scholarly journals Spatial Variability of Soil Phosphorus Indices under Two Contrasting Grassland Fields in Eastern Canada

Agronomy ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 24
Author(s):  
Jeff D. Nze Memiaghe ◽  
Athyna N. Cambouris ◽  
Noura Ziadi ◽  
Antoine Karam ◽  
Isabelle Perron

Phosphorus (P) is an essential nutrient for grassland production systems. However, continuous applications of P fertilizers result in soil P accumulations, increasing the risk of P losses in runoff and erosion. This study aims to investigate the field-scale variability of soil-test P (STP) in two contrasting grassland fields using descriptive statistics and geostatistics for accurate recommendations on soil sampling strategy and sustainable approaches to P management. A young grassland (YG; 2 years) and an old grassland (OG; 10 years under permanent pasture) were classified as humo-ferric podzol and received organic fertilizers. Soil samples were collected in 16-m by 16-m triangular grids at two depths (0–5 and 5–20 cm). They were analyzed for available P and other soil elements extracted using the Mehlich-3 method (M3). The agri-environmental P saturation index (P/Al)M3 was calculated. Phosphorus accumulation was observed in OG (0–5 cm) as a result of long-term manure applications. Repeated applications of organic fertilizers can impact the long-term buildup of soil P, thus decreasing soil P va-riability and spatial dependence in permanent grasslands. A soil sampling strategy focusing on the 0–5 cm layer should be retained in permanent grasslands for sustainable P recommendations in Eastern Canada.

2014 ◽  
Vol 38 (5) ◽  
pp. 1487-1495 ◽  
Author(s):  
Ciro Antonio Rosolem ◽  
Alexandre Merlin

Phosphorus fixation in tropical soils may decrease under no-till. In this case, P fertilizer could be surface-spread, which would improve farm operations by decreasing the time spend in reloading the planter with fertilizers. In the long term, less soluble P sources could be viable. In this experiment, the effect of surface-broadcast P fertilization with both soluble and reactive phosphates on soil P forms and availability to soybean was studied with or without fertilization with soluble P in the planting furrow in a long-term experiment in which soybean was grown in rotation with Ruzigrass (Brachiaria ruziziensis). No P or 80 kg ha-1 of P2O5 in the form of triple superphosphate or Arad reactive rock phosphate was applied on the surface of a soil with variable P fertilization history. Soil samples were taken to a depth of 60 cm and soil P was fractionated. Soybean was grown with 0, 30, and 60 kg ha-1 of P2O5 in the form of triple phosphate applied in the seed furrow. Both fertilizers applied increased available P in the uppermost soil layers and the moderately labile organic and inorganic forms of P in the soil profile, probably as result of root decay. Soybean responded to phosphates applied on the soil surface or in the seed furrow; however, application of soluble P in the seed furrow should not be discarded. In tropical soils with a history of P fertilization, soluble P sources may be substituted for natural reactive phosphates broadcast on the surface. The planting operation may be facilitated through reduction in the rate of P applied in the planting furrow in relation to the rates currently applied.


2008 ◽  
Vol 53 (No. 9) ◽  
pp. 375-381 ◽  
Author(s):  
J. Balík ◽  
D. Pavlíková ◽  
V. Vaněk ◽  
M. Kulhánek ◽  
B. Kotková

Model experiments using rhizoboxes were carried out in order to evaluate the influence of different plants (wheat, rape) on the changes in water extractable contents of P, the pH/H2O value and the activity of acidic and alkaline phosphatase in soil of plant rhizosphere. For this experiment, a Cambisol with different long-term fertilizing systems was used: (i) control (with no fertilizer application), (ii) sewage sludge, and (iii) manure. A lower content of water-soluble P was observed in close vicinities of root surfaces (up to 2 mm) at all the studied variants. The control (non-treated) variant reflected a significantly lower content of water-soluble P in the rhizosphere compared to the fertilized ones. The activities of the acidic and alkaline phosphatases were significantly higher in the rhizosphere compared to the bulk soil (soil outside the rhizosphere). The long-term application of organic fertilizers significantly increased phosphatase activity; the activity of the acidic phosphatase was significantly higher in the rhizosphere of rape plants compared to wheat. The variant treated with manure exhibited an increased activity of both the acidic and alkaline phosphatases compared to the variant treated with sewage sludge. In the case of the variant treated long-term with sewage sludge, the portion of inorganic P to total soil P content proportionally increased compared to the manure-treated variant. Soil of the rape rhizosphere showed a trend of lower pH/H<sub>2</sub>O value of all variants, whereas the wheat rhizosphere showed an opposite pH tendency.


2019 ◽  
Vol 99 (3) ◽  
pp. 292-304
Author(s):  
Tandra D. Fraser ◽  
Derek H. Lynch ◽  
Ivan P. O’Halloran ◽  
R. Paul Voroney ◽  
Martin H. Entz ◽  
...  

Soil phosphorus (P) availability may be impacted by management practices, thereby affecting plant P uptake and plant response to P amendments. The aim of this study was to determine the effects of long-term management on soil P pools and to assess the response of P bioavailability, plant growth, and P uptake to mineral versus manure P treatments. Soils were collected from plots under organic (ORG), organic with composted manure (ORG + M), conventional (CONV), and restored prairie (PRA) management. Italian ryegrass (Lolium multiflorum L.) seedlings were grown in the greenhouse for 106 d in soils amended with various rates of manure or mineral P. The ORG soil had lower concentrations of labile P (resin-P and NaHCO3-P) compared with the CONV and PRA soils, as determined by sequential P fractionation prior to planting. Ryegrass biomass (root + shoot) and shoot P uptake from soils receiving no P were significantly lower for the ORG than all other management systems. Although apparent P use efficiency of the whole plant was increased by low P rate in the ORG management system, the source of applied P, manure > mineral, only influenced Olsen test P.


1999 ◽  
Vol 79 (4) ◽  
pp. 615-625 ◽  
Author(s):  
Suzanne Beauchemin ◽  
R. R. Simard

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


Author(s):  
L.M. Condron ◽  
K.M. Goh

Changes in soil phosphorus (P) associated with the establishment and maintenance of improved ryegrass-clover pasture under different superphosphate fertiliser treatments were examined over a 20-year period (1957-77). Results showed that soil organic P increased with increasing applications of P fertiliser. This represents a dynamic balance between rates of organic P addition and breakdown in the soil. This balance is reached slowly and may be significantly altered only by drastic changes in land use. In annually fertilised soils, amounts of inorganic P increased with time. However, the potential utilisation of this residual inorganic P is limited by its apparent stability in the soil. Keywords grazed pasture, irrigation, fertiliser P, soil inorganic P, soil organic P, soil P fractionation


Soil Research ◽  
2006 ◽  
Vol 44 (2) ◽  
pp. 127 ◽  
Author(s):  
L. M. Condron ◽  
S. Sinaj ◽  
R. W. McDowell ◽  
J. Dudler-Guela ◽  
J. T. Scott ◽  
...  

This study examined the influence of irrigation on soil phosphorus (P) distribution and availability under permanent pasture in New Zealand. Soil samples (0–0.075, 0.075–0.15, 0.15–0.25 m) were taken from a long-term field experiment, which included a dryland and 2 irrigation treatments (irrigated at 10% and 20% soil moisture) that had received 25 kg P/ha annually as superphosphate for 52 years. Corresponding data for soil from an adjacent ‘wilderness’ site that had not been used for agriculture for 54 years were included for comparison. Analyses included total P, organic P, and inorganic P; isotopic exchange kinetics (IEK) was used to determine soil inorganic P pools of differing plant availability. Concentrations of total and inorganic P were greater in soil taken from the dryland treatment than the irrigated treatments at all depths. This was attributed to a combination of decreased pasture growth and P transfer in drainage and off-farm produce. Concentrations of organic P were greater in the irrigated treatments (e.g. 0–0.075 m: 672–709 mg P/kg) than in the dryland treatment (e.g. 0–0.075 m: 574 mg P/kg) as a consequence of increased pasture production and soil biological activity. Inorganic P availability (Cp and E1min) was also greater in the dryland treatment than the irrigated treatments. Furthermore, concentrations of inorganic P in the recalcitrant IEK pool (E>3m = E3m–1y + E>1y) in the 0–0.075 m soil from the dryland treatment (479 mg P/kg) were significantly greater than the 10% irrigated (346 mg P/kg) and 20% irrigated (159 mg P/kg) treatments, which was mainly attributed to physico-chemical reactions that decreased the exchangeability of accumulated inorganic P with time. Despite increased P retention capacity at depth (R/r1, 0.15–0.25 m: dryland 6.6, 10% irrigated 10.2, 20% irrigated 12.8), concentrations of total inorganic P in the 0.15–0.25 m soil layer were lower under irrigation (195–266 mg P/kg) than dryland (354 mg P/kg), which indicated that long-term flood irrigation increased P transfer by leaching. The findings of this study revealed that while irrigation improved the utilisation of applied fertiliser P it also resulted in increased P movement to depth in the soil profile.


Soil Research ◽  
2020 ◽  
Vol 58 (2) ◽  
pp. 117 ◽  
Author(s):  
Musibau O. Azeez ◽  
Gitte Holton Rubæk ◽  
Ingeborg Frøsig Pedersen ◽  
Bent T. Christensen

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 &gt;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 &gt;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.


2018 ◽  
Vol 64 (No. 9) ◽  
pp. 441-447 ◽  
Author(s):  
Jarosch Klaus A ◽  
Santner Jakob ◽  
Parvage Mohammed Masud ◽  
Gerzabek Martin Hubert ◽  
Zehetner Franz ◽  
...  

Soil phosphorus (P) availability was assessed with four different soil P tests on seven soils of the Ultuna long-term field experiment (Sweden). These four soil P tests were (1) P-H<sub>2</sub>O (water extractable P); (2) P-H<sub>2</sub>O<sub>C10</sub> (water extractable P upon 10 consecutive extractions); (3) P-AL (ammonium lactate extractable P) and (4) P-C<sub>DGT</sub> (P desorbable using diffusive gradients in thin films). The suitability of these soil P tests to predict P availability was assessed by correlation with plant P uptake (mean of preceding 11 years) and soil P balancing (input vs. output on plot level for a period of 54 years). The ability to predict these parameters was in the order P-H<sub>2</sub>O<sub>C10</sub> &gt; P-C<sub>DGT</sub> &gt; P-H<sub>2</sub>O &gt; P-AL. Thus, methods considering the P-resupply from the soil solid phase to soil solution performed clearly better than equilibrium-based extractions. Our findings suggest that the P-AL test, commonly used for P-fertilizer recommendations in Sweden, could not predict plant P uptake and the soil P balance in a satisfying way in the analysed soils.


1992 ◽  
Vol 72 (4) ◽  
pp. 581-589 ◽  
Author(s):  
R. H. McKenzie ◽  
J. W. B. Stewart ◽  
J. F. Dormaar ◽  
G. B. Schaalje

The effects of different cropping systems, fertilizer, and lime on soil phosphorus (P) dynamics in soils developed under forest vegetation have received little attention. The objective of this study was to develop an understanding of P fractions and transformations in long-term rotation plots on a Luvisolic soil at Breton, Alberta. Results have shown that crop rotation and fertilizer application have affected more inorganic soil phosphorus (Pi) and organic phosphorus (Po) fractions, as determined by a sequential extraction procedure. Continuously cropped treatments, which had not received fertilizer, resulted in P drawdown of resin-extractable Pi (resin-Pi), sodium bicarbonate-extractable Pi (bicarb-Pi), sodium hydroxide-extractable Pi (NaOH-Pi), sodium bicarbonate-extractable Po (bicarb-Po), sodium hydroxide-extractable Po (NaOH-Po) and hydrochloric acid-extractable Pi (HCl-Pi) fractions. Only the residual-P fraction (insoluble Pi and stable Po forms) was unaffected. Addition of fertilizer had an effect on all P fractions except the NaOH-Po fraction. Phosphorus fertilizer treatments positively affected the Pi fractions and N fertilizer positively affected the bicarb-Po fraction. Lime application affected soil pH, which lowered NaOH-Pi levels and increased HCl-Pi levels through formation of more stable calcium phosphate compounds. Addition of lime also resulted in lower bicarb-Po levels. Cropping without using phosphate fertilizer has resulted in a 30–40% decline in total-P in the Breton plots in the Ap horizon. Continuous cropping, with a forage crop in the rotation, coupled with modest N and P fertilizer application, had the most positive effects on P cycling and transformations. Summerfallow had no apparent beneficial effects on P transformations. Key words: Soil P transformations, Luvisolic soil, P bioavailability, sequential extraction


Soil Research ◽  
2013 ◽  
Vol 51 (5) ◽  
pp. 427 ◽  
Author(s):  
R. J. Dodd ◽  
R. W. McDowell ◽  
L. M. Condron

Long-term application of phosphorus (P) fertilisers to agricultural soils can lead to in the accumulation of P in soil. Determining the rate of decline in soil P following the cessation of P fertiliser inputs is critical to evaluating the potential for reducing P loss to surface waters. The aim of this study was to use isotope exchange kinetics to investigate the rate of decline in soil P pools and the distribution of P within these pools in grazed grassland soils following a halt to P fertiliser application. Soils were sourced from three long-term grassland trials in New Zealand, two of which were managed as sheep-grazed pasture and one where the grass was regularly cut and removed. There was no significant change in total soil P over the duration of each trial between any of the treatments, although there was a significant decrease in total inorganic P on two of the sites accompanied by an increase in the organic P pool, suggesting that over time P was becoming occluded within organic matter, reducing the plant availability. An equation was generated using the soil-P concentration exchangeable within 1 min (E1 min) and P retention of the soil to predict the time it would take for the water-extractable P (WEP) concentration to decline to a target value protective of water quality. This was compared with a similar equation generated in the previous study, which used the initial Olsen-P concentration and P retention as a predictor. The use of E1 min in place of Olsen-P did not greatly improve the fit of the model, and we suggest that the use of Olsen-P is sufficient to predict the rate of decline in WEP. Conversely, pasture production data, available for one of the trial sites, suggest that E1 min may be a better predictor of dry matter yield than Olsen-P.


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