Mehlich 3 Research Articles

Correlations of cation extractants in Costa Rican soils

Abstract Modified Olsen (MO) and N KC1 are the extractans used in Costa Rica to diagnose soil fertility. Our laboratory used Universal Soil Extractants to speed analysis and to obtain the best correlations between relative yield and nutrient level in the soils. We evaluated the aforementioned, Mehlich 3 (M3), Modified Morgan (MM) and Ammonium Acetate (AA) in four soil orders (Ultisols, Vertisols, Inceptisols, and Andisols). For calcium (Ca), all reagents gave highly significant correlations and in some cases AA, M3, and KCl showed an essentially one‐to‐one relation. The regression slope of 0.9 was for KCl‐Ca and M3‐Ca when all soils were considered as a population. KCl‐Ca and MM‐Ca regression gave an average slope of 0.94. When KC1 and M3 extractable magnesium (Mg) were regressed, we obtained highly significant correlations in all orders. The same behaviour was found for KCl‐Mg and AA‐Mg. MM showed poor correlations with the other extractants. All reagents gave highly significant correlations for potassiu...

THE CHEMICAL FORMS OF ZN AND CU EXTRACTABLE BY MEHLICH 1, MEHLICH 3, AND AMMONIUM BICARBONATE-DTPA EXTRACTIONS

Mehlich 1 (M1), Mehlich 3 (M3), and Ammonium Bicarbonate DTPA (AB-DTPA) have been used to determine the available micronutrients in soils. However, the forms of micronutrients extractable by these extractants are not known. The objectives of this study were: (i) to examine the correlation between the forms of Zn or Cu (readily soluble, organically bound, precipitated, and residual) in soils determined by a sequential extraction procedure and M1, M3, or AB-DTPA-extractable Zn or Cu and (ii) to directly determine the quantity of each form of Zn and Cu in soils that can be extracted by M1, M3, or AB-DTPA. The results show strong correlations between the organically bound or precipitated forms of Zn or Cu and the amounts extractable by any of the above three extractants. It appears that in sandy soils, Zn and Cu extractable by M1, M3, or AB-DTPA contain most of the readily soluble and the organically bound forms as well as a small fraction of the precipitated and residual forms. The rankings of these three extractants for extraction of organically bound Zn and Cu are M1 = M3 > AB-DTPA and M3 = AB-DTPA > M1, respectively. All of the above three extractants were equally effective in extracting the precipitated form of Zn or Cu. The efficacy of extraction of the residual form of Zn and Cu decreased in the order M3 > M1 = AB-DTPA.

Comparison of mehlich 3, mehlich 1, ammonium bicarbonate‐DTPA, 1.0M ammonium acetate, and 0.2M ammonium chloride for extraction of calcium, magnesium, phosphorus, and potassium for a wide range of soils

Abstract Extractants employed for routine soil analysis vary from one laboratory to another. Lack of a universal soil extractant is a serious limitation for interpretation of analytical results from various laboratories on nutritional status of a given soil. This limitation can be overcome by developing functional relationships for concentrations of a given nutrient extractable by various extradants. In this study, extractability of Ca, Mg, P, and K in a wide range of soils (0–15 cm) from citrus groves in Florida representing 21 soil series, with varying cultural operations, were compared using Mehlich 3 (M3), Mehlich 1 (M1), ammonium acetate (NH4AOc), pH = 7.0 (AA), 0.2M ammonium chloride (NH4Cl), and ammonium bicarbonate‐DTPA (AB‐DTPA) extractants. Soil pH (0.01M CaCl2) varied from 3.57 to 7.28. The concentrations of Ca or Mg extractable by M3, M1, AA, and NH4Cl were strongly correlated with soil pH (r2 = 0.381–0.482). Weak but significant correlations were also found between AB‐DTPA extractable Ca or Mg and soil pH (r2 = 0.235–0.278). Soil pH relationships with extractable K were rather weak (r2 = < 0.131) for M1 and NH4Cl but non‐significant for M3, AB‐DTPA, and AA. Concentrations of Ca, Mg, and K extractable by M3 were significantly correlated with those by either M1, AA, or NH4Cl extractants. Mehlich 3‐P was significantly correlated with P extractable by M1 extractant only. Mehlich 3 versus AB‐DTPA relationship was strong for K (r2 = 0.964), weaker for Mg and P (r2 = 0.180–0.319), and non‐significant for Ca. With the increasing emphasis on possible use of M3 as an universal soil extractant, data from this study support the hypothesis that M3 can be adapted as a suitable extractant for routine soil analysis.

Comparison of single and sequential soil extractions for predicting copper phytotoxicity

Abstract Phytotoxicity of copper (Cu) and other heavy metals is related to their forms in soil. In this study, different forms of Cu in the soil solid phase, i.e. exchangeable, sorbed, organically bound, precipitate, and residual forms were measured, using a sequential fractionation procedure (SFP), in a soil amended with various rates of Cu. The relationships between different forms of Cu by SFP in soil or Cu extractable by Mehlich 1 (M1) and Mehlich 3 (M3) and accumulation of Cu by citrus roots or shoots were examined. The results showed that Cu mainly existed in the organic fraction. An increase in soil pH decreased the organic fraction and increased the precipitate fraction of Cu. Copper concentration in citrus root was found to correlate with the water soluble, organic, or precipitate fractions of Cu in the soil. Multiple regressions using different forms of Cu in soil gave the same prediction of Cu concentration in citrus root as that using Ml‐ or M3‐extractable Cu.

Micronutrients status of Florida soils under citrus production

Abstract Micronutrient nutrition plays an important role in citrus production. Soil extraction techniques to measure the status of bio‐available micronutrients are extremely valuable in the diagnosis of deficient or toxic levels of micronutrients. Mehlich 3 (M3), Mehlich 1 (M1), ammonium bicarbonate‐DTPA (ABDTPA), and ammonium acetate, pH 7.0 (AA), extractants were evaluated for their ability to extract Cu, Fe, Mn, and Zn using 45 citrus grove soils, representing 20 soil series with widely varying physical and chemical characteristics and production practices. The mean concentrations of M3 extractable Fe, Mn, Cu, and Zn were 5.5‐, 2.2‐, 1.6‐, and 1.2‐fold greater, respectively, than those extracted by M1. ABDTPA was more efficient in the extraction of Fe, Cu, and Zn, as compared to the M1 extradant, by 3.3‐, 3.0‐, and 1.4‐fold, respectively. Among the four extractants, AA was extremely inefficient in extraction of all the four micronutrients. Evaluation of the data from all 45 citrus grove soils revealed ...

Initial calibration and correlation of inorganic‐phosphorus soil test methods with a bahiagrass field trial

Abstract In recent field studies, bahiagrass (Paspalum notatum L.), a major forage crop in Florida, did not respond to added P fertilizer even though preplant Mehlich‐1 (M‐1) soil test indicated very low extractable P (<10 mg/kg). Selected extractants for soil P were statistically compared to improve the predicted need for P fertilization. A separate field study was used to provide yield and nutrient uptake data. The field experiment was arranged in a randomized complete block design with four replications on a Myakka fine sand (hyperthermic aeric Haplaquod). Plots were fertilized in March of 1989 and 1990 with 0,17, 34, 51, and 68 kgP/ha. Soil samples were taken from the Ap horizon (0 to 15 cm) in January, 1990. Extractants included iron hydroxide impregnated filter paper (Pi), anion exchange resin (trimethyl benzyl ammonium active group), M‐1, Mehlich‐3 (M‐3), and water. There was a high correlation between Pi and the resin procedures (r2 = 0.96). These methods gave higher extractable P values compared ...

Comparing tests for soil fertility: 1. Conversion equations between olsen and mehlich 3 as phosphorus extractants for 120 soils of south italy

Abstract The multiple‐element extractant Mehlich 3 (M3) has not been tested extensively in Europe. In this Land, soil‐P test recommendations are based, since decades, on the evaluation of the Olsen‐extractable P, and the optimal soil‐P levels have been established to range between 1.5 and 3.0 mg of Olsen‐P per 100 g of soil. A research programme was started in order to assess the suitability of M3 as routine soil‐P test in European laboratories. As a first approach, we develop conversion equations from Olsen‐P to M3‐P, in order to assess the agreement and the consistency of the measurements under a wide range of chemical and physical soil properties. To this aim, 120 samples with drastically contrasting features were selected within 206 soils collected from all the regions of South Italy. Soil‐P ranges were 0.07–60.53 for M3, and 0.08–21.47 mg/100 g for Olsen. The results showed that M3‐P was a P extractant more efficient than Olsen. The amounts of M3‐P were, on the average, twice as large as the Olsen‐P ...

Comparison of mehlich‐1 and mehlich‐3 extractable soil boron with hot‐water extractable boron

Abstract The standard hot water extractant for soil boron (B) was compared with two extractants currendy in use by routine soil testing laboratories, Mehlich‐1 (M‐1) and Mehlich‐3 (M‐3). If routine extractants could be used for B, it would save the time and expense required for a separate extraction. Six states (Delaware, Maryland, Virginia, North Carolina, South Carolina, and Georgia) each selected 100 soil samples sent by growers to their State laboratories which were analyzed for routine properties (pH, P, K, Ca, Mg, and organic matter) and B by M‐1 or M‐3. The samples were then analyzed for hot‐water B (HWB) using a plastic pouch procedure and inductively‐coupled plasma emission spectrometry (ICP). M‐3 extracted more B than M‐1, and the correlation coefficients for M‐3 B with HWB were higher (r = 0. 82∗∗) than were M‐l with HWB (r = 0. 74∗∗). Correlations of soil properties with M‐l and M‐3 B were higher than with HWB, but none were notable with two exceptions. Extractable Ca was positively correlated...

Evaluation of four soil test extractants for Zimbabwe soils

Abstract The objective of this research was to compare the results from anion exchange Resin extraction of P, and the acidified ammonium acetate (AA) extraction of K and Mg with the results obtained using two single extraction procedures, Mehlich 1 (M‐l) and Mehlich 3 (M‐3). Phosphorus extracted from 72 Zimbabwe soils using M‐l and M‐3 was comparable to Resin extracted P in about 80% of the soils. Mehlich 1 extracted about half the amount of P as the Resin method, and M‐3 extracted about one and one‐half times as much. Phosphorus by M‐3 was highly correlated, (r — 0.846), with Resin extracted P from soils having 0.01M CaCl2 pH values of equal to or greater than 5.9. On soils less than pH 5.9, the r value was 0.502, and for all soils, the r value for M‐3 vs Resin P was 0.615. Mehlich 1 extracted P vs Resin P had a r value of 0.298. Acidified ammonium acetate (AA) extraction of K and Mg was comparable to M‐l and M‐3 extraction of K and Mg in 92% or more of the 72 soils. The K correlation coefficient (r) for AA vs M‐l and AA vs M‐3 was 0.918 and 0.944, respectively. The Mg correlation coefficient (r) for AA vs M‐l and AA vs M‐3 was 0.940 and 0.962, respectively.

Comparison of mehlich 1 and mehlich 3 extractants for P, K, Ca, Mg, Mn, Cu and Zn in atlantic coastal plain soils

Abstract The Mehlich 3 (M3) extractant was introduced in 1981 to improve the efficiency of soil testing laboratories by eliminating the need for multiple extractants for P, K, Ca, Mg, Mn, Cu and Zn. The M3 was also intended to be suitable for a wide range of soils, perhaps to serve as a “universal”; soil test extractant. At present, regional soil testing committees throughout the U.S. are investigating the M3 in this regard. Development of a field calibration data base for a new soil testing extractant is an essential, but expensive and time‐consuming process. An interim measure is the use of conversion equations between new and current extractant(s). These equations allow for use of the new extractant with existing field calibration data. The objectives of this study were (i) to develop conversion equations for the Mehlich 1 (M1) and M3 extractants for Atlantic Coastal Plain soils, and (ii) to determine the influence of soil pH and organic matter content on the relative extractability of P, K, Ca, Mg, Mn...

Evaluation of the modified olsen extracting reagent for Copper, Zinc and Manganese

Abstract The Modified Olsen (MO) extracting reagent is used extensively as a soil test extractant in Latin America. Little correlation or calibration research hasbeenreportedonit, however, especially for the micronutrients. wheat, corn, and soybeans were grown successively in the greenhouse to evaluate Cu, Zn, and Mn, respectively. Lime and micronutrient variables (one micronutrient per crop) were imposed on six soils representing four orders. After each cropping the soils were extracted with MO and with three other extracting reagents for which there are referenced critical levels: Mehlich‐1 (Ml), Mehlich‐3 (M3) and Soltanpour‐Schwab (SS). The correlations between nutrient uptake and the concentrations extracted were fairly similar for the four solutions, but were better for Mn and Zn than Cu. The poor relationship for Cu occurred partly because a maximum wheat concentration of about 10 mg/kg was reached, creating a curvilinear function. The amounts of nutrients extracted by the four reagents were also w...

Retention of Cadmium by Several Soils of the Southeastern United States

AbstractSince significant entry of Cd into the food chain is undesirable, soil properties important in reducing plant availability of Cd must be identified. Solubility of applied Cd in various extraction solutions is one estimate of plant availability. Cadmium nitrate was applied at rates supplying up to 1.25 mmol Cd kg−1 (140 mg kg−1) to soil from the A horizons and some B horizons of 10 mineral and three organic soils. The treated soils were incubated at 20 °C and at the end of 2, 4, and 8 weeks samples were withdrawn and extracted with 1 M KCl, Mehlich 1 (M1), and 0.2 M (NH4)2C2O4 [AO]. Length of incubation had no effect on the quantity of Cd removed by the extractants (extractability). Extractability was related linearly to Cd application rate but the effect of soil type on slope (extractable Cd/applied Cd) was more pronounced with KCl (110% variation in slopes) and AO (270%) than with M1 (27%). At the 1.25 mmol Cd kg−1 rate, KCl‐extractable Cd decreased with increasing pH but differences among soils were large. Stepwise multiple regression was performed using sand; silt; clay; pH; cation exchange capacity (CEC); exchangeable cations; organic matter; dithionite‐extractable Al and Fe; and AO‐extractable Al, Fe, and Mn as independent variables. Exchangeable Ca and pH were important soil properties related to extractability with the three extractants but values of R2 were &lt; 0.8 even for three‐variable models. Since pH was the dominant factor, the data were grouped into pH increments of 0.5 and regression repeated. Exchangeable Ca, CEC, and dithionite‐extractable Al were important factors related to extractability, but values of R2 were &lt; 0.6. Overall, the ability to estimate extractability from basic soil properties was low.

Residual Effect of Manganese Fertilization

The residual effect of Mn fertilization is not well quantified. This study was initiated to evaluate the change in extractable Mn following an application in order to improve the soil test interpretation and recommendation for this nutrient. Manganese was broadcast and incorporated in 1979 at 0, 30, and 90 kg ha−1 at seven locations which had low native Mn levels. Two extractants, Mehlich 1 (M1) and Mehlich 3 (M3), were used to extract Mn from samples of these soils annually for 5 yr. Samples from four locations were retained and extracted simultaneously in 1986. Native Mn averaged just over 8 kg ha−1 by the two methods, but was not consistent among years and locations. Values for simultaneous analysis in 1986 were more consistent but extractable Mn increased with time of storage, introducing another variable. Native Mn was averaged across years to adjust the extractable Mn levels of samples from the two fertilized treatments at each location. Effects of fertilization and time were evaluated with an empirical model; 43 and 52% of the rate applied was predicted to be extractable immediately after application with M1 and M3, respectively, then extractable Mn decreased exponentially with time. According to the model developed, if 14 kg ha−1 had been applied, it would take 6 and 8 yr with the M1 and M3 extractants, respectively, to reduce the concentration to within 1.0 kg ha−1 of the native level.

Calibration of a Manganese Availability Index for Soybean Soil Test Data

The soybean (Glycine max (L.) Merr.) plant is quite sensitive to Mn deficiency. Most recommendations for Mn fertilization in the Southeastern United States are currently based on Mehlich 1-extractable Mn and soil pH. Other extractants are now being used and calibration data on each is needed. Also, a single expression to simplify the interpretation of soil test results would be helpful. Two extractants, Mehlich 1 (M1) and Mehlich 3 (M3), were evaluated for their ability to predict Mn availability for soybeans. Yield and plant data from 38 experiment-year field studies were used to relate soil conditions to yield response and plant Mn concentration. Prediction of these factors was improved by inclusion of soil pH with extractable Mn in models, and the coefficients of determination were similar for the two extractants. The critical level of soil Mn varied with pH. At pH 6 and 7 the critical levels were 4.7 and 9.7 mg Mn L−1 for the M1 extractant and 3.9 and 8.0 mg Mn L−1 for the M3 extractant, respectively. The data indicated that coarser textured soils may have a lower critical level than finer textured ones, particularly with the M1 extractant. An availability index was developed to give a single number for interpretation. The critical level was set at an availability index of 25. As this value becomes less than 25, yield responses to Mn fertilization increase and leaf Mn concentrations decrease below 22 mg kg−1.

Mehlich 3 soil test extractant: A modification of Mehlich 2 extractant

Abstract The objectives of this study were to modify the Mehlich 2 (M2) extractant to include Cu among the extractable nutrients, retain or enhance the wide range of soils for which it is suitable and minimize it's corrosive properties. The substitution of nitrate for chloride anions and the addition of EDTA accomplished those objectives. The new extracting solution, already designated Mehlich 3 (M3) is composed of 0.2N CH3COOH‐0.25N NH4N03‐0.015NNH4F‐0.013NHN03‐0.001M EDTA. Extractions from 105 soils using M3, M2, Bray 1 (Bl) and Ammonium Acetate (AA) were compared to evaluate the new extractant. The quantity of F extracted by M3 exceeded that by M2 20% and that by Bl 4% but the results from all extractions were highly correlated. Extractions of both K and Mg by M3 were 6–8% higher than those by AA and 3–4% higher than those by M2, but, again, there was high correlation among methods. Addition of EDTA increased Cu extractions by 170%, Mn by 50% and Zn by 25%. Cu extractions by M3 correlated with those fr...

Evaluation of the Need for Copper with Several Soil Extractants1

AbstractCopper deficiencies have been observed in a number of crops grown on both organic and mineral soils in the Atlantic Coastal Plain. In order to recommend fertilization correctly, soil test calibrations are needed for the extractants used in the region. Soybeans (Glycine max), corn (Zea mays), and wheat (Triticum aestivum) were grown in the greenhouse on 15 soils fertilized with Cu at several rates. Percent maximum yield for the plant growth on each untreated soil was calculated from the dry matter produced. Four soil extractants were used: Double acid (DA); Mehlich‐Bowling (MB); Ammonium bicarbonate‐DTPA (AB); and Mehlich‐3 (M3). Percent maximum yield was expressed as a function of Cu released from the untreated soils by each extractant with a linear plateau model. The extractants performed similarly in explaining plant response, with each accounting for about 70% of the variation. The soil critical levels, determined by the junction of the response and the plateau portions of the surface, for DA, MB, AB, and M3 were similar among crops and averaged 0.26, 0.62, 0.53, and 0.37 mg L−1 Cu, respectively. Wheat and soybeans were also grown in the field on seven soils with two rates of Cu. Grain yields of the two crops were related to MB extractable Cu with the Cate‐Nelson method, which indicated a critical level of 0.70 mg L−1. Critical whole plant and leaf Cu concentrations were also determined. The critical whole plant Cu concentrations for soybeans, corn, and wheat, each grown 5 weeks in the greenhouse, were 3.8, 1.8, and 3.8 mg kg−1, respectively. Deficiency symptoms developed on corn and wheat at slightly lower values, 1.5 and 2.9 mg kg−1, respectively. In the field, the critical leaf concentrations at early flowering were 6 mg kg−1 for soybeans and 4 mg kg−1 for wheat.