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Liu M.,Nanjing Agricultural University | Chen X.,Nanjing Agricultural University | Chen X.,Teagasc | Griffiths B.S.,Teagasc | And 3 more authors.
European Journal of Soil Biology | Year: 2012

Responses of nematode assemblages and soil function (short-term decomposition) in restored and degraded soil following an experimental disturbance (copper, chloroform, heat or drying) were monitored for 65 days. We tested the hypotheses: restoration enhanced the measured soil parameters; stability to disturbance was higher in degraded soil due to induced tolerance; and whether changes of the nematode assemblage were related to soil function. Even after disturbance, greater nematode abundance (>150 vs >10 per 100g soil), nematode richness (D'>1.0 vs >0.4) and function (>1.0 vs >0.05mg CO 2g -1 week -1) were maintained in restored than in degraded soil, respectively. An increase in nematode enrichment index (from 60 to >75) following all disturbances was attributed to the relatively high abundance of tolerant fungivores. The greater stability of the nematode structure index in degraded soil following heat and drying (120% and 125% respectively of the control), than in restored soil (90% and 30% of control) was due to a higher proportion of tolerant omnivores and carnivores. Thus some higher trophic level nematodes, with high c-p values, were tolerant to disturbance. However, stability of function was greater for restored than degraded soil, with a reduction over time in the degraded soil regardless of disturbance type. The differences in the responses of nematodes and soil function to disturbance suggest that nematodes could provide complementary insights into soil stability. © 2011 Elsevier Masson SAS. Source

Shen W.,Nanjing Normal University | Shen W.,Tokyo University of Science | Xu T.,Nanjing Normal University | Liu J.,Nanjing Normal University | And 3 more authors.
Soil Science and Plant Nutrition | Year: 2015

Ammonia-oxidizing archaea (AOA) have more importance in ammonia oxidation than ammonia-oxidizing bacteria (AOB) in acidic red soils. The aim of this study was to investigate if the abundance and composition of AOA could be altered by long-term application of organic manure in an acidic red soil. The abundance and composition of AOA were evaluated by polymerase chain reaction (PCR) and denaturing gradient gel electrophoresis (DGGE) targeting archaeal amoA genes after long-term (24-year) application of mineral fertilizer and/or organic manure. The treatments were: non-fertilized control, mineral nitrogen (N) fertilizer only, mineral N, phosphorus (P) and potassium (K) fertilizer only, organic manure only, and organic manure plus mineral NPK fertilizer. The abundance of archaeal amoA genes was significantly increased after the long-term application of organic manures, either with or without mineral NPK fertilizer. So were the Shannon and Richness diversity indices of AOA deduced from the DGGE patterns. Phylogenetic analyses showed that most of the AOA sequences from various fertilization treatments were affiliated with group 1.1b thaumarchaea and only one with the group 1.1a-associated thaumarchaea. Nitrification potential was significantly increased after the long-term application of organic manures in comparison with the non-fertilized control. Our results strengthened the importance of organic manure in promoting the growth of AOA and thus nitrification potential in the acidic red soils. © 2015 Japanese Society of Soil Science and Plant Nutrition. Source

Huang S.,Jiangxi Agricultural University | Sun Y.,Jiangxi Agricultural University | Yu X.,Jiangxi Institute of Red Soil | Zhang W.,Chinese Academy of Agricultural Sciences
Biology and Fertility of Soils | Year: 2015

Temperature and moisture effects on organic carbon (C) decomposition (i.e., CO2 and CH4 emissions) determine the feedback of soil organic carbon (SOC) stocks in rice (Oryza sativa L.) paddies to climate change. In the present study, soils from a long-term (initiated in 1981) fertilization experiment [unfertilized control, combined inorganic nitrogen, phosphorus, and potassium fertilization (NPK), inorganic NPK plus organic manure (NPKM)] were incubated at 20 and 30 °C under both aerobic and anaerobic conditions. Relative to aerobic conditions, anaerobic conditions significantly reduced CO2 and total C release, but led to CH4 production. On average, the temperature sensitivity (Q10) of CH4 production was 7.4 times greater than that of CO2 production. Under anaerobic conditions, the contribution rates of CH4 production to total C release significantly increased from an average of 2.4 % at 20 °C to 14.5 % at 30 °C, and to the global warming potential (GWP) from 18.1 to 59.9 %, respectively. Anaerobic conditions significantly reduced the Q10 of CO2 and total C release, but increased that of GWP. Manure-amended soils showed higher CO2 and CH4 production on a per gram soil C basis and lower Q10 of CO2 and total C production, but higher Q10 of CH4 production than those of the control and NPK soils. Therefore, our results suggest that there are significant interactive effects of temperature, moisture, and fertilization regimes on SOC decomposition in the paddy soil. © 2015 Springer-Verlag Berlin Heidelberg Source

Sun Y.,Nanjing Agricultural University | Huang S.,Jiangxi Agricultural University | Yu X.,Jiangxi Institute of Red Soil | Zhang W.,Nanjing Agricultural University | Zhang W.,Chinese Academy of Agricultural Sciences
Journal of Soils and Sediments | Year: 2013

Purpose: Soil organic carbon (SOC) sequestration in croplands plays a critical role in climate change mitigation and food security, whereas the stability and saturation of the sequestered SOC have not been well understood yet, particularly in rice (Oryza sativa L.) fields. The objective of this study was to determine the long-term effect of inorganic fertilization alone or combined with organic amendments on SOC stability in a double rice cropping system, and to characterize the saturation behavior of the total SOC and its fractions in the paddy soil. Materials and methods: Soils were collected from a long-term field experiment in subtropical China where different fertilization regimes have been carried out for 31 years. The total SOC pool was separated into four fractions, characteristic of different turnover rates through chemical fractionation. Annual organic carbon (C) inputs were also estimated by determining the C content in crop residues and organic amendments. Results and discussion: Relative to the initial level, long-term double rice cropping without any fertilizer application significantly increased SOC concentration, suggesting that double rice cropping facilitates the storage and accumulation of SOC. The partial substitution of inorganic fertilizers with organic amendments significantly increased total SOC concentration compared to the unfertilized control. Total SOC increased significantly with greater C inputs and did not show any saturation behavior. Increased SOC was primarily stored in the labile fraction with input from organic amendments. However, other less labile SOC fractions showed no further increase with greater C inputs exhibiting C saturation. Conclusions: While the paddy soil holds a high potential for SOC sequestration, stable C fractions saturate with increasing C inputs, and thus, additional C inputs mainly accumulate in labile soil C pools. © 2013 Springer-Verlag Berlin Heidelberg. Source

Jing Y.,Nanjing Agricultural University | Chen X.-M.,Nanjing Agricultural University | Liu Z.-X.,Nanjing Agricultural University | Huang Q.-R.,Jiangxi Institute of Red Soil | And 3 more authors.
Chinese Journal of Applied Ecology | Year: 2013

Aiming at the low content of available phosphorus in upland red soil of Southern China, this paper studied the effects of combined application of biochar and inorganic fertilizers on the available phosphorus and organic carbon contents and the pH of this soil. With the combined application of biochar and inorganic fertilizers, the soil physical and chemical properties improved to different degrees. As compared with the control, the soil pH and the soil organic carbon and available phosphorus contents at different growth stages of oil rape after the combined application of biochar and inorganic fertilizers all had an improvement, with the increments at bolting stage, flowering stage, and ripening stage being 16%, 24% and 26%, 23%, 34% and 38%, and 100%, 191% and 317%, respectively. The soil pH and the soil organic carbon and available phosphorus contents were increased with the increasing amount of applied biochar. Under the application of biochar, the soil available phosphorus had a significant correlation with the soil pH and soil organic carbon content. This study could provide scientific basis to improve the phosphorus deficiency and the physical and chemical properties of upland red soil. Source

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