scholarly journals Phosphate sorption indices as affected by the calcareousness of soils

2019 ◽  
Vol 28 (1) ◽  
pp. 93-110
Author(s):  
Tasmeena Sultana Yousuf ◽  
Mohammad Enayet Hossain ◽  
Mohammad Zafar Afsar ◽  
Khan Towhid Osman
Keyword(s):  
Soil Solution ◽  
Calcareous Soils ◽  
Threshold Value ◽  
Phosphate Sorption ◽  
Soil P ◽  
Freundlich Isotherms ◽  
Centrifuge Tube ◽  
Phosphorus Buffering Capacity ◽  
Langmuir And Freundlich Equations ◽  
High Phosphate

An experiment was carried out to study the effects of calcareousness on phosphate sorption indices of soils using three representative calcareous soils, namely Sara (Aquic Eutrochrept), Gopalpur (Aquic Eutrochrept), and Ishurdi (Aeric Haplaquept) series of Bangladesh. Three non-calcareous soils, namely Belabo (Typic dystrudepts), Sonatala (Aeric Endoaquepts) and Ghatail (Aeric Haplaquept) series were also selected for comparison purposes. Phosphate sorption indices of soils were calculated using Langmuir and Freundlich isotherms. Isotherms were constructed taking one gram of air-dried sieved (< 2 mm) soil into a 50 ml centrifuge tube, and subsequently adding seven initial P concentrations, namely 0, 1, 10, 25, 50, 100 and 150 μg/ml to each centrifuge tube employing a soil/solution ratio of 1 : 20 (w/v). According to the Langmuir equation, the amount of phosphate sorbed followed the order: Sonatala > Ghatail > Sara = Gopalpur > Ishurdi > Belabo. The abundance of amorphous iron rather than the calcareousness was putatively responsible for the high phosphate sorption capacity of soils. Maximum phosphorus buffering capacity (MPBC) of the calcareous soils ranged from 33.4 - 62.8 l/kg. Langmuir and Freundlich equations produced different values for soil P requirements (SPR) at 0.2 and 1.0 mg P/l. Calcareous soils would require 27 - 44 mg P/kg soil to attain 0.2 mg P/l soil solution, which is deemed sufficient for crop growth. The soils would require 32 - 58 mg P/kg soil to reach 1.0 mg P/l soil solution, which is regarded to be safe for soils in terms of susceptibility to P losses. The calculated Langmuir constant b values were higher than the threshold value of 0.07 l/mg for two of the calcareous soils. Therefore, even though the non-calcareous soils sorbed more phosphate, higher bonding energy of P sorption for calcareous soils makes them less vulnerable to loss via surface runoff. Dhaka Univ. J. Biol. Sci. 28(1): 93-110, 2019 (January)

scholarly journals Phosphorus sorption characteristics of some representative soils of south India

2015 ◽  
Vol 13 (1) ◽  
pp. 14-26 ◽  
Author(s):  
I Rashmi ◽  
AK Biswas ◽  
VRR Parama ◽  
AS Rao
Keyword(s):  
Soil Solution ◽  
Management Strategies ◽  
Phosphorus Sorption ◽  
Binding Strength ◽  
P Sorption ◽  
Strength Coefficient ◽  
P Fertilizer ◽  
Phosphorus Buffering Capacity ◽  
Langmuir And Freundlich Equations ◽  
Sorption Characteristics

Studies were conducted to investigate P sorption characteristics of representative soils from ten locations of alfisol and ultisol of India using Langmuir and Freundlich equations. The P sorption maxima (b) of soils derived from Langmuir equation in alfisol varied from 520.6 to 574.7 ?g g-1 and ultisol varied from 561.6 to 678.1 ?g g-1. The maximum phosphorus buffering capacity (MPBC) in alfisol ranged from 80.7 to 180.2 ml ?g-1 and ultisol ranged from 162.1 to 284.4 ml ?g-1. Phosphorus sorption maxima was significantly correlated with clay (r2=0.70), Al (r2= 0.73) and Fe (r2=0.81) forms, MPBC (r2=0.67) and Freundlich constants (r2=0.82). The standard P requirement (SPR) to maintain 0.2 mg l-1 P in soil solution for alfisol ranged from 15.62 to 27.62 mg kg-1 and ultisol from 41.98 to 46.35 mg kg-1. The SPR (0.2 mg l-1) was significantly correlated with binding strength coefficient (r2= 0.97) and binding strength coefficient supporting the fact that energy coefficient of a soil is an important index for planning P management strategies. Among the two soil orders in order to maintain optimum P concentration in soil solution for crop growth, ultisol will be required to supply with more P fertilizer as compared to alfisol.SAARC J. Agri., 13(1): 14-26 (2015)

Relationship between phosphorus fractions and properties of highly calcareous soils

Soil Research ◽  
2007 ◽  
Vol 45 (4) ◽  
pp. 255 ◽  
Author(s):  
Ebrahim Adhami ◽  
Hamid Reza Memarian ◽  
Farzad Rassaei ◽  
Ehsan Mahdavi ◽  
Manouchehr Maftoun ◽  
...  
Keyword(s):  
Calcareous Soils ◽  
Hydroxylamine Hydrochloride ◽  
Inorganic Phosphorus ◽  
Influential Factor ◽  
Sequential Fractionation ◽  
Inorganic P ◽  
Soil P ◽  
Fractionation Procedure ◽  
Extractable P ◽  
P Content

Inorganic phosphorus (P) sequential fractionation schemes are applicable techniques to interpret soil P status. The present study was initiated to determine the origin of various P fractions in highly calcareous soils. Inorganic P forms were determined by a sequential fractionation procedure extracting with NaOH (NaOH-P), Na citrate-bicarbonate (CB-P), Na citrate 2 times (C1-P and C2-P), Na citrate-ascorbate (CAs-P), Na citrate-bicarbonate-dithionite (CBD-P), Na acetate (NaAc-P), and HCl (HCl-P). Results showed that NaOH-P was negatively correlated with active iron oxides. CB-P was positively correlated with silt content and negatively related to citrate-bicarbonate-dithionite extractable Fe (Fed). This result illustrates the weathering effect on Ca-P, with Ca-P content declining as a consequence of weathering. A negative correlation was observed between C1-P and citrate ascorbate extractable Fe (FeCAs). Second citrate extractable P (C2-P) was negatively related to calcium carbonate equivalent and positively related to hydroxylamine-hydrochloride and neutral ammonium acetate-hydroquinone extractable Mn (Mnh and Mnq). Fine silt (Fsilt) was the most influential factor affecting CAs-P. It seemed citrate-dithionite-bicarbonate extractable Al (Ald), Mnh, and Mnq have been sinks for CBD-P, while free iron oxide compounds (Feo, Fec, and FeCAs) were a major contributing factor for the formation of NaAc-P. Stable P compounds (HCl-P) of highly calcareous soils originated from coarse silt (Csilt) and hydroxylamine-hydrochloride extractable Mn (Mnh).

EFFECT OF EDTA AND DTPA ON AVAILABLE-P EXTRACTION WITH THE KELOWNA MULTIPLE ELEMENT EXTRACTANT

1989 ◽  
Vol 69 (2) ◽  
pp. 191-197
Author(s):  
W. VAN LIEROP
Keyword(s):  
Key Words ◽  
Reference Values ◽  
Calcareous Soils ◽  
Acid Soils ◽  
Available P ◽  
Complexing Agents ◽  
Simultaneous Extraction ◽  
Soil P ◽  
Regression Techniques

The objective of this study was to determine the effect of adding either 0.001M EDTA or 0.005M DTPA on the amount of P removed from acid and calcareous soils by the Kelowna and 0.25M HO Ac extractants. These complexing agents were studied for possible simultaneous extraction and determination of available Zn. To achieve that end, P-concentrations removed by these solutions from a group of acid, calcareous, and combined soils were compared against reference values obtained with 0.5M NaHCO3 (Olsen et al.) and the Kelowna extractant (0.25M HOAc + 0.015M NH4F) by means of graphing, correlation and regression techniques. Of the 80 soils studied, 40 were acid with pH (H2O) values ranging from 4.2 to 6.9 and the remainder having higher values up to 9.3. Results indicated that additions of either 0.001M EDTA or 0.005M DTPA to the Kelowna solution increased average extracted P concentrations by about 20 and 60%, respectively. Values removed by either of the new KEDTA and KDTPA solutions were closely related to those extracted with 0.5M NaHCO3 and Kelowna solutions on acid and calcareous soils (r values ≥ 0.96**). As EDTA and DTPA increased extracted soil P, these were added at 0.001 and 0.005M as NH4 preparations to 0.25M HOAc (AADTPA & AAEDTA; without fluoride), respectively, for determining whether these complexing agents could supplant F for P extraction. These solutions removed proportionally related amounts (r ≈ 0.94**) of P from calcareous, compared to the Kelowna and 0.5M NaHCO3 solutions, but relationships were less precise for acid soils (r ≈ 0.76**). These results suggest that the AADTPA or AAEDTA solution should be evaluated further before adoption for routine P determination in multiple element extractions. Key words: Mehlich in, acid soils, calcareous soils

Soil phosphorus saturation degree: Review of some indices and their suitability for P management in Québec, Canada

1999 ◽  
Vol 79 (4) ◽  
pp. 615-625 ◽  
Author(s):  
Suzanne Beauchemin ◽  
R. R. Simard
Keyword(s):  
Environmental Fate ◽  
Saturation Index ◽  
Soil Phosphorus ◽  
Ammonium Oxalate ◽  
Calcareous Soils ◽  
Environmental Indicators ◽  
Saturation Degree ◽  
Soil P ◽  
Phosphorus Saturation ◽  
Soil Groups

Many agricultural fields contain excessive labile soil P in regard to crop needs. Its environmental fate must be assessed. The concept of P saturation degree is meaningful as it describes the portion of the soil binding sites already covered with P, and indicates the potential desorbability of soil P. The first objective of this study was to review different indices that have been proposed to estimate the degree of soil P saturation and the relationships between soil P saturation degree and P solubility. The second objective is to discuss their suitability as environmental indicators for P management in the province of Québec, Canada. In the Netherlands, the P saturation index is defined as the ratio of P to Al + Fe contents extracted by ammonium oxalate [Pox/( Alox + Feox ) or ( Pox/0.5( Alox + Feox )]. This approach has been mainly used with non-calcareous soils. In Québec, the ratio of Mehlich-III extractable P to Al (M3P/AlM3) is proposed as an alternative, which relies on routine laboratory test. However, the suitability of the M3P/AlM3 ratio has yet to be determined for some specific soil groups (e.g. gleyed soils, soils with Alox content >6 g kg−1) and for subsoil horizons. Regardless of the chosen index, it is suggested that the best way to manage the risk of water contamination by P in Québec (namely, defining critical levels of soil P saturation) may be to form homogeneous soil groups to account for their distinctive behaviour and characteristics. Key words: Phosphorus, saturation, management

Osmotic and ionic effects of various electrolytes on the growth of wheat

Soil Research ◽  
2010 ◽  
Vol 48 (2) ◽  
pp. 120 ◽  
Author(s):  
Pichu Rengasamy
Keyword(s):  
Soil Solution ◽  
Sandy Loam ◽  
Field Capacity ◽  
Threshold Value ◽  
Electrolyte Solutions ◽  
Osmotic Effect ◽  
Matter Production ◽  
Loam Soil ◽  
Hoagland Nutrient Solution ◽  
Ionic Effects

Pot experiments were conducted using a sandy loam soil and various electrolyte solutions such as NaCl, CaCl2, Na2SO4, and Hoagland nutrient solution containing all macro- and micro-nutrient elements in appropriate proportions, inducing different electrical conductivity (EC) levels of the soil solution during the growth of Krichauff wheat while the water content in the pot soils was maintained at field capacity. The resulting differences in dry matter production after 40 days of growth clearly indicated the continuous operation of osmotic effect as the EC of the soil solution increased from 0.7 to 41.0 dS/m. However, the osmotic effect became dominant and severely restricted plant growth when the soil solution EC increased above a ‘threshold value’, which was 25 dS/m, corresponding to an osmotic pressure of 900 kPa, in this experiment. Below this EC value, particularly at low EC values, ionic effects due to Na+, Ca2+, SO42–, and Cl– were also evident, but it could not be concluded whether these effects were due to toxicity or ion imbalance. The osmotic effect at EC values above the threshold resulted in greatly reduced water uptake from pot soils, the unused water being in the range 89–96% of the field capacity of the soil. Water use efficiency is a major factor in profitable and sustainable dryland agriculture. Both soil management and selection and breeding of salt-tolerant plants should concentrate on ensuring that the threshold EC value for severe osmotic effects is not reached under field conditions.

Direct and residual effect of phosphorus on dryland barley

1996 ◽  
Vol 126 (2) ◽  
pp. 137-141 ◽  
Author(s):  
P. I. Orphanos
Keyword(s):  
Surface Soil ◽  
Maximum Yield ◽  
Balance Sheet ◽  
Residual Effect ◽  
Threshold Value ◽  
Soil P ◽  
Extractable P ◽  
P Content ◽  
P Balance ◽  
Cropping Seasons

SUMMARYIn a 14-year experiment conducted at Athalassa in the central plain of Cyprus, phosphorus was applied (0, 30 or 60 kg P/ha) annually over the first 5-year period to rainfed barley continually grown and cut for hay at the milk stage of the grain. The bicarbonate-extractable P content in the surface soil was 4 mg/kg at the start and increased to 16 and 25 mg/kg after the five annual applications of 30 and 60 kg P/ha, respectively. The residual effect of P was monitored in the following seven crop seasons, by the end of which soil P had dropped to below the recognised 6 mg/kg threshold value for response to P. The application of P was resumed in the last two experimental seasons (1992/93 and 1993/94). In two cropping seasons, rainfall was < 140 mm and no harvestable yield was obtained. In another two seasons, in which there was adequate rainfall in December and January, there was no response to P, but in the other seasons 30 kg P/ha was sufficient for maximum yield. Concentration of P in the dry matter (DM) harvested increased in proportion to the P applied.A P balance sheet made after the first five P applications and taking into account the amount of P removed in the DM and the increase in soil bicarbonate-extractable P indicated that 29 and 26 % of the P applied with the 30 and 60 kg P/ha rates, respectively, was accounted for.The data indicate that the established threshold value of 6 mg P/kg is valid. The soil tested 180 mg/kg exchangeable K. but application of 240 or 480 kg K/ha did not increase yield.

Soil phosphorus: its measurement, and its uptake by plants

Soil Research ◽  
1997 ◽  
Vol 35 (2) ◽  
pp. 227 ◽  
Author(s):  
I. C. R. Holford
Keyword(s):  
Soil Solution ◽  
Small Proportion ◽  
Plant Uptake ◽  
Solid Phase ◽  
Calcareous Soils ◽  
Buffering Capacity ◽  
Available P ◽  
P Availability ◽  
The World ◽  
Labile P

Phosphorus (P) is the most important nutrient element (after nitrogen) limiting agricultural production in most regions of the world. It is extremely chemically reactive, and more than 170 phosphate minerals have been identified. In all its natural forms, including organic forms, P is very stable or insoluble, and only a very small proportion exists in the soil solution at any one time. Plant-available P may be considered in either its quantitative or intensive dimension. The quantity of available P is time-specific and crop-specific, because it is the amount of P that will come into the soil solution and be taken up by the crop during its life cycle. The intensity of available P (availability) is most easily identified with its concentration in the soil solution. The soil property controlling the relationship between the solid phase P and its concentration in solution is known as the buffering capacity. The solid phase P involved in this relationship is only a small proportion of the total P, and is known as labile P. It is usually measured by isotopic exchange, but this exchangeable P component does not include the sparingly soluble compounds that also replenish the soil solution as its concentration is depleted by plant uptake. The buffering capacity is the ability of the soil solution to resist a change in its P concentration as P is removed by plant uptake or added in fertilisers or organic materials. Buffering capacity is synonymous with sorptivity, which is a preferable term in the context of the reactivity of P fertiliser with soil. It is usually measured from an adsorption isotherm. By fitting a suitable equation, such as the Langmuir, the total sorption capacity as well as the sorption strength can be determined. Both parameters are important in understanding P availability in soils. Buffering capacity has a major effect on the uptake of labile P because it is inversely related to the ease of desorption of solid phase P and its diffusion. Available P therefore is a direct function of the quantity of labile P and an inverse function of buffering capacity. This has been demonstrated in plant uptake studies. Similarly, the most effective methods of measuring available P (soil tests) are those which remove a proportion of labile P that is inversely related to buffer capacity. Soil tests which measure the concentration of P in solution actually measure availability rather than available P, and their efficacy on a range of soils will depend on the uniformity of the soils" buffer capacities. The most effective soil test usually consists of an anionic extractant. Acidic lactate or fluoride have been found most effective in New South Wales, on a wide range of soils, except calcareous soils which neutralise the acidic component (usually hydrochloric or acetic acid) of the extractant. Sodium bicarbonate (pH 8 · 5) has been found effective on calcareous soils and is widely used throughout the world. It has proved unreliable on NSW soils, and may need more thorough evaluation on non-calcareous soils in other parts of Australia.

scholarly journals A Single Incident of Soil P Leaching in a Mature Forest Corresponds to 10 Years of Average Leaching

2018 ◽  
Author(s):  
Ann-Mari Fransson
Keyword(s):  
Soil Solution ◽  
Heavy Rainfall ◽  
Continuous Monitoring ◽  
Agricultural Soils ◽  
Mineral Soil ◽  
Point Sources ◽  
Spruce Forest ◽  
Soil P ◽  
Second Year ◽  
P Leaching

Incidental P losses from non-point sources may contribute to eutrophication and to decreased soil fertility. These incidents have been related to heavy rainfall on freshly fertilized agricultural soils and little is known about such incidents on more natural soils or in forests. The aim of this work is to determine if incidents of high P leaching also occur in spruce forests, and if such incidents are of significance in P cycling. We found a peak in the mineral soil solution showing that single events of high P leaching occur. The orthophosphate concentration in the Bf-horizon of the 80-year old spruce forest peaked in the autumn of the second year of a continuous monitoring. The concentration increased by more than 85 times compared to the highest concentration obtained earlier during the sampling. The amount leached during this 6 months peak is 10 times higher than the average annual leaching. This P leaching might be due to a combination of high P deposition/through-fall and a high anion exchange with dissolved-organic-carbon and Cl-. We suggest that single events of high sub-surface P leaching may contribute to the overall P leaching, and might increase with the global warming as more DOC is expected to be released to the soil solution.

Effects of decalcification on the phosphate sorption characteristics of eight calcareous soils

Soil Research ◽  
1990 ◽  
Vol 28 (6) ◽  
pp. 919 ◽  
Author(s):  
ICR Holford ◽  
M Chater ◽  
GEG Mattingly
Keyword(s):  
Calcareous Soils ◽  
Sorption Isotherms ◽  
Phosphate Sorption ◽  
Surface Equation ◽  
P Sorption ◽  
Surface Areas ◽  
Freundlich Equation ◽  
Sorption Parameters ◽  
Parameter Values ◽  
Sorption Characteristics

Phosphate sorption isotherms and parameter values were determined on eight calcareous soils which were carefully decalcified using a procedure which minimized changes in cation saturation. Calcite content of the original soils varied from 0.8 to 24 2% and calcite surface areas from 4 . 0 to 8.5 m2 g-1. Sorption parameters were derived from the Langmuir 'two-surface' equation. Decalcification increased phosphate sorption at low residual P concentrations (<0.8 mg L-1) but decreased it at higher concentrations. The higher P sorption was associated with an increase in affinity because the calculated sorption capacities of high-affinity surfaces were not increased. These sorption capacities were well correlated with iron oxide contents of the soils, so the increase in phosphate affinity of these surfaces was consistent with the decrease in pH (0.5 to 1.5 units) of the decalcified soils. The lower P sorption at higher concentrations was associated with a substantial decrease in sorption capacity of the postulated low-affinity surfaces. These latter decreases were quantitatively correlated with the calcite surface areas of the original soils. These and other changes in phosphate sorption characteristics support the utility of the Langmuir 'two-surface' equation in providing information, compatible with what would be expected from more complex mechanistic models, and which exceeds what one would expect from other simpler models such as the Freundlich equation. They also support an hypothesis that an important component of low-affinity surfaces of these calcareous soils is calcite on which organic anions are co-adsorbed.

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