Leaching of dissolved phosphorus from tile-drained agricultural areas

Abstract We investigated leaching of dissolved phosphorus (P) from 45 tile-drains representing animal husbandry farms in all regions of Denmark. Leaching of P via tile-drains exhibits a high degree of spatial heterogeneity with a low concentration in the majority of tile-drains and few tile-drains (15% in our investigation) having high to very high concentration of dissolved P. The share of dissolved organic P (DOP) was high (up to 96%). Leaching of DOP has hitherto been a somewhat overlooked P loss pathway in Danish soils and the mechanisms of mobilization and transport of DOP needs more investigation. We found a high correlation between Olsen-P and water extractable P. Water extractable P is regarded as an indicator of risk of loss of dissolved P. Our findings indicate that Olsen-P, which is measured routinely in Danish agricultural soils, may be a useful proxy for the P leaching potential of soils. However, we found no straight-forward correlation between leaching potential of the top soil layer (expressed as either degree of P saturation, Olsen-P or water extractable P) and the measured concentration of dissolved P in the tile-drain. This underlines that not only the source of P but also the P loss pathway must be taken into account when evaluating the risk of P loss.

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A comparison of some surface soil phosphorus tests that could be used to assess P export potential

Soil Research ◽

10.1071/sr06142 ◽

2007 ◽

Vol 45 (5) ◽

pp. 397 ◽

Cited By ~ 11

Author(s):

David Nash ◽

Murray Hannah ◽

Kirsten Barlow ◽

Fiona Robertson ◽

Nicole Mathers ◽

...

Keyword(s):

Organic P ◽

Soil Tests ◽

Soil P ◽

Olsen P ◽

P Sorption ◽

P Loss ◽

Extractable P ◽

Soil P Tests ◽

Total P ◽

Water Extractable

Phosphorus (P) exports from agricultural land are a problem world-wide and soil tests are often used to identify high risk areas. A recent study investigated changes in soil (0–20 mm), soil water and overland flow in 4 recently laser-graded (<1 year) and 4 established (laser-graded >10 years) irrigated pastures in south-eastern Australia before and after 3 years of irrigated dairy production. We use the results from that study to briefly examine the relationships between a series of ‘agronomic’ (Olsen P, Colwell P), environmental (water-extractable P, calcium chloride extractable P, P sorption saturation, and P sorption), and other (total P, organic P) soil P tests. Of the 2 ‘agronomic’ soil P tests, Colwell P explained 91% of the variation in Olsen P, and Colwell P was better correlated with the other soil tests. With the exception of P sorption, all soil P tests explained 57% or more of the total variation in Colwell P, while they explained 61% or less of Olsen P possibly due to the importance of organic P in this soil. Variations in total P were best explained by the organic P (85%), Calcium chloride extractable P (83%), water-extractable P (78%), and P sorption saturation (76%). None of the tests adequately predicted the variation in P sorption at 5 mg P/L equilibrating solution concentration. The results of this limited study highlight the variability between soil P tests that may be used to estimate P loss potential. Moreover, these results suggest that empirical relationships between specific soil P tests and P export potential will have limited resolution where different soil tests are used, as the errors in the relationship between soil test P and P loss potential are compounded by between test variation. We conclude that broader study is needed to determine the relationships between soil P tests for Australian soils, and based on that study a standard protocol for assessing the potential for P loss should be developed.

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Depletion, accumulation and availability of soil phosphorus in the Askov long-term field experiment

Soil Research ◽

10.1071/sr19203 ◽

2020 ◽

Vol 58 (2) ◽

pp. 117 ◽

Cited By ~ 1

Author(s):

Musibau O. Azeez ◽

Gitte Holton Rubæk ◽

Ingeborg Frøsig Pedersen ◽

Bent T. Christensen

Keyword(s):

Rock Phosphate ◽

Soil Phosphorus ◽

Available P ◽

Soil P ◽

Olsen P ◽

Extractable P ◽

P Application ◽

Plant Available P ◽

Water Extractable

Soil phosphorus (P) reserves, built up over decades of intensive agriculture, may account for most of the crop P uptake, provided adequate supply of other plant nutrients. Whether crops grown on soils with reduced supply of other nutrients obtain similar use-efficiency of soil P reserves remains unclear. In treatments of the Askov Long-Term Experiment (initiated in 1894 on light sandy loam), we quantified changes in soil total P and in plant-available P (Olsen P, water extractable P and P offtake in wheat grains) when P-depleted soil started receiving P in rock phosphate and when P application to soil with moderate P levels ceased during 1997–2017. Additionally we studied treatments with soil kept unfertilised for >100 years and with soil first being P depleted and then exposed to surplus dressings of P, nitrogen (N) and potassium in cattle manure. For soil kept unfertilised for >100 years, average grain P offtake was 6 kg ha–1 and Olsen P averaged 4.6 mg kg–1, representing the lower asymptotic level of plant-available P. Adding igneous rock phosphate to severely P-depleted soil with no N fertilisation had little effect on Olsen P, water extractable P (Pw), grain yields and P offtake. For soils with moderate levels of available P, withholding P application for 20 years reduced contents of Olsen P by 56% (from 16 to 7 mg P kg–1) and of Pw by 63% (from 4.5 to 1.7 mg P kg–1). However, the level of plant-available P was still above that of unfertilised soil. Application of animal manure to P-depleted soil gradually raised soil P availability, grain yield and P offtake, but it took 20 years to restore levels of plant-available P. Our study suggests symmetry between rates of depletion and accumulation of plant-available P in soil.

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Hotspots of Legacy Phosphorus in Agricultural Landscapes: Revisiting Water-Extractable Phosphorus Pools in Soils

Water ◽

10.3390/w13081006 ◽

2021 ◽

Vol 13 (8) ◽

pp. 1006

Author(s):

Taylor Roswall ◽

Emileigh Lucas ◽

Yun-Ya Yang ◽

Charles Burgis ◽

Isis S.P.C. Scott ◽

...

Keyword(s):

Agricultural Landscapes ◽

Sequential Extractions ◽

Equilibrium Constraints ◽

Dominant Form ◽

P Loss ◽

Extractable P ◽

Soluble P ◽

Agricultural Areas ◽

Water Ratio ◽

Water Extractable

Controlling phosphorus (P) losses from intensive agricultural areas to water bodies is an ongoing challenge. A critical component of mitigating P losses lies in accurately predicting dissolved P loss from soils, which often includes estimating the amount of soluble P extracted with a laboratory-based extraction, i.e., water-extractable P (WEP). A standard extraction method to determine the WEP pool in soils is critical to accurately quantify and assess the risk of P loss from soils to receiving waters. We hypothesized that narrower soil-to-water ratios (1:10 or 1:20) used in current methods underestimate the pool of WEP in high or legacy P soils due to the equilibrium constraints that limit the further release of P from the solid-to-solution phase. To investigate P release and develop a more exhaustive and robust method for measuring WEP, soils from eight legacy P fields (Mehlich 3–P of 502 to 1127 mg kg−1; total P of 692 to 2235 mg kg−1) were used for WEP extractions by varying soil-to-water ratios from 1:10 to 1:100 (weight:volume) and in eight sequential extractions (equivalent to 1:800 soil-to-water ratio). Extracts were analyzed for total (WEPt) and inorganic (WEPi) pools, and organic (WEPo) pool was calculated. As the ratios widened, mean WEPi increased from 23.7 mg kg−1 (at 1:10) to 58.5 mg kg−1 (at 1:100). Further, WEPi became the dominant form, encompassing 92.9% of WEPt at 1:100 in comparison to 79.0% of WEPt at 1:10. Four of the eight selected soils were extracted using a 1:100 ratio in eight sequential extractions to fully exhaust WEP, which removed a cumulative WEPt of 125 to 549 mg kg−1, equivalent to 276–416% increase from the first 1:100 extraction. Although WEP concentrations significantly declined after the first sequential extraction, WEP was not exhausted during the subsequent extractions, indicating a sizeable pool of soluble P in legacy P soils. We conclude that (i) legacy P soils are long-term sources of soluble P in agricultural landscapes and (ii) the use of a 1:100 soil-to-water ratio can improve quantification and risk assessment of WEP loss in legacy P soils.

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A new model for dung decomposition and phosphorus transformations and loss in runoff

Soil Research ◽

10.1071/sr10195 ◽

2011 ◽

Vol 49 (4) ◽

pp. 367 ◽

Cited By ~ 12

Author(s):

P. A. Vadas ◽

S. R. Aarons ◽

D. M. Butler ◽

W. J. Dougherty

Keyword(s):

Soil Surface ◽

Weather Conditions ◽

Cattle Dung ◽

New Model ◽

P Loss ◽

Grazing Cattle ◽

Extractable P ◽

Using Data ◽

The Impact ◽

Water Extractable

Non point-source pollution of fresh waters by agricultural phosphorus (P) can accelerate eutrophication of surface waters and limit their use for drinking, recreation, and industry. An important pathway of agricultural P transport is surface runoff, to which unincorporated dung from grazing cattle can be a significant contributor. Computer models commonly used to identify agricultural areas with a high potential for P export do not adequately simulate dung application to the soil surface, dung disappearance, and dung P loss to runoff. We developed a new model to simulate these processes for grazing cattle dung. The model simulates dung organic matter decomposition and assimilation into soil by bioturbation as a function of air temperature and dung moisture. We validated that the model can accurately predict rates of dung disappearance, using data from 12 published studies. The model also simulates four pools of inorganic and organic P, P mineralisation to water-extractable P, leaching of dung water-extractable P into soil by rain, and loss of dissolved inorganic P in runoff. We validated the ability of the model to reliably simulate these P processes, using data from six published dung P transformation studies and six runoff studies. Overall, the model represents a novel approach for assessing the environmental impact of grazing dairy and beef cattle. Research should investigate the impact of dung deposition rate as a function of time and animal diet and type, where deposition occurs relative to runoff movement, weather conditions, and the ability of dung pad crusting to reduce P release to runoff.

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Overwinter changes in Olsen phosphorus in a 24-year crop rotation study in southwestern Saskatchewan

Canadian Journal of Soil Science ◽

10.4141/cjss93-012 ◽

1993 ◽

Vol 73 (1) ◽

pp. 123-128 ◽

Cited By ~ 3

Author(s):

C. A. Campbell ◽

R. P. Zentner

Keyword(s):

Cropping Systems ◽

Soil Testing ◽

Available Phosphorus ◽

Canadian Prairie ◽

Olsen P ◽

Extractable P ◽

P Fertilizer ◽

Soil Test P ◽

Nutrient Analyses ◽

Rotation Study

In the Canadian prairie, producers generally sample soils in the autumn for nutrient analyses, whereas calibration of crop responses has been made based on soils sampled in the spring prior to seeding. A recent report suggests that available phosphorus (P) in soil increases between autumn and spring. At Swift Current, Saskatchewan, we have monitored bicarbonate-extractable P (Olsen P) every autumn and spring for the past 24 years, in four cropping systems: continuous wheat (Cont W), fallow-wheat (F-W), and two fallow-wheat-wheat (F-W-W) rotations. The first three systems received nitrogen (N) and P each crop year, with one F-W-W rotation receiving only N. These data were analyzed to test the authenticity of the aforementioned observations. We found that although there were some apparent overwinter increases in Olsen P there were also some decreases. Further, because of the considerable variability in Olsen P, relatively few of the overwinter changes were significant (P = 0.10). Efforts to correlate the changes in Olsen P to overwinter temperature or precipitation were unsuccessful. We concluded that Saskatchewan soil testing laboratories need not make adjustments to P fertilizer recommendations to account for changes in overwinter soil test P levels. Key words: Soil testing, bicarbonate-extractable P, crop rotations, available P

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Phosphorus loss potential and phosphatase activities in paddy soils

Plant Soil and Environment ◽

10.17221/626/2013-pse ◽

2013 ◽

Vol 59 (No. 11) ◽

pp. 530-536 ◽

Cited By ~ 5

Author(s):

S. Wang ◽

X. Liang ◽

G. Liu ◽

H. Li ◽

X. Liu ◽

...

Keyword(s):

Shallow Groundwater ◽

Paddy Soils ◽

Pig Manure ◽

Lake Basin ◽

Phosphatase Activities ◽

Olsen P ◽

P Loss ◽

Free Treatment ◽

P Fertilizer ◽

Total P

The effects of phosphorus (P) fertilizer on P loss potential, soil Olsen-P and neutral phosphatase activities in paddy soils fertilized with superphosphate or pig manure (PM) were evaluated in this paper. Data were collected from a field experiment in the Tai Lake Basin, China. Superphosphate rates were 0, 17.5, 26.7, and 35.0 kg P/ha, and PM rates were 0, 1.4, 2.1, and 2.8 t/ha for each crop, respectively. Soil Olsen-P in the plow layer increased to a greater extent with PM than with superphosphate. Pig manure increased neutral phosphatase activities in the plow layer compared with PM-free treatment. In contrast, superphosphate inhibited neutral phosphatase activities compared with superphosphate-free treatment. Spring application of P fertilizer markedly increased the total P of surface water in November (< 0.01 vs. 0.10 mg/L) compared with P-free treatment. The total P of shallow groundwater at a 75 cm depth was ~0.01 mg/L. Phosphorus fertilizer did not influence Olsen-P or neutral phosphatase activities under the plow layer. Downward movement of P did not occur. Appropriate rate of P application of 26.2 kg P/ha for each crop in this soil reduced the risk of P loss in the paddy wetland ecosystem.

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Phosphorus effects on competitive interactions of smooth pigweed (Amaranthus hybridus) and common purslane (Portulaca oleracea) with lettuce (Lactuca sativa)

Weed Science ◽

10.1017/s0043174500089463 ◽

1998 ◽

Vol 46 (3) ◽

pp. 307-312 ◽

Cited By ~ 17

Author(s):

Bielinski M. Santos ◽

Joan A. Dusky ◽

William M. Stall ◽

Donn G. Shilling ◽

Thomas A. Bewick

Keyword(s):

Competitive Ability ◽

Organic Soils ◽

Weed Species ◽

Population Densities ◽

Replacement Series ◽

Amaranthus Hybridus ◽

Extractable P ◽

Common Purslane ◽

Smooth Pigweed ◽

Water Extractable

Replacement series studies were conducted under controlled conditions to determine the effect of phosphorus (P) rates and population densities on the competitiveness of smooth pigweed and common purslane with lettuce. Densities were 2, 4, and 8 plants per 113 cm2, whereas P rates were 0, 0.4, and 0.8 g PL−1soil. A P-deficient Histosol (0.3 mg water-extractable P L−1soil) was used. High P fertility enhanced the competitive ability of lettuce in smooth pigweed-lettuce mixtures. Smooth pigweed was not responsive to P rates. However, luxurious P consumption by smooth pigweed occurred, reducing the amount of the nutrient available for lettuce absorption. In common purslane-lettuce mixtures, the weed was responsive to P rates, increasing its competitive ability, whereas no increase in lettuce competitive ability was observed. Both weed species were more competitive than lettuce. Competition for P appears to be the main mechanism of common purslane interference on lettuce grown in low-P organic soils. Alternative fertilization strategies (i.e., banded applications) may reduce the effect of smooth pigweed on lettuce.

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A laboratory study of phosphorus mobilisation from commercial fertilisers

Soil Research ◽

10.1071/sr03024 ◽

2003 ◽

Vol 41 (6) ◽

pp. 1201 ◽

Cited By ~ 16

Author(s):

D. Nash ◽

M. Hannah ◽

L. Clemow ◽

D. Halliwell ◽

B. Webb ◽

...

Keyword(s):

Soil Moisture ◽

Total Variation ◽

Laboratory Study ◽

High Moisture ◽

Single Superphosphate ◽

South Eastern ◽

Extractable P ◽

Eastern Australia ◽

Water Extractable ◽

South Eastern Australia

Phosphorus (P) exported from pastures following fertiliser application contributes to the nutrients and associated problems in the streams and rivers of south-eastern Australia. This laboratory study examined whether attributes of P fertilisers may affect P exports soon after their application to field soils; 3 commercial fertilisers [diammonium phosphate (DAP), single superphosphate (SSP), and sulfur-coated single superphosphate (CSSP)] were applied to 2 repacked soils (Arawata and Ellinbank) at 5 moisture contents.Soil type was the most important factor affecting water-extractable P (expressed as a percentage of the P added as fertiliser), accounting for 30% of the total variation. The majority of this variation is explained by the water-extractable P concentrations in the Arawata low moisture treatments. These treatments [7, 6, and 6% soil moisture when equilibrated at 99, 95, and 86.5% relative humidity (RH), respectively] contained water-extractable P concentrations c. 3 times higher than the high moisture (c. 20 and 25% soil moisture) or the Ellinbank treatments. This result probably reflects differences in soil properties including the extent of water repellency and P adsorption.Fertiliser type explained only 6.9% (P < 0.001) of the total variation in water-extractable P, partially as a result of the 86.5% RH (a low moisture) Arawata treatment. In this Arawata low moisture treatment, the mean extractable P was similar for both DAP and SSP, 13.1% [least significant interval (l.s.i.) 16.7–10.3] and 11.3% (l.s.i. 14.3–8.9), respectively, but for SSP, water-extractable P increased over time unlike any other treatment. Water-extractable P from DAP was approximately double that from SSP for the Ellinbank and high moisture treatments. The higher water-extractable P following DAP application is explained in terms of its chemical properties and reaction products. Sulfur coating the SSP granules (CSSP) increased water-extractable P, as did higher soil moisture.This study suggests that under conditions present in most pastures in south-eastern Australia and depending on soil hydrology, water-extractable P and P export from fertilisers may increase in the order DAP > CSSP > SSP if overland flow occurs soon after their application.

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Short-term legacy effects of feedlot manure amendments on water-extractable organic carbon in a clay loam soil profile

Canadian Journal of Soil Science ◽

10.1139/cjss-2018-0087 ◽

2019 ◽

Vol 99 (1) ◽

pp. 36-45 ◽

Cited By ~ 3

Author(s):

J.J. Miller ◽

M.L. Owen ◽

X. Hao ◽

C.F. Drury ◽

D.S. Chanasyk

Keyword(s):

Organic Carbon ◽

Soil Profile ◽

Land Application ◽

Legacy Effects ◽

Clay Loam ◽

Clay Loam Soil ◽

Leaching Potential ◽

Water Extractable Organic Carbon ◽

Loam Soil ◽

Water Extractable

Limited research exists on legacy effects of land application of feedlot manure on accumulation, redistribution, and leaching potential of water-extractable organic carbon (WEOC) in soil profiles. We sampled a clay loam soil at six depths (0–1.50 m) 2 yr after the last application (2014) of 17 continuous annual manure applications (since 1998). The amendment treatments were stockpiled (SM) or composted (CM) feedlot manure containing straw (ST) or wood-chip (WD) bedding at three application rates (13, 39, and 77 Mg ha−1dry basis). There was also an unamended control (CON) and inorganic fertilizer (IN) treatment. The soil samples were analyzed for concentrations of WEOC. The total mass or accumulation of WEOC in the soil profile was greater (P ≤ 0.05) by 1.2–3.3 times for the CM-ST-77 treatment than 12 of 14 other treatments, and it was significantly greater for amended than CON or IN treatments. The total WEOC mass was 14%–20% greater for CM-ST than CM-WD, SM-ST, and SM-WD treatments, and it was 16%–22% greater for CM than SM at the 39 and 77 Mg ha−1rates. The 77 Mg ha−1rate of the four manure type-bedding treatments had the significantly greatest (by 37%–527%) concentrations of WEOC at the six depths compared with other treatments, suggesting greater redistribution and leaching potential. Significant manure effects occurred on soil WEOC 2 yr after the manure was last applied following 17 continuous applications, and it indicated an increased risk of leaching potential at the higher application rate.

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The effects of humic substances on DNA isolation from soils

PeerJ ◽

10.7717/peerj.9378 ◽

2020 ◽

Vol 8 ◽

pp. e9378

Author(s):

Ewa Wnuk ◽

Adam Waśko ◽

Anna Walkiewicz ◽

Piotr Bartmiński ◽

Romualda Bejger ◽

...

Keyword(s):

Humic Substances ◽

Dna Isolation ◽

Arable Land ◽

Soil Layer ◽

Soil Samples ◽

Total Carbon ◽

High Concentration ◽

Soil Dna ◽

Total Carbon Content ◽

Direct Cell

Background Humic substances (HS) are compounds with a complicated structure, present in the humus soil layer, water, lake sediments, peat, brown coal and shales. Due to their similar physicochemical properties to DNA, they may have an adverse effect on the subsequent use of the isolated material. The main aim of this research was to examine the effect of HS on DNA isolation depending on the soil type and land use, taking into account the spectroscopic full characteristics of HS fractions. Methods The research was conducted on eight types of soil sample. Soils represented the most important Soil Reference Groups for temperate climates: Fluvisols, Regosols, Cambisols, Arenosols, Histosols and Luvisols. Soil samples were also collected from areas diversified in terms of use: arable land, grassland and forest. The extraction of HS fractions was performed using the procedure recommended by the International HS Society. The fractional composition of HS was characterized by UV–Vis and fluorescence methods. Soil DNA is extracted by direct cell lysis in the using a CTAB-based method with a commonly-used commercial soil DNA isolation kit. The basis for assessing the quantity and quality of extracted DNA was the Polymerase chain reaction (PCR) reaction since the analysis of soil DNA often relies on the use of PCR to study soil microorganisms. Results Based on the results, it can be concluded that in the presence of a high concentration of HS, the isolated DNA was low quality and the additional purification procedure was necessary. Despite the differentiation of the internal structure of HS fractions, the decisive factor in the efficiency of DNA isolation from soil samples was the total carbon content in HS. Reduced DNA yields can significantly constrain PCR detection limits to levels inadequate for metagenomic analysis, especially from humus-rich soils.

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