The objectives for this study were to determine changes in soil organic carbon(SOC)components and water-stable aggregates for soil profi les from diff erent ages of plantations of Liriodendron chinense and to clarify ...The objectives for this study were to determine changes in soil organic carbon(SOC)components and water-stable aggregates for soil profi les from diff erent ages of plantations of Liriodendron chinense and to clarify which organic carbon component is more closely associated with the formation and stability of soil aggregates.Three layers of soil(depths 0–20 cm,20–40 cm,40–60 cm)were collected from young,half-mature and mature stages of L.chinense.SOC,readily oxidizable organic carbon,chemically stable organic carbon and aggregate composition were determined.Intermediate stable organic carbon,the microbial quotient and aggregate stability(mean weight diameter)were calculated.SOC and aggregate stability in the L.chinense plantation did not increase linearly with an increase in L.chinense age;rather,they fi rst decreased,then increased with increasing age of L.chinense.The microbial quotient had a negative eff ect on the level of organic carbon and the stability of aggregates,while chemically stable organic carbon had a positive eff ect,which explained 55.0%and 19.3%of the total variation,respectively(P<0.01).Therefore,more attention should be paid of these two indicators in the future.展开更多
The dynamics of soil organic carbon （SOC） was analyzed by using laboratory incubation and double exponential model that mineralizable SOC was separated into active carbon pools and slow carbon pools in forest soils ...The dynamics of soil organic carbon （SOC） was analyzed by using laboratory incubation and double exponential model that mineralizable SOC was separated into active carbon pools and slow carbon pools in forest soils derived from Changbai and Qilian Mountain areas. By analyzing and fitting the CO2 evolved rates with SOC mineralization, the results showed that active carbon pools accounted tor 1.0% to 8.5% of SOC with an average of mean resistant times （MRTs） for 24 days, and slow carbon pools accounted for 91% to 99% of SOC with an average of MRTs for 179 years. The sizes and MRTs of slow carbon pools showed that SOC in Qilian Mountain sites was more difficult to decompose than that in Changbai Mountain sites. By analyzing the effects of temperature, soil clay content and elevation on SOC mineralization, results indicated that mineralization of SOC was directly related to temperature and that content of accumulated SOC and size of slow carbon pools from Changbai Mountain and Qilian Mountain sites increased linearly with increasing clay content, respectively, which showed temperature and clay content could make greater effect on mineralization of SOC.展开更多
Soil organic carbon(SOC)mineralization is closely related to carbon source or sink of terrestrial ecosystem.Natural stands of Larix olgensis on the Jincang forest farm,Jilin Province were selected to investigate the d...Soil organic carbon(SOC)mineralization is closely related to carbon source or sink of terrestrial ecosystem.Natural stands of Larix olgensis on the Jincang forest farm,Jilin Province were selected to investigate the dynamics of SOC mineralization and its correlations with other soil properties in a young forest and mid-aged forest at soil depths of 0–10,>10–20,>20–40 and>40–60 cm.The results showed that compared with a mid-aged forest,the SOC stock in the young forest was 32%higher.Potentially mineralizable soil carbon(C0)in the young forest was 1.1–2.5 g kg^-1,accounting for 5.5–8.1%of total SOC during the 105 days incubation period and 0.3–1.5 g kg^-1 in the mid-aged forest at different soil depths,occupying 2.8–3.4%of total SOC.There was a significant difference in C0 among the soil depths.The dynamics of the SOC mineralization was a good fit to a three-pool(labile,intermediate and stable)carbon decomposition kinetic model.The SOC decomposition rate for different stand ages and different soil depths reached high levels for the first 15 days.Correlation analysis revealed that the C0 was significantly positively related with SOC content,soil total N(TN)and readily available K(AK)concentration.The labile soil carbon pool was significantly related to SOC and TN concentration,and significantly negatively correlated with soil bulk density.The intermediate carbon pool was positively associated with TN and AK.The stable carbon pool had negative correlations with SOC,TN and AK.展开更多
Urban forest soil is often disturbed by rapid urbanization. Organic mulching is effective for improving soil quality and aggregate stability. This study evaluated how soil binding agents changed aggregate stability th...Urban forest soil is often disturbed by rapid urbanization. Organic mulching is effective for improving soil quality and aggregate stability. This study evaluated how soil binding agents changed aggregate stability through organic mulching in urban forest soils. Three treatments were applied in Jiufeng National Forest Park, Beijing: (1) no organic mulch (control);(2) wood chips alone (5 cm thickness);and, (3) wood chips + wood compost (This mulch was divided into two layers, the upper layer of wood chips (2.5 cm), the lower layer wood compost (2.5 cm)). Soil samples were collected from the surface 10- cm soil layer and fraction into four aggregates. Glomalin-related soil protein and soil organic carbon were measured in bulk soil and the four aggregates. The results show that wood chips + wood compost increased the proportion of large and small macroaggregates, mean weight diameter and geometric mean diameter. The total and easily extractable glomalin-related soil protein were higher in the wood chips + wood compost. However, soil organic carbon was lower in the wood chips alone application compared to the controls and wood chips + wood compost. Easily extractable / total glomalin-related soil protein and glomalin-related soil protein / soil organic carbon ratios of wood chips alone and wood chips + wood compost had increased trend compared to the controls but did not reach significant levels (p > 0.05). Mean weight diameter and geometric mean diameter correlated positively with total and easily extractable glomalin-related soil protein but were not positively correlated with soil organic carbon, the ratios of easily extractable and total glomalin-related soil protein, and the ratios of glomalin-related soil protein and soil organic carbon. Redundancy analysis revealed that total glomalin-related soil protein was the most important driver for soil aggregate stability, especially the total glomalin-related soil protein of small macroaggregates. The results suggest that wood chips + wood compost enhanced soil aggregate stability through the increase of glomalin-related soil protein. Wood chips alone cannot enhance soil aggregate stability in urban forests in the short term.展开更多
Ridge culture is a special conservation tillage method, but the long-term influence of this tillage system on soil aggregate-size stability in paddy fields is largely unknown in southwest of China. The paper is to eva...Ridge culture is a special conservation tillage method, but the long-term influence of this tillage system on soil aggregate-size stability in paddy fields is largely unknown in southwest of China. The paper is to evaluate soil aggregate stability and to determine the relationship between soil organic carbon (SOC) and soil aggregate stability. Soil samples at 0 cm-20 cm layer were adopted from a long-term (16 a) field experiment including conventional tillage: plain culture, summer rice crop and winter upland crop under drained conditions (PUR-r); and conservation tillage: ridge culture without tillage, summer rice and winter fallow with floodwater layer annually (NTR-f), winter upland crop under drained conditions (NTR-r), and wide ridge culture without tillage, summer rice crop and winter upland crop under conditions (NTRw-r), respectively. Different pretreatments, such as slaking in fast wetting, wetting and subsequent slaking, were applied to simulate the breakdown mechanisms of aggregates in paddy soil. The results show that soil particles contents were mainly consisted of silt (0.050 mm to 1.000 mm) in fraction of 42.9% to 51.2%, sand (0.050 mm to 0.001 mm) in fraction of 28.0% to 31.8%, and clay (<0.001 mm) in fraction of 17.9% to 25.4%. The amount of aggregate-size was greatly observed in fraction of 2.000 mm-6.720 mm under ridge culture in paddy soil (more than 50$) under slaking and wetting pretreatment. The proportion of soil macro-aggregates (>0.250 mm) in conservation tillage was greatly higher than that in conventional tillage under subsequent fast slaking treatment. Minimal differences of aggregate stability between slaking in fast wetting and wetting were observed, while significant differences were found between ridge culture and plain culture. The aggregate stability under slaking treatment ranked in the order of NTR-r>NTRw-r> NTR-f > PUR-r, while under wetting was NTRw-r > NTR-r > NTR-f >PUR-r. There was a positive correlation between the aggregate stability and SOC concentration under wetting, and a low correlation was observed under slaking pretreatment. Soil exposure with tillage and lack of rice/rape-seed stubble inputs caused declines in aggregation and organic carbon, both of which make soil susceptible to water erosion. Adoption of ridge culture with no-tillage integrated with crop rotation and stubble mulch significantly altered soil organic concentration. It was a valuable conservation practice for soil aggregation and soil organic carbon sequestration on paddy soil.展开更多
基金the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
文摘The objectives for this study were to determine changes in soil organic carbon(SOC)components and water-stable aggregates for soil profi les from diff erent ages of plantations of Liriodendron chinense and to clarify which organic carbon component is more closely associated with the formation and stability of soil aggregates.Three layers of soil(depths 0–20 cm,20–40 cm,40–60 cm)were collected from young,half-mature and mature stages of L.chinense.SOC,readily oxidizable organic carbon,chemically stable organic carbon and aggregate composition were determined.Intermediate stable organic carbon,the microbial quotient and aggregate stability(mean weight diameter)were calculated.SOC and aggregate stability in the L.chinense plantation did not increase linearly with an increase in L.chinense age;rather,they fi rst decreased,then increased with increasing age of L.chinense.The microbial quotient had a negative eff ect on the level of organic carbon and the stability of aggregates,while chemically stable organic carbon had a positive eff ect,which explained 55.0%and 19.3%of the total variation,respectively(P<0.01).Therefore,more attention should be paid of these two indicators in the future.
基金The research was funded by National Natural Science Foundation （40231016） and Canadian International Development Agency （CIDA）.
文摘The dynamics of soil organic carbon （SOC） was analyzed by using laboratory incubation and double exponential model that mineralizable SOC was separated into active carbon pools and slow carbon pools in forest soils derived from Changbai and Qilian Mountain areas. By analyzing and fitting the CO2 evolved rates with SOC mineralization, the results showed that active carbon pools accounted tor 1.0% to 8.5% of SOC with an average of mean resistant times （MRTs） for 24 days, and slow carbon pools accounted for 91% to 99% of SOC with an average of MRTs for 179 years. The sizes and MRTs of slow carbon pools showed that SOC in Qilian Mountain sites was more difficult to decompose than that in Changbai Mountain sites. By analyzing the effects of temperature, soil clay content and elevation on SOC mineralization, results indicated that mineralization of SOC was directly related to temperature and that content of accumulated SOC and size of slow carbon pools from Changbai Mountain and Qilian Mountain sites increased linearly with increasing clay content, respectively, which showed temperature and clay content could make greater effect on mineralization of SOC.
基金jointly supported by National Key R&D Program of China(Grant No.2017YFC0504002)Natural Science Foundation of China(No.31270679)
文摘Soil organic carbon(SOC)mineralization is closely related to carbon source or sink of terrestrial ecosystem.Natural stands of Larix olgensis on the Jincang forest farm,Jilin Province were selected to investigate the dynamics of SOC mineralization and its correlations with other soil properties in a young forest and mid-aged forest at soil depths of 0–10,>10–20,>20–40 and>40–60 cm.The results showed that compared with a mid-aged forest,the SOC stock in the young forest was 32%higher.Potentially mineralizable soil carbon(C0)in the young forest was 1.1–2.5 g kg^-1,accounting for 5.5–8.1%of total SOC during the 105 days incubation period and 0.3–1.5 g kg^-1 in the mid-aged forest at different soil depths,occupying 2.8–3.4%of total SOC.There was a significant difference in C0 among the soil depths.The dynamics of the SOC mineralization was a good fit to a three-pool(labile,intermediate and stable)carbon decomposition kinetic model.The SOC decomposition rate for different stand ages and different soil depths reached high levels for the first 15 days.Correlation analysis revealed that the C0 was significantly positively related with SOC content,soil total N(TN)and readily available K(AK)concentration.The labile soil carbon pool was significantly related to SOC and TN concentration,and significantly negatively correlated with soil bulk density.The intermediate carbon pool was positively associated with TN and AK.The stable carbon pool had negative correlations with SOC,TN and AK.
基金This project was supported fi nancially by the Natural Science Foundation of Beijing Municipality(Grant number 6202021).
文摘Urban forest soil is often disturbed by rapid urbanization. Organic mulching is effective for improving soil quality and aggregate stability. This study evaluated how soil binding agents changed aggregate stability through organic mulching in urban forest soils. Three treatments were applied in Jiufeng National Forest Park, Beijing: (1) no organic mulch (control);(2) wood chips alone (5 cm thickness);and, (3) wood chips + wood compost (This mulch was divided into two layers, the upper layer of wood chips (2.5 cm), the lower layer wood compost (2.5 cm)). Soil samples were collected from the surface 10- cm soil layer and fraction into four aggregates. Glomalin-related soil protein and soil organic carbon were measured in bulk soil and the four aggregates. The results show that wood chips + wood compost increased the proportion of large and small macroaggregates, mean weight diameter and geometric mean diameter. The total and easily extractable glomalin-related soil protein were higher in the wood chips + wood compost. However, soil organic carbon was lower in the wood chips alone application compared to the controls and wood chips + wood compost. Easily extractable / total glomalin-related soil protein and glomalin-related soil protein / soil organic carbon ratios of wood chips alone and wood chips + wood compost had increased trend compared to the controls but did not reach significant levels (p > 0.05). Mean weight diameter and geometric mean diameter correlated positively with total and easily extractable glomalin-related soil protein but were not positively correlated with soil organic carbon, the ratios of easily extractable and total glomalin-related soil protein, and the ratios of glomalin-related soil protein and soil organic carbon. Redundancy analysis revealed that total glomalin-related soil protein was the most important driver for soil aggregate stability, especially the total glomalin-related soil protein of small macroaggregates. The results suggest that wood chips + wood compost enhanced soil aggregate stability through the increase of glomalin-related soil protein. Wood chips alone cannot enhance soil aggregate stability in urban forests in the short term.
基金Funded by the Key Projects of National Science & Technology Pillar Program (No.2006BAD05B0-02) Sichuan Educational Committee for Youths (No.09ZB049)
文摘Ridge culture is a special conservation tillage method, but the long-term influence of this tillage system on soil aggregate-size stability in paddy fields is largely unknown in southwest of China. The paper is to evaluate soil aggregate stability and to determine the relationship between soil organic carbon (SOC) and soil aggregate stability. Soil samples at 0 cm-20 cm layer were adopted from a long-term (16 a) field experiment including conventional tillage: plain culture, summer rice crop and winter upland crop under drained conditions (PUR-r); and conservation tillage: ridge culture without tillage, summer rice and winter fallow with floodwater layer annually (NTR-f), winter upland crop under drained conditions (NTR-r), and wide ridge culture without tillage, summer rice crop and winter upland crop under conditions (NTRw-r), respectively. Different pretreatments, such as slaking in fast wetting, wetting and subsequent slaking, were applied to simulate the breakdown mechanisms of aggregates in paddy soil. The results show that soil particles contents were mainly consisted of silt (0.050 mm to 1.000 mm) in fraction of 42.9% to 51.2%, sand (0.050 mm to 0.001 mm) in fraction of 28.0% to 31.8%, and clay (<0.001 mm) in fraction of 17.9% to 25.4%. The amount of aggregate-size was greatly observed in fraction of 2.000 mm-6.720 mm under ridge culture in paddy soil (more than 50$) under slaking and wetting pretreatment. The proportion of soil macro-aggregates (>0.250 mm) in conservation tillage was greatly higher than that in conventional tillage under subsequent fast slaking treatment. Minimal differences of aggregate stability between slaking in fast wetting and wetting were observed, while significant differences were found between ridge culture and plain culture. The aggregate stability under slaking treatment ranked in the order of NTR-r>NTRw-r> NTR-f > PUR-r, while under wetting was NTRw-r > NTR-r > NTR-f >PUR-r. There was a positive correlation between the aggregate stability and SOC concentration under wetting, and a low correlation was observed under slaking pretreatment. Soil exposure with tillage and lack of rice/rape-seed stubble inputs caused declines in aggregation and organic carbon, both of which make soil susceptible to water erosion. Adoption of ridge culture with no-tillage integrated with crop rotation and stubble mulch significantly altered soil organic concentration. It was a valuable conservation practice for soil aggregation and soil organic carbon sequestration on paddy soil.
