Mulching practices alter soil microbial functional diversity and benefit to soil quality in orchards on the Loess Plateau.

To improve our understanding about the responses of microbial functional diversity to different mulching practices, this study used a metagenomic approach to reveal soil microbial functional specificity under four tillage regimes: conventional tillage (CT), organic mulch practices with ryegrass (Lolium perenne L.) intercropping cover (RE) and cornstalk mulch (CS), and inorganic mulching with black ground fabric (BF) in a 7-year field experiment in an apple orchard of the Loess Plateau in China. Enzyme activity and soil physicochemical properties were measured. A redundancy analysis showed that the RE and CS treatments had positive effects on soil nutrient and enzyme activity compared to that of the BF and CT treatments. The CS and RE treatments increased ß-glucosidase, cellobiohydrolase, and ß-xylosidase activities. In addition, the CS treatment significantly enhanced the ß-N-acetylglucosaminidase and urease activities compared to that under CT treatment. However, the activity of these enzyme was reduced in the BF treatment compared with that of the CT treatment. The results also indicated that the enzymes activities were not completely consistent with the changing trends of the genes encoding these enzymes. In addition, the RE and CS treatments also increased the abundance of genes encoding carbohydrate enzymes. It is interesting that the RE and CS treatments had more pathway genes associated with the carbon cycle, nitrogen cycle, and amino acid metabolism compared with the BF treatment. Remarkably, RE and CS treatments effectively increased the abundance of carbon fixation gene cbbL compared to CT treatment. In summary, organic mulching practices increased the soil microbiological functional diversity related to the carbon and nitrogen cycle, while inorganic mulching practice reduced them. This study enhanced our understanding of how mulching practices may alter soil microbial functional diversity and benefit soil quality.

Long-term grass mulching waste recycling and evaluation activation of dissolved organic carbon.

This study aimed to clarify that long-term leguminous grass mulching (crown vetch (CV) and white clover (WC)) and gramineous grass (orchardgrass (OG)) drive the distribution of soil aggregates and are associated with dissolved organic matter (DOM) components. Excitation emission spectroscopy and parallel factor analysis (EEM-PARAFAC) were used to evaluate the influence of different grass mulches among aggregates. The results indicated that legumes had a more significant impact on the distribution of aggregates and DOM content than gramineae grass mulching. Leguminous grass mulching significantly increased the proportion of macroaggregates >250 µm (74.65%-83.50%) and aggregates associated with dissolved organic carbon (DOC), especially in microaggregates <250 µm (172.27 mg kg-1 to 391.55 mg kg-1). In addition, leguminous grass mulching (CV and WC) contributed more to the increase in soil total nitrogen (TN) and three identified fluorescent components (UVC humic-like, UVA humic-like and protein-like). The component of UVC humic-like relative abundance decreased (48.66%-36.57%), and the protein-like component increased (21.88%-36.50%) as the aggregate size decreased, but the DOM three compositions did not change. The DOM of macroaggregates had higher aromaticity and lower molecular weight than microaggregates, and the highest abundance of UVC humic-like component (54.52%) was found in the gramineous (OG) large macroaggregates, while the higher abundance of protein-like components (31.07%-36.50%) occurs in leguminous mulching (CV and WC) microaggregates. The results contribute to a further understanding of the dynamic process by which grass mulching mediates aggregate formation and DOM component transformation in semiarid apple orchards under grass waste management.

Pollution control in biochar-driven clean composting: Emphasize on heavy metal passivation and gaseous emissions mitigation.

Present study was focus on the pollution control aspect of gaseous mitigation and heavy metal passivation as well as their associated bacterial communities driven by apple tree branch biochar (BB) during sheep manure composting. Six treatment was performed with distinct concentration of BB from 0%, 2.5%, 5%, 7.5%, 10%, and 12.5% as T1 to T6. Compared with compost without additive, biochar-based composting recorded faster thermophilic process (4thd) and longer duration (12-14d), lower gaseous emission in terms of ammonia (5.37-10.29 g), nitrous oxide (0.12-0.47 g) and methane (4.38-30.29 g). Notably highest temperature (65.3 â„ƒ) and active thermophilic duration (14d), minimized gaseous volatilization were detected in 10%BB composting. Aspect of non-degradability and enrichment-concentration properties of heavy metals, the total copper (Cu) and zinc (Zn) were increased (from initial 12.71-17.91 to final 16.36-29.36 mg/kg and 107.39-146.58-161.48-211.91 mg/kg). In view of available diethylene triamine pentacetic acid (DTPA) extractable form, DTPA-Cu and DTPA-Zn from 4.29 to 6.57 and 31.66-39.32 mg/kg decreased to 3.75-4.82 and 23.43-40.54 mg/kg, especially the maximized passivation rate of 46.95% and 56.27% were present in 10%BB composting. Additionally, bacterial diversity of biochar-based composting was increased (1817-2310 OTUs) than control (1686 OTUs) and dominant by Firmicutes (52.75%), Bacteroidetes (28.41%) and Actinobacteriota (13.98%). Validated 10% biochar-based composting is the optimal option for effectively control environmental pollution to obtain hygienic composting.

Pharmacokinetics and tissue distribution of methcathinone in rabbits.

Methcathinone is one of the most commonly abused designer narcotics. The pharmacokinetics and tissue distribution of methcathinone is not well understood. In this study, methcathinone was intravenously or intragastrically administered to rabbits in order to investigate the pharmacokinetics and tissue distribution of methcathinone. The plasma concentrations of methcathinone and its metabolite cathinone at various timepoints post-methcathinone administration as well as the distribution of methcathinone and cathinone in various tissues were determined and quantified using a liquid chromatography-tandem mass spectrometry (LC-MS/MS). According to our results, the elimination of methcathinone and cathinone was faster after intravenous administration than that after intragastric administration. The methcathinone or cathinone concentration in the plasma dramatically dropped at 16-18 h post-methcathinone administration followed by a rebound. Gastric content and stomach tissue could be better samples for the identification of methcathinone abuse by oral administration while bile and stomach tissue could be ideal samples for the identification of methcathinone abuse in intravenous injection cases. The pharmacokinetic characteristics and tissue distribution pattern of methcathinone and its metabolite cathinone described in this study could benefit future study on identification and control of methcathinone abuse in forensic toxicological analysis.