Liming-Induced Changes in Phosphorus Availability and Soil–Plant Interactions in Acidic Soils

Acidic soils constitute a major constraint to agricultural productivity in Estonia, particularly in the southern regions, affecting approximately 54.5% of the country’s agricultural land. Soil acidity adversely influences nutrient availability, base saturation, and crop performance, making liming a key management practice for sustainable crop production. This study investigates the effectiveness of Corestone, a newly developed limestone-based liming material produced by grinding limestone overburden excavated during oil shale mining operations, in enhancing the chemical properties of acidic soils and improving nutrient uptake in oilseed rape (Brassica napus L.) under controlled experimental conditions.

A pot experiment was conducted using four chemically distinct acidic soils treated with Corestone at two application rates corresponding to 50% and 100% of the calculated lime requirement. Winter oilseed rape cultivar ‘Fenja’ was grown on the treated soils. Soil pH and plant-available phosphorus (P), potassium (K), magnesium (Mg), and calcium (Ca) were determined before and after the experiment. Aboveground biomass production and nutrient concentrations in plant tissue were also analysed.

Liming with Corestone resulted in a consistent increase in soil pH across all soils, with application at 100% of the lime requirement leading to neutral or near-neutral pH values. Soil calcium concentrations increased significantly following liming, particularly in the most acidic soil with the highest lime demand. Although the Ca:Mg ratio improved after treatment, optimal ratios were not fully achieved. Responses of plant-available phosphorus varied among soils, whereas potassium concentrations generally declined following liming. Soil magnesium concentrations increased in most treatments.

No statistically significant differences in rapeseed biomass were observed between liming rates; however, a clear positive trend in biomass production was evident, except in one soil. This response may be attributed to reduced micronutrient availability under elevated pH conditions. Plant tissue analysis revealed consistently low phosphorus and potassium concentrations, while calcium and magnesium concentrations were relatively high. Positive correlations were observed between changes in soil and plant phosphorus and magnesium contents. In contrast, increasing soil calcium concentrations and rising soil pH were associated with higher plant phosphorus but lower plant calcium concentrations, indicating complex nutrient interactions following liming.

Overall, the results demonstrate that Corestone is an effective liming material for alleviating soil acidity, while emphasizing the importance of soil-specific nutrient dynamics when optimizing liming strategies for oilseed rape cultivation.