Duration of continuous cropping with straw return affects the composition and structure of soil bacterial communities in cotton fields

Abstract

Salinized land in the China's Xinjiang Region is being reclaimed for continuous cotton production. The specific objectives of this field study were (i) to compare bacterial composition and diversity in unfarmed (i.e., unreclaimed) and continuously (5, 10, 15, and 20 years) cropped soils and (ii) to explore correlations between soil properties and the bacterial communities identified by Illumina MiSeq sequencing. The results showed that bacterial species richness and diversity increased for 10-15 years and then declined when salinized land was reclaimed for cotton production. Proteobacteria and Firmicutes were the dominant phyla in unfarmed soil. Continuous cropping reduced the abundance of Firmicutes but increased that of Chloroflexi, Acidobacteria, and Actinobacteria. Cluster analyses showed that the greatest similarities in bacterial communities were between the 5- and 10-year treatments and between the 15- and 20-year treatments. Soil pH, electrical conductivity, alkali-hydrolyzable N, and available P were significantly correlated with bacterial community distribution. Overall, cotton production improved soil physicochemical properties and altered the structure and composition of soil bacterial communities compared with unfarmed soil. These positive effects began to decrease after 10-15 years of continuous cotton production.

Effects of Continuous Sugar Beet Cropping on Rhizospheric Microbial Communities

“…The dominant genus Pseudombrophila in T5 (14.3%) became one of the least abundant genera in T30 (1.5%). These observed differences in different groups further support previous reports demonstrating that the abundance and structure of fungal communities are highly influenced by continuous cropping [11][12][13][14].…”

“…Rhizosphere microflora has been shown to be a key component of agricultural ecosystems that not only plays a significant role in basic soil processes, but is also actively involved in enhancing soil fertility and crop productivity [9]. Previous studies on soybean, ginger, potato, cucumber, and cotton have found that the alpha diversity of bacteria and fungi was decreased due to continuous cropping year, and the soil microbial metabolic diversity and soil physicochemical properties were also significantly affected [10][11][12][13]. The relative abundance of pathogenic fungi in rhizospheric soil was revealed to be significantly higher in continuous cropping than in cropping rotation systems [14].…”

Effects of Continuous Cropping on Bacterial Community Structure in Rhizospheric Soil of Sweet Potato

“…The PCR reactions were performed in triplicate 20 μL mixture containing 4 μL of 5 × FastPfu Buffer, 2 μL of 2.5 mM dNTPs, 0.8 μL of each primer (5 μM), 0.4 μL of FastPfu Polymerase, and 10 ng of template DNA. The extraction and puri cation of amplicons were performed according to the report by Yang et al [34]. Puri ed PCR products were quanti ed using Qubit®3.0 (Life Invitrogen) and every 24 amplicons whose barcodes were different were mixed equally.…”

“…In order to obtain high quality sequences, quality control and sequence quality ltering were applied according to Yang et al [34] to remove low quality sequences. Operational taxonomic units (OTUs) were clustered with 97% similarity cutoff using UPARSE version 7.1 http://drive5.com/uparse/) and chimeric sequences were identi ed and removed using UCHIME.…”

Efeito do uso do solo ao longo do tempo em comunidades microbianas do ciclo do nitrogênio em solos tropicais

“…O solo AGR de 5 anos e as RIZ 2 e 5 anos apresentaram uma maior abundância do filo (P=0,05). Micro-organismos relacionados a este filo já foram verificados em ambientes como terra preta da China e solos de agricultura com sistema de cultivo semelhante ao plantio direto (LIU et al, 2014;YANG et al, 2017).…”