scholarly journals Phosphorus availability in hydromorphic soils of Eastern Croatia

2011 ◽  
Vol 49 (No. 9) ◽  
pp. 394-401 ◽  
Author(s):  
D. Petosić ◽  
V. Kovacević ◽  
M. Josipović
Keyword(s):  
Surface Layer ◽  
High Frequency ◽  
Agricultural Land ◽  
Phosphorus Availability ◽  
Available P ◽  
Soil Profiles ◽  
P Availability ◽  
Hydromorphic Soils ◽  
Ammonium Lactate ◽  
Plant Available P

The phosphorus (P) availability was tested on hydromorphic soils located in theSavavalley. 480 soil profiles covering the area of31 227 hawas analysed in our study. The plant available P was determined by the Ammonium-Lactate method. The P availability in the surface layer (0–30 cm) is very low (up to 5 mg P2O5/100 g of soil) in about 30% of the tested agricultural land (9 440 ha), next 32% (9 897 ha) is in the range of a low P availability (from 5.1 to 10 mg), while only 17% (5 445 ha) has a good or very good P availability (above 20 mg). Especially high frequency of low P availability was found in vertic gley, amphygley and hypogley soils (total8 680 haor 28% of tested agricultural land).

Agricultural use of municipal wastewater sludges: phosphorus availability of biological excess phosphorus removal sludges

2006 ◽  
Vol 54 (5) ◽  
pp. 131-138 ◽  
Author(s):  
A. Erdincler ◽  
L.D. Seyhan
Keyword(s):  
Phosphorus Removal ◽  
Municipal Wastewater ◽  
Phosphorus Availability ◽  
Available P ◽  
P Availability ◽  
Alkaline Soil ◽  
Biological Phosphorus Removal ◽  
Pot Experiments ◽  
Agricultural Use ◽  
Biological Phosphorus

Reuse of sewage sludges as phosphorus fertiliser requires the estimation of the plant availabilities of phosphorus (P) from different sludges. This study investigates the effect of lime stabilisation on the phosphorus availability from biological phosphorus removal sludges. In the first part of the study, pot experiments were carried out to assess the fertilising effect of a dewatered biological phosphorus removal sludge. Availability of P was determined in terms of plant-uptake. In the second part of the study, incubation tests were carried out to observe the change in the available P with time when the waste activated sludge (WAS) from an enhanced biological phosphorus removal (EBPR) process is mixed with the same soil. In this part, the plant available P was measured in terms of Olsen extractable P. A P-deficient, alkaline soil was used in the experiments and Lollium Perenne was selected as the testing plant. The results of the pot experiments revealed that lime-stabilisation of the sludge considerably decreased or retarded the availability of P in the sludge. In the incubation tests, the availability of phosphorus in the lime stabilised and non-stabilised sludge amended soil samples was close to each other. In general, P-availability was increased due to the sludge application except for the lime-stabilised dewatered sludge.

scholarly journals Phosphorus extracted by ion exchange resins and mehlich-1 from oxisols (latosols) treated with different phosphorus rates and sources for varied soil-source contact periods

2013 ◽  
Vol 37 (3) ◽  
pp. 667-677 ◽  
Author(s):  
Irio Fernando de Freitas ◽  
Roberto Ferreira Novais ◽  
Ecila Mercês de Albuquerque Villani ◽  
Sarah Vieira Novais
Keyword(s):  
Sandy Loam ◽  
Extraction Methods ◽  
Available P ◽  
Molar Ratio ◽  
P Availability ◽  
Triple Superphosphate ◽  
Experimental Conditions ◽  
Reactive Phosphate ◽  
Exchange Resins ◽  
P Sources

Despite the large number of studies addressing the quantification of phosphorus (P) availability by different extraction methods, many questions remain unanswered. The aim of this paper was to compare the effectiveness of the extractors Mehlich-1, Anionic Resin (AR) and Mixed Resin (MR), to determine the availability of P under different experimental conditions. The laboratory study was arranged in randomized blocks in a [(3 x 3 x 2) + 3] x 4 factorial design, with four replications, testing the response of three soils with different texture: a very clayey Red Latosol (LV), a sandy clay loam Red Yellow Latosol (LVA), and a sandy loam Yellow Latosol (LA), to three sources (triple superphosphate, reactive phosphate rock from Gafsa-Tunisia; and natural phosphate from Araxá-Minas Gerais) at two P rates (75 and 150 mg dm-3), plus three control treatments (each soil without P application) after four contact periods (15, 30, 60, and 120 days) of the P sources with soil. The soil acidity of LV and LVA was adjusted by raising base saturation to 60 % with the application of CaCO3 and MgCO3 at a 4:1 molar ratio (LA required no correction). These samples were maintained at field moisture capacity for 30 days. After the contact periods, the samples were collected to quantify the available P concentrations by the three extractants. In general, all three indicated that the available P-content in soils was reduced after longer contact periods with the P sources. Of the three sources, this reduction was most pronounced for triple superphosphate, intermediate for reactive phosphate, while Araxá phosphate was least sensitive to the effect of time. It was observed that AR extracted lower P levels from all three soils when the sources were phosphate rocks, while MR extracted values close to Mehlich-1 in LV (clay) and LVA (medium texture) for reactive phosphate. For Araxá phosphate, much higher P values were determined by Mehlich-1 than by the resins, because of the acidity of the extractor. For triple superphosphate, both resins extracted higher P levels than Mehlich-1, due to the consumption of this extractor, particularly when used for LV and LVA.

scholarly journals Features of the Surface and Subsurface Waves Application for Ultrasonic Evaluation of Physicomechanical Properties of Solids. Part 2. Strenghtned Inhomogeneous Surface Layer

2019 ◽  
Vol 10 (1) ◽  
pp. 69-79
Author(s):  
A. R. Baev ◽  
A. L Mayorov ◽  
N. V. Levkovich ◽  
M. V. Asadchaya
Keyword(s):  
Experimental Data ◽  
Surface Layer ◽  
Spatial Distribution ◽  
Surface Wave ◽  
High Frequency ◽  
Hardened Layer ◽  
Gray Iron ◽  
Physicomechanical Properties ◽  
Inhomogeneous Surface ◽  
Ultrasonic Evaluation

The propagation of a pulsed signal of a surface wave over an object with a non-uniform surface layer, obtained, for example, as a result of surface hardening, with structural damage, is accompanied by the dispersion of the velocity of the wave carrying important information about the parameters of such a layer. The aim of the work is to study the relationship between the acoustic parameters of a pulsed acoustic signal of a surface and subsurface waves and the surface layer of steel specimens hardened by high-frequency hardening, and gray iron-chill. Features of the surface and subsurface waves application for ultrasonic evaluation of physicomechanical properties of solids. Strenghtned inhomogeneous surface layer.A brief analysis of the known works on determining the depth of hardened surface layers by various methods, including high-frequency hardening, cementation, etc., is carried out. Based on the Oulder integral expression. The dependence connecting the wave velocity, its frequency, the depth of the hardened layer and the spatial distribution of hardness represented as a step with a changing slope of its side surface simulating the transition zone of the hardened layer are calculated.Using the pulse method and low-aperture transducers with a frequency of 1−3.8 MHz, the dependences of the surface wave velocity on the cutting height of a layer hardened by HDTV hardening are obtained. A comparison of experimental data and calculations of the theoretical model showed a good qualitative correspondence between them, demonstrate a high «sensitivity» of the method in relation to the nature of the change in hardness over the depth of the hardened layer. It is shown that the proposed approach is promising for solving the inverse problem of restoring the spatial distribution of hardness based on experimental data.The goniometric method was approbated to determine the dependence between amplitude-angle characteristics and depth of the surface steel layers hardened by high-frequency hardening and depth of hardened gray iron specimens layer – with chill. It is shown that the optimal angle corresponding maximum of excited surface wave amplitude in steel specimens is decreasing up to 24–26'vs. hardened depth layer. But when the tested specimens from cast iron this angle decreasing is nearly of 6°. Recommendations on the use of research results in practice are given.

Modeling Of Thermophysical Processes In The Case Of Surface Modifying Of Metal During Induction Treatment

2017 ◽  
Vol 12 (1) ◽  
pp. 91-96
Author(s):  
Vladimir Popov ◽  
Vladimir Shchukin
Keyword(s):  
Numerical Simulation ◽  
Electromagnetic Field ◽  
Surface Layer ◽  
Temperature Field ◽  
High Frequency ◽  
Induction Treatment ◽  
High Frequency Electromagnetic Field ◽  
Modes Of Processing

Process of modifying of the surface layer of metals under influence of high-frequency electromagnetic field was considered using numerical simulation. The temperature field and the size of modified region were determined at various modes of processing.

The Characteristic and Mechanism of Lead Pollution in Soil Profiles from a Sulphuric Acid Slag Pile Sit in Guangdong,China

2011 ◽  
Vol 474-476 ◽  
pp. 172-177 ◽  
Author(s):  
Jing Yong Liu ◽  
Xun An Ning
Keyword(s):  
Organic Matter ◽  
Surface Layer ◽  
Sulfuric Acid ◽  
Guangdong Province ◽  
Soil Samples ◽  
Soil Profiles ◽  
Lead Pollution ◽  
Acid Plant ◽  
Sulfuric Acid Plant ◽  
Main Factors

The soil samples in a profile were collected around the pyrite slag pile site near a sulfuric acid plant in Guangdong province and the contents of lead were investigated detail. At the same time, the mechanism of lead pollution was principium analyzed. The research found that the lead pollutants were mainly concentrated in soils surface layer about 0-10cm and shown characteristics of contents rapidly decreasing along the uprights. the main factors that affected the transference of lead from the slag to the soil were the filtering by acid rain and itself acidification of the slag. Iron oxide colloid and organic matter may have been responsible for the lead retention in soil.<b></b>

scholarly journals Integrated Effects of Co-Inoculation with Phosphate-Solubilizing Bacteria and N2-Fixing Bacteria on Microbial Population and Soil Amendment Under C Deficiency

2019 ◽  
Vol 16 (13) ◽  
pp. 2442 ◽  
Author(s):  
Zhikang Wang ◽  
Ziyun Chen ◽  
Xiangxiang Fu
Keyword(s):  
Plant Growth ◽  
Soil Properties ◽  
Soil Amendment ◽  
Growth Promotion ◽  
Synergistic Effects ◽  
Available P ◽  
P Availability ◽  
Phosphate Solubilizing Bacteria ◽  
Unsterilized Soil ◽  
Phosphate Solubilizing

The inoculation of beneficial microorganisms to improve plant growth and soil properties is a promising strategy in the soil amendment. However, the effects of co-inoculation with phosphate-solubilizing bacteria (PSB) and N2-fixing bacteria (NFB) on the soil properties of typical C-deficient soil remain unclear. Based on a controlled experiment and a pot experiment, we examined the effects of PSB (M: Bacillus megaterium and F: Pseudomonas fluorescens), NFB (C: Azotobacter chroococcum and B: Azospirillum brasilence), and combined PSB and NFB treatments on C, N, P availability, and enzyme activities in sterilized soil, as well as the growth of Cyclocarya Paliurus seedlings grow in unsterilized soil. During a 60-day culture, prominent increases in soil inorganic N and available P contents were detected after bacteria additions. Three patterns were observed for different additions according to the dynamic bacterial growth. Synergistic effects between NFB and PSB were obvious, co-inoculations with NFB enhanced the accumulation of available P. However, decreases in soil available P and N were observed on the 60th day, which was induced by the decreases in bacterial quantities under C deficiency. Besides, co-inoculations with PSB and NFB resulted in greater performance in plant growth promotion. Aimed at amending soil with a C supply shortage, combined PSB and NFB treatments are more appropriate for practical fertilization at intervals of 30–45 days. The results demonstrate that co-inoculations could have synergistic interactions during culture and application, which may help with understanding the possible mechanism of soil amendment driven by microorganisms under C deficiency, thereby providing an alternative option for amending such soil.

scholarly journals Land Use Changes Affecting Soil Organic Matter Accumulation in Topsoil and Subsoil in Northeast Thailand

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Benjapon Kunlanit ◽  
Laksanara Khwanchum ◽  
Patma Vityakon
Keyword(s):  
Land Use ◽  
Organic Matter ◽  
Soil Organic Matter ◽  
Agricultural Land ◽  
Soil Depth ◽  
General Pattern ◽  
Clay Fraction ◽  
High Rate ◽  
Soil Profiles ◽  
Land Uses

The objectives of this study were to investigate effects of land use on accumulation of soil organic matter (SOM) in the soil profile (0–100 cm) and to determine pattern of SOM stock distribution in soil profiles. Soil samples were collected from five soil depths at 20 cm intervals from 0 to 100 cm under four adjacent land uses including forest, cassava, sugarcane, and paddy lands located in six districts of Maha Sarakham province in the Northeast of Thailand. When considering SOM stock among different land uses in all locations, forest soils had significantly higher total SOM stocks in 0–100 cm (193 Mg·C·ha−1) than those in cassava, sugarcane, and paddy soils in all locations. Leaf litter and remaining rice stover on soil surfaces resulted in a higher amount of SOM stocks in topsoil (0–20 cm) than subsoil (20–100 cm) in some forest and paddy land uses. General pattern of SOM stock distribution in soil profiles was such that the SOM stock declined with soil depth. Although SOM stocks decreased with depth, the subsoil stock contributes to longer term storage of C than topsoils as they are more stabilized through adsorption onto clay fraction in finer textured subsoil than those of the topsoils. Agricultural practices, notably applications of organic materials, such as cattle manure, could increase subsoil SOM stock as found in some agricultural land uses (cassava and sugarcane) in some location in our study. Upland agricultural land uses, notably cassava, caused high rate of soil degradation. To restore soil fertility of these agricultural lands, appropriate agronomic practices including application of organic soil amendments, return of crop residues, and reduction of soil disturbance to increase and maintain SOM stock, should be practiced.

scholarly journals Towards optimal use of phosphorus fertiliser

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Mart B. H. Ros ◽  
Gerwin F. Koopmans ◽  
Kees Jan van Groenigen ◽  
Diego Abalos ◽  
Oene Oenema ◽  
...  
Keyword(s):  
Agricultural Land ◽  
Meta Analysis ◽  
P Availability ◽  
Agricultural Systems ◽  
Application Rates ◽  
P Application ◽  
Fertiliser Application ◽  
Fertiliser Use ◽  
Yield Responses ◽  
Effective Use

Abstract Because phosphorus (P) is one of the most limiting nutrients in agricultural systems, P fertilisation is essential to feed the world. However, declining P reserves demand far more effective use of this crucial resource. Here, we use meta-analysis to synthesize yield responses to P fertilisation in grasslands, the most common type of agricultural land, to identify under which conditions P fertilisation is most effective. Yield responses to P fertilisation were 40–100% higher in (a) tropical vs temperate regions; (b) grass/legume mixtures vs grass monocultures; and (c) soil pH of 5–6 vs other pHs. The agronomic efficiency of P fertilisation decreased for greater P application rates. Moreover, soils with low P availability reacted disproportionately strong to fertilisation. Hence, low fertiliser application rates to P-deficient soils result in stronger absolute yield benefits than high rates applied to soils with a higher P status. Overall, our results suggest that optimising P fertiliser use is key to sustainable intensification of agricultural systems.

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