Soil Calcium Carbonate Content Research Articles

Data presentation, interpretation, and communication

K, Ca and Mg concentrations in tillering stage winter wheat (Triticum aestivum L.) shoot, as well as acidic (pH 4.65) ammonium‐acetate + EDTA ‐ soluble (LE‐, Lakanen and Erviö, 1971) and neutral ammonium acetate‐ exchangeable (Wanasuria et al., 1981) soil K, Ca and Mg contents were determined for a network of 28‐year‐old National Long‐term Fertilization Trials (NLFT) with different K fertilization rates at eight experimental sites representing various agro‐ecological and soil conditions of Hungary. All the sites had the same fertilization pattern. Correlation between the two soil Ca and the two soil Mg methods, between soil and shoot Ca, and Mg, as well as between shoot K and shoot Ca+Mg contents were evaluated. Close, linear correlations were found between NH4OAc‐Ca and LE‐Ca and between NH4OAc‐Mg and LE‐Mg on non‐calcareous soils (r = 0.95). Acidic LE‐extractant dissolved significant amounts of Ca and Mg from the Ca‐ and Mg‐carbonates in the calcareous soils. Neutral NH4OAc‐Ca values increased with increasing soil calcium carbonate contents. Neutral NH4OAc‐Mg values, however, were the lowest in the calcareous soils, probably due to the large quantities of Ca2+ more strongly adsorbed to the cation exchange sites of the colloids compared to Mg2+. Exchangeable K+ values were also small in the calcareous soils, although all of the soils were loams with medium clay contents. There was a positive logarithmic correlation between soil LE‐Ca and shoot Ca (R = 0.55), and a quadratic polynomial one between soil LE‐Mg and shoot Mg contents, resp. (R = 0.45). The positive logarithmic correlation between NH4OAc‐Ca and shoot Ca was even closer (R = 0.60). However, there was no correlation between NH4OAc‐Mg and shoot Mg values. A close negative, logarithmic correlation was found between wheat shoot K contents and Ca + Mg contents (R = 0.78).

Phosphorus in calcareous soils. II.—Determination of the organic phosphorus content of calcareous soils and its relation to soil calcium carbonate content

AbstractThe organic phosphorus content of 33 calcareous soils (0.1‐52.4% CaCO3,) was determined by the ignition method and by hydrogen peroxide oxidation. Mean values for organic phosphorus expressed as a percentage of the total phosphorus were 14.5% and 15.6% for the two methods respectively, although a few individual soils showed wide differences. Organic phosphorus as n percentage of total phosphorus was significantly correlated with % CaCO3 in the soils.