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Aims: To investigate the ability of higher nitrogen (N) use efficiency (NUE) in rice production to achieve higher grain yields by optimal N management (OPT). Methods: In 2012 and 2013, four field experiments were conducted in Liyang and Rugao counties, Jiangsu Province, China to investigate the ability of the N-nutrient index (NNI) to mediate the effects of N-free control (CK), farmers' fertilizer practice (FFP), and OPT N management methods on grain yield and NUE through regulating the leaf functions of rice. Results: Compared with FFP, the average rice yield and NUE for OPT were increased, while the N rate was reduced. NNI showed a dynamic change that reached an optimal status in OPT at the harvest stage. N management had a remarkable effect on the leaf area index (LAI), with OPT mitigating the differences between leaf positions, such that basal leaf LAI was improved to compensate for the decreased LAI of the top three leaves. During the grain-filling process, the top three leaves exhibited higher net photosynthesis rate (Pn) and higher grain weights and shorter grain-filling periods of both superior and inferior spikelets in OPT. Based on the contribution of different organs to grain production from the heading to harvest stage, two strategies of yield formation were observed, in which OPT enhanced the dependence on the stems (stem, sheath, and other leaves), while FFP was more dependent on the top three leaves. Conclusions: Our results indicate that optimizing N application improves NNI and leaf functions to increase rice yield and NUE. [ABSTRACT FROM AUTHOR]

Research into plastic-degrading bacteria and fungi is important for understanding how microorganisms can be used to address the problem of plastic pollution and for developing new approaches to sustainable waste management and bioplastic production. In the present study, we isolated 55 bacterial and 184 fungal strains degrading polycaprolactone (PCL) in plastic waste samples from Dafeng coastal salt marshes, Jiangsu, China. Of these, Jonesia and Streptomyces bacteria also showed potential to degrade other types of petroleum-based polymers. The metabarcoding results proved the existence of plastisphere as a distinct ecological niche regardless of the plastic types where 27 bacterial and 29 fungal amplicon sequence variants (ASVs) were found to be significantly (p < 0.05) enriched, including some belonging to Alternaria (Ascomycota, Fungi) and Pseudomonas (Gammaproteobacteria, Bacteria) that were also mined out by the method of cultivation. Further assembly analyses demonstrated the importance of deterministic processes especially the environmental filtering effect of carbon content and pH on bacteria as well as the carbon and cation content on fungi in shaping the plastisphere communities in this ecosystem. Thus, the unique microbiome of the plastisphere in the terrestrial-marine ecotone is enriched with microorganisms that are potentially capable of utilizing petroleum-based polymers, making it a valuable resource for screening plastic biodegraders. [Display omitted] • Coastal plastic debris has a unique microbiome compared to surrounding soil. • Deterministic processes dominate the microbial assembly in plastisphere. • 55 bacteria and 184 fungi capable of degrading PCL were found. • Plant pathogenic fungi are more frequent in plastisphere compared to saprotrophs. • Jonesia spp. bacteria show potential as bioeffectors for plastic degradation. [ABSTRACT FROM AUTHOR]

Highlights: [•] We selected seven experiment sites which have different soil fertility in Jiangsu province. [•] There was a negative relationship between panicles per unit area and spikelets per panicle. [•] Optimize fertilization could mitigate the contradictions between yield formation factors. [•] Optimize fertilization improved yield mainly by increasing the spikelets per unit area. [•] Yield-promotion could be divided into primary and advanced nutrient contribution stages. [ABSTRACT FROM AUTHOR]

A large amount of organic compost, produced with agricultural and breeding industry wastes by composting, is widely used in agriculture in China. The microbial decomposition of organic compost is a major flux in the nutrition cycle in sustainable agricultural soils. To explore the mechanism of organic compost mineralization in soil, in situ decomposition experiments of organic compost buried in soils were arranged in three different latitude regions located in Jilin, Jiangsu, and Yunnan in China. The results showed that organic compost had different decomposition rates at the three different sites, with the highest decomposition rate in Yunnan, followed by Jiangsu and Jilin. The decomposition rates of unsterilized organic compost were significantly greater than those of sterilized organic compost, indicating that the microorganisms in organic compost also made important contributions to the decomposition process. The soil microbial diversity and community structure among the three sites were significantly different. The fungal community, especially fungal richness, rather than the bacterial community in the soil, plays a major role in the decomposition of organic compost. The annual average temperature is an important environmental factor affecting fungal richness. This study will provide a reference for formulating agricultural fertilization models in different regions. • Organic composts had the highest decomposition rate in Yunnan, followed in Jiangsu and Jilin. • The microorganism in organic compost also made important contributions to the decomposition process. • The soil microbial diversity and community structure among the three sites are significantly different. • The fungal community in the soil plays a major role in the decomposition of organic composts, especially fungal richness. [ABSTRACT FROM AUTHOR]

Closing yield (YG) and nitrogen use efficiency (NUE) gaps amongst smallholder farmers are critical to ensuring food security and environmental sustainability. Here we report a comprehensive analysis of a data set derived from farm-surveys and previously published studies in a typical high N input area of China. Using scenario analysis, farmers from both sources were divided into four rice production levels to assess the YG and NUE of smallholder farmers. Farm surveys showed that rice yield and partial factor productivity of applied N (PFPN) averaged 8273 kg ha−1 and 23.1 kg kg−1 at regional-scale, with a potential increase of 21–43% and 33–52%, respectively. A wide variation in yield and PFPN across different types of farmer was observed. Optimized N management significantly narrowed YGs by 3.7% and PFPN gap by 63.5% on average based on the published literature. Multiple factors, including excessive N rates, small rice planting area (0.33 ha), the aging (51 years old) and low education level (6 years of education) of the major labor force, can partly explain causes of yield and NUE gaps. These findings provide farm-based evidence that centralized management, good agronomy plus advances in knowledge and technologies are essential for future agricultural development. [ABSTRACT FROM AUTHOR]