INFLUENCE OF DRAINING AND FIELD MANAGEMENT ON CHEMICAL-PROPERTIES OF SOD-PODZOLIC WEAKLY GLEYIC SOILS, OF DRAINAGE AND SOIL WATERS

The effect of drainage proved to be conspicuous in the subarable horiz ons. It consisted in the increase of exchangeable aluminium and bases content, in the decrease of amorphous iron compounds concentrations. T he arable horizon is mainly changed by field management measures havin g produced increments in humus, mobile phosphorus, and exchangeable po tassium, as well as diminishment of all the forms of soil acidity. Dra inage waters contain more salts than the soil solution. Heavy metals c oncentration in Vorya River waters, which accumulates the drainage run off, is frequently beyond the permissible levels.