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Direct-seeding is an effective canola cultivation method for saving production costs compared with transplanting seedling. The aim of this study was to understand the effects of wide–narrow row arrangement and of plant density on canola yield as well as its related parameters under mechanized direct-seeding farming system. A 3-year field experiment was conducted to evaluate the influences of different row spacing arrangements and plant densities on seed yield and canopy radiation use efficiency in three growing seasons (2009–2012). Treatments included two levels of plant densities (15 and 45 plants m −2 ), in combination with six levels of row spacing arrangements (three uniform row spacings and three wide–narrow row spacings). Results showed that the wide–narrow row arrangements of “20 + 20 + 40” cm (S6) increased average seed yields by 10% above the conventional 30 cm spacing (S2) in three experimental seasons. The treatment of “17.5 + 17.5 + 17.5 + 35 + 17.5 + 17.5 + 17.5 + 60” cm (S4) was exclusively designed as a wide–narrow row plantation for purpose of mechanization management, but yield of S4 did not decrease compared with S2. Meanwhile, plant density of 45 plants m −2 produced more yield than that of 15 plants m −2 by 4% in 2009–2010, by 7% in 2010–2011 and by 10% in 2011–2012. More effective pods per plant (about 17%) were achieved in wide–narrow row arrangements comparing with uniform ones, which were further supported by higher leaf area index and radiation use efficiency. S6 had 10–28% greater radiation use efficiency than S2 in three seasons. Hence an appropriate wide–narrow row arrangement could not only intercept more favorable photosynthetic active radiation, but also led to record substantially higher above-ground biomass accumulation (22%–33%) and more seed number per m 2 (approximately 28%) compared with S2. Based on yield performance, the combination of 45 plants m −2 and S6 is the optimal scheme for canola production, and S4 is a promising alternative for planting mechanization under direct-seeding cropping system in Central China. [ABSTRACT FROM AUTHOR]

Microplastic pollution resulting from industrialization and urbanization is increasingly serious. Hangzhou is a city with high industrial/urban growth in Southeast China. Focusing on the microplastic pollution in the Hangzhou section Qiantang River, six samples were collected and analyzed during different hydrological periods (normal, wet, and dry periods) and the relationship between microplastic pollution and economic development was investigated. Results showed that more microplastics were found during the dry period than that of the wet period (49.8 vs. 13.2%). Microplastic abundance was 1.5–9.4 items L−1, showing significant spatial differences in sampling sites. Among the collecting microplastics, debris and fibers accounted for 36.4 and 30.9%. Polyethylene terephthalate and polyvinyl chloride were the main polymers, accounting for 48.3 and 31.8%, respectively. Microplastics with size <1 mm accounted for 60% of the microplastics in surface water samples. Spatially, microplastic abundance was the highest in the middle of the river. Redundant analysis revealed that the per capita GDP (p = 0.002), high-end equipment industry (p = 0.028) and fashion manufacturing (p = 0.006) influenced microplastic abundance. Urbanization coupled with rapid economic development led to increase in local microplastic pollution. Our results provide insight into microplastic distribution patterns in urban river systems in China. [Display omitted] • PVC and PET are the major microplastic components in the Qiantang River. • Microplastic pollution is related to the Per Capita GDP and industry structure. • Urbanization and economic development contributed to the microplastic pollution. [ABSTRACT FROM AUTHOR]