Evaluating the impact of cultivation systems for improving the management of agricultural soil is difficult. Traditional ploughing cultivation can contribute to soil erosion. An alternative to conventional tillage is conservation tillage. The aim of our study was to determine the influence of different cultivation systems on the biochemical and biological activity of soil under sugar beets. The conventional tillage treatment with soil ploughing to a depth of 35 cm was the control treatment (CT). For comparison, we analysed the following conservation tillage systems consisting of shallow or deep-soil ripping:
1. Tillage to a depth of 35 cm and sowing into stubble mulch (MS35).
2. Tillage to a depth of 15 cm and sowing into stubble mulch (MS15).
3. Tillage to a depth of 15 cm and sowing into white mustard mulch (MG).
4. Strip-till on stubble mulch to a depth of 25 cm and instantaneous beet seed sowing (STS).
5. Strip-till to a depth of 25 cm on white mustard mulch and instantaneous beet seed sowing (STG).
The soil samples that were used for biochemical and microbiological analyses were collected during four terms in each year, which coincided with the four consecutive stages of the development of sugar beets.
During both years of research we obtained results concerning the influence of different soil cultivation methods on the number of selected groups of soil microorganisms and the enzymatic activity under sugar beets. In 2012-13 the highest bioactivity was noted in the period of the greatest demand of sugar beets for nutrients, at the phase when the rows of plants were closing in. At that time the content of actinobacteria in the soil collected from the sites where STS had been applied was 42% greater than in the soil from the ploughing cultivation system. Apart from that, in this same term, whenever conservation tillage was applied the activity of dehydrogenases and phosphatases always increased.