Mehlich 3 as a generic soil test extractant for environmental phosphorus risk assessment across Alabama soil regions

Bhatta, Anjan; Prasad, Rishi; Chakraborty, Debolina; Shaw, Joey N.; Lamba, Jasmeet; Brantley, Eve; Torbert, H. Allen

doi:10.1002/agg2.20187

Cited by 4 publications

(2 citation statements)

References 36 publications

(79 reference statements)

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“…Soil samples were dried overnight and soil nutrients concentration was determined using Mehlich III extraction (28). Briefly, 2.5 g of soil were sieved through a 0.5 mm screen (10 mesh) into an extraction tube (125 mL).…”

Section: Soil and Leaf Nutrient Analysismentioning

confidence: 99%

Effect of fabric mulch ground covers on lemon trees rhizosphere microbiome in Florida flatwood soils

Santiago

Fox²,

Guzmán³

et al. 2023

Front. Soil Sci.

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IntroductionThe rhizosphere community composition has been shown to provide benefits in nutrient acquisition and plant health. Rhizosphere communities can be heavily influenced by cultural practices in citrus production systems, providing benefits in soil and root health, and plant physiology. Florida growers are implementing new and more sustainable soil management practices, such as using fabric mulch ground covers to improve weed and pest control, while retaining soil moisture. Little is known regarding the influence of these ground covers on the rhizosphere microbial communities of lemon trees, especially under endemic Huanglongbing pressure. Understanding how lemon roots and the rhizosphere microbiome are influenced by fabric mulch ground covers can potentially lead to improved management practices. The aim of this research was to evaluate the effects of fabric mulch ground covers on lemon tree rhizosphere health.MethodsThe experiment was conducted in a commercial citrus grove located in Fort Pierce, FL, US. Plant material consisted of four-year old lemon trees cv. ‘Meyer’ (Citrus limon) grafted on ‘sour orange’ (Citrus × aurantium) rootstocks. The experiment consisted of two treatments, which included trees grown with fabric mulch ground covers and trees grown without fabric mulch ground covers. Rhizosphere DNA was extracted, sequenced, and analyzed to assess differences in diversity and composition (alpha and beta diversity) of rhizosphere bacteria among treatments.Results and DiscussionObtained results showed that lemon trees treated with fabric mulch ground covers had significantly greater rhizosphere bacterial diversity when compared to the uncovered trees. The presence of fabric mulch ground covers resulted in significantly greater soil Zn, soil Mn, soil temperatures and pH, potentially contributing towards the significant more diverse rhizosphere bacterial commu nity composition compared than those grown without fabric mulch ground covers.

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Section: Soil and Leaf Nutrient Analysismentioning

confidence: 99%

Effect of fabric mulch ground covers on lemon trees rhizosphere microbiome in Florida flatwood soils

Santiago

Fox²,

Guzmán³

et al. 2023

Front. Soil Sci.

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“…The cores were later pooled to form one 1 L sample per plot, which were later dried overnight. The nutrient concentrations were determined using Mehlich-3 extraction [29]. Approximately 25 mL of Mehlich III extractant solution (0.2 M CH 3 COOH + 0.015 M NH 4 F + 0.013 M HNO 3 + 0.001 M EDTA + 0.25 M H 4 NO 3 ) was pipetted into an extraction tube containing the dry soil samples of 2.5 g (±0.05).…”

Section: Soil Nutrient Temperature and Moisure Analysismentioning

confidence: 99%

Impacts of Oak Mulch Amendments on Rhizosphere Microbiome of Citrus Trees Grown in Florida Flatwood Soils

Santiago,

Hallman,

Fox

et al. 2023

Microorganisms

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Rhizosphere interactions are an understudied component of citrus production. This is even more important in Florida flatwood soils, which pose significant challenges in achieving sustainable and effective fruit production due to low natural fertility and organic matter. Citrus growers apply soil amendments, including oak mulch, to ameliorate their soil conditions. Thus, the aim of this research was to evaluate the effects of oak mulch on citrus nutrient uptake, soil characteristics, and rhizosphere composition. The plant material consisted of ‘Valencia’ sweet orange (Citrus × sinensis) trees grafted on ‘US-812’ (C. reticulata × C. trifoliata) rootstock. The experiment consisted of two treatments, which included trees treated with oak mulch (300 kg of mulch per plot) and a control. The soil and leaf nutrient contents, soil pH, cation exchange capacity, moisture, temperature, and rhizosphere bacterial compositions were examined over the course of one year (spring and fall 2021). During the spring samplings, the citrus trees treated with oak mulch resulted in significantly greater soil Zn and Mn contents, greater soil moisture, and greater rhizosphere bacterial diversity compared to the control, while during the fall samplings, only a greater soil moisture content was observed in the treated trees. The soil Zn and Mn content detected during the spring samplings correlated with the significant increases in the diversity of the rhizosphere bacterial community composition. Similarly, the reduced rates of leaching and evaporation (at the soil surface) of oak mulch applied to Florida sandy soils likely played a large role in the significant increase in moisture and nutrient retention.

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A machine learning approach to predicting plant available phosphorus that accounts for soil heterogeneity and regional variability

Hall,

de Santana,

Grunsky

et al. 2023

J Soils Sediments

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Purpose Mehlich-3 extractable P, Al, Ca, and Fe combined with pH can be used to help explain soil chemical processes which regulate P retention, such as the role of Al, Ca, Fe, and pH levels in P fixation and buffering capacity. However, Mehlich-3 is not always the standard test used in agriculture. The objective of this study is to assess the most reliable conversion of Mehlich-3 Al, Ca, Fe, and P and pH into a commonly used soil P test, Morgan’s P, and specifically to predict values into decision support for fertiliser recommendations. Methods A geochemical database of 5631 mineral soil samples which covered the northern area of Ireland was used to model soil test P and P indices using Mehlich-3 data. Results A random forest machine learning algorithm produced an R2 of 0.96 and accurately predicted soil P index from external validation in 90% of samples (with an error range of ± 1 mg L−1). The model accuracy was reduced when predicted Morgan’s P concentration was outside of the sampled area. Conclusions It is recommended that random forest is used to produce Mehlich-3 conversions, especially when data covers large spatial scales with large heterogeneity in soil types and regional variations. To implement conversion models into P testing regimes, it is recommended that representative soil types/geochemical attributes are present in the dataset. Furthermore, completion of a national scale geochemical survey is needed. This will enable accurate predictions of Morgan’s P concentration for a wider range of soils and geographical scale.

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Mehlich 3 as a generic soil test extractant for environmental phosphorus risk assessment across Alabama soil regions

Cited by 4 publications

References 36 publications

Effect of fabric mulch ground covers on lemon trees rhizosphere microbiome in Florida flatwood soils

Effect of fabric mulch ground covers on lemon trees rhizosphere microbiome in Florida flatwood soils

Impacts of Oak Mulch Amendments on Rhizosphere Microbiome of Citrus Trees Grown in Florida Flatwood Soils

A machine learning approach to predicting plant available phosphorus that accounts for soil heterogeneity and regional variability

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