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.

中文翻译：

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在干旱的农业生态系统中，湿耕或干播对土壤细菌群落组成的影响大于耕作方式。

目的

由于农业主要依赖这些农业生态系统中的灌溉，因此在干旱地区实施使水分利用效率最大化的实践非常重要。这项研究的目的是确定将不同的播种灌溉方法（干式和湿式）与对比耕作方法（常规做法和保护性农业）相结合对诺曼·E·博洛格实验田（CENEB）土壤中细菌群落结构的影响，索诺拉Yaqui谷。

材料和方法

播种后的一个月内，在CENEB的干湿播种下，从永久性耕作床和常规耕作床中连续四个月收集土壤样品。通过Illumina MiSeq测序对土壤进行鉴定，并鉴定细菌群落，并以16S rRNA基因为靶标。

结果和讨论

细菌群落结构受土壤水分的影响。链霉菌和Balneimonas在播种的干燥土壤中富集，前者在常规耕作的土壤中富集，而在永久性耕种的土壤中富集，而不动杆菌在保护性农业的湿润的土壤中富集。香农指数表明，传统做法和保护性农业都有很高的物种多样性。

结论

土壤含水量是影响细菌群落结构的主要因素。在干，湿播过程中，耕作方式中水分含量的差异会影响到最主要的三种门，但在属水平上，这些波动更为明显。