Short- and Long-Term Effects of Lime and Gypsum Applications on Acid Soils in a Water-Limited Environment: 3. Soil Solution Chemistry

Aluminum (Al) toxicity imposes a significant limitation to crop production in South Western Australia. This paper examines the impact of surface-applied lime and gypsum on soil solution chemistry short term (1 year) long-term (10 years) water limited environments. In experiments, we measured using paste extract profile samples collected depth 50 cm. We then used chemical equilibrium model MINTEQ predict presence relative concentrations Al species that are toxic root growth (Al associated with Al3+ AlOH2 or Toxic-Al) less non-toxic forms bound sulfate, other hydroxide organic matter. A feature soils experiment is they have low capacity adsorb sulfate. term, despite amount rainfall (279 mm), sulfate derived from surface application rapidly leached into profile. There was no self-liming effect, as evidenced by there being change pH. The gypsum, increased ionic strength 524–681% 0–10 cm layer declining 75–109% 30–40 due an increase calcium concentrations. Calcium displaces exchange sites activity treatments 155–233% 70–196% long 40 However, effect Toxic-Al precipitation. leaching results decline strength. Application alkalinity leading decreased 30 but it did not affect term. Combining had same properties alone