[Regional differences of inputs of organic matter and chemical fertilizer in South Central China].

This article analyzed the inputs of organic matter and chemical fertilizer in the cropland of South Central China, i.e., Hunan, Hubei, Guangdong and Guangxi, and then calculated the budgets of nitrogen (N), phosphorus (P) and potassium (K), based on the data from field investigations and peasant household surveys in the four provinces.

[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).

[Effects of applying pig manure on lettuce yield and nitrate content and soil nutrients].

A pot experiment with two representative soils (purple soil and yellow soil) in Southwest China was conducted to study the effects of applying pig manure on the lettuce (Lactuca sativa L. var. capitata L.

[Quantifying rice (Oryza sativa L.) photo-assimilated carbon input into soil organic carbon pools following continuous 14C labeling].

The microcosm experiment was carried out to quantify the input and distribution of photo-assimilated C into soil C pools by using a 14C continuous labeling technique. Destructive samplings of rice (Oryza sativa) were conducted after labeling for 80 days. The allocation of 14C-labeled photosynthates in plants and soil C pools such as dissolved organic C (DOC) and microbial biomass C (MBC) in rice-planted soil were examined over the 14C labeling span.

[Effects of selective microbial inhibitors on the microbial transformation of phosphorous in aggregates of highly weathered red soil with rice straw amendment].

In order to further understand the mechanisms of microbial immobilization of phosphorous (P) in highly weathered red soil with organic amendment, an incubation test was conducted to investigate the roles of microbial functional groups in the transformation of P in 0.2-2 mm soil aggregates. Throughout the 90-day incubation period, amendment with rice straw induced a substantial increase in the amounts of microbial biomass C and P, Olsen-P, and organic P in the aggregates.

[Effects of water content on redox potential and carbon mineralization of wetland sediments].

To better understand the effect of soil water contents on redox potential (Eh), and their impacts on C mineralization in natural wetland, sediment samples from 3 types of wetlands (fen, humus marsh and marshy meadow) in the San-jiang Plate region of North China were incubated (25 degrees C) for 155 d under a range of reducing and oxidizing conditions by controlling water contents (varied from 24% to 232% of water holding capacity) (WHC). CO2-C evolved during incubation was measured at different time intervals. Results showed that Eh of sediments decreased significantly as water content increased from 24% WHC (lighted moisturized) to about 100% WHC, then decreased slightly as water content increased further to a level of submersed (about 2 cm water-depths).

[Effects of temperature on organic carbon mineralization in paddy soils with different clay content].

An incubation test with three kinds of paddy soil (sandy loam, clay loam, and silty clay soils) in subtropical region was conducted at 10, 15, 20, 25 and 30 degrees C to examine the response of the mineralization of soil organic carbon (SOC) to temperature change. The results showed that during the period of 160 d incubation, the accumulative mineralized amount of SOC in sandy loam, clay loam, and silty clay soils at 30 degrees C was 3.5, 5.

[Advances in extraction and purification of soil microorganism].

For the studies on soil microbial ecology and bio-diversity as well as on the dynamics of C, N, S and P in soil, it is necessary to quantitatively extract microorganism from soil. The recent advances on extraction and purification of microorganism from soil were reviewed in this paper. The procedure for extracting microorganism from soil was comprised of three steps, i.