Abstract:Composting is considered to be the primary treatment method for livestock manure and rice straw, and high degree of maturity is the principal requirement for safe land application of composting product. In this study pilot-scale experiments were carried out to characterize the co-composting of livestock manure and rice straw, as well as to establish a maturity evaluation index system for the composts obtained.Two pilot composting piles with different feedstocks were conducted for 3 months: (1) swine manure and rice straw (SM-RS); and (2) dairy manure and rice straw (DM-RS).During the composting process, parameters including temperature, moisture, pH, total organic carbon (TOC), organic matter (OM), different forms of nitrogen (total, ammonia and nitrate), and humification index (humic acid and fulvic acid) were monitored in addition to germination index (GI), plant growth index (PGI) and Solvita maturity index. OM loss followed the first-order kinetics equation in both piles, and slightly higher OM mineralization rate was achieved in SM-RS pile. Also, SM-RS pile exhibited slightly better performance than DM-RS from the evolutions of temperature, OM degradation, GI and PGI. The C/N ratio, GI and PGI could be included in the maturity evaluation index system in which GI > 120% and PGI >1.00 signal mature co-composts.

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A novel satellite-like structure of metal nanocrystals decorated on silicon@carbon core–shell nanoparticles achieves boosting of the initial coulombic efficiency.

Semiconducting metal oxides with abundant active sites are regarded as promising candidates for environmental monitoring and breath analysis because of their excellent gas sensing performance and stability. Herein, mesoporous WO 3 nanofibers with a crystalline framework and uniform pore size is successfully synthesized in an aqueous phase using an electrospinning method, with ammonium metatungstate as the tungsten sources, and SiO 2 nanoparticles and polyvinylpyrrolidone as the sacrificial templates. The obtained mesoporous WO 3 nanofibers exhibit a controllable pore size of 26.3–42.2 nm, specific surface area of 24.1–34.4 m 2 g −1 , and a pore volume of 0.15–0.24 cm 3 g −1 . This unique hierarchical structure, with uniform mesopores and interconnected channels, could facilitate the diffusion and transportation of gas molecules in the framework. Gas sensors, based on mesoporous WO 3 nanofibers, exhibit an excellent performance in acetone sensing with a low limit of detection (<1 ppm), short response-recovery time (24 s/27 s), a linear relationship in a broad range, and good selectivity.

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With the rise of large-scale crop plantation in China, inexpensive but efficient remotesensing measures for predicting the nitrogen status of crops are needed for optimal fertilizer management. In this research, a conventional digital camera with a charge coupled device was integrated into an unmanned aerial vehicle (UAV) to capture digital aerial images of paddy rice (Oryza sativa L.) at an altitude of 50 m. The fluorescence emissions of the rice leaves under light excitation were used by Multiplex® to non-destructively assess the chlorophyll and polyphenol content. The nitrogen balance index (NBI) of the rice leaves, known as the ratio of chlorophyll to polyphenols, was used to accurately determine canopy nitrogen concentrations. The dark green colour index (DGCI) available from the aerial images was used to assess the nitrogen concentrations in the field. It was found that DGCI values predicted the nitrogen concentrations and NBI with R 2 (coefficient of determination) = 0.672 (p < 0.001) and R 2 = 0.711 (p < 0.001), respectively. The results indicated that aerial photography from UAV had the ability to assess plant nitrogen status in the field in large-scale crop plantations.

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