[Atmospheric Ammonia/Ammonium-nitrogen Concentrations and Wet and Dry Deposition Rates in a Double Rice Region in Subtropical China].

Ammonia (NH) is the most abundant alkaline gas in the ambient air, and it is also one of the important precursors for the ammonium salts in aerosol and rainwater. Though the emission intensities of NH and acidic gases are high, the concentrations and deposition rates of atmospheric ammonia-nitrogen (NH-N), particulate ammonium-nitrogen (NH-N) and rainwater ammonium-nitrogen (NH-N) in double rice regions in subtropical China are still less known. In this study, atmospheric concentrations of NH-N, NH-N in PM and NH-N and related meteorological parameters were observed simultaneously in a typical double rice region in the subtropical hilly region of China, with the aim to clarify the characteristics and influencing factors of atmospheric NH/NH-N concentrations and to quantify the wet and dry deposition rates of atmospheric NH/NH-N.

[Physiological Characteristics and Nitrogen and Phosphorus Uptake of Under High Ammonium Conditions].

Ammonium nitrogen (NH-N) at high concentrations is toxic to plants. In order to explore the NH-N tolerance of () and its ability of nitrogen (N) and phosphorus (P) uptake, this study used a nutrient solution with three NH-N levels (70, 210, 420 mg·L) to incubate for 21 d. The characteristics of plant physiology and N and P uptake of were measured.

[Distribution and Dynamics of Cropland Soil Organic Carbon in Jianghan Plain: A Case Study of Qianjiang City].

Taking an example of Qianjiang City in Jianghan Plain, the distribution and dynamics of soil organic carbon (SOC) in croplands was studied in present study. The cropland included both paddy field and dry land. SOC contents were analyzed by taking soil samples of topsoil (0-20 cm) in 2011 according to land uses and soil types, and then compared with the initial SOC conducted in the period of the second soil survey (1983).