Olsen Test Research Articles

A short-term phosphate fertiliser advice model for grazed pasture as applied to soils in northern North Island, New Zealand

Abstract A short-term (3–4 years) phosphate (P) fertiliser advice model for permanent pasture was developed and applied to field data obtained on highly P-sorbing soils and some low — medium P-sorbing soils in the northern North Island, New Zealand. The model demands that only results from those trials that estimate herbage yield responses to rates of P fertiliser under good rotational grazing management can be used. On highly P-sorbing soils, P status as measured by the Olsen test (to 75 mm depth) correlates positively with the Mitscherlich slope parameter, suggesting that residual P increases the availability of newly applied P. On two soil categories, it was possible to provide P requirement/ Olsen regressions that could be used to give advice on individual fields. On a very large proportion of land, however, there was insufficient field evidence to do so.

Phosphorus effectiveness in fertilized soils evaluated by chemical solutions and residual value for wheat growth

Nineteen soils from the south east of the Province of Buenos Aires (Argentina) that had been fertilized with moderate amounts of P (10–40 kgP/ha) during the last 10 years were used to investigate the effect of time on the decline of P availability as measured by three soil tests (Bray 1, Bray 2, Olsen) and the null-point method. Differences in rates of P decline among soils and chemical methods were characterized by an exponential coefficient for time (b2) in equations which describe the changes of the added P retained by the soil (Pr =acb1tb2). The rate of decline of P for the nineteen soils calculated for the soil test methods was ordered decreasingly as: null-point > Olsen > Bray 1 > Bray 2. The ability of the chemical methods for assessing the residual value of P for wheat growth (RV) was tested in a pot experiment on seven of the soils that differed in their individual rates of reaction with P. Differences between soils in the rate of reaction with P as measured in the laboratory by the null-point method and by the Olsen test were reflected in different residual values for P fertilizer for wheat plants. Thus the value ofb2 for these methods was well correlated with the observed residual values. The soil properties commonly associated with the retention of P were not related to the value ofb2 suggesting that more than one soil property may be involved in the measure ofb2. The exponent for timeb2 may be used as an index of the ability of the soil test to reflect the decline of P availability with time.

INFLUENCE OF SALT CONCENTRATION AND SODICITY ON THE SOLUBILITY OF PHOSPHATE IN SOILS

The effects of electrolyte concentration and exchangeable sodium (sodicity) on the solubility of native phosphate (P) in some Brown Chernozemic soils (Haploborolls) from Saskatchewan, Canada were evaluated using a flow (miscible displacement) technique. Phosphate concentration was measured in leachate from soil columns treated with a series of NaCl-CaCl2 solutions having fixed sodium adsorption ratio (SAR) with electrical conductivity (EC) decreasing from about 10 to 0.1 dS m−1. The results show that the P content of the leachate was strongly influenced by both EC and SAR and that these two variables were interactive in their effect. Leachate P was usually low (<0.1 mg L−1) when EC was high, but it increased as EC decreased, particularly when SAR was high. Values as high as 3 to 5 mg P L−1 were attained under conditions of low EC and high sodicity (SAR 20–40). Samples of leached soil were subjected to a chemical fractionation procedure to determine how the various forms of inorganic P responded to the imposed salinity and sodicity treatments. In the absence of Na (SAR O), there was relatively little change in the distribution of P during the leaching sequence but, as sodicity increased, the water-extractability of P increased substantially. The main effect of sodicity was that it made the weakly adsorbed P fraction (NaHCO3-P) more labile. Increasing sodicity had little effect on the more strongly adsorbed P fraction (NaOH-P) or on Ca-bound P (HCl-P). The results of this study suggest that electrolyte concentration and sodicity may have an important bearing on the P nutrition of crops grown on Canadian prairie soils. However, the widely-used Olsen test appears to be insensitive to the influence of these variables. It is possible that the poor performance of this test noted in recent reports is partly related to salt and/or sodicity effects.

Effects of pH and sodium ions on NaHCO3 extractable phosphate in calcareous/sodic soils

AbstractOne calcareous and one sodic soil were treated with solutions of either sodium carbonate (Na2CO3) or sodium perchlorate (NaCIO4) to increase their sodium (Na) saturation before extracting with sodium bicarbonate (NaHCO3) to measure the recovery of native plus added phosphate (P). The Na2CO3 additions also increased pH, and by comparing with the NaCIO4 treatments, it was possible to separate the effects of added Na and pH on extractable P. For the calcareous soil both added Na and increased pH led to increases in the amount of NaHCO3‐extractable P. For the sodic soil the amount of extractable P was mainly affected by pH, with little, if any, effect of the added Na. The suitability of the Olsen test for soil P for Na‐affected soils is discussed.

Comparison of Olsen and Pi soil tests for evaluating phosphorus bioavailability in a calcareous soil treated with single superphosphate and partially acidulated phosphate rock

The Pi test for phosphorus (P) is a new method in which strips of iron oxide impregnated filter paper are used as a sink to sorb and extract P from a soil solution. In a greenhouse experiment, the Olsen and Pi tests were compared for their effectiveness in evaluating P availability to maize on calcareous soils. Phosphate rock from Togo, partially acidulated with H2SO4 at 50% acidulation level (PAPR 50% H2SO4) and single superphosphate (SSP) were applied at different rates to a calcareous soil (Vernon Clay, pH 8.2, CaCO3 18.9%) which was preincubated with KH2PO4 to raise plant-available P to different levels. In soils treated with SSP, dry-matter yield of maize correlated equally well with Pi-P and with Olsen-P (r = 0.96***). P uptake correlated significantly with Pi-P (r = 0.94***) as well as Olsen-P (r = 0.97***). Likewise, in soils fertilized with PAPR, significant correlations were found between dry-matter yield and Pi-P (r = 0.97***) and between dry-matter yield and Olsen-P (r = 0.94***). When all the data were pooled, Pi-P and Olsen-P correlated equally well with both dry-matter weight (r = 0.97***) and P uptake (r = 0.94***). Phosphorus extracted by the Pi test correlated significantly with P extracted by the Olsen test (r = 0.99***).

Soil and foliar characterization for Prosopis clones on sites with contrasting productivity in semi-arid South Texas

A thornless Prosopis alba clone produced 21·7 dry Mg/ha in its third growing season in Kingsville, Texas, with 682 mm rainfall, while it only produced 3·22 Mg/ha in its third growing season at Zachry Ranch, Texas, with 560 mm rainfall. The contrasting differences in productivity suggest that fertility as well as rainfall must limit productivity. Field foliar concentrations of N, P, K, Ca, Mg, Na, Fe, Mn, Zn and Cu were compared to previously established greenhouse sufficiency levels of these nutrients. Based on foliar analyses, only Cu would be limiting at the low productivity site, but based on soil standards for maize, P, Fe and Zn would be limiting. Foliar P, K, Na, Fe, Mn, Zn and Cu were highly correlated ( r = 0·933; p = 0·001) with the silt content. Highly significant, negative correlations occurred between Olsen's test for available soil P and every foliar nutrient except for Ca and Mg. Considerable discrepancy exists between leaf and soil diagnostic criteria, and extreme caution should be used in basing fertilizer recommendations for tree legumes on standard soil tests.

The double reverse olsen and stretch—Draw tests for evaluating adhesion of metallic coatings on sheet steel

Two simulative forming tests for assessing the adhesion of metallic coatings on sheet steel, the double reverse Olsen adhesion test and a new test, the stretch-draw adhesion test, are contrasted. The strain states, the nature of the test results, and the responses of various hot dip galvanized and electroplated zinc and zinc alloy coatings are compared. The quantitative mass loss measurements of both tests are shown to have greater relevance than the qualitative visual rating system most commonly used with the double reverse Olsen test. Both tests effectively differentiate good and poor adhesion of alloy coatings. Only small amounts of zinc coatings are lost in both tests. The double reverse Olsen test is easier to perform but represents a sequence of strain states seldom encountered in actual stamping operations.

Wheat P requirements on calcareous moroccan soils: I. A comparison of olsen, soltanpour and CaCl2soil tests

Abstract Wheat [Triticum aestivum(L.)] is the major cereal crop of the Chaouia (dryland) region of Morocco. Efforts for self‐sufficiency in wheat will require improved fertility management on the calcareous soils of this region. This research was undertaken to evaluate the suitability of five soil P extractors for predicting the need for P fertilization on 15 important soils in this region. The Olsen (0.5MNaHCO3), the Soltanpour (1.0MNH4HCO3+ 0.005MDTPA) and their dilution modifications, and CaCl2solution P method were evaluated in laboratory and greenhouse experiments. Ten of the 15 soils responded to P fertilization. The five soils for which a significant P response was not measured were from the P plateau of the Chaouia region. The P extractors performed equally to predict the need for P fertilization. The critical levels below which a response would be highly probably and above which no response would be anticipated varied by extractor and method used to interpret the soil test values. A graphic method indicated the critical P values to be: Olsen 10.2, modified Olsen 18.0; Soltanpour 2.0; modified Soltanpour 12.5 and CaCl20.20 mg P kg‐1. A second degree polynomial method indi cated the critical P values to be: Olsen 8.2; modified Olsen 14.0; Soltanpour 1.1; modified Soltanpour 5.1 and CaCl20.12 mg P kg‐1. This limited data will permit the interpretation of soil test values as to whether a response to P fertilization is highly probable for the dominant soils of this wheat region. Results from this study suggest that any of the five P extractors evaluated could be selected to calibrate P response under field conditions. It might be best to concentrate future research efforts on the Olsen test because most field P calibration data published with similar soils, climate and crops are with this extractor

Polyphosphates as sources of phosphorus for plants

Polyphosphates vary in their rates of hydrolysis and degree of sorption by soil constituents, which could affect the efficiency of P recovery from these compounds by plants. In this study, four linear oligophosphates (P2, P3, P15, and P45) and one cyclic polyphosphate (trimetaphosphate) were tested in greenhouse experiments for their ability to supply P to plants, compared with that of the conventional P source, orthophosphate (P1). Annual ryegrass (Lolium multiflorum Lam.) and corn (Zea mays) were used as the indicator plants. Ryegrass was grown on four Iowa soils (Clarion, Webster, Primghar, and Ida), treated at the rates of 0, 20, 40, and 80 mg P kg−1 soil (1.8 kg of soil pot−1) and harvested four times at 30-day intervals. The soils of the control pots were recovered, repotted (150 g pot−1), and seeded with corn after treatment with polyphosphates at the same rates as given. The corn plants were harvested after 35 d. With all P sources, dry matter yield and P yield increased with increasing rates of P application for both ryegrass and corn. Statistical analysis (Duncan's Multiple Range Test) of P yields of ryegrass and corn grown in soils amended with the various P sources indicated that there were no P compounds that consistently showed significantly greater amounts of P recovery in plant tissue. Considering all the P sources and rates of P application, dry matter yield was significantly correlated (exponentially) with P uptake by ryegrass from all four soils. The dry matter yield of corn was significantly correlated (linearly) with rates of P application with all P sources, indicating that the effectiveness of a unit of P taken up by plants in increasing the dry matter yield was similar among the polyphosphates and the conventional P fertilizer, orthophosphate. Measurements of extractable P (Bray-Kurtz I on the acid Clarion, Webster, and Primghar soils and Olsen's test on the alkaline Ida soil) upon completion of each experiment indicated that the residual P effects were similar among the P compounds after the short cropping period with corn (35 days) and the long cropping period with ryegrass (120 days).

Comparisons of soil test phosphorus by Olsen, Bray P1, Mehlich I and Mehlich III methods

Abstract A study was undertaken to evaluate the agreement among different university laboratories performing the Olsen, Bray P1, and Mehlich I tests for P on a diverse group of noncalcareous agricultural soils and to develop relationships among the Olsen, Bray P1, Mehlich I, and Mehlich III soil tests. For each test, the results from the individual laboratories were highly correlated (r2 ≥ 0.90) and in almost all instances the slopes of the equations describing the relationships among laboratories approached one, The results indicate that the Olsen, Bray P1 and Mehlich I soil tests may be performed with a high degree of precision when standard soil test procedures are followed. Of the three most commonly performed tests in the U.S. (Olsen, Bray P1, and Mehlich I), the Olsen and Mehlich I tests were the most highly correlated (r2 = 0.87) although the Mehlich I test removed approximately one and one half times more P than did the Olsen test. Bray P1 and Olsen and Mehlich I P were less highly correlated (r2 ≤ 0.72) and the relationships between these variables were influenced by the texture of the soils. The quantity of P removed by the Bray P1 test was on the order of two and three times greater than that removed by the Olsen and Mehlich I tests, respectively. The Bray P1 and Mehlich III soil tests were highly correlated (r2 = 0.97) and similar quantities of P were extracted from the soil by the two tests.

Greenhouse Evaluation of Four Phosphorus Soil Tests in Relation to Phosphate Buffering and Labile Phosphate in Soils

AbstractFour soil P tests — Olsen, Colwell, Bray, and Mehlich — were evaluated in a greenhouse experiment in relation to plant uptake, relative yield, labile P, and buffer capacity on 30 soils varying in pH from 5.4 to 8.1. The Olsen and Colwell tests were most highly correlated with plant uptake, and the Olsen and Bray tests with relative yield. When the soils were stratified into weakly, moderately, and strongly buffered groups, it was found that extraction of labile P was depressed by increasing buffer capacity most in the Bray test, followed by the Olsen test, and least in the Colwell test. The Bray test tended to overcompensate for the effects of buffering on plant uptake and therefore underestimated the amount of available P in strongly buffered soils, whereas the Colwell method tended to overestimate it in strongly buffered soils. The Olsen test appeared to be correctly sensitive to buffering and therefore gave the highest correlations with both plant parameters. The Mehlich test extracted large amounts of nonlabile P in soils with pH &gt;6.0 and was therefore weakly correlated with plant uptake and relative yield. The results showed that in a successful soil test, increasing buffer capacity will depress the extraction of labile P in the same way as it depresses uptake by plants.

Some phosphorus test values and fractions of inorganic phosphorus in soils

The relation between the P test values obtained by four methods and the inorganic phosphorus fractions of soil was studied on the basis of a material consisting of 346 samples of mineral soils originating from the surface layer and from the deeper layers. Fairly large differences were found in the results between the sand and finesand soils and the clay soils. The Bray 1 test gave higher average values in the former soils than in the latter group, and the contrary was true with the acetic acid test. On the average, the Bray 1 test and the Olsen test extracted equal amounts of phosphorus, the values of the acetate test were very low, and the acetic acid test values were between these except in the deeper layers of loam and silt soils and clay soils in which the acetic acid values tended to be higher than the other ones. The Bray 1 test values and the Olsen test values were closely correlated with each other, and somewhat less closely correlated with the acetate values. The acetic acid values were correlated with the other test values only in the sand and fine sand soils. The variation in the Bray 1 test values was most closely connected with the variation in the NH4F-soluble P, and only in the clay soils the NH4CI-soluble and the alkali-soluble fractions appeared to be of importance. In the Olsen test both the NH4F-soluble and the alkali-soluble fractions had to be taken into account, in clay soils also the NH4CI-soluble fraction. Adding the acid-soluble fraction did not increase the part of the variation in these two test values which could be explained. The acetate test value was most closely associated with the NH4CI-soluble fraction, except in the sand and finesand soils where the alkali-soluble P appeared to be of importance. Taking into account the acid-soluble fraction increased to some extent the part of the variation in the acetate values which could be explained by the variation in the three other fractions. The variation in the acetic acid test value, on the other hand, appeared to depend only on the acid-soluble fraction in other groups than the sand and finesand soils. Less than one half of the variation in it could be explained by the variation in these four fractions or soil pH. It is suggested that the Bray 1 test and the Olsen test would be recommendable for the measurement of the capacity factor of the soil P status.