrium microbial activity water repellency

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Fine Root Patterning and Balanced Inorganic Phosphorus Distribution in the soil Indicate Distinctive Adaptation of Maize plants to Phosphorus Deficiency

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Pedosphere 2012年第6期22卷 870-877页

作者： ZHANG Yu YU Peng PENG Yun-Feng LI Xue-Xiun CHEN Fan-Jun LI Chun-Jian Key Laboratory of plant-soil Interactions Ministry of EducationDepartment of Plant NutritionChina Agricultural UniversityBeijing 100193(China)

plants have diverse strategies to cope with phosphorus （P） deficiency. To better understand how maize responds to P deficiency, a field experiment with two P levels, 0 and 100 kg P205 ha-1 （P0 and P100, respectively）, was carried out as a part of a long-term Pfertilizer field trial. plant and soil analyses showed that P-deficient maize reduced its growth rate, increased P use efficiency, and formed more thin roots with the diameter less than 0.6 mm at jointing and silking stages, compared to the plants treated with P100. Further, there were no differences in major inorganic P fractions （Ca2-P, Cas-P, Al-P, Fe-P, occluded P and Ca10-P） between the rhizospheric and bulk soils at each harvest, even when soil Olsen-P was only 1.38 mg kg-1. These results suggested that maize responded to P deficiency by reducing the internal P demand for growth and increasing P acquisition ability by favorable root morphological alteration at low carbon cost.

关键词： inorganic phosphorus fractions phosphorus starvation rhizosphere root length root morphology

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Contribution of Root Proliferation in Nutrient-Rich soil Patches to Nutrient Uptake and Growth of Maize

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Pedosphere 2012年第6期22卷 776-784页

作者： LI Hong-Bo ZHANG Fu-Suo SHEN Jian-Bo department of plant nutrition China Agricultural UniversityKey Laboratory of Plant-Soil InteractionsMinistry of EducationBeijing 100193(China)

Root proliferation can be stimulated in a heterogeneous nutrient patch; however, the functions of the root proliferation in the nutrient-rich soil patches are not fully understood. In the present study, a two-year field experiment was conducted to examine the comparative effects of localized application of ammonium and phosphorus (P) at early or late stages on root growth, nutrient uptake, and biomass of maize (Zea mays L.) on a calcareous soil in an intensive farming system. Localized supply of ammonium and P had a more evident effect on shoot and root growth, and especially stimulated fine root development at the early seedling stage, with most of the maize roots being allocated to the nutrient-rich patch in the topsoil. Although localized ammonium and P supply at the late stage also enhanced the fine root growth, the plant roots in the patch accounted for a low proportion of the whole maize roots in the topsoil at the flowering stage. Compared with the early stage, fine root length in the short-lived nutrient patch decreased by 44%-62% and the shoot dry weight was not different between heterogeneous and homogeneous nutrient supply at the late growth stage. Localized supply of ammonium and P significantly increased N and P accumulation by maize at 35 and 47 days after sowing (DAS); however, no significant difference was found among the treatments at 82 DAS and the later growth stages. The increased nutrient uptake and plant growth was related to the higher proportion of root length in the localized nutrient-enriched patch. The results indicated that root proliferation in nutrient patches contributed more to maize growth and nutrient uptake at the early than late stages.

关键词： biomass growth stage intensive farming system localized nutrient supply root length

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