Soil peroxidase and polyphenoloxidase activity under soil conservation practices on sloping terrains

Abstract

Soil water erosion in Bulgaria has a significant negative impact on the arable inclined lands. Two experiments were conducted with wheat and maize with application of traditional and soil protection technologies, on Calcic Chernozem soil, on the slope of 5°. Calcic Chernozems are soils exposed to frequent water erosion processes due to significant structural deficiency and low aggregate stability. The first survey was carried out in the period 2018-2020, and in addition to conventional technologies, surface and vertical mulching (with manure as mulching material) were also tested. The second was carried out in 2020-2023 and included minimal treatments for growing wheat and maize and the inclusion of cover crop (barley) in the crop rotation. An increase in the amount of soil organic carbon was found, as well as an increase of the soil peroxidase and polyphenoloxidase activity. The ratio between two enzymes, is considered as humification factor, is higher in the variants under soil protection technologies. The application of soil conservation treatments such as surface mulching with manure, minimum tillage with vertical manure mulching, as well as minimum tillage combined with cover crop in a wheat-maize rotation on sloping farmlands lead to an improvement of soil organic carbon as well as an increase of soil polyphenoloxidase activity.