TILLAGE ALTERS THE MICROBIAL COMMUNITY COMPOSITION AND ACTIVITY

Adopting soil preservation practices and prevention of agricultural soil erosion is crucial for sustainable agriculture. Conventional tillage of fields cause physical disturbances of the soil upper layer, characterized by more uniform physical characteristics and nutrient distribution. Tillage may results in less organic matter, mineralizable N and humidity. Little is known about the long-term effect of tillage management on the soil microbiome. In the present study the dynamics of microbial communities, their variation in composition and activity over time was monitored for 3 consecutive years under three levels of tillage practice: conventional tillage (CT), minimal tillage (MT) and no-tillage (NT) in two sites: Moledet (MO) and Ein Harod Meuhad (EHM). We found that NT practice significantly increased soil hydrolytic and oxidative potential activity. Bacterial communities were shifted in correlation to tillage intensity as CT and NT were clustered apart, while MT samples clustered with either CT or NT samples in MO and EHM, respectively. This shift between CT and NT communities was shown to be statistically significant by Anosim analysis. The species richness, as reflected by Alpha diversity indexes, was not affected by the treatments. Taxonomically, NT samples exhibited specific elevation in relative abundance of members of the class Alphaproteobacteria and specifically in the order Rhizobiales while in CT soil the relative abundance of Nitrososphaerales was elevated.

Using high resolution next generation sequencing, and temporal analysis of the soil microbial communities structure and function, we demonstrate the beneficial effect of No-till on soil microbial community, providing an insight of how the anthropogenic effect of agriculture influences the complex soil microbial eco-system.