Changes in humic substances content in prolonged turf formation of dark chestnut soil in an irrigated orchard.

摘要

Studies were conducted in Ukraine, using plum [Prunus domestica] cultivars Kirk and Vengerka ital'yanskaya, grafted on Prunus divaricata rootstock. Data over a period of 14 years were collected. Plots were set up on dark chestnut light solonetz light clayey soil on loess. The ground cover treatments studied were black fallow (control), Medicago sativa + Festuca pratensis and Agrostis stolonifera. Data on humic substances content in soil layers and carbon fractions of humic substances are tabulated. Use of fodder crops as ground cover resulted in an accumulation of 11-20% of humic substances as compared to the control. The highest accumulation of humic substances was achieved in the M. sativa + F. pratensis treatment (32.5 t/ha in the 0-100 cm layer).