Antagonistic bacteria in the soil after cover crops cultivation

Abstract

The purpose of the studies was to establish the quantitative composition of bacteria Bacillus spp. and Pseudomonas spp. and their antagonistic effect towards soil-borne fungi after the cultivation of oats, spring vetch and tansy phacelia as intercrop cover plants. The total population of bacteria in 1 g dry weight of the soil from the experimental combination where mulch of oats was used was larger than in the combination with spring vetch or tansy phacelia. Totally, approximately three times as much Bacillus spp. was obtained from soil samples as compared to Pseudomonas spp. Tests showed that the most isolates of antagonistic bacteria out of the enumerated genera occurred in the soil after oats cultivation, and the least in the soil after the cultivation of tansy phacelia. Antagonistic Bacillus spp. and Pseudomonas spp. inhibited the growth and development of Fusarium oxysporum, Haematonectria haematococca and Thanatephorus cucumeris in the most effective way. The greatest total antagonistic effect of Bacillus spp. and Pseudomonas spp. towards Altenaria alternata, F. culmorum, F. oxysporum, H. haematococca, P. irregulare and T. cucumeris was found out after managing the mulch of oats. The smallest total antagonistic effect of bacteria was observed after managing the mulch of tansy phacelia.