Nitrogen addition shifts the microbial community in the rhizosphere of Pinus tabuliformis in Northwestern China

Atmospheric nitrogen (N) deposition profoundly alters the soil microbial communities and will thus affect nutrient cycles. The effects of N availability on microbial community, however, are not clear. We used PLFA analysis to evaluate the effects of a gradient of N addition (0, 2.8, 5.6, 11.2, and 22.4 g N m(-2) y(-1)) for three years on the rhizospheric microbial community of Pinus tabuliformis seedlings. The main factors influencing the community were quantified using structural equation modelling and redundancy analysis. At the microbial-community level, N addition increased the total phospholipid fatty acids content by increasing the dissolved organic carbon (DOC) and root biomass. Increases in soil microbial biomass carbon and N, however, was attributed to the increased DOC, N content and decreased pH. At the microbial-groups level, Fungal, arbuscular mycorrhizal fungal (AMF), gram-positive bacterial (GP) abundances and the GP:GN ratio first increased and then decreased with N addition. Nitrogen addition increased the abundances of bacteria, fungi, and actinomycetes mainly by increasing the DOC content and decreasing root biomass. Additionally, the decrease of pH and ammonium N caused by N addition increased the fungal abundances and reduced actinomycete abundances, respectively. Nitrogen addition shifted the rhizospheric microbial community mainly by altering the DOC content and root biomass. The current rate of N deposition (2.5 g N m(-2) y(-1)) benefits plant growth and increases the abundances of fungi, arbuscular mycorrhizal fungi, GP, actinomycetes and the GP:GN ratio

Parental Smoking and Breastfeeding in Xinjiang, PR China

A cohort of 1088 couples in Xinjiang, PR China, were recruited to study infant feeding practices and paternal smoking. Mothers were interviewed in hospital and at 0.5, 1.5, 2.5, 3.5, 4.5, and 6 months. Survival analysis was used to calculate breastfeeding rates in smokers and nonsmokers. The paternal smoking rate was 64.8% and maternal smoking rate 1.7% (P < .01). The rates for any breastfeeding in the smoking group were significantly lower than in the nonsmoking group from 3.5 months to 6 months (P < .05). The rates for exclusive breastfeeding in the paternal smoking group were lower than in the nonsmoking group from discharge to 6 months (P < .05). The median duration of exclusive breastfeeding in the paternal smoking group was shorter than in the nonsmoking group. Paternal smoking was a risk factor for stopping any breastfeeding (hazard risk, 1.84; 95% confidence interval, 1.11-3.04) and exclusive breastfeeding (hazard risk, 1.33; 95% CI, 1.09-1.64) compared with nonsmokers. J Hum Lact. 26(3):242-247