Comparing two theories about the nature of soil phosphate

2020 ◽  
Author(s):  
N. J. Barrow
Keyword(s):  
Soil Phosphate

Phosphorus equivalence ofaspergillus nigerphytase for growing pigs

1995 ◽  
Vol 1995 ◽  
pp. 40-40
Author(s):  
Naheeda Khan ◽  
D.J.A. Cole
Keyword(s):  
Total Phosphorus ◽  
Current Literature ◽  
Livestock Production ◽  
Growing Pigs ◽  
Environmental Constraints ◽  
Experimental Conditions ◽  
Production Sector ◽  
Soil Phosphate ◽  
Phosphorus Requirements ◽  
Inorganic Phosphates

Inconsistencies in the estimated phosphorus requirements of growing pigs have come to light in recent years due to environmental constraints being imposed on the livestock production sector. Values of a net requirement estimated by the ARC (1981) extend from 4.6 g/day for 25kg liveweight to 5.2 g/day for 45kg pigs, but current literature suggesting that the actual requirement may be lower (eg Jongbloed and Everts, 1991) calls for a revision of previous recommendations.Around two thirds of the total phosphorus in cereals exists in the form of insoluble phytates which must be degraded before the phosphorus can be absorbed in the intestine. Under experimental conditions, the use of phytase in pig diets has demonstrated consistent improvements in phosphorus digestibility. The enzyme hydrolyses phytate by stepwise removal of orthophosphates, which become available for absorption in the gut. Although quantification of phytase/phosphorus substitution is as yet undetermined, digestibility results so far indicate that if used correctly the enzyme could largely replace inorganic phosphates, particularly in regions where soil phosphate levels are of concern.

scholarly journals Proteome adaptations under contrasting soil phosphate regimes of Rhizophagus irregularis engaged in a common mycorrhizal network

2021 ◽  
Vol 147 ◽  
pp. 103517
Author(s):  
Ghislaine Recorbet ◽  
Silvia Calabrese ◽  
Thierry Balliau ◽  
Michel Zivy ◽  
Daniel Wipf ◽  
...  
Keyword(s):  
Rhizophagus Irregularis ◽  
Soil Phosphate ◽  
Mycorrhizal Network ◽  
Common Mycorrhizal Network

Soil Phosphate Stable Oxygen Isotopes across Rainfall and Bedrock Gradients

2012 ◽  
Vol 46 (4) ◽  
pp. 2156-2162 ◽  
Author(s):  
Alon Angert ◽  
Tal Weiner ◽  
Shunit Mazeh ◽  
Marcelo Sternberg
Keyword(s):  
Oxygen Isotopes ◽  
Stable Oxygen Isotopes ◽  
Soil Phosphate ◽  
Stable Oxygen

scholarly journals Закономірності росту фосфатмобілізувальних бактерій у різних типах живильних середовищ

2010 ◽  
Vol 1 (1) ◽  
pp. 78-82
Author(s):  
K. V. Lavrentyeva ◽  
N. V. Cherevach ◽  
A. I. Vinnikov
Keyword(s):  
Pseudomonas Putida ◽  
Growth Pattern ◽  
Physiological Parameters ◽  
Mineral Medium ◽  
Bacterial Cells ◽  
Bacteria Growth ◽  
Soil Phosphate ◽  
Constant Ph

Regularities of two strains of soil phosphate-mobilizing bacteria growth were investigated in different media. Curve of growth and physiological parameters were defined for Pseudomonas putida and Enterobacter dissolvens. Growth pattern of investigated strains was better in the broth medium than in mineral. In these conditions higher concentration of viable bacterial cells was common for E. dissolvens. It was shown that during cultivation pH of mineral medium went down to 4.4-4.5, but broth medium had constant pH 7.0.

A Rapid Chemical Field Test for Archaeological Site Surveying

1973 ◽  
Vol 38 (2) ◽  
pp. 206-210 ◽  
Author(s):  
Robert C. Eidt
Keyword(s):  
Field Test ◽  
Archaeological Site ◽  
Field Method ◽  
Spot Test ◽  
Efficient Technique ◽  
Relative Duration ◽  
Soil Phosphate

AbstractA simple and inexpensive qualitative chemical field method, or spot test, is described for ascertaining the presence of enriched soil phosphate. The spot test is an efficient technique for rapid archaeological site surveying, for elimination of guesswork in establishing trench lines, and for creating phosphate maps depicting type, extent, and relative duration of abandoned settlement features.

Yield responsiveness and response curvature as essential criteria for the evaluation and calibration of soil phosphate tests for wheat

Soil Research ◽  
1985 ◽  
Vol 23 (2) ◽  
pp. 167 ◽  
Author(s):  
ICR Holford ◽  
JM Morgan ◽  
J Bradley ◽  
BR Cullis
Keyword(s):  
Field Experiments ◽  
Yield Response ◽  
Soil Test ◽  
Wheat Field ◽  
Fertilizer Effectiveness ◽  
Soil Phosphate ◽  
Fertilizer Requirement ◽  
Dry Conditions ◽  
Using Data ◽  
Actual Response

In a study using data from 57 wheat field experiments on the central-western slopes of New South Wales, eight soil phosphate tests (Bray,, Bray,, alkaline fluoride, Mehlich, Truog, lactate, Olsen and Colwell) were evaluated and calibrated in terms of responsiveness (�) and response curvature (C) parameters derived from the Mitscherlich equation. The results showed that, regardless of how well correlated a soil test is with yield responsiveness, it cannot give a satisfactory estimate of fertilizer requirement unless yield response curvature is also taken into account. The tendency of soil test values, especially of the Colwell test, to be negatively related to response curvature, and hence inversely related to fertilizer effectiveness, compounded the problem of directly relating soil test values to fertilizer requirement. The best test (lactate) accounted for only 28% of the variance in fertilizer requirement, compared with 50% of the variance in responsiveness, and the worst test (Colwell) was completely unrelated to fertilizer requirements. When fertilizer requirement was estimated from the lactate test value and the actual response curvature for each experiment, 68% of the variance (from the actual fertilizer requirement) was accounted for. Thirteen experiments were subject to drier conditions than the others, and these were less responsive and had lower fertilizer requirements relative to soil test values. In relation to yield responsiveness, the Colwell test was most sensitive (P < 0.001) to dry conditions, while the two best tests (lactate and Bray,) were the least sensitive (P > 0.05). The results demonstrated the superiority of acidic anionic extractants over alkaline bicarbonate extractants on moderately acid to alkaline wheat-growing soils.

Phosphate analysis

1982 ◽  
Vol 48 (S1) ◽  
pp. 50-57
Author(s):  
N D Balaam ◽  
H M Porter
Keyword(s):  
Archaeological Survey ◽  
Soil Phosphate ◽  
Total Phosphate ◽  
Phosphate Analysis ◽  
High Level ◽  
Future Work ◽  
Principal Method ◽  
Alkaline Oxidation

The principal method adopted for the soil phosphate analysis for the Shaugh Moor project was a slightly modified version of that published by Dick and Tabatabai (1977). This method involves extraction of soil phosphate by alkaline oxidation with Sodium hypobromite (NaOBr-NaOh). It has been calculated that this process extracts about 60-70% of total phosphate from soils such as those on Shaugh Moor (Ralph, pers comm). This was considered satisfactory foe the purposes of this project.It is thought that this method has not been used before in archaeological survey work but it is suggested that the simplicity of the technique and the relatively high level of phosphate extraction might prove of value in future work.

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