Removal of Lithium Citrate from H3A for Determination of Plant Available P

Abstract

The soil extractant, H3A, has undergone several iterations to extract calcium (Ca), iron (Fe), aluminum (Al), potassium (K), phosphorus (P), ammonium (NH 4 -N) and nitrate (NO 3 -N) under ambient soil conditions. Few soil extractants currently used by commercial and university soil testing laboratories can perform multi-nutrient extraction without over-or under-estimating at least one nutrient. Soil pH and plant root exudates have a strong influence on nutrient availability and H3A was developed to mimic soil conditions. Lithium citrate was previously used in the H3A formulation, but resulted in a cloudy supernatant in some samples, complicating laboratory analyses. In this study, we removed lithium citrate and compared the nutrients extracted from the modified (H3A-4) to the established (H3A-3) solutions. We found that the new extractant, H3A-4, produced a clear supernatant even in soils with low pH and high iron and aluminum concentrations. H3A-4 accurately predicts plant available nutrients and is a viable choice for commercial and laboratory settings due to its ease of use.

Agroecosystem management responses to Haney soil health test in the southeastern United States

“…Because WEOC and WEON contents represent the bioavailable portions of total C and N, respectively, the HSHT considers the WEOC/WEON ratio as a more sensitive indicator of soil microbial activity than the traditional total C/N ratio (Haney et al., 2012). The HSHT includes a new extractant termed H3A (Haney, Haney, Hossner, and Arnold), which was designed to mimic the chemical composition of plant root exudates (Haney, Haney, Hossner, & Arnold, 2006; Haney, Haney, Hossner, & Arnold, 2010, 2017). This extractant is a combination of three organic acids (citric acid, oxalic acid, and acetic acid) and is used to extract inorganic N (ammonium‐N [NH 4 –N] and nitrate‐N [NO 3 –N]) and other nutrients from soil.…”

Comparing Biological and Conventional Chemical Soil Tests in Long‐Term Tillage, Rotation, N Rate Field Study

“…The Haney Soil Health Test utilizes water and an organic acid extractant, H 3 A (including citric acid, malic acid, and oxalic acid), which was designed to mimic plant root exudates to accurately measure plant available nutrients (Haney et al, 2006, 2010, 2017). The Solvita test measures the CO 2 respired over 24‐h after rewetting a dried soil sample and has been proposed for use in quantifying microbial activity and mineralizable N and P (Haney et al, 2008a, 2008b, 2015).…”

Relationships between the Haney H3A and Conventional Soil Tests for Phosphorus and Potassium in Kansas Soils

“…The Haney H3A extracting solution is intended to simulate the chemistry of actively growing roots more closely (Haney et al, 2006). The H3A extracting solution is comprised of a dilute mixture of organic acids, but has undergone numerous iterations since its initial development (Haney et al, 2017). The current iteration, version 4, is comprised of malic, citric, and oxalic acids, and has a weakly buffered pH of approximately 3.75 (Haney et al, 2017).…”

“…The H3A extracting solution is comprised of a dilute mixture of organic acids, but has undergone numerous iterations since its initial development (Haney et al, 2017). The current iteration, version 4, is comprised of malic, citric, and oxalic acids, and has a weakly buffered pH of approximately 3.75 (Haney et al, 2017). The primary objectives of this study were to investigate relationships between M3 and H3A soil test P and K in selected Kansas soils.…”