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Field experiments of sweet corn were carried out in Boluo county and Huiyang county of Guangdong province simultaneously in 2017 to determine the effects of one-off application of controlled-release urea combined with common urea on the biomass accumulation and nitrogen accumulation of spring sweet corn. Four treatments were employed in the experiments, including no nitrogen application treatment(CK), conventional nitrogen application treatment(U100, three times application) and 2 controlled-release urea combined with common urea under one-off application treatments (CCU100 and CCU80, which denoted 0% and 20% reduction of N rate based on U100, respectively). The blending ratio of controlled-release urea and common urea in CCU100 and CCU80 was 7:3. The results showed that nitrogen release characteristics of controlled-release urea in soil under spring sowing sweet corn were similar to the "S" line, and more than 85% of nitrogen from controlled-release urea had been released. The cumulative release rate of nitrogen from controlled-release urea was correlated with accumulated temperature positively. Comparing with U100, the biomass of sweet corn in CCU100 were increased by 4.68% (Boluo) and 6.75% (Huiyang) averagely, the nitrogen uptake of sweet corn in CCU100 were increased by 2.74% (Boluo) and 6.20% (Huiyang) averagely. No significant differences in accumulative of biomass of sweet corn between CCU80 and U100 treatments were observed. During harvest, the N uptake of sweet corn at Boluo in CCU80 treatment was 10.02% lower than that of U100 treatment (P<0.05). Compared with U100 treatment, the yield of CCU100 and CCU80 treatment did not decrease significantly. Compared with U100 treatment, the agronomic N use efficiencies and N recovery efficiency were significantly increased in CCU80 treatment(P<0.05), with an increase of 14.20% (Boluo) and 10.16% (Huiyang), and 4.92% (Boluo) and 22.03% (Huiyang) respectively. During harvest, N contents of straw and ear were increased significantly due to nitrogen application, but no significant differences in the nitrogen, phosphorus and potassium contents of straw and ear were observed among different N fertilization treatments. To sum up, for the production of spring sowing sweet corn in Guangdong province, one-off application of controlled-release urea combined with conventional urea could increase the nitrogen use efficiency while maintained crop yield, so it's an effective way to save labor and increase profit. [ABSTRACT FROM AUTHOR]

The CRF01_AE and CRF07_BC clades dominate the human immunodeficiency virus (HIV) epidemics in China. Both clades have been identified in the men who have sex with men (MSM) population in Guangdong province, raising a serious concern of possible complex recombination events ahead. Here, we report the first case of CRF01_AE/CRF07_BC recombinant sampled from a MSM patient in southern China. The genomic structure of this case is a mosaic with some regions resembling the CRF01_AE and CRF07_BC clades. Our phylogenetic analyses show that the two parental lineages of this recombinant virus were mainly found in the MSM population. This case has a different genomic composition compared with other recombinants descended from the same parental clades CRF01_AE and CRF07_BC. Our finding suggests that the MSM populations have become a hotspot for expanding viral diversity through the viral recombination mechanism. Therefore, further epidemiologic surveillance and monitoring should be conducted within the MSM populations to help advance our knowledge of viral transmission mechanisms. Additionally, these measures will serve to enhance the control and prevention of HIV/acquired immunodeficiency syndrome in China. [ABSTRACT FROM AUTHOR]