Leaching of plant nutrients from cultivated soils: II Leaching of anions

Abstract

Abstract. Leaching of anions from three soil samples (sand, fine sand and sandy clay) representing the plough layer was studied in a lysimeter experiment under conditions corresponding to the fallow. The effect of fertilization and that of acid irrigation solution on the amounts of anions washed out was also studied.The extraction of anions from different soils seems to correspond to that of cations; the coarser the soil, the higher the nutrient losses. This was valid for nitrate and sulfate, but the amounts of phosphate extracted were insignificant. The sum of the anion equivalents leached was lower than the respective sum of cations in all the leachates indicating that a part of the cations was leached as bicarbonate.The physical properties of the soil regulating the infiltration of water affect the movement of anions bonded non-specifically. The anions in pores of soil aggregates seem to be protected against leaching to a certain degree. However, the biological value of an anion is an important factor. It seems that microbiological processes may decrease the leaching losses of nitrate.

Leaching of Phosphorus, Calcium, Magnesium and Potassium in Barley, Grass and Fallow Lysimeters

“…Therefore, most of the phosphorus is adsorbed to soil particles and is transported to watercourses by surface runoff waters (Ekholm et al, 1991;Catt, 1993;Turtola, 1993). However, particulate phosphorus can also be transported with dispersed clay and colloidal soil particles in percolation water (Hartikainen, 1978a;Catt, 1993).…”