Nitrogen mineralization processes of soils from natural saline-alkalined wetlands, Xianghai National Nature Reserve, China

2005 ◽  
Vol 85 (3) ◽  
pp. 359-367 ◽  
Author(s):  
Junhong Bai ◽  
Hua Ouyang ◽  
Wei Deng ◽  
Qinggai Wang ◽  
Hui Chen ◽  
...  

Nitrogen mineralization was evaluated using a 12-wk anaerobic incubation at 30°C in two wetland soils located in Xianghai National Nature Reserve, China. The Erbaifangzi wetland is an open wetland because it hydrologically connected to the surrounding ecosystem, whereas the Fulaowenpao wetland is a closed wetland, which is not hydrologically connected. Nitrogen mineralization was fitted to an effective cumulative temperature model. Nitrogen mineralization increased gradually with increases in the cumulative temperature and decreased with depth in the soil profile. Nitrogen mineralization was positively correlated with total N (TN) or soil organic matter (SOM), but not with soil pH. Basal N mineralization was found to be greater in the Fulaowenpao wetland (0 .314g N m-2 d-1) than the Erbaifangzi wetland (0.230 g N m-2 d-1). Key words: Saline-alkalined wetland; marsh soils; nitrogen mineralization; anaerobic incubation; the effective cumulative temperature model

1971 ◽  
Vol 7 (4) ◽  
pp. 345-349
Author(s):  
I. S. Cornforth

SUMMARYSoil properties influencing N mineralization, and hence the potential N-supplying power of 154 West Indian soils, have been studied. Mineralizable N was correlated with the activity of the soil biomass measured as extractable glucose, with exchangeable bases in base-deficient soils and with total N in soils well supplied with bases, but not with other estimates of the nature of soil organic matter (e.g. extractable chlorophyll or C : N ratio). It is suggested that cation exchange capacity and percentage base saturation may influence the N-supplying power of West Indian soils more than their total N content.


2017 ◽  
Vol 111 ◽  
pp. 44-59 ◽  
Author(s):  
Hugues Clivot ◽  
Bruno Mary ◽  
Matthieu Valé ◽  
Jean-Pierre Cohan ◽  
Luc Champolivier ◽  
...  

Soil Research ◽  
1998 ◽  
Vol 36 (4) ◽  
pp. 655 ◽  
Author(s):  
A. Conteh ◽  
G. J. Blair ◽  
I. J. Rochester

The contribution of cotton stubble to the soil organic matter content of Vertisols under cotton production is not well understood. A 3-year experiment was conducted at the Australian Cotton Research Institute to study the effects of burning and incorporating cotton stubble on the recovery of fertiliser nitrogen (N), lint yield, and organic matter levels. This study reports on the changes in soil organic matter fractions as affected by burning and incorporating cotton stubble into the soil. Soil samples collected at the start and end of the 3-year experiment were analysed for total carbon (CT), total N (NT), and δ13C (a measure of 13C/12C isotopic ratios). Labile carbon (CL) was determined by ease of oxidation and non-labile carbon (CNL) was calculated as the difference between CT and CL. Based on the changes in CT, CL, and CNL, a carbon management index (CMI) was calculated. Further analyses were made for total polysaccharides (PT), labile polysaccharides (PL), and light fraction C (LF-C). Stubble management did not significantly affect the NT content of the soil. After 3 years, the stubble-incorporated plots had a significantly higher content of CT, CL, and polysaccharides. Incorporation of stubble into the soil increased the CMI by 41%, whereas burning decreased the CMI by 6%. The amount of LF-C obtained after 3 years in the stubble-incorporated soil was almost double that obtained in the stubble-burnt soil. It was concluded that for sustainable management of soil organic matter in the Vertisols used for cotton production, stubble produced in the system should be incorporated instead of burnt.


Soil Research ◽  
2002 ◽  
Vol 40 (1) ◽  
pp. 161 ◽  
Author(s):  
A. Möller ◽  
K. Kaiser ◽  
N. Kanchanakool ◽  
C. Anecksamphant ◽  
W. Jirasuktaveekul ◽  
...  

Sulfur, besides phosphorus, is crucial for the nutrition of plants on tropical soils. Its availability is closely related to the turnover of soil organic matter. To get a better insight into transformation of soil S forms during the decomposition of organic matter, we studied inorganic and organic S pools in bulk samples and alkaline extracts of soils under different land uses representative of the tropical highlands of northern Thailand. Samples were taken from a cabbage cultivation, a Pinus reforestation, a secondary forest, and a primary forest. Total S ranged from 483 549 mg/kg in the subsoil to 1909 376 mg/kg in the organic layers, which is relatively high for tropical soils. The major S component in soil was organic S, comprising 75–99% of total S. Organic S was significantly correlated with total S, organic C, and total N, indicating that there is a close relationship between C, N, and S cycling in soil. C-bonded S was the predominant form in the topsoils (35–99% of total S) but its presence decreased with soil depth. The maximum concentrations of ester SO4-S were found in the A horizons (128 49 mg/kg), whereas the concentrations of inorganic SO4-S were small in all horizons. Compared with the forest site, the cabbage cultivation site was strongly depleted in S. C-bonded S was more depleted than ester SO4-S. A comparison of the S forms in NaOH extracts with S forms in bulk soil and C forms as indicated by 13C-NMR spectroscopy showed (i) that the extracts were very representative of soil organic S fractions and (ii) that ester SO4-S was mainly associated with O-substituted aliphatic C. In contrast, C-bonded S seemed to be connected to more-or-less all C binding types. transformation of soil organic matter, sulfate.


2011 ◽  
Vol 174 (4) ◽  
pp. 576-586 ◽  
Author(s):  
Sabine Heumann ◽  
André Schlichting ◽  
Jürgen Böttcher ◽  
Peter Leinweber

Author(s):  
Zhiyang Lie ◽  
Zhuomin Wang ◽  
Li Xue

With one-year-old Tephrosia candida trees as experimental material, influence of stand density on soil nutrient content and enzyme activity was studied. The results showed that density had little influenced on pH value in 2, 4 and 8 trees m2 stands. The contents of soil organic matter, effective nitrogen and effective phosphorus significantly increased in 2 trees m2 stands. The contents of soil organic matter and effective nitrogen significantly increased, whereas total N, total P, total K, effective N, effective P and effective K significantly decreased in 4 trees/m2 stand. Soil organic matter and nutrients except for total P significantly decreased in 8 trees m2 stand. Among the three density stands, the activities of urease, catalase and phosphatase were the lowest in 8 trees m2 stand.


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