Effect of Long-Term Cropping Systems on the Diversity of the Soil Bacterial Communities

Abstract

Soil microbial communities are involved in the maintenance of productivity and health of agricultural systems; therefore an adequate understanding of soil biodiversity plays a key role in ensuring sustainable use of soil. In the present study, we evaluated the influence of different cropping systems on the biodiversity of the soil bacterial communities, based on a 54-year field experiment established in Martonvásár, Hungary. Terminal restriction fragment length polymorphism (T-RFLP) fingerprinting technique was used to assess soil bacterial diversity and community structure in maize monoculture and three different crop rotations (maize-alfalfa, maize-wheat and the maize-barley-peas-wheat Norfolk type). No differences in richness and diversity were detected between maize monoculture and crop rotations except for the most intense rotation system (Norfolk-type). Although the principal component analysis did not reveal a clear separation between maize monoculture and the other rotation systems, the pairwise tests of analysis of similarity (ANOSIM) revealed that there are significant differences in the composition of bacterial communities between the maize monoculture and maize-alfalfa rotation as well as between wheat-maize and Norfolk-type rotation.

Comparison of Soil Bacterial Communities from Juvenile Maize Plants of a Long-Term Monoculture and a Natural Grassland

“…All studied samples were predominated by Proteobacteria, which was in accordance with the findings of other studies [7,15,16,24,[52][53][54][55]. In addition, the dominant presence of both the so-called "copiotrophic" phyla (Actinobacteria, Bacteroidetes) and "oligotrophic" phyla (Acidobacteria, Verrucomicrobia) was detected, as classified by Fierer et al [56].…”

“…The studied maize monoculture experimental field situated near the town of Martonvásár (47.331177 N; 18.789910 E) in Hungary has been under the same agricultural management for almost 60 years [21,24]. A nearby "Natura 2000" grassland (47.469602 N; 18.656065 E), which was a cattle pasture until the 1990s, was used for comparison.…”

“…The most important experiments include monocultures vs. crop rotations, comparative fertilization experiments, organic and mineral fertilizer interaction experiments, NPK dose-experiments and polyfactorial experiments [21]. However, exploration of soil microbiota from these long-term experiments just recently started in detail [22][23][24]. The impact of long-term agricultural practices on the structural and functional diversity of soil microbial communities is most pronounced in comparison with natural habitats.…”

Defining the wheat microbiome: Towards microbiome-facilitated crop production

“…Long-term monoculture can change soil properties, affecting bacterial diversity and this has been demonstrated [45] . Although they used maize monoculture, they were able to show that humus content was lower when compared to maize-wheat rotation, suggesting that lower concentrations of humus could decrease the amount of available nutrients for plant growth and decrease microbial richness.…”

Nutrient Recycling, Wheat Straw Decomposition, and the Potential Effect of Straw Shear Strength on Soil Mechanical Properties

“…From the perspective of soil and its microorganisms, the PRP conditions might have deeply disturbed the soil [20], which led to the more significant changes in soil, creating more space in soil particles that enhances microorganism activities [21], while under RP and PR conditions, these activities are weaker due to less space. Moreover, during the rice growing season, more dry situations led to temporal and space changes in the field temperature [22] that might deter the activities of the microorganisms in the soil [23], which resulted in different decomposition of straw as observed for the lower RR under different tillage operations. In addition, different stages had different influences on the RR of the straw TOC.…”