scholarly journals Degree of Phosphorus Saturation and Soil Phosphorus Thresholds in an Ultisol Amended with Triple Superphosphate and Phosphate Rocks

2011 ◽  
Vol 11 ◽  
pp. 1421-1441 ◽  
Author(s):  
E. W. Gikonyo ◽  
A. R. Zaharah ◽  
M. M. Hanafi ◽  
A. R. Anuar

Soil phosphorus (P) release capability could be assessed through the degree of P saturation (DPS). Our main objective was to determine DPS and, hence, P threshold DPS values of an Ultisol treated with triple superphosphate (TSP), Gafsa phosphate rocks (GPR), or Christmas Island phosphate rocks (CIPR), plus or minus manure. P release was determined by the iron oxide—impregnated paper strip (strip P), while DPS was determined from ammonium oxalate—extractable aluminum (Al), iron (Fe), and P. Soils were sampled from a closed incubation study involving soils treated with TSP, GPR, and CIPR at 0–400 mg P kg-1, and a field study where soils were fertilized with the same P sources at 100–300 kg P ha-1plus or minus manure. The DPS was significantly influenced by P source x P rate, P source x manure (incubated soils), and by P source x P rate x time (field-sampled soils). Incubated soil results indicated that both initial P and total strip P were related to DPS by exponential functions: initial strip P = 1.38exp0.18DPS, R2= 0.82** and total strip P = 8.01exp0.13DPS, R2 = 0.65**. Initial strip P was linearly related to total P; total P = 2.45, initial P + 8.41, R2= 0.85**. The threshold DPS value established was about 22% (incubated soil). Field soils had lower DPS values <12% and strip P was related to initial DPS and average DPS in exponential functions: strip P = 2.6exp0.44DPS, R2= 0.77** and strip P = 1.1DPS2— 2.4DPS + 6.2, R2= 0.58**, respectively. The threshold values were both at ≈8% and P release was 11–14 mg P kg-1. Results are evident that DPS can be used to predict P release, but the threshold values are environmentally sensitive; hence, recommendations should be based on field trials.

2010 ◽  
Vol 10 ◽  
pp. 1679-1693
Author(s):  
E. W. Gikonyo ◽  
A. R. Zaharah ◽  
M. M. Hanafi ◽  
A. R. Anuar

The effectiveness of different soil tests in assessing soil phosphorus (P) in soils amended with phosphate rocks (PRs) is uncertain. We evaluated the effects of triple superphosphate (TSP) and PRs on extractable P by conventional soil tests (Mehlich 3 [Meh3] and Bray-1 [B1]) and a nonconventional test (iron oxide–impregnated paper, strip). Extracted amounts of P were in the order: Meh3 >B1 > strip. All the tests were significantly correlated (p= 0.001). Acidic reagents extracted more P from TSP than PRs, while the strip removed equal amounts from the two sources. The P removed by the three tests was related significantly to dry matter yield (DMY), but only in the first harvest, except for B1. Established critical P levels (CPLs) differed for TSP and PRs. In PR-fertilized soils, CPLs were 27, 17, and 12 mg P kg-1soil for Meh3, B1, and strip, respectively, and 42, 31, and 12 mg P kg-1soil, respectively, in TSP-fertilized soils. Thus, the strip resulted in a common CPL for TSP and PRs (12 mg P kg-1soil). This method can be used effectively in soils where integrated nutrient sources have been used, but there is need to establish CPLs for different crops. For cost-effective fertilizer P recommendations based on conventional soil tests, there is a need to conduct separate calibrations for TSP- and PR-fertilized soils.


1997 ◽  
Vol 37 (8) ◽  
pp. 885 ◽  
Author(s):  
M. J. McLaughlin ◽  
N. K. Fleming ◽  
P. G. Simpson ◽  
M. D. A. Bolland ◽  
R. J. Gilkes ◽  
...  

Summary. Field-based cutting trials, which formed part of the National Reactive Phosphate Rock Project, were established across Australia in a range of environments to evaluate the agronomic effectiveness of 5 phosphate rocks, and 1 partially acidulated phosphate rock, relative to either single superphosphate or triple superphosphate. The phosphate rocks differed in reactivity. Sechura (Bayovar) and North Carolina phosphate rocks were highly reactive (>70% solubility in 2% formic acid), whilst Khouribja (Moroccan) and Hamrawein (Egypt) phosphate rock were moderately reactive. Duchess phosphate rock from Queensland was relatively unreactive (<45% solubility in 2% formic acid). Phosphate rock effectiveness was assessed by measuring pasture production over a range of phosphorus levels, and by monitoring bicarbonate-soluble phosphorus extracted from soil samples collected before the start of each growing season. Other treatments included single large applications of triple superphosphate, partially acidulated phosphate rock and North Carolina phosphate rock applied at 2 rates, and the application of monocalcium phosphate and North Carolina phosphate rock sources without sulfur to evaluate the importance of sulfur in the potential use of phosphate rock fertilisers at each site. A broad range of environments were represented over the 30 sites which were based on pastures using annual and/or perennial legumes and perennial grasses. Rainfall across the network of sites ranged from 560 to 4320 mm, soil pH (CaCl2) from 4.0 to 5.1, and Colwell-extractable phosphorus ranged from 3 to 47 µg/g before fertiliser application. Two core experiments were established at each site. The first measured the effects of phosphate rock reactivity on agronomic effectiveness, while the second measured the effects of the degree of water solubility of the phosphorus source on agronomic effectiveness. The National Reactive Phosphate Rock Project trials gave the opportunity to confirm the suitability of accepted procedures to model fertiliser response and to develop new approaches for comparing different fertiliser responses. The Project also provided the framework for subsidiary studies such as the effect of fertiliser source on soil phosphorus extractability, cadmium and fluorine concentrations in herbage, evaluation of soil phosphorus tests, and the influence of particle size on phosphate rock effectiveness. The National Reactive Phosphate Rock Project presents a valuable model for a large, Australia-wide, collaborative team approach to an important agricultural issue. The use of standard and consistent experimental methodologies at every site ensured that maximum benefit was obtained from data generated. The aims, rationale and methods used for the experiments across the network are presented and discussed.


2018 ◽  
Vol 64 (No. 4) ◽  
pp. 192-201 ◽  
Author(s):  
Zehetner Franz ◽  
Wuenscher Rosemarie ◽  
Peticzka Robert ◽  
Unterfrauner Hans

The aim of this study was to test different soil phosphorus (P) extraction methods in relation to plant P uptake. A greenhouse pot experiment was conducted with spring wheat. The soils were extracted with the following methods/extractants: H<sub>2</sub>O, CaCl<sub>2</sub>, LiCl, iron oxide impregnated filter papers (Fe-oxide P<sub>i</sub>), Olsen, calcium-acetate-lactate (CAL), cation and anion exchange membranes (CAEM), Mehlich 3, Bray and Kurtz II (Bray II), citrate-bicarbonate-dithionite, organic P, HCl, acid ammonium oxalate, total P. Plant P uptake was in the range of the P extracted by neutral salt solutions (CaCl<sub>2</sub>, LiCl). P extracted with H<sub>2</sub>O, CaCl<sub>2</sub> and CAEM correlated best with plant P uptake over one growing season, while several established soil P test methods, including CAL, Mehlich 3 and Bray II, did not show significant correlations. When grouping the soils according to pH, the weaker extraction methods (H<sub>2</sub>O, CaCl<sub>2</sub>, LiCl) showed significant correlations with plant P uptake only for the low and intermediate pH groups (pH in 1 mol/L KCl ≤ 6.6), while some of the stronger extraction methods (CAL, Mehlich 3, Bray II, dithionite, oxalate, total P) showed significant correlations only for the high pH group (&gt; 6.6) comprised of calcareous soils. It was concluded that weaker P extraction methods, especially neutral salt solutions best predict plant-available P in the short term. However, they do not perform well for calcareous (and clayey) soils and do not account for P that may become available beyond one growing season.


2000 ◽  
Vol 41 (4-5) ◽  
pp. 503-508 ◽  
Author(s):  
R.F. Gonçalves ◽  
F. Rogalla

This work describes laboratory scale research about Enhanced Biological Phosphorus Removal (EBPR) in a submerged biofilter under Anaerobic/Oxic (A/O) alternation and continuous feed. Its main purpose is to detail the behaviour of the reactor throughout the anaerobic and the aerobic phases of the A/O cycle, to study the importance of the anaerobic phase in the selection of the EBPR bacteria in the biofilm and to evaluate the consumption and the importance of the organic substrate during the anaerobic phase. The mass balance over the Phosphorus (P) element indicates that long anaerobic phases (6 h) are more efficient than short ones (3 h) as a selector of EBPR bacteria in biofilms. In both comparisons, thespecific mass of P released in a 6 h period represents almost 50% more than the amount of P release in the shorter period (3 h). However, the presence of rapidly biodegradable COD in the influent of the anaerobic phase is a more effective selector, more important than the duration of the anaerobic phase: by doubling the amount of acetic acid in the influent, a similar 50% increase of P-release can be achieved at short anaerobic periods of 3 h. The effect of the strategy adopted in this study, focusing on selecting EBPR bacteria in biofilm, is shown by the P levels of 4% (total P/SST) in the sludge removed from the BF by backwashing in all periods.


Author(s):  
Tomáš Lošák ◽  
Jaroslav Hlušek ◽  
Ivana Lampartová ◽  
Jakub Elbl ◽  
Gabriela Mühlbachová ◽  
...  

The pot experiment was established in vegetation hall in the year 2015. Spring barley, variety KWS Irina, was grown. Two different soils – chernozem from Brno (with a low phosphorus content and alkali soil reaction – 7.37) and haplic luvisol from Jaroměřice nad Rokytnou (with a high phosphorus content and slightly acid soil reaction – 6.01) were used for comparison. The rates of phosphorus in the form of triple superphosphate (45 % P2O5) were increased from 0.3 – 0.6 – 1.2 g per pot (5 kg of soil – Mitscherlich pots). Nitrogen was applied in the form of CAN (27 % N) at a rate of 1 g N per pot in all the treatments incl. the control. Using statistical analysis, significant differences were found between the two soil types both in terms of the postharvest soil P content and yields of aboveground biomass. The content of post‑harvest soil phosphorus increased significantly with the applied rate (96 – 141 – 210 mg/kg in chernozem and 128 – 179 – 277 mg/kg in haplic luvisol). Dry matter yields of the aboveground biomass grown on chernozem were the lowest in the control treatment not fertilised with P (38.97 g per pot) and increased significantly with the P rate applied (46.02 – 47.28 g per pot), although there were no significant differences among the fertilised treatments. On haplic luvisol phosphorus fertilisation was not seen at all, demonstrating that the weight of the biomass in all the treatments was balanced (48.12 – 49.63 g per pot).


2009 ◽  
Vol 57 (1) ◽  
pp. 87-94
Author(s):  
I. Ogoke ◽  
A. Togun

Two seasons of cropping were carried out at three sites in the Guinea savanna to evaluate the residual effects of soyabean on maize. The experiment was laid out as a splitplot design in a randomized complete block with three replications. In the first season, four soyabean varieties with a fallow treatment (control) received phosphorus (P) applied as triple superphosphate (20% P) at the rates of 30 and 60 kg P ha −1 . Maize was grown in these plots in the second season without fertilizer application. At all sites, regardless of the previous crop, total soil N remained low (<1.5 g kg −1 ). Available P was affected by the P rate in the previous year at all sites. From initial values ranging from 5.2–16.2 mg kg −1 in the first season, available P significantly (p<0.05) increased in the second season to 9.8–42.8 mg kg −1 when 30 or 60 kg P ha −1 was applied, compared to 7.7–18.6 mg kg –1 at no P application. Relative to no P application in the previous year, the application of 60 kg P ha −1 significantly increased total dry matter at 6 weeks after planting by 19%, total harvest dry matter by 28%, and grain yield by 37%.


Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1783 ◽  
Author(s):  
Catharina S. Nisbeth ◽  
Søren Jessen ◽  
Ole Bennike ◽  
Jacob Kidmose ◽  
Kasper Reitzel

This study explores the under-investigated issue of groundwater-borne geogenic phosphorus (P) as the potential driving factor behind accumulation of P in lake sediment. The annual internally released P load from the sediment of the shallow, hypereutrophic and groundwater-fed lake, Nørresø, Denmark, was quantified based on total P (TP) depth profiles. By comparing this load with previously determined external P loadings entering the lake throughout the year 2016–2017, it was evident that internal P release was the immediate controller of the trophic state of the lake. Nevertheless, by extrapolating back through the Holocene, assuming a groundwater P load corresponding to the one found at present time, the total groundwater P input to the lake was found to be in the same order of magnitude as the total deposit P in the lake sediment. This suggests that groundwater-transported P was the original source of the now internally cycled P. For many lakes, internal P cycling is the immediate controller of their trophic state. Yet, this does not take away the importance of the external and possibly geogenic origin of the P accumulating in lake sediments, and subsequently being released to the water column.


Hydrobiologia ◽  
2019 ◽  
Vol 847 (21) ◽  
pp. 4389-4400 ◽  
Author(s):  
Kristiina Vuorio ◽  
Marko Järvinen ◽  
Niina Kotamäki

AbstractCyanobacteria may limit recreational use of waters and have negative impacts on ecosystem services. The aim of this study was to determine phosphorus (P) thresholds for cyanobacterial taxa, which form toxin-producing blooms (mass occurrences) in boreal lakes. These thresholds help to set robust P reduction targets for restoration measures. We used long-term (> 40 years) June–August data from > 2000 Finnish lakes to evaluate the total P (TP) thresholds for the most important bloom-forming cyanobacterial genera and selected Microcystis and Dolichospermum species. The analyses were carried out separately for oligohumic, mesohumic and polyhumic lakes. TP threshold values varied between 10 and 61 µg l−1. The values were lower in oligohumic (water colour < 30 mg Pt l−1) than mesohumic (water colour 30–90 mg Pt l−1) lakes. The highest TP threshold (50 µg l−1) was observed for Microcystis in polyhumic lakes, and the lowest (10 µg l−1) for Planktothrix in oligohumic lakes.


1976 ◽  
Vol 86 (1) ◽  
pp. 181-187 ◽  
Author(s):  
A. P. Draycott ◽  
M. J. Durrant

SUMMARYTwenty experiments between 1970 and 1974 tested the effect of five amounts of triple superphosphate (0–110 kg P/ha) on sugar-beet yield in fields where soil contained little sodium bicarbonate-soluble phosphorus. The average yield without phosphorus fertilizer was 6·69 t/ha sugar and the increase from the optimum dressing 0·46 t/ha; the average soil concentration was 12 mg P/l. The fertilizer increased yield by 0·77 t/ha sugar on fields with 0–9 mg/l soil phosphorus, by 0·31 t/ha when soil phosphorus was 10–15 mg/l and had little effect on soils containing larger amounts.The concentration of phosphorus in plants harvested in mid-summer contained on average 0·29% P in dried tops and 0·13% in roots when given no phosphorus fertilizer, representing a total of 19·3 kg/ha P uptake. Giving superphosphate increased the phosphorus in both dried tops and roots by up to 0·03% and there was 3·7 and 1·7 kg/ha more phosphorus in tops and roots respectively. On the most responsive fields (0–9 mg/l soil P), the fertilizer increased the phosphorus in tops and roots by 0·05% and total uptake by 7 kg P/ha. The increase in uptake (or recovery) of fertilizer varied from 15% when 14 kg P/ha was given to less than 5% when 110 kg P/ha was used.A dressing of 27 kg P/ha was adequate for maximum yield on 19 of the 20 fields. When fields were grouped, 0–9, 10–15, 16–25 and > 26 mg/l NaHCO3-soluble soil phosphorus, and taking into account the value of the increased sugar yield, the cost of the fertilizer and its residual value, 60, 30, 20 and 10 kg P/ha respectively were the most profitable dressings. These experiments provide evidence, however, that the fertilizer would be used more efficiently if fields containing 0–9 mg soil phosphorus were subdivided into those with 0–4·5 and those with 4·6–9·0 mg/l and the groups given 80 and 40 kg P/ha respectively. These recommendations are substantially less than those used at present; they are adequate for sugar beet but other crops in the rotation would need similar close examination to ensure maximum yield and maintain adequate soil reserves of phosphorus.


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