RESPONSE OF SOIL MICROBIAL COMMUNITY TO AGRICULTURAL PRACTICES

Different tillage management practices can affect soil`s physical, chemical, and biological properties, crop productivity and overall soil quality. "No-tillage" practice is emerging as an important soil management strategy to preserve soil fertility and avoid soil erosion. In this study, we examined the effect of tillage practices on soil bacterial community structure and function, as these communities provide ecological services crucial for soil health and fertility.

Two plots (Moledet-MO and Ein Harod Meuhad-EHM) were subjected to conventional- (CT), minimal- (MT) and no- tillage (NT) treatments. Replicates from each treatment and plot were sampled twice a year (post seeding and post harvesting) for two consecutive years and analyzed for microbial activities and community composition. Significant increase in overall soil hydrolytic and oxidative potential activity and mild increase in soil respiration was detected in NT samples compared with CT and MT samples. PCoA analysis of soil bacterial community structure, based on a total of 2,222,717 16S rRNA sequences, revealed that NT significantly affected bacterial community structure as the community of these samples shifted from those of CT and MT samples. Taxonomically, this shift reflected in higher resemblance to non-agricultural control soil, with specific elevation in relative abundance of members of the class Alphaproteobacteria in NT samples. The species richness as reflected by Alpha diversity indexes, slightly changed with time but was not affected by the treatments. Overall, different tillage practices induced major effects on soil microbiology. We found that NT practice increased the overall microbial potential activity and prevented tillage-induced alterations of the microbial community structure, suggesting that NT improves the microbiological properties of soil. This supports the hypothesis that NT is a relative sustainable practice.