Influence of calcium carbonate on the dissolution of Sechura phosphate rock in soils

1992 ◽  
Vol 32 (1) ◽  
pp. 91-99 ◽  
Author(s):  
J. S. Robinson ◽  
J. K. Syers ◽  
N. S. Bolan
Keyword(s):  
Calcium Carbonate ◽  
Phosphate Rock ◽  
Sechura Phosphate Rock

ALTERNATIVE P-FERTILISERS FOR NORTHLAND SOILS

1986 ◽  
pp. 229-232
Author(s):  
P.W. Shannon
Keyword(s):  
Phosphate Rock ◽  
Growth Responses ◽  
Triple Superphosphate ◽  
Rock Phosphates ◽  
Distribution Costs ◽  
Phosphate Retention ◽  
Sechura Phosphate Rock ◽  
Local Product ◽  
Application Frequency ◽  
Chatham Rise Phosphorite

Increasing material, processing, and distribution costs have raised superphosphate prices to a point where many farms cannot support the costs of meeting maintenance phosphate requires men& Alternatives to superphosphate, particularly those that have lower processing costs and contain more P, may offer a solution to the problem provided they are agronomically as effective. Phosphate rock may indeed be such an alternative. Preliminary results from a series of five trials in Northland show that on soils of moderate P fertility, with low phosphate retention (PR) and high pH (5.9.6.0), initial pasture growth responses to rock phosphates are smaller than those from single or triple superphosphate. On one soil of higher PR and lower pH, the differences in yield between the rock-phosphates and the super. phosphates were smaller. Of the rock phosphates tested, Sechura and North Carolina (unground and ungranulated) tended to be more effective than ground and granulated Chatham Rise phosphorite. The effect on production of applying fertilisers once every three years, as opposed to annual applications is being investigated using triple superphosphate and Sechura phosphate rock. After two years, production levels appear largely unaffected by differences in application frequency. A comparison of locally-produced superphosphate with a reference standard showed that both performed similarly, indicating that the local product was of satisfactory quality.

scholarly journals Phosphorus status of pastoral soils where reactive phosphate rock fertilisers have been used

1995 ◽  
pp. 133-137
Author(s):  
K.W. Perrott ◽  
B.E. Kerr ◽  
J.H. Watkinson ◽  
J.E. Waller
Keyword(s):  
Dissolution Rate ◽  
Phosphate Rock ◽  
Linear Regression Analysis ◽  
Soil Test ◽  
Site Factors ◽  
Soil P ◽  
Reactive Phosphate ◽  
Reactive Phosphate Rock ◽  
Sechura Phosphate Rock ◽  
Fertiliser Application

The dissolution rate of Sechura phosphate rock (particle size 75-150 pm) was determined at 95 New Zealand sites with a range of soil and environmental properties. Rates ranged from 0 to 70% of the phosphate rock dissolved per year with an average dissolution rate of 3 1 %/year. An initial model based on stepwise linear regression analysis indicated that the rate of dissolution was negatively associated with soil pH and positively associated with rainfall and exchangeable soil magnesium. There was also an effect of soil type and drainage. The amount of residual RPR accumulated from previous fertiliser application can be determined by a new soil test. This, together with the dissolution rate estimated from the nature of the RF'R and the soil and site factors, can be used to indicate likely soil P status. Keywords: dissolution, fertiliser, phosphorus, reactive phosphate rock, soil test

scholarly journals The long-term effectiveness of reactive phosphate rock as a phosphate fertiliser for New Zealand pastures

1990 ◽  
pp. 101-104 ◽  
Author(s):  
A.G. Sinclair ◽  
C.B. Dyson ◽  
P.W. Shannon
Keyword(s):  
New Zealand ◽  
Phosphate Rock ◽  
Field Trials ◽  
Superior Performance ◽  
Single Superphosphate ◽  
Reactive Phosphate ◽  
Application Rates ◽  
Phosphate Retention ◽  
Reactive Phosphate Rock ◽  
Sechura Phosphate Rock

Sechura reactive phosphate rock (SPR) and triple superphosphate (TSP) have been compared as phosphate fertihsers for pastures in a series of 19 field trials dispersed throughout New Zealand, each continuing for 3-6 years. Both fertilisers were applied annuaIly at 4 rates. In the first 2 years SPR was much less effective at increasing dry matter yields than TSP, but its performance improved markedly with time. In year 6 SPR outyielded TSP at alI application rates for all sites combined. The relative performance of SPR and TSP differed markedly at different sites. Very high soil phosphate retention and a combination of low moisture and high pH appeared to be unfavourable for SPR performance. In most sites SPR was equal or superior to TSP by year 6. SPR substantially raised molybdenum concentration in clovers, and this may have contributed to its superior performance at some sites. As TSP and single superphosphate were equally effective, the good performauce of SPR and the relative cheapness of reactive phosphate rocks suggest an important role for the latter on New Zealand pastures. Keywords Sechura phosphate rock, reactive phosphate rock, RPR, superphosphates, phosphate fertilisers

scholarly journals Effects of frequency of maintenance phosphate fertiliser application on dry matter production from permanent pastures

1992 ◽  
pp. 55-58
Author(s):  
W.H. Risk ◽  
L.C. Smith ◽  
A.G. Sinclair ◽  
P.D. Johnstone ◽  
P.W. Shannop ◽  
...  
Keyword(s):  
Phosphate Rock ◽  
Rock Phosphate ◽  
First Year ◽  
Triple Superphosphate ◽  
Matter Production ◽  
Phosphate Fertiliser ◽  
Sechura Phosphate Rock ◽  
Application Frequency ◽  
Fertiliser Application ◽  
Annual Application

In a series of 12 field uials located throughout New Zealand annual application of phosphate(P) fertiliser was compared with ttiennial application using rates which applied the same total amount of P over 6 years. Test materials were triple supetphosphate (TSP) and Sechura phosphate rock (SPR), both of which were applied annually at rates which provided 0.75 times the calculated maintenance P requirement (0.75 M) and triennially at 2.25 M.For the 12 sites combined there was a significant response to P fertiliser each year. Application frequency had no significant effect on total DM yield over the 6 year period with either TSP or SPR. A cyclic effect with triennial applications was appsrent for both fertllisers, with approximately 2-4% higher yields in the first year and 2-4% lower yields in the third year of both 3 year cycles. These results indicate that on well developed pastures a change from annual to triennial application frequency of phosphate fertillser, with either TSP or slow release SPR, will have little effect on DM production providing the same total amount of P is applied. This gives farmers the opportunity to make some adjustment to P fertiliser application frequency according to fluctuations in availability of finance. However, these conclusions do not apply to other nutrients such as sulphur, potassium and trace elements for which annual applications may he necessary. Keywords triple superphosphate, Sechura phosphate rock, phosphate fertilisers, annual application, triennial application, application frequency, reactive phosphate reck

Effects of triple superphosphate and Sechura phosphate rock on clover and nitrogen content of pasture

1994 ◽  
Vol 37 (4) ◽  
pp. 569-575 ◽  
Author(s):  
J. D. Morton ◽  
M. B. O'Connor ◽  
W. H. Risk ◽  
L. Nguyen ◽  
A. G. Sinclair ◽  
...  
Keyword(s):  
Nitrogen Content ◽  
Phosphate Rock ◽  
Triple Superphosphate ◽  
Sechura Phosphate Rock

Sechura phosphate rock supplies plant-available molybdenum for pastures

1990 ◽  
Vol 33 (3) ◽  
pp. 499-502 ◽  
Author(s):  
A. G. Sinclair ◽  
P. W. Shannon ◽  
W. H. Risk
Keyword(s):  
Phosphate Rock ◽  
Sechura Phosphate Rock

Application strategies for Sechura phosphate rock use on permanent pasture

1988 ◽  
Vol 17 (3) ◽  
pp. 219-234 ◽  
Author(s):  
P. E. H. Gregg ◽  
A. D. Mackay ◽  
L. D. Currie ◽  
J. K. Syers
Keyword(s):  
Phosphate Rock ◽  
Permanent Pasture ◽  
Sechura Phosphate Rock
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