Investigation on the effect of ploughing and some minimal soil tillages on the soil organic matter condition in the haplic chernozems

摘要

In a stationary field experiment the effect of different type of soil tillage systems on the change of total carbon and nitorgen in the soil units different in size after dry structural analysis of soil was studied. The research was carried out at the end of the two rotations. Six systems for chiselling were selected from the 24 systems for tillage in a 6-field rotation system - constant direct sowing, disking and cutter tillages at various depths, as well as the combinations between them. Tree depths were studied: 0-10 cm, 10-20 cm and 20-30 cm, as well as soil units of the following sizes: > 10 mm, 10-5, 5-3, 3-1, 1-0.25 and < 0.25 mm. The carbon and nitrogen distribution according to the size of soil units is related to the primary accumulation of products from the organic matter humification depending on the type of soil tillage systems and the horizon depth. The minimal tillage and the tillage without turning of soil, used independently and in combination, had the highest contribution to preserving the organic matter in the Haplic Chernozems in Dobroudja, Bulgaria