Peer review

Purpose. Implementing practices that maximize water use efficiency in arid zones is important as agriculture relies mostly on irrigation in these agroecosystems. The aim of this study was to identify the effect of combining different sowing irrigation methods (dry and wet) with contrasting tillage practices (conventional practices and conservation agriculture) on bacterial community structure in soils from the Norman E. Borlaug experimental field (CENEB), Yaqui Valley, Sonora. Materials and methods. Soil samples were collected consecutively four times in the month after sowing from permanent and conventionally tilled beds under wet and dry sowing at CENEB. Soils were characterized and the bacterial communities were identified with Illumina MiSeq sequencing where the 16S rRNA gene was targeted. Results and discussion. The bacterial community structure was affected by soil water content. Streptomyces and Balneimonas were enriched in dry sowed soil, the first in conventionally tilled beds and the latter in permanent beds, while Acinetobacter was enriched in wet sowed soil under conservation agriculture. Shannon index indicated that there was a high species diversity in both conventional practices and conservation agriculture. Conclusions. Soil water content was the principal factor shaping the bacterial community structure. While the three most dominant phyla were affected by the difference in water content in the tillage practices under dry and wet sowing, it was at the genera level that these fluctuations were more obvious.

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