[Effects of Long-term Fertilization on Enzyme Activities in Profile of Paddy Soil Profiles].

The enzyme activity, which is closely related to soil material cycling (mineralization, transformation, etc.), can reflect soil quality and nutrient status. In order to explore the effect of long-term fertilization on the enzyme activity in paddy soil profile (0-40 cm), soils with organic fertilizer and inorganic fertilizer, and non-fertilized soils were selected, and the carbon and nitrogen contents, and the activities of -1,4-glucosidase (BG), and -1,4--acetylglucosaminidase (NAG) in 10cm depths of soil were analyzed.

[Dynamics of Rice Photosynthesized Carbon Input and Its Response to Nitrogen Fertilization at the Jointing Stage: C-CO Pulse-labeling].

Photosynthesized carbon (C) is an important source of soil organic C in paddy fields, and its input and distribution are affected by rice growth and soil fertility. Fertilizer application plays an important role in rice growth. The C pulse-labeling method was used to quantify the dynamics and distribution of input photosynthesized C in the rice-(rhizosphere-and bulk-) soil system and its response to nitrogen fertilizer (N) application.

[Responses of Extracellular Enzymes to Nitrogen Application in Rice of Various Ages with Rhizosphere and Bulk Soil].

Ecological enzyme activities are closely relevant to the carbon and nitrogen decomposition and mineralization of paddy soils, which can reflect the growth and metabolism of microorganisms. In order to clarify the response to nitrogen application by different enzymes in the rhizosphere and bulk soil of rice, the rhizosphere and bulk soil were identified using a rhizosphere bag. In addition, the -1,4-glucosidase (BG) enzyme; -1,4--acetylglucosaminidase (NAG) enzyme; and the effects of the rhizosphere, nitrogen application, and growth period on soil enzyme activities were analyzed.

[Characteristics and Influencing Factors of Biologically-based Phosphorus Fractions in the Farmland Soil].

A suitable fractionation method of phosphorus (P) is a key to effective assessment of soil P componential features. Here a new biologically-based P (BBP) method was used to evaluate the P fractions in the upland and paddy soils across large-scale area in China. The soil P was divided into four components:① soluble or rhizosphere-intercepted (CaCl-P), ② organic acid activated and inorganic weakly bound (Citrate-P), ③ enzyme mineralization of organic P (Enzyme-P), ④ potential activation of inorganic P (HCl-P).

[Characteristic of Abundances and Diversity of Carbon Dioxide Fixation Microbes in Paddy Soils].

To get a better understanding of the microbial autotrophic carbon sequestration potential of paddy fields and its mechanisms, soil incubation experiment was conducted for four representative paddy soils. The molecular biological methods[quantitative PCR (qPCR), clone library and terminal-restriction fragment length polymorphism (T-RFLP) technique] based on and genes encoding the key enzymes[ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO)] of Calvin cycle were used to determine the abundance and diversity of autotrophic microbes. The results showed that, after 45 days of incubation, carbon dioxide fixation autotrophic microbial abundances were generally increased compared with those before incubation, and gene abundances were approximately three magnitudes higher than those of .

[Effects of Different Plantation Type on the Abundance and Diversity of Soil Microbes in Subtropical Red Soils].

Soil microbe plays an important role in carbon cycling, however, the effect of land use on soil microbe remain unclear. In present study, soil samples were collected from a long-term field experiment (Pantang Agroecosystem) in subtropical China (established in 1989), including paddy-rice (PR), upland-crop (UC), and paddy rice-upland crop rotation (PU) on soil bacterial (bacteria and Archaea) community structures. The effects of long-term different land uses were determined using terminal restriction fragment length polymorphism (T-RFLP) and quantitative PCR (RT-PCR) of the 16S rRNA gene.

[Effects of long-term fertilization on bacterial and archaeal diversity and community structure within subtropical red paddy soils].

Paddy soils not only function as an important sink for "missing carbon" but also play an important role in the production of greenhouse gases such as N2O and CH4. Dynamic changes in greenhouse gases in the atmosphere are closely related to microbially mediated carbon and nitrogen transformation processes occurring in soil. Using soil samples collected from a long-term fertilization experimental site in Taojiang County, subtropical China (established in 1986), we determined the effects of long-term (>25 years) non-fertilization (CK), chemical fertilization (NPK), and NPK combined with rice straw residues (NPKS) on soil bacterial and archaeal community structures.

[Characteristics of the mineralization and transformation of autotrophic microbes-assimilated carbon in upland and paddy soils].

In this study, the mineralization and decomposition of autotrophic microbe assimilated carbon (new carbon) and native organic carbon in three upland and three paddy soils in subtropical China were measured using the 14C-labelled tracer technique. The results showed that, during the 100-d incubation, the mineralization of the 'new carbon' displayed three stages: a rise in the first 10 days, a slowdown from 11-d to 50-d, and a stabilization stage after 50 d. The mineralization ratio of the 'new carbon' ranged between 8.

[Input and distribution of rice photosynthesized carbon in the tillering stage under different nitrogen application following continuous 13C labeling].

The input of rice-photosynthesized carbon (C) into soil plays an important role in soil C cycling. A 13C-labelled microcosm experiment was carried out to quantify the input of photosynthesized C into soil C pools in a rice-soil system during the tillering stage. Growing rice (Oryza sativa L.

[Application of magnetic materials in analysis on Chinese herb medicines].

China is the cradle of Chinese herb medicines,with rich plant resources. However, traditional processing methods have many disadvantages, such as high comsumption of organic solvent, long extraction time and high loss of effective constituents. For the purpose of rational use of Chinese herb medicines and accurate analysis on their constituents,the sample pre-treatment method with magnetic nanoparticles as the carrier brought new opportunities in recent years.