An isotope injection technique to measure agronomic effectiveness of different phosphate sources in undisturbed soils

1995 ◽  
Vol 35 (4) ◽  
pp. 489 ◽  
Author(s):  
HJ Di ◽  
R Harrison ◽  
AS Campbell
Keyword(s):  
North Carolina ◽  
Phosphate Rock ◽  
Specific Activity ◽  
P Uptake ◽  
Injection Technique ◽  
Agronomic Effectiveness ◽  
Single Superphosphate ◽  
Simple Method ◽  
North Carolina Phosphate Rock ◽  
Undisturbed Soils

This paper describes the use of an isotope injection technique for assessing the agronomic effectiveness of phosphate sources in undisturbed soils in field and glasshouse experiments. A special injection apparatus consisting of 20 syringe needles linked to a common reservoir was used to label soil cores 150 mm in diameter and 150 mm in height, without significantly disturbing the soil structure and established perennial ryegrass (Lolium perenne) root patterns. Variations in the amount of phosphorus (P) taken up by plants from single superphosphate (applied at 30, 60, and 100 kg P/ha), from 30% acidulated North Carolina phosphate rock (60 g P/ha), and from 'as received' North Carolina phosphate rock (60 kg P/ha) were indicated by the specific activity of the plant P. Percentages of plant P derived from the fertilisers were calculated on the basis of the specific activity of the fertilised treatments and the controls. The technique provides a simple method of comparing the agronomic effectiveness of phosphate sources in undisturbed soils and, unlike total dry matter yield and P uptake, is relatively unaffected by environmental factors.

An economic analysis of the field performance of North Carolina reactive phosphate rock compared with single superphosphate for selected sites from the National Reactive Phosphate Rock Project

1997 ◽  
Vol 37 (8) ◽  
pp. 1061 ◽  
Author(s):  
P. G. Simpson ◽  
P. W. G. Sale ◽  
S. B. Tennakoon
Keyword(s):  
North Carolina ◽  
Economic Analysis ◽  
Phosphate Rock ◽  
Financial Benefit ◽  
Single Superphosphate ◽  
Lag Effects ◽  
Soil P ◽  
North Carolina Phosphate Rock ◽  
Reactive Phosphate ◽  
Reactive Phosphate Rock

Summary. An economic analysis was undertaken using pasture yield data from 8 selected sites from the National Reactive Phosphate Rock Project, that encompassed 7 different performance scenarios for North Carolina phosphate rock. The aims were to determine whether the use of North Carolina phosphate rock in place of single superphosphate might result in a positive financial benefit in the 4th year, and after 4 years of annual applications of fertiliser. The analysis was carried out using annual P applications of North Carolina phosphate rock and single superphosphate, that resulted in pasture yields equivalent to 50, 70 or 90% of the maximum yield response of single superphosphate in the 4th year. Annual pasture dry matter yields, produced by these fertiliser applications, were converted to stocking rates, and dollar incomes were derived by applying appropriate gross margins. The analysis was also undertaken to determine the financial benefit from large, year-1 applications of North Carolina phosphate rock. Single superphosphate was priced at $168/t while North Carolina phosphate rock plus sulfur was priced at $180/t. The economic analysis found that a positive financial benefit with North Carolina phosphate rock occurred for only one scenario where the agronomic performance of North Carolina phosphate rock and single superphosphate were equivalent in the 4th year of annual fertiliser application. For 3 other scenarios where the performance of North Carolina phosphate rock and single superphosphate were also equivalent in the 4th year, the economic performance of North Carolina phosphate rock was poor due to (i) a ‘lag’ effect where pasture yield with North Carolina phosphate rock was generally less than that with single superphosphate in years 1–3, and/or to (ii) a seasonal effect where the autumn–early winter pasture responses with North Carolina phosphate rock were less than those with single superphosphate, necessitating a reduction in annual stocking rates on the North Carolina phosphate rock-fertilised pasture. A key finding was that large, single, year-1 applications of North Carolina phosphate rock generally overcame these seasonal and/or yearly lag effects, and led to positive financial benefits from North Carolina phosphate rock applied in this way. Annual applications of North Carolina phosphate rock were economically viable at sandy, high rainfall sites where water-soluble P from single superphosphate would be readily leached from the root zone, provided that the soil P status was adequate and conditions were conducive to reactive phosphate rock dissolution. However, North Carolina phosphate rock was not an economically viable fertiliser to apply annually at (i) non-leaching sites where the soil P status was low and marked yield penalties occurred in the first few years of North Carolina phosphate rock use, (ii) where the soil had a very high P-sorption capacity, and (iii) where North Carolina phosphate rock dissolution was restricted by low rainfall or high pH. The inclusion of estimated residual P value had only a small impact on the economic outcome for scenarios which had not already performed poorly due to seasonal or lag effects.

National Reactive Phosphate Rock Project —aims, experimental approach and site characteristics

1997 ◽  
Vol 37 (8) ◽  
pp. 885 ◽  
Author(s):  
M. J. McLaughlin ◽  
N. K. Fleming ◽  
P. G. Simpson ◽  
M. D. A. Bolland ◽  
R. J. Gilkes ◽  
...  
Keyword(s):  
North Carolina ◽  
Formic Acid ◽  
Phosphate Rock ◽  
Soil Phosphorus ◽  
Triple Superphosphate ◽  
Phosphate Rocks ◽  
Agronomic Effectiveness ◽  
North Carolina Phosphate Rock ◽  
Reactive Phosphate ◽  
Reactive Phosphate Rock

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.

Agronomic effectiveness of a partially acidulated reactive phosphate rock fertiliser

1997 ◽  
Vol 37 (8) ◽  
pp. 985 ◽  
Author(s):  
D. C. Lewis ◽  
P. W. G. Sale ◽  
D. Johnson
Keyword(s):  
North Carolina ◽  
Phosphate Rock ◽  
Agronomic Effectiveness ◽  
Permanent Pasture ◽  
North Carolina Phosphate Rock ◽  
Reactive Phosphate ◽  
Reactive Phosphate Rock ◽  
Papr Performance ◽  
Yield Responses ◽  
Very High

Summary. The agronomic effectiveness of a partially acidulated phosphate rock (PAPR), produced by the 50% acidulation of North Carolina phosphate rock with sulfuric acid, was compared over 4 growing seasons with triple superphosphate (TSP) and the highly reactive North Carolina phosphate rock at 22 permanent pasture sites in the National Reactive Phosphate Rock Project. The performance of PAPR as a phosphorus (P) fertiliser for permanent pasture was determined by calculating the substitution value of TSP for PAPR at 50% of the maximum yield response for TSP from the fitted annual dry matter response curves. PAPR performance varied both between sites, and between years at individual sites. Annual yield responses with PAPR were larger than those with TSP at 1 high rainfall site where water-soluble P from TSP was thought to leach from the root zone. PAPR was superior to TSP at another site and generally similar in effectiveness to TSP at 4 sites with light-textured, low or medium P-sorbing soils with a moderate annual rainfall (500–750 mm). The mean substitution value over the 4 years for these sites was >0.9. PAPR performance at other sites where highly reactive phosphate rocks were effective in the short or medium term was variable: there were equivalent yield responses to TSP in some years but much smaller yield responses in other years. PAPR performed very poorly in a third group of sites where the soil had a high to very high P sorption capacity or where there was a very high demand for fertiliser P due to large legume responses on a P-deficient soil. Although generally inferior to TSP, the PAPR was more effective than North Carolina phosphate rock at the majority of sites during the 4-year study.

Effect of fertiliser type on cadmium and fluorine concentrations in clover herbage

1997 ◽  
Vol 37 (8) ◽  
pp. 1019 ◽  
Author(s):  
M. J. McLaughlin ◽  
P. G. Simpson ◽  
M. K. Smart ◽  
N. Fleming ◽  
D. P. Stevens ◽  
...  
Keyword(s):  
North Carolina ◽  
Phosphate Rock ◽  
Partially Acidulated Phosphate Rock ◽  
Single Superphosphate ◽  
North Carolina Phosphate Rock ◽  
Reactive Phosphate ◽  
Reactive Phosphate Rock

Summary. This study investigated whether changing phosphatic fertiliser type affects the accumulation of cadmium (Cd) and fluorine (F) in pasture herbage. North Carolina phosphate rock, and partially acidulated fertilisers derived from this rock, generally have higher Cd and F concentrations compared with single superphosphate currently manufactured in Australia. Clover herbage from sites of the National Reactive Phosphate Rock trial was collected and analysed for concentrations of Cd (11 sites) and F (4 sites). A comparison was made between pastures fertilised with 4 rates of single superphosphate, North Carolina phosphate rock, and partially acidulated phosphate rock having Cd concentrations of 283, 481 and 420 mg/kg P respectively, and F concentrations of 170, 271 and 274 g/kg P respectively. One site used Hamrawein (Egypt) phosphate rock (HRP) having a Cd and F concentration of 78 mg Cd/kg P and 256 g F/kg P respectively. To help identify differences in herbage Cd concentrations between sites, unfertilised soils from each site were analysed for total and extractable Cd contents. At one site Cd concentrations in bulk herbage (clover, grasses and weeds) were related to infestation of the pasture by capeweed (Arctotheca calendula L. Levyns). There were no significant differences between F in herbage from plots fertilised with either single superphosphate, partially acidulated phosphate rock or North Carolina phosphate rock, or between sites. Concentrations of F in herbage were low, generally less than 10 mg/kg. However, there were large differences in Cd concentrations in herbage between sites, while differences between fertiliser treatments were small in comparison. The site differences were only weakly related to total or extractable (0.01 mol CaCl2/L) Cd concentrations in soil. Significant differences in Cd concentrations in clover due to fertiliser type were found at 5 sites. North Carolina phosphate rock treatments had significantly higher Cd concentrations in clover compared with single superphosphate at 2 sites. Partially acidulated phosphate rock treatments had significantly higher Cd concentrations in clover compared with single superphosphate at 4 sites. At the site where Hamrawein was tested, this treatment had significantly lower Cd concentrations in clover compared with both single superphosphate and North Carolina phosphate rock treatments.

The agronomic effectiveness of reactive phosphate rocks 5. The effect of particle size of a moderately reactive phosphate rock

1997 ◽  
Vol 37 (8) ◽  
pp. 969 ◽  
Author(s):  
A. M. Babare ◽  
P. W. G. Sale ◽  
N. Fleming ◽  
D. L. Garden ◽  
D. Johnson
Keyword(s):  
North Carolina ◽  
Particle Size ◽  
Phosphate Rock ◽  
Agronomic Effectiveness ◽  
Monocalcium Phosphate ◽  
Particle Size Fractions ◽  
North Carolina Phosphate Rock ◽  
Reactive Phosphate ◽  
Reactive Phosphate Rock ◽  
Effect Of Particle Size

Summary. The effect of particle size on the agronomic effectiveness of a moderately reactive phosphate rock (from the Hamrawein deposit in Egypt) was investigated at 4 of the field sites in the National Reactive Phosphate Rock Project. The aim of these experiments was to determine whether the agronomic effectiveness of this fertiliser was increased by removing particles greater than 0.5 mm in diameter (these coarser particles constituted 28% of the fertiliser). The more reactive North Carolina phosphate rock was used as a reference fertiliser. Soils from 3 of the field sites were also used for glasshouse experiments. The forms of Hamrawein phosphate rock used in these experiments were the less than 0.50 mm particle size fraction (as was used in the field experiments), the 0.075–0.15 mm fraction, and the less than 0.50 mm particle size fraction finely ground. Subterranean clover was used as the test plant and North Carolina phosphate rock and monocalcium phosphate were used as reference fertilisers. A series of laboratory experiments were also undertaken to investigate the effect of particle size. The agronomic effectiveness of Hamrawein phosphate rock was not affected by the different particle size treatments used in the field and glasshouse experiments. The Hamrawein phosphate rock was about equal in effectiveness to North Carolina phosphate rock at the high rainfall leaching site that had acidic sandy soil, and was less effective than North Carolina phosphate rock at the other 2 field sites. The Hamrawein phosphate rock was similar in effectiveness to North Carolina phosphate rock and monocalcium phosphate in the glasshouse experiments with the 2 low P-sorbing soils and was much less effective than North Carolina phosphate rock and monocalcium phosphate in the high P-sorbing soil. Laboratory studies found that there were minimal differences in the amount and rate of dissolution of different particle size fractions of the Hamrawein phosphate rock in moist incubated soil. Free carbonate, most likely in the form of dolomite, was found in all particle size fractions of the Hamrawein phosphate rock and was particularly concentrated in the particle size fractions less than 0.15 mm. This fine dolomite fraction may have suppressed the extent that Hamrawein phosphate rock dissolves in soil, and may have negated any potential beneficial effect that reducing particle size by sieving or by grinding may have had on the agronomic effectiveness of Hamrawein phosphate rock in the field and glasshouse experiments.

The effect of phosphate buffering capacity and other soil properties on North Carolina phosphate rock dissolution, availability of dissolved phosphorus and relative agronomic effectiveness

1997 ◽  
Vol 37 (8) ◽  
pp. 1037 ◽  
Author(s):  
A. M. Babare ◽  
R. J. Gilkes ◽  
P. W. G. Sale
Keyword(s):  
North Carolina ◽  
Soil Properties ◽  
Phosphate Rock ◽  
Relative Effectiveness ◽  
Buffering Capacity ◽  
Available P ◽  
Surface Soils ◽  
Agronomic Effectiveness ◽  
North Carolina Phosphate Rock ◽  
P Buffering Capacity

Summary. The dissolution of North Carolina phosphate rock (NCPR) in soil was investigated in a laboratory study using surface soils sampled from 28 permanent pasture sites. The relationships between phosphorus (P) dissolved, P availability and various soil properties were investigated using simple and multiple linear regression and the findings related to the relative effectiveness of NCPR for pasture production at the sites. The extent of dissolution of NCPR was positively correlated to P buffering capacity (r2 = 0.42). Phosphorus buffering capacity and titratable acidity together accounted for 72% of the variance in dissolution. Bicarbonate-extractable P (‘available’ P) generally increased as dissolution increased. However, the increase in available P was consistently lower for soils with higher P buffering capacity. The proportion of dissolved P that was available also decreased with increasing P buffering capacity (r2 = 0.63). Consequently, the increase in available P was highest for soils with very low to low P buffering capacity. This suggests that the effectiveness of NCPR as a fertiliser may be more closely related to the availability of dissolved P, than to the amount of NCPR dissolved in a soil. Consistent with this laboratory finding, the agronomic effectiveness of NCPR relative to superphosphate measured in the field tended to decrease with increasing P buffering capacity. The agronomic effectiveness of NCPR was comparable with superphosphate only at certain sites, and with some noted exceptions, most of these had surface soils with very low to low P buffering capacity. The high relative effectiveness of NCPR at these sites was mostly attributed to the loss of superphosphate by leaching. Since NCPR dissolves much more slowly than superphosphate, only a small amount of the P applied as NCPR would be lost during leaching events. Slow dissolution of the remaining NCPR probably supplied a small amount of dissolved P over an extended period of time, and due to the low P buffering capacity, much of this was available to plants.

The agronomic effectiveness of reactive phosphate rocks 1. Effect of the pasture environment

1997 ◽  
Vol 37 (8) ◽  
pp. 921 ◽  
Author(s):  
P. W. G Sale ◽  
R. J. Gilkes ◽  
M. D. A. Bolland ◽  
P. G. Simpson ◽  
D. C. Lewis ◽  
...  
Keyword(s):  
North Carolina ◽  
Phosphate Rock ◽  
Surface Soil ◽  
Annual Rainfall ◽  
Triple Superphosphate ◽  
Agronomic Effectiveness ◽  
P Sorption ◽  
Reactive Phosphate ◽  
Reactive Phosphate Rock ◽  
Very High

Summary. The agronomic effectiveness of directly applied North Carolina reactive phosphate rock was determined for 4 years from annual dry matter responses at 26 permanent pasture sites across Australia as part of the National Reactive Phosphate Rock Project. Fertiliser comparisons were based on the substitution value of North Carolina reactive phosphate rock for triple superphosphate (the SV50). The SV50 was calculated from fitted response curves for both fertilisers at the 50% of maximum yield response level of triple superphosphate. The reactive phosphate rock was judged to be as effective as triple superphosphate in the 1st year (and every year thereafter) at 4 sites (SV50 >0.9), and was as effective by the 4th year at 5 sites. At another 9 sites the reactive phosphate rock was only moderately effective with SV50 values between 0.5 and 0.8 in the 4th year, and at the final 8 sites it performed poorly with the 4th year SV50 being less than 0.5. Pasture environments where the reactive phosphate rock was effective in the 1st year were: (i) those on sandy, humic or peaty podsols with an annual rainfall in excess of 850 mm; (ii) those on soils that experienced prolonged winter inundation and lateral surface flow; and (iii) tropical grass pastures in very high rainfall areas (>2300 mm) on the wet tropical coast on North Queensland. The highly reactive North Carolina phosphate rock became effective by the 4th year at sites in southern Australia where annual rainfall exceeded 700 mm, and where the surface soil was acidic [pH (CaCl2) <5.0] and not excessively sandy (sand fraction in the A1 horizon <67%) but had some phosphorus (P) sorption capacity. Sites that were unsuitable for reactive phosphate rock use in the medium term (up to 4 years at least) were on very high P-sorbing krasnozem soils or high P-sorbing lateritic or red earth soils supporting subterranean-clover-dominant pasture, or on lower rainfall (< 600 mm) pastures growing on soils with a sandy A1 horizon (sand component >84%). No single environmental feature adequately predicted reactive phosphate rock performance although the surface pH of the soil was most closely correlated with the year-4 SV50 (r = 0.67). Multiple linear regression analysis found that available soil P (0–10 cm) and the P sorption class of the surface soil (0–2 cm), together with annual rainfall and a measure of the surface soil"s ability to retain moisture, could explain about two-thirds of the variance in the year-4 SV50 . The results from this Project indicate that there are a number of specific pasture environments in the higher rainfall regions of Australia where North Carolina reactive phosphate rock can be considered as an effective substitute P fertiliser for improved pasture.

scholarly journals Lettuce Response to Phosphorus Fertilization with Struvite Recovered from Municipal Wastewater

HortScience ◽  
2009 ◽  
Vol 44 (2) ◽  
pp. 426-430 ◽  
Author(s):  
Ricardo González-Ponce ◽  
Esther G. López-de-Sá ◽  
César Plaza
Keyword(s):  
Phosphate Rock ◽  
Municipal Wastewater ◽  
P Uptake ◽  
Environmental Benefits ◽  
Phosphorus Fertilization ◽  
Single Superphosphate ◽  
Loamy Sand Soil ◽  
P Fertilizer ◽  
P Rate ◽  
Spanish Research

Struvite (MgNH4PO4·6H2O) production is widely studied as a way to remove phosphorus (P) from wastewater and generate a potentially marketable P fertilizer, but its effects on crops have yet to be researched more thoroughly. This study was conducted to evaluate struvite recovered by the Spanish Research Council (CSIC) pilot process (STR) as a source of P for lettuce (Lactuca sativa L.) by comparing its effectiveness with that of single superphosphate (SUP), a common P fertilizer derived from phosphate rock. In a greenhouse pot experiment, a P-deficient loamy sand soil was amended with either SUP or STR at P rates of 0, 4, 8, 12, 16, and 20 mg·kg−1. Nitrogen and potassium were uniformly supplied to all treatments. The response of lettuce head fresh weight and P uptake to P rate exhibited statistically significant quadratic relationships for both SUP and STR. With respect to SUP, STR was significantly more effective in increasing lettuce yield and P uptake, probably because of the larger amount of magnesium (Mg) incorporated with this material and a synergistic effect on P uptake. This work supports previous findings based on other test crops in suggesting that STR can be a P source attractive to the fertilizer market with additional agronomic and environmental benefits such as providing available Mg and nitrogen, helping attenuate consumption of phosphate rock, and reducing release of P by discharge of treated wastewaters to surface and groundwater systems.

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