Mehlich-1 Extractants Research Articles

Mobility and Availability to Plants of Two Zinc Sources Applied to a Calcareous Soil

The objective of this study was to compare the migration, availability, and relative effectiveness of Zn from liquid Zn-amino acids (Zn-AA) and Zn-DTPA-HEDTA-EDTA (Zn-CH: DTPA, diethylenetriaminepentaacetate; HEDTA, N-2-hydroxyethyl-ethylenedinitrilotriacetate; EDTA, ethylenedinitrilotetraacetate) sources by applying different Zn levels to a calcareous soil in incubation, column, and greenhouse experiments. Zinc soil behavior was evaluated by sequential fractionation, and DTPA and Mehlich-3 extractions. The results of the incubation study showed that amounts of Zn in the most labile fraction (water soluble plus exchangeable) were detected only when Zn-CH fertilizer was applied. A large portion of Zn applied to soil occurred in the amorphous Fe oxide bound fraction in all fertilization treatments. The results of the column study showed that addition of Zn-CH resulted in greatly increased mobility of Zn through the column as compared with the control and the Zn-AA source, and 49% of Zn applied as Zn-CH was leached from the column. The results of the greenhouse study showed in the absence of leaching that the application of two Zn sources significantly increased maize (Zea mays L.) dry matter yield compared with the control treatment although the increase in the Zn dosage did not increase dry matter further. The fertilizer treatments also significantly increased Zn concentration in plants, except the lowest dosage of Zn-AA. Zn-CH was more effective than Zn-AA. The differences in plant Zn uptake in the greenhouse experiment between two Zn sources was correlated with the water soluble plus exchangeable fraction and DTPA extractable Zn in the incubation experiment.

Phosphorus extractants for forest species of different successional groups

The Mehlich-1, Mehlich-3, and ion-exchange resin (IER) extractants were compared for their ability to assess phosphorus (P) bioavailability. Five P doses (0, 100, 250, 500, and 800 mg dm−3) were applied into a Humic Rhodic Haplustox. Seedlings of pioneer and climax tree species were grown under greenhouse conditions. After 90 days, the plants were harvested and the shoot dry matter, the P content, and the P utilization efficiency were determined. Plant growth was affected by P availability with differences among successional groups and species. The extractants presented similar performance regarding the P availability determination. For the pioneer species, which have faster growth rates, it was found a significant relationship between dry matter yield, P content, and soil available P for all extractants. On the other hand, the climax species, which have slower growth rates, showed low responses to soil P status. The kind of response to nutrient furnishment seems to be conditioning the predictive efficiency of the soil testing procedures for different forest species.

Evaluation of Mehlich-1 and Mehlich-3 extraction procedures for plant nutrients in acid mineral soils of Florida*1

Increasing number of soil testing laboratories in the mid-Atlantic and southeastern states of the United States are adopting Mehlich-3 (M-3) as the official extraction procedure in place of Mehlich-1 (M-1) or the dilute double acid method. Several studies have indicated that the M-3 has at least equivalent if not better extractability, particularly of micronutrients in the acidic and mineral soils in these regions. The objective of this study was to determine the correlation between the two Mehlich procedures and to provide conversion equations from M-1 to M-3 procedure. This is expected to serve as an estimate of nutrient availabilities particularly by the extension personnel and crop professionals evaluating different test procedures. A set of 519 mineral soil samples received at the UF/IFAS Extension Soil Testing Laboratory were selected and assayed with both M-1 and M-3 extracting solutions. The concentrations of phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), copper (Cu), zinc (Zn), manganese (Mn), and boron (B) in the extracted solutions were determined and comparative equations were developed. Highly significant linear correlation coefficients were found for all the nutrients extracted with both M-3 and M-1. Acidic to near neutral soil pH range of the soils had no influence on the efficiencies of extraction solutions. The equations developed showed that P, Cu, Mn, and B extracted were 47%, 94%, 101%, and 111% more with M-3 than with M-1 while for K, Mg, and Zn generally remained the same for both methods. *This work was supported in part by Caisse Nationale de l'Assurance Maladie des Travailleurs Salariés—Institut National de la Santé et de la Recherche Médicale (CNAMTS INSERM) grant no. 3 AM 055 Paris, France, Association pour la Recherche sur le Temps Biologique (A.R.T.B.C.), Villejuif, France, and Compagnie de Développement Aguettant, Lyon, France.

Relationships between biosolids treatment process and soil phosphorus availability.

Laws mandating phosphorus (P)-based nutrient management plans have been passed in several U.S. Mid-Atlantic states. Biosolids (sewage sludge) are frequently applied to agricultural land and in this study we evaluated how biosolids treatment processes and biosolids P tests were related to P behavior in biosolids-amended soils. Eight biosolids generated by different treatment processes, with respect to digestion and iron (Fe), aluminum (Al), and lime addition, and a poultry litter (PL), were incubated with an Elkton silt loam (fine-silty, mixed, active, mesic Typic Endoaquult) and a Suffolk sandy loam (fine-loamy, siliceous, semiactive, thermic Typic Hapludult) for 51 d. The amended soils were analyzed at 1 and 51 d for water-soluble phosphorus (WSP), iron-oxide strip--extractable phosphorus (FeO-P), Mehlich-1 P and pH. The biosolids and PL were analyzed for P, Fe, and Al by USEPA 3050 acid-peroxide digestion and acid ammonium oxalate, Mehlich-1, and Mehlich-3 extractions. Biosolids and PL amendments increased extractable P in the Suffolk sandy loam to a greater extent than in the Elkton silt loam throughout the 51 d of the incubation. The trend of extractable WSP, FeO-P, and Mehlich-1 P generally followed the pattern: [soils amended with biosolids produced without the use of Fe or Al] > [PL and biosolids produced using Fe or Al and lime] > [biosolids produced using only Fe and Al salts]. Mehlich-3 P and the molar ratio of P to [Al + Fe] by either the USEPA 3050 digestion or oxalate extraction of the biosolids were good predictors of changes in soil-extractable P following biosolids but not PL amendment. Therefore, the testing of biosolids for P availability, rather than total P, is a more appropriate tool for predicting extractable P from the biosolids-amended soils used in this study.

EFICACIA DE CUATRO EXTRACTANTES EN LA EVALUACIÓN DE LA DISPONIBILIDAD DE COBRE PARA MAÍZ Y SOJA

El presente trabajo se llevó a cabo en invernadero con el objetivo de comparar la eficacia de cuatro métodos de extracción: Mehlich-3, Mehlich-1, DTPA y AB-DTPA para evaluar el contenido de Cu disponible para maíz y soja. Se emplearon 61 muestras superficiales de suelo de diversas regiones del Estado de São Paulo para el experimento de maíz y 59 para soja. Se aplicaron nutrientes a las muestras de suelo de tal modo que aquellas que presentaban contenidos de Cu bajos (<0,2 mg.dm-3) extraídos con DTPA, se separaron en dos tratamientos: completo - que recibió todos los nutrientes e además 1 mg.dm-3 de Cu en la forma de sulfato de cobre y completo menos cobre que no recibió Cu, mientras que no se aplicó Cu a las muestras que contenían más de 0,2 mg.dm-3 de Cu. Considerando la totalidad de las muestras, las disoluciones AB-DTPA y Mehlich-3 presentaron mayor capacidad de extracción para el maíz, mientras que para la soja resultó ser el Mehlich-3. Las correlaciones, entre métodos, en las muestras de suelo, fueron muy significativas (p > 0,01), resultando siempre superiores para el maíz en comparación con los valores obtenidos para la soja. Además, se evaluó la eficacia de cada una de las disoluciones, considerando el contenido de Cu en la parte aérea de la planta, siendo el Mehlich-3 ligeramente superior en la evaluación de la disponibilid del Cu disponible, en los tratamientos completo y completo menos cobre, así como para ambos cultivos.

Data presentation, interpretation, and communication

Mehlich 2 (M2) and DTPA extractants have been used for soil testing in the Czech Republic for more than ten years. The objective of this study was to compare M2, DTPA and Mehlich 3 (M3) extractants for the determination of available nutrients (phosphorus, potassium, magnesium, calcium) and micronutrients (copper, zinc, iron, manganese) in Czech agricultural soils. For comparison of M2 and M3 extractants for nutrients 2799 agriculture soils were collected (311 light soils, 1889 medium soils, 599 heavy soils, 369 soils with carbonate content higher than 5%). For comparison of DTPA and M3 extractants for micronutrients 95 soils were collected. The soil samples represented all major soil types, climatic regions and proportion of agronomic cultures in the Czech Republic. Highly significant correlations were found between M2 and M3 for all nutrients (correlation coefficients in the range 0.97–0.99) and between DTPA and M3 for copper and zinc, (correlations coefficients in the range 0.86–0.88). For iron and manganese the correlation was also highly significant but not suitable for recalculation of the criteria. The determination of iron and manganese by M3 extracting solution would need more precise calibration of the method based on field and pot experiments. For all other elements conversion equations can be used instead of a new expensive and time‐consuming field calibrating study.

Calagem e adubação fosfatada para o arroz em solos inundados: I. teores de ferro e fósforo nos solos

A dinâmica do P em solos e sedimentos inundados tem grande significado ambiental e parece estar fundamentalmente associada às reações de oxirredução dos compostos de ferro. Com o objetivo de verificar os efeitos da calagem e da adubação fosfatada nos teores de Fe e P no solo, amostras de nove solos de várzeas do estado de Minas Gerais foram tratadas com dois níveis de calcário e seis níveis de fósforo. Após um período de incubação aeróbica, foram determinados os teores de Fe e P dos solos por extração com acetato de amônio, Mehlich-1 e oxalato de amônio. Os solos foram, então, inundados, determinando-se, periodicamente, os teores de fósforo pelo uso do papel aniônico. Verificou-se que a calagem e a adubação fosfatada tenderam a diminuir os teores de Fe e aumentar os teores de P extraível por acetato de amônio e pelo Mehlich-1. Em amostras recentemente inundadas, a calagem tendeu a aumentar o fósforo determinado pelo papel aniônico, ao passo que o contrário ocorreu após maior período de inundação das amostras de solo.

Comparison of Mehlich 3‐ and bray 1‐extractable phosphorus levels in a Starr clay loam amended with poultry litter

Two soil tests commonly used to characterize the availability of soil phosphorus (P) are Bray P1 (B1) and Mehlich 3 (M3) extradants. The objective of this investigation was to compare M3‐ and B1‐extractable P levels in a Starr clay loam (fine‐loamy mixed thermic Fluventic Dystrochrepts) amended with relatively low to high surface applications of poultry litter (PL). The following eight treatments were applied to the soil for pasture renovation in 1991 and 1992: 1) a control, 2) P application as monocalcium phosphate [Ca(H2PO4)2‐H2O], 3) P application as Ca(H2PO4)2‐H2O and nitrogen (N) application as ammonium nitrate (NH4NO3) and urea, and 4) five levels of poultry litter (PL) based on N content. The five P levels as PL were 56.6, 113.2, 169.8, 226.4, and 283.0 kg ha‐1 in 1991, and 49.2, 98.5, 147.7, 196.9, and 246.1 kg ha‐1 in 1992, respectively. Soil samples were obtained from the 0‐ to 5‐cm layer in the spring of 1992 and 1993 for extractable P determination. Levels of P extracted from all treatments by the M3 and B1 extractants were linearly correlated both years (r2=0.96 in 1991 and r2=0.99 in 1992). However, M3 extracted more P from the PL treatments, whereas B1 extracted more P from the control, P application, and N and P application treatments. Curvilinear relationships were obtained between P uptake and levels of either M3‐ or B1‐extractable P for the PL treatments (r2=0.713 for M3 and 0.663 for B1 in 1991 and r2=0.925 for M3 and 0.933 for B1 in 1992). These close relationships in 1992 between extractable P and uptake of P for the PL‐ treated soils indicate that both the B1 and M3 extractants could be used to evaluate excess P in PL‐amended soils.

Extratores de fósforo em solos da Amazônia tratados com fertilizantes fosfatados

Com o objetivo de avaliar a disponibilidade de fósforo em amostras de solos representativos da Amazônia, desenvolveu-se um experimento em casa de vegetação do Centro de Energia Nuclear na Agricultura, Piracicaba (SP), de outubro de 1993 a março de 1994, utilizando-se amostras da camada superficial de cinco solos (LA-médio, LA-argiloso, LA-muito argiloso, PV-argiloso e PV-muito argiloso). Foram usados, como fontes de P, superfosfato triplo, termofosfato yoorin em pó, termofosfato yoorin semi-acabado e fosfato natural da Carolina do Norte, nas doses de P equivalentes a 0, 40, 80 e 120 mg kg-1 de solo. Caupi e arroz foram usados como plantas-testes, e os resultados de produção de matéria seca e de P acumulado na parte aérea foram correlacionados com os de teores de P nas amostras de cada solo. A extração de P foi efetuada por meio dos métodos da resina trocadora de ânions, Mehlich-1, Mehlich-3 e Bray-I. Os resultados obtidos demonstraram que o extrator Mehlich-1 extraiu grandes quantidades de fósforo nos tratamentos com fosfato natural da Carolina do Norte. Independentemente da fonte de fósforo utilizada, o extrator Mehlich-3 apresentou as melhores correlações com o caupi e o arroz. Os extratores Mehlich-3 e Bray-I apresentaram maior sensibilidade às variações de solo. O extrator Mehlich-3 mostrou-se adequado na avaliação da disponibilidade de fósforo para as plantas, em diferentes condições de solos e fontes de fósforo.

Potassium Source and Rate for Polyethylene-mulched Tomatoes

Tomato (Lycopersicon esculentum Mill.) was grown with polyethylene mulch at five locations during a total of nine seasons to evaluate the effects of K source and K rate on fruit yield and leaf K concentration with drip and subsurface irrigation. K sources evaluated were KCl, K2SO4, and KNO3, and K rates varied from 0 to 400 kg·ha-1. Preplant soil K concentrations by Mehlich-1 extraction on the sandy soils and loamy sands used in the study varied from 12 mg·kg-1 (very low) to 60 mg·kg-1 (medium). In seven of the eight studies, K source did not significantly influence fruit yield or leaf K concentration. In the other study with subsurface irrigation at Bradenton in Spring 1992, marketable yields were significantly higher with KNO3 than with KCl as the K source. Tomato fruit yield responded to the application of K in all studies. At Gainesville, Quincy, and Live Oak, with drip irrigation on soils testing low to medium in K, maximum yields were produced with 75 to 150 kg·ha-1 K where the K was broadcast preplant. These rates were 25% to 30% higher than those predicted by soil test. At Bradenton and West Palm Beach on soils testing low to very low in K, where all or part of the K was applied in double bands on the bed shoulder with subsurface irrigation, yield responses were obtained to 225 to 300 kg·ha-1 K. These rates exceeded the maximum recommended K rate of 150 kg·ha-1. Tomato leaf tissue K concentrations increased linearly with increased rates of K application, but were not influenced by K source. These data suggest that the recommendation for K on soils testing low in K be increased from 150 to 210 kg·ha-1 and that this increase should suffice for tomatoes grown with either drip or subsurface irrigation.

Correction of Limed‐Biosolid Induced Manganese Deficiency on a Long‐Term Field Experiment

AbstractLand application of lime‐stabilized biosolids has been reported to cause Mn deficiency in wheat (Triticum aestivum L.) and soybean [Glycine max (L.) Merr.]. Deficiencies were observed on a long‐term biosolid research experiment in Beltsville, MD, that had been established on a Galestown sand (sandy, siliceous, mesic Psammentic Hapludult) in 1976 with lime‐stabilized biosolids applied at 224 and 448 Mg ha−1. For the present study, a randomized complete block experiment was set up in plot areas of the original study. Soil amendments included MnO at 50, 100, and 200 kg ha−1, and MnSO4 at 200 kg ha−1. Plots were split with random half plots receiving a foliar application of MnSO4 at 0.5 kg ha−1 Mn. Soybean and wheat were double cropped for two seasons (1993–1995). Measured indexes of deficiency included youngest emerged blade (YEB) and grain Mn, plant chlorophyll, and yield. Wheat exhibited severe Mn deficiency for both seasons in the 224 Mg ha−1 biosolid plots. Only plants grown in the MnSO4‐amended soils were not deficient in Mn. Foliar Mn spray also alleviated Mn deficiency. Although soybean plants were not Mn deficient, plants in the MnSO4‐treated plots had higher YEB Mn concentrations. Soil extractions to reflect phytoavailable Mn, including Mehlich 1 (M1), Mehlich 3 (M3), and DTPA were conducted on moist soils. Results from M3 and DTPA extractions mirrored plant response. The M1 extraction did not predict plant response indicating that this extraction is not appropriate for predicting Mn deficiency in coarse‐textured high pH soils.

Copper geochemistry and availability in cultivated soils contaminated by a copper smelter

The average amounts of Cu forms in sixteen soils contaminated by the Glogow copper smelter (Poland) determined by means of the McLaren and Crawford sequential extraction were: Ex 0.078; AAC 11.76; PYR 69.36; OX 26.20 and RES 14.10 mg kg −1. The distribution of soil copper between different Cu fractions was not influenced by soil properties. The average total content of Cu amounted to 134.9 mg kg −1 and was highly correlated with the AAC, PYR and OX forms of Cu. Soil tests, in descending order, extracted the following amounts of Cu: HNO 3 108.6; Lindsay 50.0; Mehlich-1 46.2; HCI 44.5; Mehlich-3 11.1; NaNO 30.42 mg kg −1. All these tests were poorly related to soil properties but highly related to the total Cu content. The AAC and PYR Cu fractions influenced the amounts of Cu extracted by 1 M HCI, Mehlich-1 and Mehlich-3 extraction solutions. The other tests highly depended on AAC and RES copper fractions. Copper concentration in both roots and shoots of flax may be treated as indicative of its bioavailability from the soils studied. The 1 M NaNO 3 and Mehlich-3 chemical extractants seem to be the best predictors of plant-available copper.

Interpretation of Soil Phosphorus Tests for Corn in Soils with Varying pH and Calcium Carbonate Content

There is uncertainty about appropriate soil-test extractants and interpretations in regions with soils varying in pH and calcium carbonate content. The objective of this research was to compare extractable P using the Bray-P 1 (B1), Olsen, and Mehlich-3 (M3) extractants and to obtain soil-test interpretations for corn (Zea mays L.) in soils varying in pH and calcium carbonate equivalent (CCE). The extractants were compared by correlating the amounts of P extracted from 350 soil samples and by calibrations based on 61 field response trials. Correlations between P extracted by the B1 extractant and the Olsen or M3 extractants improved markedly when calcareous soils were excluded from the analyses. The correlation between the Olsen and M3 extractants was high and independent of soil pH. Neither soil pH, CCE, soil type, nor organic matter content completely explained the low correlations between P extracted by the B1 and the Olsen or M3 methods in high pH soils. Critical concentrations across all soils defined by the Cate-Nelson and linear-plateau models were 7 and 9 ppm for the Olsen extractant and 14 and 24 ppm for the M3 extractant. When highly calcareous soils were excluded, the critical concentrations for the B1 extractant were 11 and 20 ppm, respectively. The Olsen and M3 extractants are more reliable than the B1 for estimating plant-available P of Iowa soils over a broad range of soil pH and CCE.

EXTRACTABILITY OF ZINC, CADMIUM, AND NICKEL IN SOILS AMENDED WITH EDTA

Synthetic chelating agents are produced in large quantities for use in many industrial applications. Certain chelates, such as ethylenediaminetetraacetic acid (EDTA), are persistent in the environment. The presence of EDTA in soil may alter the mobility and transport of Zn, Cd, and Ni in soils because of the formation of water soluble chelates, thus increasing the potential for metal pollution of natural waters. Mobility of metals is related to their extractability. To investigate metal extractability affected by EDTA, Zn, Cd, and Ni were added to a portion of eight Georgia topsoil samples at rates of 75.9, 1.62, and 4.30 mg kg{sup -1}, respectively. Both natural and metal-amended soils were treated with Na{sub 2-}EDTA at rates of 0, 1.0, and 2.0 g kg{sup -1}. After 5 months of incubation, soil samples were extracted with Mehlich-1, DTPA (diethylenetriamine-pentaacetic acid) and 1 M Mg(NO{sub 3}){sub 2}, the latter of which extracts the exchangeable form of metals. Results showed that Zn and Ni in Mehlich-1 and DTPA extractions increased with increasing rates of EDTA. The increase for Cd was not as great as for Zn or Ni. Similar changes were found for the Mg(NO{sub 3}){sub 2} extraction. As a percentage of total metal concentration,more » the Mehlich-1 and DTPA extractable Zn was greater than Ni in the natural soils, and the order for the metal-amended soils was Cd > Zn > Ni. The results also suggested that EDTA significantly elevated the extractability of Zn and Ni in both natural and metal-amended soils. The order of mobility based on extractability was: Cd > Zn > Ni for metals added to soils, but when EDTA was present, added Ni was more extractable than Zn or Cd. 36 refs., 5 tabs.« less

RELATING SOIL TEST P TO P UPTAKE BY PADDY RICE

In Arkansas, the Mehlich-3 extraetant is used in the determination of soil test P for both upland and lowland crops. However, this technique does not consistently predict a response by paddy rice (Oryza sativa L.) to P fertilization. The objective of this research was to relate soil test P determined by four extractants to P uptake by paddy rice grown on two rice-producing soils. The soils in this study were a Crowley silt loam and two Hillemann silt loam samples collected from fields where P deficiencies in rice were observed the previous summer. Rice was grown on these soils in the greenhouse at fertilizer rates of 0, 5, 10, 20 and 40 mg P kg-1. Plant uptake and tissue concentrations of P were measured and related to soil test P extracted by Mehlich-3, Bray-1, Olsen, or ion exchange resin at 0, 24, 31, and 124 days after flooding (DAF). The Crowley had the highest soil test P obtained with all extractants at all flooding dates compared with the two Hillemann soil samples. Mehlich-3 and Bray-1 extractants consistently gave higher soil test P values on the Crowley soil than did Olsen and resin extractants. Only the resin showed a consistent correlation between soil test P measured at 0 DAF and % P in shoot and total P uptake measured at 24, 31, and 124 DAF. This correlation was improved when P uptake was related to soil test P measured on anaerobic soils. Although Mehlich-3 is convenient for soil test laboratories, the resin appears to be a more appropriate extractant to estimate plant available P for paddy rice.

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...

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.