LONG-TERM IMPACT OF MAIZE AGROECOLOGICAL MANAGEMENT ON BACTERIAL COMMUNITIES AND SOIL HEALTH IN THE ARID NORTH OF MEXICO

Abstract

Background. Soil management practices modify the microbial communities and the carbon stocks (organic, inorganic, and total). The increase in microbiological communities’ diversity improves the production of plants; thus, it is essential to understand the predominant bacterial taxa in the soil. Objective. The objective of the present study was to establish the bacterial communities’ alteration by agroecological management in maize crops in arid northern Mexico. Methodology. Bacterial diversity and composition were determined in soils from Coahuila, Mexico, under three different scenarios: i) Agroecological management (AM), ii) Conventional management (CM), and iii) Control (T, with no vegetation). In addition, pH, electrical conductivity (EC), and soil organic matter (SOM) were analyzed using standard methods. Bacterial DNA was extracted from the soil, amplifying the V3-V4 region of the 16S rRNA gene and sequencing with Illumina. The gene sequences were analyzed in QIIME. Results. A total of 20 bacterial phyla and 631 genera were registered. For AM, CM, and T, respectively, the most abundant genera were Tepidisphaera (7.02, 9.29, and 9.93 %), Sphingomonas (6.55, 5.15, and 4.06 %), Microvirga (2.64, 2.39, and 3.63 %), and Blastococcus (2.91, 3.10, and 3.37 %). A significant difference was observed among groups (p = 0.004), where AM was different, which suggests that the type of substrate determines the diversity and abundance of the bacterial community. Significant differences were found for pH and EC, with higher pH in CM (7.87) and T (7.86) soils. The EC was higher in AM (446 μ Scm^-1) and T (419 μ Scm^-1). On the other hand, AM showed the best result in SOM content (21.80 ± 1.10 gC kg^-1). Implication. Therefore, AM in maize crops has the potential to conserve or restore C stock in degraded arid lands, increasing bacterial diversity, favoring the health of the soil. Conclusion. Agroecological management of maize crops soils in arid North of Mexico promotes greater bacterial diversity, which will favor the availability of nutrients for the future development of healthy plants.