Micro- and nanoplastics in agricultural soils: Assessing impacts and navigating mitigation.

Micro-/nanoplastic contamination in agricultural soils raises concerns on agroecosystems and poses potential health risks. Some of agricultural soils have received significant amounts of micro-/nanoplastics (MNPs) through plastic mulch film and biosolid applications. However, a comprehensive understanding of the MNP impacts on soils and plants remains elusive. The interaction between soil particles and MNPs is an extremely complex issue due to the different properties and heterogeneity of soils and the diverse characteristics of MNPs. Moreover, MNPs are a class of relatively new anthropogenic pollutants that may negatively affect plants and food. Herein, we presented a comprehensive review of the impacts of MNPs on the properties of soil and the growth of plants. We also discussed different strategies for mitigating or eliminating MNP contamination. Moreover, perspectives for future research on MNP contamination in the agricultural soils are also highlighted.

A Simple and Effective Method to Enhance the Mechanical Properties, Dimensional Stability, and Mildew Resistance of Bamboo Scrimber.

Given the increasingly prominent contradiction between the supply of and demand for wood, the abundant resource of bamboo can be a good substitute. Bamboo scrimber can effectively improve the utilization rate of bamboo and has good mechanical properties. However, bamboo scrimber has the problem of poor mildew resistance, and does not meet the requirements for outdoor applications. In this study, in order to further improve the mildew resistance and mechanical properties of bamboo scrimber, alkali treatment was used to remove some nutrients from the bamboo bundles and change the pH of the bamboo scrimber. The results showed that nutrients such as hemicellulose, lignin, starch, and sugar were notably removed from bamboo bundles, and the pH of bamboo was slightly alkaline. The anti-mildew effect was significantly enhanced, which could allow use in outdoor environments, and the mechanical properties and dimensional stability were also improved. Among them, TB6 bamboo scrimber showed comprehensively excellent properties. The infection time in the laboratory mildew test increased from 3 days to more than 30 days, and the infection time in the outdoor mildew resistance test increased from 1 week to more than 8 weeks; the static bending intensity of TB6 increased by 62.6% to 150 MPa, and the bending modulus increased by 71.7% to 14.2 GPa; the change rate of water absorption thickness was reduced to 0.58%. This modification method effectively improved the mildew resistance of bamboo scrimber, while maintaining high mechanical strength, and provides a new method for the outdoor application of bamboo scrimber.

[Effects of addition of sorghum stubble rhizosphere soil on growth and rhizosphere microbes of continuous cropping cucumber]. / æ·»åŠ é«˜ç²±æ ¹èŒ¬æ ¹é™ åœŸå¯¹è¿žä½œé»„ç“œç”Ÿé•¿å’Œæ ¹é™ å¾®ç”Ÿç‰©çš„å½±å“.

We explored the effects of addition of sorghum stubble rhizosphere soil on the growth of continuous cropping cucumber and rhizosphere microbial community in a pot experiment. The diffe-rences in soil bacterial and fungal community composition were analyzed with fluorescence quantitative PCR and high-throughput sequencing technology. There were four treatments: CK (no fertilization), T1(fertilizer only), T2(optimized fertilization), and T3(optimized fertilization + rhizosphere soil of sorghum stubble). The results showed that compared with other treatments, T3 promoted the growth and development of cucumber, and increased the abundance of 16S rRNA and ITS rRNA genes in soil. Compared with the T1 treatment, T2 and T3 significantly increased the richness and diversity of bacterial communities. There was no significant difference in fungal community richness and diversity among different treatments. Adding rhizosphere soil of sorghum stubble changed the composition of bacterial and fungal communities at both phylum and genus levels. For bacteria, it increased the abundances of Acidobacteria and Bacteroides, but decreased that of Proteobacteria, Firmicutes, Nitrospira and Bacillus. For fungi, it increased the abundance of Basidiomycota, Trichoderma and Pseudurotium, but decreased that of Fusarium and Metarhizium. Results of redundancy analysis showed that soil nitrate and organic matter were the key factors affecting the difference of bacterial and fungal community composition, respectively. In conclusion, addition of sorghum stubble rhizosphere soil improved the total abundance of soil microorganisms and bacterial diversity for continuous cropping cucumber. It increased the abundance of beneficial bacteria Trichoderma, reduced that of pathogenic Fusarium, and maintained the survival rate of cucumber, thus provided a feasible solution for alleviating the barriers for the continuous cropping of cucumber.