Conservation tillage increases soil bacterial diversity in the dryland of northern China

International audienceAbstractAgricultural practices change soil’s physical and chemical properties, therefore modifying soil microbial communities. Conservation tillage is widely used to improve the soil texture and nutrient status in the dryland regions of northern China. However, little is known about the influence of soil properties on microbes, in particular on the effect of conservation tillage on soil bacterial communities. Here, we studied the effect of a 5-year tillage treatment on soil properties and soil bacterial communities in the dryland regions of northern China using a high-throughput sequencing technology and quantitative PCR of 16S rRNA genes. We compared the changes in soil bacterial diversity, and composition was measured for conservation tillage, including zero plow or chisel plow, and for conventional tillage using plow. Our results show that conservation tillage increased the Simpson index by 378 % and exhibited significantly dissimilar polygenetic diversity, with r of 1, and taxonomic diversity, of r higher than 0.49, compared to conventional tillage. This finding demonstrates that conservation tillage modifies soil bacterial diversity. Chisel plow and zero tillage increase the abundance of the genus Bacillus, including 85 % of the phylum Firmicutes, and of Rhizobiales belonging to the Alphaproteobacteria. Overall conservation tillage increased the abundance of profitable functional bacteria species

Effect of Tillage Treatment on the Diversity of Soil Arbuscular Mycorrhizal Fungal and Soil Aggregate-Associated Carbon Content

No-tillage agriculture can sustain productivity and protect the environment. A comprehensive understanding of soil arbuscular mycorrhizal (AM) fungal diversity and soil carbon distribution within aggregate fractions is essential to the evaluation of no-tillage agriculture. The long-term field experiment included two tillage treatments (1) no tillage with straw returned to the soil (NTS), and (2) conventional mouldboard-plowing tillage without straw (CT), and was conducted on the Loess Plateau, north-western China, from October 2009. The soil samples were collected from the surface layer (0–20 cm depth) at the maturation stage of the summer maize (Zea mays L.) for analyzing aggregates separated by the dry-sieving method. The organic carbon content in the bulk soil and different particle size aggregates were measured using the dichromate oxidization method. The species compositions of soil AM fungi were compared by applying high-throughput sequencing of 18S rRNA. The results showed that the NTS had 9.1–12.2% higher percentage of soil macro-aggregates, resulting in 9.8% increase in mean weight diameter and 10.0% increase in bulk soil organic carbon content as compared with CT treatment. In addition, the NTS treatment had significantly higher percentages of Septoglomus and Glomus than the CT treatment. We also found some significant differences in the fungal communities of the soils of the two treatments. There was a strong positive relationship between bulk soil organic carbon and the percentages of Septoglomus and Glomus. Our results suggested that the NTS treatment had a protective effect on AM fungal community structures, which might play a key role in the development of agricultural sustainability in the Loess Plateau of China

Soil microbial community parameters affected by microplastics and other plastic residues

Introduction: The impact of plastics on terrestrial ecosystems is receiving increasing attention. Although of great importance to soil biogeochemical processes, how plastics influence soil microbes have yet to be systematically studied. The primary objectives of this study are to evaluate whether plastics lead to divergent responses of soil microbial community parameters, and explore the potential driving factors. Methods: We performed a meta-analysis of 710 paired observations from 48 published articles to quantify the impact of plastic on the diversity, biomass, and functionality of soil microbial communities. Results and discussion: This study indicated that plastics accelerated soil organic carbon loss (effect size = −0.05, p = 0.004) and increased microbial functionality (effect size = 0.04, p = 0.003), but also reduced microbial biomass (effect size = −0.07, p < 0.001) and the stability of co-occurrence networks. Polyethylene significantly reduced microbial richness (effect size = −0.07, p < 0.001) while polypropylene significantly increased it (effect size = 0.17, p < 0.001). Degradable plastics always had an insignificant effect on the microbial community. The effect of the plastic amount on microbial functionality followed the “hormetic dose–response” model, the infection point was about 40 g/kg. Approximately 3564.78 μm was the size of the plastic at which the response of microbial functionality changed from positive to negative. Changes in soil pH, soil organic carbon, and total nitrogen were significantly positively correlated with soil microbial functionality, biomass, and richness (R2 = 0.04–0.73, p < 0.05). The changes in microbial diversity were decoupled from microbial community structure and functionality. We emphasize the negative impacts of plastics on soil microbial communities such as microbial abundance, essential to reducing the risk of ecological surprise in terrestrial ecosystems. Our comprehensive assessment of plastics on soil microbial community parameters deepens the understanding of environmental impacts and ecological risks from this emerging pollution

Metagenomics reveals the abundance and accumulation trend of antibiotic resistance gene profile under long-term no tillage in a rainfed agroecosystem

Widespread soil resistance can seriously endanger sustainable food production and soil health. Conservation tillage is a promising practice for improving soil structure and health. However, the impact of long-term no-tillage on the presence of antibiotic resistance genes in agricultural soils remains unexplored. Based on the long-term (&gt;11 yr) tillage experimental fields that include both conservation tillage practices [no tillage (ZT)] and conventional tillage practices [plough tillage (PT)], we investigated the accumulation trend of antibiotic resistance genes (ARGs) in farmland soils under long-term no-tillage conditions. We aimed to provide a scientific basis for formulating agricultural production strategies to promote ecological environment safety and human health. In comparison to PT, ZT led to a considerable reduction in the relative abundance of both antibiotic resistance genes and antibiotic target gene families in the soil. Furthermore, the abundance of all ARGs were considerably lower in the ZT soil. The classification of drug resistance showed that ZT substantially decreased the relative abundance of Ethambutol (59.97%), β-lactams (44.87%), Fosfomycin (35.82%), Sulfonamides (34.64%), Polymyxins (33.67%), MLSB (32.78%), Chloramphenicol (28.57%), Multi-drug resistance (26.22%), Efflux pump (23.46%), Aminoglycosides (16.79%), Trimethoprim (13.21%), Isoniazid (11.34%), Fluoroquinolone (6.21%) resistance genes, compared to PT soil. In addition, the abundance of the bacterial phyla Proteobacteria, Actinobacteria, Acidobacteria, and Gemmatimonadetes decreased considerably. The Mantel test indicated that long-term ZT practices substantially increased the abundance of beneficial microbial flora and inhibited the enrichment of ARGs in soil by improving soil microbial diversity, metabolic activity, increasing SOC, TN, and available Zn, and decreasing pH. Overall, long-term no-tillage practices inhibit the accumulation of antibiotic resistance genes in farmland soil, which is a promising agricultural management measure to reduce the accumulation risk of soil ARGs

Wo steht mein Schreibtisch in der virtuellen Bibliothek?

Die Krise, in der die Bibliothekare ihren Beruf augenscheinlich permanent sehen, hat Ihre Ursache in einer Diskrepanz zwischen dem Muster spezialisierter Tätigkeiten (Bibliothekarberuf) und dem gesellschaftlichen Funktionsausschnitt, auf den sich der Beruf bezieht (gesellschaftliche Rolle der Bibliotheken). Zukünftig wird es darauf ankommen, ein bibliothekarisches Berufsbild institutionsunabhängig zu formulieren. Es werden Trends umrissen, die auf das Bibliothekswesen und verwandte Bereiche einwirken oder innerhalb des Bibliothekswesens oder verwandter Bereiche entstehen: rechtliche, technische, politische, wirtschaftliche Rahmenbedingungen, die Annäherung des wissenschaftlichen und öffentlichen Bibliothekswesens, des Dokumentations- und Archivbereichs, Ausbildung, Studium und Berufsinhalte, interne und externe Organisation, Finanzierung, bibliothekarische Dienstleistungen, Ziele und Leitbilder. Bibliothekare werden sich auf vielfältige Aufgaben der Informations- und Medienbeschaffung, -selektion, -aufbereitung, -erschließung, -vermittlung, -archivierung in allen möglichen Branchen und Bereichen, aber weniger in Bibliotheken einzustellen haben

Soil microbial community parameters affected by microplastics and other plastic residues

IntroductionThe impact of plastics on terrestrial ecosystems is receiving increasing attention. Although of great importance to soil biogeochemical processes, how plastics influence soil microbes have yet to be systematically studied. The primary objectives of this study are to evaluate whether plastics lead to divergent responses of soil microbial community parameters, and explore the potential driving factors.MethodsWe performed a meta-analysis of 710 paired observations from 48 published articles to quantify the impact of plastic on the diversity, biomass, and functionality of soil microbial communities.Results and discussionThis study indicated that plastics accelerated soil organic carbon loss (effect size = −0.05, p = 0.004) and increased microbial functionality (effect size = 0.04, p = 0.003), but also reduced microbial biomass (effect size = −0.07, p &lt; 0.001) and the stability of co-occurrence networks. Polyethylene significantly reduced microbial richness (effect size = −0.07, p &lt; 0.001) while polypropylene significantly increased it (effect size = 0.17, p &lt; 0.001). Degradable plastics always had an insignificant effect on the microbial community. The effect of the plastic amount on microbial functionality followed the “hormetic dose–response” model, the infection point was about 40 g/kg. Approximately 3564.78 μm was the size of the plastic at which the response of microbial functionality changed from positive to negative. Changes in soil pH, soil organic carbon, and total nitrogen were significantly positively correlated with soil microbial functionality, biomass, and richness (R2 = 0.04–0.73, p &lt; 0.05). The changes in microbial diversity were decoupled from microbial community structure and functionality. We emphasize the negative impacts of plastics on soil microbial communities such as microbial abundance, essential to reducing the risk of ecological surprise in terrestrial ecosystems. Our comprehensive assessment of plastics on soil microbial community parameters deepens the understanding of environmental impacts and ecological risks from this emerging pollution

Conservation tillage increases carbon sequestration of winter wheat-summer maize farmland on Loess Plateau in China.

The idea of mitigating anthropogenic CO2 emissions by increasing soil organic carbon (SOC) is notable. However, the estimation of the net ecosystem carbon balance after conversion from conventional tillage to conservational tillage has been poorly quantified for the Loess Plateau in China. A 2-year field experiment was conducted to estimate the agroecosystem carbon balance of a winter wheat-summer maize rotation system using a full carbon cycle analysis. The results showed that a positive net ecosystem carbon balance value in the cases of rotary tillage with straw incorporation, chisel plow tillage with straw incorporation, and no tillage with straw mulching treatments. Note that a negative value was detected for the conventional moldboard plowing tillage without crop straw treatment. The conversion from conventional tillage to conservational tillage substantially enhanced the carbon sink potential from 0.84 t C ha-1 yr-1 to 2.69 t C ha-1 yr-1 in both years. Our findings suggest that the expansion of conservational tillage could enhance the potential carbon sink of the rain-fed land in China

Tillage and crop straw methods affect energy use efficiency, economics and greenhouse gas emissions in rainfed winter wheat field of Loess Plateau in China

Data from a field experiment conducted in China's Loess Plateau (2013–2015) were used to determine the energy balance of winter wheat (Triticum aestivum L.) as affected by tillage and straw treatments. Tillage treatments included chisel plow, no tillage, and mouldboard plow. Crop straw levels included straw returning and straw removed. The energy balance was evaluated by comparing the following parameters: net energy, energy profitability, energy use efficiency, and energy intensity. The yield parameters were significantly influenced by the tillage treatments and revealed that the chisel plow entailed fewer field operations and lower energy requirements with a higher yield than mouldboard plowing tillage. The highest proportion of energy input came from a nitrogen fertiliser, followed by diesel fuel. The total energy input applied per hectare increased with an increase in the tillage intensity, and the lowest energy input was required for the no tillage case with the straw returning treatment, and the highest for the case of mouldboard plow with the straw returning treatment. The lowest average energy intensity was recorded for the no tillage case, followed by the case of chisel plow tillage in both cropping seasons. Moreover, in the case of mouldboard plough tillage, the maximum energy intensity was recorded in both cropping seasons. In the cases of the chisel plow tillage and the no tillage, we observed the maximum energy gain, while in the no tillage case, we observed the maximum energy use efficiency. The net return and the benefit/cost ratio were higher in the case of straw returning than those in the case of no straw treatment. We concluded that no tillage and chisel plow tillage with straw returning could improve the energy use efficiency and the benefit/cost ratio of winter wheat production systems

Study of the Properties of a Hybrid Piezoelectric and Electromagnetic Energy Harvester for a Civil Engineering Low-Frequency Sloshing Environment

In this paper a novel hybrid piezoelectric and electromagnetic energy harvester for civil engineering low-frequency sloshing environment is reported. The architecture, fabrication and characterization of the harvester are discussed. The hybrid energy harvester is composed of a permanent magnet, copper coil, and PVDF(polyvinylidene difluoride) piezoelectric film, and the upper U-tube device containing a cylindrical fluid barrier is connected to the foundation support plate by a hinge and spring. The two primary means of energy collection were through the vortex street, which alternately impacted the PVDF piezoelectric film through fluid shedding, and the electromotive force (EMF) induced by changes in the magnetic field position in the conducting coil. Experimentally, the maximum output power of the piezoelectric transformer of the hybrid energy harvester was 2.47 μW (circuit load 270 kΩ; liquid level height 80 mm); and the maximum output power of the electromagnetic generator was 2.72 μW (circuit load 470 kΩ; liquid level height 60 mm). The low-frequency sloshing energy collected by this energy harvester can drive microsensors for civil engineering monitoring