Effect of acidifying amendments on P availability in calcareous soils

Abstract

Phosphorus (P) reactions in calcareous soils limit the concentration of P in the soil solution for plant uptake. Calcareous soils with high calcium carbonate content (CaCO3) and high pH have low P fertiliser efficiency, leading to crop deficiency and limited crop productivity. The aim of this work was to test if soil acidifying amendments could reduce soil pH and improve the solubility of fertiliser P to improve crop P nutrition and biomass. Three calcareous soils with varying CaCO3 content (14–29% w/w) were used to test acidifying amendments both with and without mono-ammonium phosphate (MAP). Soil was amended with oxalic acid, sulfuric acid, glucose, ammonium sulfate and elemental sulfur (S0). Initial titrations demonstrated the ability of oxalic and sulfuric acids to reduce pH and improve P solubility in all three soils. Incubation of the acidifying amendments in the soil with the lowest carbonate content over 14 days (52 days for S0) showed increased P solubility and diffusion from MAP granules in soil amended with glucose, sulfuric acid and oxalic acid. There was, however, no improvement in P fertiliser uptake in wheat crops grown in these highly calcareous soils.

Synthesis and characterization of a dental cement based on bioactive glass/zinc oxide modified with organic resin as a novel pulp capping agent

“…Assessment of the alkalinity/acidity of the solutions showed a reduction in pH in groups containing hemaphosphate which can be related to the release of more phosphorus ions in these groups. Phosphorus ions can acidify the solution [30], such that the two groups containing HEMA phosphate in to BG a trend towards neutrality compared with the group containing BG alone. The alkaline environment in the MTA group is due to the release of a large amount of calcium ions.…”

The Impacts of Salt Affected Soil on Soil and Plant Growth and Management Options with Organic and Inorganic Amendments A: Reviewv

“…Elemental S, when oxidized by soil microbes and combined with water, reacts to form sulfuric acid (H2SO4), which reacts with naturally occurring Ca2+ carbonate (CaCO3), releasing "free" Ca2 + . This Ca2 + in the soil solution can then exchange for Na + in the form of Na2SO4, which can be leached from the soil (Brownrigg, 2022).…”

“…BFs are one kind of fertilizer that contains living cells from various microorganisms and can transform via biological mechanisms; nutrients are converted from the inaccessible to the accessible form. Recently, many studies have described the potential of BF in salt tolerance enhancement (Brownrigg, 2022). The application of BF in wheat seedlings lessened the negative effects of salinity by increasing chlorophyll content and decreasing proline content, and improved plant growth and yield.…”

In recognition of Mike Hedley: fate of fertiliser in soil and mobilisation of recalcitrant nutrients

“…All the papers are focused on P and have often used the P fractionation technique. However, much like the diversity of topics covered over Mike's career, these papers cover topics such as: minimising P losses from fertiliser to water (Wang et al 2022); improving the efficiency of P use in grassland and cropping systems (Bilotto et al 2022;Bouray et al 2022;Hu et al 2022;Schwerdtner et al 2022;Touhami et al 2022), assessing the effect of different amendments on the availability of P in the soil (Brownrigg et al 2022;Kruse et al 2022); and fertiliser value of waste streams (Battisti et al 2022).…”