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In order to explore the suitable harvest period of winter sweet corn straw in western Guangdong, Jinyinsu NO. 2, which is widely planted in western Guangdong, was selected as the test material and planted in the experimental field of Guangdong Ocean University. Straw was harvested 5, 10 and 15 days after fresh ears were picked, and the nutrients, fermentation quality and rumen degradation rate were measured after 60 days of silage fermentation. The results showed that with the extension of the harvest period, the concentrations of dry matter (DM), crude protein (CP), soluble sugar (SS), starch, acid detergent insoluble protein (ADICP), soluble protein (SCP), rumen degrading protein (RDP), and the degradation rate of neutral detergent fiber (NDFD) and dry matter degradation rate (DMD) at 24 and 48 h were significantly increased (P<0.05). The contentrations of ammoniacal nitrogen (NH3-N), NH3-N/TN and acetic acid (AA) were the highest in the straw silage harvested on the 15th day (P<0.05). The study indicates that it is advisable to harvest straw 15 days after harvesting the ears for winter planting Jinyinsu NO.2 in western Guangdong. [ABSTRACT FROM AUTHOR]

Arid and semi-arid regions in West China are ecologically fragile zones. Increasing attention has been focused on soil pollution triggered by mining and smelting in those areas. Nine heavy metals in the soil around a mining and smelting plant in Xinjiang were investigated using multivariate analysis, the geoaccumulation index, and GIS techniques. The heavy metals Cu and As were identified as the main pollutants in the study area. The accumulation of the heavy metals Cr, Zn, Ni, and Cd is small and weakly disturbed by human activity. Anthropogenic accumulation of Co and Pb was observed at a few sampling sites; its degree was also small. Anthropogenic accumulation of Mn in soil was not apparent. The factor analysis indicates two sources for the nine heavy metals in the soils. Source 1 includes As, Cu, Ni, Cr, Zn, Cd, and Co, while Source 2 includes Mn and Pb. The spatial distribution suggests that the sites with the highest As, Cu, Ni, Cr, Zn, Pb, Cd, and Co concentrations are in areas close to the tailing dump. The sealing tailing dump is the prior way to prevent the spread of heavy metals. The results also reveal that the PCA/APCS receptor model is not applicable for the quantification of the contribution of heavy metals in soils in this case.