Factors affecting the agronomic effectiveness of phosphate rock for direct application

1995 ◽  
Vol 41 (3) ◽  
pp. 227-234 ◽  
Author(s):  
S. H. Chien ◽  
R. G. Menon
Keyword(s):  
Phosphate Rock ◽  
Direct Application ◽  
Agronomic Effectiveness ◽  
Factors Affecting

Developments in some aspects of reactive phosphate rock research and use in New Zealand

1997 ◽  
Vol 37 (8) ◽  
pp. 861 ◽  
Author(s):  
N. S. Bolan ◽  
M. J. Hedley
Keyword(s):  
New Zealand ◽  
Phosphate Rock ◽  
Direct Application ◽  
Soil Test ◽  
Phosphate Rocks ◽  
Agronomic Effectiveness ◽  
Olsen P ◽  
The North ◽  
Soluble P ◽  
P Sources

Summary. There has been over 50 years of use and research into the agronomic effectiveness of reactive phosphate rocks (RPR) directly applied to New Zealand pastures. In recent years RPR-carrying fertilisers made up about 16% of phosphatic fertiliser sales in the North Island of New Zealand. Most is applied, as maintenance fertiliser, to hill country sheep and beef farms. Use has been recommended on soils with pH <6 and in annual rainfall regimes >800 mm. This is based on the poor performance of Sechura phosphate rock in summer dry areas receiving <750 mm of rainfall annually. Phosphate rocks that have more than 30% of their total phosphate soluble in 2% citric acid have been classed as ‘reactive’ and suitable for direct application. More recent research indicates that extraction with 2% formic acid, or a dissolution test performed in a simulated soil solution at a fixed pH, will provide improved measures of RPR quality. Field trials, undertaken by the New Zealand Ministry of Agriculture and Fisheries [MAF; now AgResearch Crown Research Institute (CRI)] and others, to evaluate the relative agronomic effectiveness of RPR versus soluble P fertilisers in adequate to marginally P-deficient soils have proven to be a painstaking task. Long periods (3–6 years) of fertiliser withdrawal were required for pasture growth on some soils to become significantly responsive to applied P. Only then did differences between P sources become significant. This problem has encouraged efforts to relate measurements of the extent of RPR dissolution in soils to their agronomic effectiveness. Three main modelling approaches have been used to achieve this objective: Kirk and Nye (1986a, 1986b, 1986c); Sinclair et al. (1993a); and Watkinson (1994b). These models are reviewed and their explanation of RPR dissolution in mowing trials tested. Components of each model have then been combined to produce models to predict the agronomic effectiveness of RPR. The development of P tests for soils receiving RPR-containing fertilisers is reviewed. Separate Olsen P test–yield response calibration curves are required for soils fertilised with soluble P fertilisers and soils fertilised with sparingly soluble P sources or soluble P in the presence of heavy lime applications. Whereas alkaline P tests such as Olsen or Colwell underestimate the amount of plant-available P in these soils, acid P tests such as Bray 1 are likely to overestimate the available P. Tests involving cation and anion exchange resin membranes appear to be more appropriate for soils with unknown histories of soluble P and RPR use and may permit the use of single calibration curves. Trends observed in Olsen P soil test values, from farms on the North Island of New Zealand that have a history (3–15 years) of RPR use are presented. A predictive dissolution model is used to explain these trends but it is evident that spatial and temporal variation in soil test results on farmers’ paddocks will be a major constraint to the precision to which this or similar models may be used. The model, however, may provide the basis for sound advice on the strategic use of RPR for direct application to New Zealand pasture soils. It may prove useful in explaining the variation in RPR effectiveness in a wider range of climates and soils.

scholarly journals Direct application of reactive phosphate rock on improving maize yield in tidal swampland

2021 ◽  
Vol 648 (1) ◽  
pp. 012175
Author(s):  
A F Siregar ◽  
Husnain ◽  
I W Suastika ◽  
N P S Ratmini ◽  
I A Sipahutar ◽  
...  
Keyword(s):  
Phosphate Rock ◽  
Maize Yield ◽  
Direct Application ◽  
Reactive Phosphate ◽  
Reactive Phosphate Rock

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.

Agronomic effectiveness of partially acidulated phosphate rock as influenced by soil phosphorus-fixing capacity

1989 ◽  
Vol 120 (2) ◽  
pp. 159-164 ◽  
Author(s):  
S. H. Chien ◽  
L. L. Hammond
Keyword(s):  
Phosphate Rock ◽  
Soil Phosphorus ◽  
Partially Acidulated Phosphate Rock ◽  
Agronomic Effectiveness

The effect of direct application of phosphate rock on increasing crop yield and improving properties of red soil

1996 ◽  
Vol 46 (3) ◽  
pp. 235-239 ◽  
Author(s):  
Hu Hong-Qing ◽  
Li Xue-Yuan ◽  
Liu Jung-Fu ◽  
Xu Feng-Lin ◽  
Liu Jung ◽  
...  
Keyword(s):  
Crop Yield ◽  
Phosphate Rock ◽  
Red Soil ◽  
Direct Application

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.

scholarly journals ASSESSMENT OF PHOSPHORUS AVAILABILITY FROM UNREACTIVE TOGO PHOSPHATE ROCK BY LEGUME AND CEREAL CROPS IN TWO GHANAIAN SOILS

2020 ◽  
Vol 5 (1) ◽  
pp. 1
Author(s):  
Alex Boateng ◽  
Prof. Emmanuel Owusu- Bennoah
Keyword(s):  
Phosphate Rock ◽  
Dry Matter ◽  
P Uptake ◽  
Phosphorus Availability ◽  
Direct Application ◽  
Water Soluble ◽  
Cereal Crops ◽  
Dry Matter Yield ◽  
Water Soluble P ◽  
Soluble P

Purpose: In recent years, phosphate rock (PR) for direct application has been tested in tropical acid soils as a potential alternative to conventional water-soluble P fertilizers like Single Superphosphate (SSP) and Triple Superphosphate (TSP). However, direct application of PR with low reactivity does not always give satisfactory results. Legume and cereal crops represent a strategy that can be used to solubilize P from some of these unreactive PRs. The objective of this study was to assess the availability of P from unreactive Togo Phosphate Rock (TPR) relative to TSP by six (6) crop species in two Ghanaian soils. Methodology:  The study was conducted in the greenhouse of the Crop Science Department, University of Ghana. Three P rates, 0mg, 50mg and 100mg P of TPR and TSP were applied to a kilogram of soil per pot in the two soil series. Randomized Complete Block Design was used to do the analyses. Results/Findings: Application of TSP resulted in higher dry matter and P uptake irrespective of the soil type. Among the legumes, cowpea gave the highest dry matter yield. Fairly, a similar trend was obtained with the application of TPR. Among the cereals, the average P uptake by sorghum from TPR was the highest, followed by maize and millet in the Nzema soil. In the Adenta series, P uptake by maize was the highest, followed by sorghum and millet. Phosphorus (P) uptake by the cereals from TPR was generally better in the Adenta than the Nzema soil. Unique contribution to theories, practice and policy: Results show increasing the rate of TPR to 100mg P/pot resulted in an increase in dry matter yield and P uptake in both soils, but was inferior to 100mg P/pot TSP application. Consequently, the rate of application of TPR should always be high if farmers want the best from their investments. Again, the low relative agronomic effectiveness of TPR for all the crops, proved the low reactivity of the material and its subsequent low performance compared with the water-soluble P. The low reactivity and the high molar mass of PO43-/CO32- of the TPR will always make it difficult for P to be made available from the TPR despite the acidity of the soil, the high density of the crops and the ability of the tested crops to exude organic acids, which facilitate phosphorus availability from TPR, therefore making TPR unsuitable for direct application.

Dissolution of phosphate rock fertilisers in some soils of Okinawa, Japan

Soil Research ◽  
1999 ◽  
Vol 37 (1) ◽  
pp. 115 ◽  
Author(s):  
Daniel E. Dodor ◽  
Yoshihiro Tokashiki ◽  
Kazuhiro Oya ◽  
Moritaka Shimo
Keyword(s):  
South Africa ◽  
Regression Analysis ◽  
Regression Model ◽  
Soil Properties ◽  
Phosphate Rock ◽  
Soil Samples ◽  
Direct Application ◽  
Primary Concern ◽  
Rapid Estimation ◽  
Rate Of Dissolution

The ability of phosphate rock (PR) to dissolve rapidly in soil is a primary concern in its direct application as P fertiliser. The dissolution of 4 PR materials (Togo, South Africa, Florida, Morocco PRs) in 15 soil samples in Okinawa was investigated in a closed-incubation system for 7 days. The fertilisers were mixed with the soils at rates of addition of 600–1200 µg Ca/g soil. The extent and rate of dissolution of the PRs were determined by measuring the increase in extractable Ca of the fertilised soils compared with unfertilised soils, i.e. the delta Ca (ΔCa) technique. Generally, the amounts of dissolution of 3 of the PRs were very low (mean 6·7% for Togo PR, 13·6% for South Africa PR, and 20·8% for Florida PR). However, Morocco PR dissolved to an appreciable extent (mean 60·8%), suggesting that it can be an alternative P source, especially in the red and yellow soils of Okinawa. Soil properties identified as affecting dissolution were different for the different PRs. In order to predict the suitability of Morocco PR for Okinawan soils, the extent of its dissolution was related to soil properties in a multiple regression analysis. Results indicated that the best regression model for predicting the amount of dissolution was the combination of pH, Ca saturation, and Truog P (r2 = 0·55**). Measured values of percentage dissolution of Morocco PR were significantly correlated with calculated percentages (r = 0·844***), indicating that the equation obtained could offer a rapid estimation of amount of dissolution of Morocco PR in Okinawan soils.

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