The agrochemical profile of sod-podzoil heavy loam soil in a long stationary experiment

Abstract

During a stationary experiment (Perm Institute for Agrochemical Studies) in fifth rotation of an 8-field crop rotation after the 2nd year clover we studied the agrochemical profile of sod-podzoil soil for the growing dosages of mineral fertilizers (0, 30, 60, 90, 120, 150 kg of acting matter/ha). We have found that during a long term full fertilizer usage in crop rotation the main agrochemical parameters change in top layer of 0-40 cm. Increasing high dosages of fertilizers leads to soil acidation, mobile phosphorus saving in arable horizon up to 51.3 mg/100 g, and to fixation the initial humus content in variants N120Р120К120 and N150Р150К150. Profile humus distribution is decreasing, doesn’t depend on a long term experiment variants, it is common for sod-podzolic type of soil. On the l40-100 cm layer the humus composition changes weakly, it's around 0.5-0.6 %. The mobile phosphorus composition, exchangeable Ca and Mg cations is 1.5-2 times higher in depth horizons than in upper layer of 0-20 cm. Fractional humus composition is fulvate or humate fulvate, which is common for zonal genetic conditions of soil formation. Using mineral fertilizers leads to neogeic humic substances increase and expansion of relation Сha: Сfa from 0.70 on controle to 0.98 on the variant of N150Р150К150. Heavy granulometric content blocks humic acids migration lower than 40 cm. Сha /Сfa relation in the layer lower than 40 cm varies from 0.24 up to 0.50. Fulvate acids (except for FA-1 fraction) were defined in all the layers of soil up to 100 cm.

Keywords

• sod-podzoil soil
• mineral fertilizers
• agrochemical characteristics
• fractional composition of humus
• soil profile