Soil aggregate is the basic structural unit of soil,which is the foundation for supporting ecosystem functions,while its composition and stability is significantly affected by the external environment.This study was c...Soil aggregate is the basic structural unit of soil,which is the foundation for supporting ecosystem functions,while its composition and stability is significantly affected by the external environment.This study was conducted to explore the effect of external environment(wetting-drying cycles and acidic conditions)on the soil aggregate distribution and stability and identify the key soil physicochemical factors that affect the soil aggregate stability.The yellow‒brown soil from the Three Gorges Reservoir area(TGRA)was used,and 8 wetting-drying conditions(0,1,2,3,4,5,10 and 15 cycles)were simulated under 4 acidic conditions(pH=3,4,5 and 7).The particle size distribution and soil aggregate stability were determined by wet sieving method,the contribution of environmental factors(acid condition,wetting-drying cycle and their combined action)to the soil aggregate stability was clarified and the key soil physicochemical factors that affect the soil aggregate stability under wetting-drying cycles and acidic conditions were determined by using the Pearson’s correlation analysis,Partial least squares path modeling(PLS‒PM)and multiple linear regression analysis.The results indicate that wetting-drying cycles and acidic conditions have significant effects on the stability of soil aggregates,the soil aggregate stability gradually decreases with increasing number of wetting-drying cycles and it obviously decreases with the increase of acidity.Moreover,the combination of wetting-drying cycles and acidic conditions aggravate the reduction in the soil aggregate stability.The wetting-drying cycles,acidic conditions and their combined effect imposes significant impact on the soil aggregate stability,and the wetting-drying cycles exert the greatest influence.The soil aggregate stability is significantly correlated with the pH,Ca^(2+),Mg^(2+),maximum disintegration index(MDI)and soil bulk density(SBD).The PLS‒PM and multiple linear regression analysis further reveal that the soil aggregate stability is primarily influenced by SBD,Ca^(2+),and MDI.These results offer a scientific basis for understanding the soil aggregate breakdown mechanism and are helpful for clarifying the coupled effect of wetting-drying cycles and acid rain on terrestrial ecosystems in the TGRA.展开更多
The vertical variation and storage of nitrogen in the depth of 0-150 cm of an aquic brown soil were studied under 14 years of four land use patterns, i.e., paddy field, maize field, fallow field and woodland in Shenya...The vertical variation and storage of nitrogen in the depth of 0-150 cm of an aquic brown soil were studied under 14 years of four land use patterns, i.e., paddy field, maize field, fallow field and woodland in Shenyang Experimental Station of Ecology, Chinese Academy of Sciences in November of 2003. The results showed that different land uses had different profile distributions of soil total nitrogen (STN), alkali N, ammonium (NH4+-N) and nitrate (NO3--N). The sequence of STN storage was woodland >maize field > fallow field > paddy field, while that of NO3--N content was maize field > paddy field > woodland > fallow field, suggesting the different root biomass and biological N cycling under various land uses. The STN storage in the depth of 0-100 cm of woodland averaged to 11.41 thm-1, being 1.65 and 1.25 times as much as that in paddy and maize fields, respec-tively, while there was no significant difference between maize and fallow fields. The comparatively higher amount of NO3--N in maize and paddy fields may be due to nitrogen fertilization and anthropogenic disturbance. Soil alkali N was significantly related with STN, and the correlation could be expressed by a linear regression model under each land use (R20.929, p<0.001). Such a correlation was slightly closer in nature (woodland and fallow field) than in agro ecosystems (paddy and maize fields). Heavy N fertilization induced an excess of crop need, and led to a comparatively higher amount of soil NO3--N in cultivated fields than in fallow field and woodland. It is suggested that agroforestry practices have the potential to make a significant contribution to both crop production and environment protection.展开更多
Through laboratory simulation, the influence of cadmium on soil respiratory intensity and microbial community were studied by adding different concentrations of heavy metal cadmium. The results indicated that, the soi...Through laboratory simulation, the influence of cadmium on soil respiratory intensity and microbial community were studied by adding different concentrations of heavy metal cadmium. The results indicated that, the soil respiration had a signifi- cant weakening trend in the same culture days with increasing exogenous cadmium content; the soil respiration intensity was decreased obviously with the increase of culture time, especially after 14 d when the soil exogenous cadmium content was in the range of 0.5-3.0 mg/kg, while the soil respiration had not obvious variation over time when the exogenous cadmium content was in the range of 5.0-10.0 mg/kg. The soil microbial communities decreased significantly and were much lower than that of the control treatment in the same culture days with the increasing of soil exogenous cadmium content; the soil microbial community declined significantly with increasing of culture time for all exogenous cadmium treatments. The number of soil microbial communities in treatment with 10 mg/kg of exogenous cadmium were only 46.43%, 32.26%, 28.74%, 27.39% and 24.62% of that in control treatment on the 7th, 14th, 21st, 28th and 42rd of culture, respectively. It indicated that higher concen- tration of cadmium in dark brown soil had a significant inhibitory effect on soil mi- crobial growth.展开更多
[Objective] This study was conducted to investigate the effects of tradition-al fertilization and formula fertilization by soil testing on the chemical forms of nitro-gen in dark brown soil and its distribution in dif...[Objective] This study was conducted to investigate the effects of tradition-al fertilization and formula fertilization by soil testing on the chemical forms of nitro-gen in dark brown soil and its distribution in different aggregates. [Method] A physi-co-chemistry method was adopted in a comparative study on the chemical forms of nitrogen and their distribution in different-sized aggregates of dark brown soil under traditional fertilization and formula fertilization by soil testing respectively. [Result] Compared with traditional fertilization in spring and autumn, the formula fertilization by soil testing averagely decreased, the total nitrogen in soil by 23.2% in spring and by 20% in autumn in the soil layer of 0-20 cm, by 48.8% in the layer of 20-40 cm. Ammonium nitrogen was so sensitive to the methods of fertilization that the content of ammonium nitrogen was reduced much more under formula fertitization by soil testing in autumn than under traditional fertilization. Nitrogen in soil under traditional fertilization pattern was mainly distributed in the aggregates of 0-0.25 and 0.5-1 mm, while in formula fertilization by soil testing it was mainly distributed in the aggregates of 0.25-0.5 and 0-0.25 mm. [Conclusion] The study proved that for-mula fertilization by soil testing helped to reduce the risk of nitrogen pol ution and had huge effects on the chemical forms and distribution of nitrogen in different ag-gregates in dark brown soil.展开更多
The vertical distribution of the dominant genera of plant nematodes at the depth of 0–150 cm of an aquic brown soil were studied for four land use patterns, i.e., paddy field, maize field, fallow field and woodland i...The vertical distribution of the dominant genera of plant nematodes at the depth of 0–150 cm of an aquic brown soil were studied for four land use patterns, i.e., paddy field, maize field, fallow field and woodland in the Shenyang Experimental Station of Ecology, Chi- nese Academy of Sciences in November of 2003. The results showed that the numbers of some dominant genera under different land uses decreased with the increase of soil depth. Helicotylenchus was most dominant genus under each land use type. Genera of Filenchus, Psilen- chus and Tylenchus in paddy field occurred at the depth of 0–20 cm; while Paratylenchus in fallow field and woodland, as well as Praty- lenchus in maize field presented in the deeper soil layers (0–80 cm). Significant correlations between the numbers of dominant genera of plant nematodes and soil chemical properties were found in this study. The number of Helicotylenchus under different land uses was posi- tively correlated with C/N ratio, total C, total N, total P, alkai-N, and Olsen-P. The numbers of Filenchus and Paratylenchus in paddy field, Pratylenchus in maize field and Paratylenchus in fallow field were negatively correlated with soil pH, and positively correlated with total C, total N and alkai-N. This study results showed that it is essential to sample at a certain depth according to the vertical distribution informa- tion of different genera of plant nematodes in adequately assessing the population size of plant nematodes.展开更多
Many attempts have been made to estimate the soil organic carbon (SOC) storage under different land uses, especiallyfrom the conversion of forest land or grassland into cultivated field, but limited reports were found...Many attempts have been made to estimate the soil organic carbon (SOC) storage under different land uses, especiallyfrom the conversion of forest land or grassland into cultivated field, but limited reports were found on the estimation ofthis storage after cultivated field converted into woodland or grassland, especially in small scales. This study is aimed toinvestigate the dynamics of SOC concentration, its storage and carbon /nitrogen (C/N) ratio in an aquic brown soil at theShenyang Experimental Station of Ecology, Chinese Academy of Sciences under four land use patterns over 14 years. Thefour land use patterns were paddy field (PF), maize field (MF), fallow field (FF) and woodland (WL). In each pedon at 0-150cm depth, soil samples were collected from ten layers. The results showed that the profile distribution of SOC was differentunder different land uses, indicating the effect of land use on SOC. Soil organic carbon was significantly related with soiltotal N, and the correlation was slightly closer in nature ecosystems (with R2=0.990 and P<0.001 in both WL and FF, n=30)than in agroecosystems (with R2=0.976 and P<0.001 in PF, and R2=0.980 and P<0.001 in MF, n=30). The C/N ratio in theprofiles decreased generally with depth under the four land use patterns, and was comparatively higher in WL and lowerin PF. The C/N ratio of the FF was closer to that in the same soil depths of MF than to that of PF. Within 100 cm depth, theannual sequestration of SOC was 4.25, 2.87, and 4.48 t ha-1 more in WL than in PF, MF and FF, the annual SOC increasingrate being 6.15, 3.26, and 5.09 % higher, respectively. As a result, the SOC storage was significantly greater in WL than inany of the other three land use patterns, P=0.001, 0.008, and 0.008 as compared with PF, MF, and FF, respectively, whilethere was no significant difference among the other three land uses. It is suggested that woodland has the potential tomake a significant contribution to C storage and environmental quality.展开更多
Different proportions of A1 and B horizons dark brown forest soils （A1∶B=1∶2） were utilized to set the soil nutrient deficient conditions, and Larix olgensis seedlings were cultivated. By simulating organic acids ...Different proportions of A1 and B horizons dark brown forest soils （A1∶B=1∶2） were utilized to set the soil nutrient deficient conditions, and Larix olgensis seedlings were cultivated. By simulating organic acids concentrations in forest litter leachates of northeast China, the effects and mechanism of different concentrations of organic acid solutions on phosphorus （P） availability of dark brown forest soils and P absorption of Larix olgensis seedlings with nutrient deficiency were studied. The results showed that, compared with A1 horizon soils, available P contents of mixed soils in A1 and B horizons decreased, and P accumulation and efficiency of P uptake in root and leaves of Larix olgensis seedlings also decreased, but efficiency of P utilization increased. After treatments of exogenous organic acids, available P contents of mixed soils increased and the impact sequence of different organic acids were succinic acid 〉 citric acid 〉 oxalic acid; the concentration of 5.0 mmol/L had the best function, and the best effect of organic acids was at 20 d. Organic acids also increased P accumulation and efficiency of P uptake in roots and leaves of Larix olgensis seedlings, but decreased efficiency of P utilization. The impact strength of organic acids on P accumulation and efficiency of P uptake varied with treatment time, type and concentration of organic acids. The results of 20 d and 30 d in roots were higher than those of 10 d, however, the results of 10 d and 20 d in leaves were higher than those of 30 d, thus, at the earlier stage of organic acids treatments, more P absorbed were transferred to leaves, and at the later stage, more P would be accumulated in roots. The concentration of 10.0 mmol/L had the best function, and the impact sequence of different organic acids was succinic acid 〉 citric acid 〉 oxalic acid. Therefore, organic acids might contribute to P absorption and accumulation by Larix olgensis seedlings, final y increasing the adaptability and endurance of Larix olgensis seedlings to nutrient deficient soils.展开更多
An analysis of the seasonal and vertical distribution of soil nematode communities under three contrasting land uses,i.e.,cropland,abandoned cropland and woodland was conducted in an aquic brown soil.The results showe...An analysis of the seasonal and vertical distribution of soil nematode communities under three contrasting land uses,i.e.,cropland,abandoned cropland and woodland was conducted in an aquic brown soil.The results showed that different land-use types affected the spatiotemporal distribution of soil nematodes and their dominant genera,and different dominant genera showed different responses to land use.In the abandoned cropland and woodland,most dominant genera were present in the 0–20 cm layers and Chiloplacus was mainly distributed in the 5–30 cm layers,while in the cropland,Pratylenchus exhibited an even distribution from the 0–5 cm to the 40–50 cm depth.Soil environmental parameters under different land use could influence soil nematodes;soil porosity,total organic C,total N and the C/N ratio could positively influence the abundance of some dominant genera.Faunal profiles revealed that environmental stability and the homeostasis in the abandoned cropland and woodland lead to higher levels of community structure,and the soil food web tends to succeed to maturity.Nematode faunal analyses are a useful indicator for interpreting the stress and/or nutrient conditions under different land uses.展开更多
A field experiment was carried out at the Shenyang Experimental Station of Ecology (CAS) in order to study the effects of slow-release urea fertilizers high polymer-coated urea (SRU1), SRU1 mixed with dicyandiamide DC...A field experiment was carried out at the Shenyang Experimental Station of Ecology (CAS) in order to study the effects of slow-release urea fertilizers high polymer-coated urea (SRU1), SRU1 mixed with dicyandiamide DCD (SRU2), and SRU1 mixed with calcium carbide CaC2 (SRU3) on urease activity, microbial biomass C and N, and nematode communities in an aquic brown soil during the maize growth period. The results demonstrated that the application of slow-release urea fertilizers inhibits soil urease activity and increases the soil NH4+-N content.Soil available N increment could promote its immobilization by microorganisms. Determination of soil microbial biomass N indicated that a combined application of coated urea and nitrification inhibitors increased the soil active N pool. The population of predators/omnivores indicated that treatment with SRU2 could provide enough soil NH4+-N to promote maize growth and increased the food resource for the soil fauna compared with the other treatments.展开更多
This contribution analyzes the similarities and differences between the measured activities of 137Cs and excess 210Pb(210Pbex) in the cultivated brown and cinnamon soils of the Yimeng Mountain area, discusses the infl...This contribution analyzes the similarities and differences between the measured activities of 137Cs and excess 210Pb(210Pbex) in the cultivated brown and cinnamon soils of the Yimeng Mountain area, discusses the influence of soil texture on the measurement of 210Pbex, and presents differences between the two types of soils. Fields A and B were selected to represent the fields that contain cultivated brown and cinnamon soils, respectively. From either study field, one site of sectioned core and six bulk cores were collected to measure 137Cs levels, 210Pbex levels, and the particle-size composition of soil samples. Three undisturbed soil samples were collected to measure capillary and aeration porosities. The 137Cs inventories for the two study fields are very similar. The 137Cs is a man-made radionuclide, which means that its measured levels for soils are unaffected by soil texture. In contrast, levels of the naturally occurring 210Pbex of soils from Field A were lower than those of Field B by about 50%. In contrast to aquatic sediments, levels of 210Pbex in terrestrial surface soils are affected by the emanation of 222Rn from the soils. It can be assumed that the coarser the soils, the greater the emanation of 222Rn; in addition, the lower the measured 210Pbex, the greater the underestimate of this value. The cultivated brown soils in Field A are coarser than the cultivated cinnamon soils in Field B. As a result, 222Rn in Field A will diffuse more easily into the atmosphere than that in Field B. As a consequence, the measured 210Pbex in soils from Field A is much lower than the actual value, whereas the value measured for Field B is much closer to the actual value.展开更多
[Objective] This study aimed to investigate the effects of long-term differ- ent fertilization in three types of soils on wheat yield and soil nutrient variation in Shandong Province. [Method] A 30-year located experi...[Objective] This study aimed to investigate the effects of long-term differ- ent fertilization in three types of soils on wheat yield and soil nutrient variation in Shandong Province. [Method] A 30-year located experiment in Jinan of Shandong Province was selected and the results of soil nutrient and crop yield in 1984, 1987, 1988, 1989, 1990, 2001, 2005, 2006, 2007 and 2010 were measured and collected. In this study, five treatments： CK, NP, NK, PK and NPK of the located experiment were selected. [Result] The three types of soils in wheat yields decreased signifi- cantly in the first several years and in 2006. Wheat yields of the treatments with P fertilizers were obviously higher than those without P fertilizers; it was shown that phosphorus is the primary nutritional factor for high-yielding of wheat. The highest yield is from cinnamon soil, followed by that from brown soil, and the lowest pro- duction is from fluvo-aquic soil. Under the same fertilization, the influence of other factors on wheat yield of brown soil is the smallest, while cinnamon soil is vulnera- ble to the influence of external conditions, resulting in larger fluctuation of annual wheat yield. The alkali-hydro nitrogen contents of three kinds of soils first de- creased, then raised, and at last reduced apparently. Since 2007, the change of al- kali-hydro nitrogen content appeared rebounded. The available P contents of no- phosphorus treatments decreased over time while those of the treatments with P fertilizers increased at first, then decreased, and after that kept relatively stable. The available K contents of no K treatments decreased slowly. The treatments of PK and NK had higher available K content than NPK treatment. [Conclusion] Thus, it is an effective fertilization measure to improve the wheat yield by supplying reasonable phosphate fertilizer and nitrogen fertilizer and making up potassium fertilizer.展开更多
基金co-funded by the National Natural Science Foundation of China(U204020742277323)+2 种基金the 111 Project of Hubei Province(2021EJD026)the open fund of Key Laboratory of Geological Hazards on Three Gorges Reservoir Area(China Three Gorges University)Ministry of Education(2022KDZ24).
文摘Soil aggregate is the basic structural unit of soil,which is the foundation for supporting ecosystem functions,while its composition and stability is significantly affected by the external environment.This study was conducted to explore the effect of external environment(wetting-drying cycles and acidic conditions)on the soil aggregate distribution and stability and identify the key soil physicochemical factors that affect the soil aggregate stability.The yellow‒brown soil from the Three Gorges Reservoir area(TGRA)was used,and 8 wetting-drying conditions(0,1,2,3,4,5,10 and 15 cycles)were simulated under 4 acidic conditions(pH=3,4,5 and 7).The particle size distribution and soil aggregate stability were determined by wet sieving method,the contribution of environmental factors(acid condition,wetting-drying cycle and their combined action)to the soil aggregate stability was clarified and the key soil physicochemical factors that affect the soil aggregate stability under wetting-drying cycles and acidic conditions were determined by using the Pearson’s correlation analysis,Partial least squares path modeling(PLS‒PM)and multiple linear regression analysis.The results indicate that wetting-drying cycles and acidic conditions have significant effects on the stability of soil aggregates,the soil aggregate stability gradually decreases with increasing number of wetting-drying cycles and it obviously decreases with the increase of acidity.Moreover,the combination of wetting-drying cycles and acidic conditions aggravate the reduction in the soil aggregate stability.The wetting-drying cycles,acidic conditions and their combined effect imposes significant impact on the soil aggregate stability,and the wetting-drying cycles exert the greatest influence.The soil aggregate stability is significantly correlated with the pH,Ca^(2+),Mg^(2+),maximum disintegration index(MDI)and soil bulk density(SBD).The PLS‒PM and multiple linear regression analysis further reveal that the soil aggregate stability is primarily influenced by SBD,Ca^(2+),and MDI.These results offer a scientific basis for understanding the soil aggregate breakdown mechanism and are helpful for clarifying the coupled effect of wetting-drying cycles and acid rain on terrestrial ecosystems in the TGRA.
文摘The vertical variation and storage of nitrogen in the depth of 0-150 cm of an aquic brown soil were studied under 14 years of four land use patterns, i.e., paddy field, maize field, fallow field and woodland in Shenyang Experimental Station of Ecology, Chinese Academy of Sciences in November of 2003. The results showed that different land uses had different profile distributions of soil total nitrogen (STN), alkali N, ammonium (NH4+-N) and nitrate (NO3--N). The sequence of STN storage was woodland >maize field > fallow field > paddy field, while that of NO3--N content was maize field > paddy field > woodland > fallow field, suggesting the different root biomass and biological N cycling under various land uses. The STN storage in the depth of 0-100 cm of woodland averaged to 11.41 thm-1, being 1.65 and 1.25 times as much as that in paddy and maize fields, respec-tively, while there was no significant difference between maize and fallow fields. The comparatively higher amount of NO3--N in maize and paddy fields may be due to nitrogen fertilization and anthropogenic disturbance. Soil alkali N was significantly related with STN, and the correlation could be expressed by a linear regression model under each land use (R20.929, p<0.001). Such a correlation was slightly closer in nature (woodland and fallow field) than in agro ecosystems (paddy and maize fields). Heavy N fertilization induced an excess of crop need, and led to a comparatively higher amount of soil NO3--N in cultivated fields than in fallow field and woodland. It is suggested that agroforestry practices have the potential to make a significant contribution to both crop production and environment protection.
基金Supported by Science and Technology Development Plan of Jilin Province(201105012)~~
文摘Through laboratory simulation, the influence of cadmium on soil respiratory intensity and microbial community were studied by adding different concentrations of heavy metal cadmium. The results indicated that, the soil respiration had a signifi- cant weakening trend in the same culture days with increasing exogenous cadmium content; the soil respiration intensity was decreased obviously with the increase of culture time, especially after 14 d when the soil exogenous cadmium content was in the range of 0.5-3.0 mg/kg, while the soil respiration had not obvious variation over time when the exogenous cadmium content was in the range of 5.0-10.0 mg/kg. The soil microbial communities decreased significantly and were much lower than that of the control treatment in the same culture days with the increasing of soil exogenous cadmium content; the soil microbial community declined significantly with increasing of culture time for all exogenous cadmium treatments. The number of soil microbial communities in treatment with 10 mg/kg of exogenous cadmium were only 46.43%, 32.26%, 28.74%, 27.39% and 24.62% of that in control treatment on the 7th, 14th, 21st, 28th and 42rd of culture, respectively. It indicated that higher concen- tration of cadmium in dark brown soil had a significant inhibitory effect on soil mi- crobial growth.
文摘[Objective] This study was conducted to investigate the effects of tradition-al fertilization and formula fertilization by soil testing on the chemical forms of nitro-gen in dark brown soil and its distribution in different aggregates. [Method] A physi-co-chemistry method was adopted in a comparative study on the chemical forms of nitrogen and their distribution in different-sized aggregates of dark brown soil under traditional fertilization and formula fertilization by soil testing respectively. [Result] Compared with traditional fertilization in spring and autumn, the formula fertilization by soil testing averagely decreased, the total nitrogen in soil by 23.2% in spring and by 20% in autumn in the soil layer of 0-20 cm, by 48.8% in the layer of 20-40 cm. Ammonium nitrogen was so sensitive to the methods of fertilization that the content of ammonium nitrogen was reduced much more under formula fertitization by soil testing in autumn than under traditional fertilization. Nitrogen in soil under traditional fertilization pattern was mainly distributed in the aggregates of 0-0.25 and 0.5-1 mm, while in formula fertilization by soil testing it was mainly distributed in the aggregates of 0.25-0.5 and 0-0.25 mm. [Conclusion] The study proved that for-mula fertilization by soil testing helped to reduce the risk of nitrogen pol ution and had huge effects on the chemical forms and distribution of nitrogen in different ag-gregates in dark brown soil.
文摘The vertical distribution of the dominant genera of plant nematodes at the depth of 0–150 cm of an aquic brown soil were studied for four land use patterns, i.e., paddy field, maize field, fallow field and woodland in the Shenyang Experimental Station of Ecology, Chi- nese Academy of Sciences in November of 2003. The results showed that the numbers of some dominant genera under different land uses decreased with the increase of soil depth. Helicotylenchus was most dominant genus under each land use type. Genera of Filenchus, Psilen- chus and Tylenchus in paddy field occurred at the depth of 0–20 cm; while Paratylenchus in fallow field and woodland, as well as Praty- lenchus in maize field presented in the deeper soil layers (0–80 cm). Significant correlations between the numbers of dominant genera of plant nematodes and soil chemical properties were found in this study. The number of Helicotylenchus under different land uses was posi- tively correlated with C/N ratio, total C, total N, total P, alkai-N, and Olsen-P. The numbers of Filenchus and Paratylenchus in paddy field, Pratylenchus in maize field and Paratylenchus in fallow field were negatively correlated with soil pH, and positively correlated with total C, total N and alkai-N. This study results showed that it is essential to sample at a certain depth according to the vertical distribution informa- tion of different genera of plant nematodes in adequately assessing the population size of plant nematodes.
基金This work was supported by the grants of the Know-ledge Innovation Program of the Chinese Academy of Sciences(KZCX2-413)the fund of Shenyang Experimental Station of Ecology,Chinese Academy of Sciences(SYZ0204).
文摘Many attempts have been made to estimate the soil organic carbon (SOC) storage under different land uses, especiallyfrom the conversion of forest land or grassland into cultivated field, but limited reports were found on the estimation ofthis storage after cultivated field converted into woodland or grassland, especially in small scales. This study is aimed toinvestigate the dynamics of SOC concentration, its storage and carbon /nitrogen (C/N) ratio in an aquic brown soil at theShenyang Experimental Station of Ecology, Chinese Academy of Sciences under four land use patterns over 14 years. Thefour land use patterns were paddy field (PF), maize field (MF), fallow field (FF) and woodland (WL). In each pedon at 0-150cm depth, soil samples were collected from ten layers. The results showed that the profile distribution of SOC was differentunder different land uses, indicating the effect of land use on SOC. Soil organic carbon was significantly related with soiltotal N, and the correlation was slightly closer in nature ecosystems (with R2=0.990 and P<0.001 in both WL and FF, n=30)than in agroecosystems (with R2=0.976 and P<0.001 in PF, and R2=0.980 and P<0.001 in MF, n=30). The C/N ratio in theprofiles decreased generally with depth under the four land use patterns, and was comparatively higher in WL and lowerin PF. The C/N ratio of the FF was closer to that in the same soil depths of MF than to that of PF. Within 100 cm depth, theannual sequestration of SOC was 4.25, 2.87, and 4.48 t ha-1 more in WL than in PF, MF and FF, the annual SOC increasingrate being 6.15, 3.26, and 5.09 % higher, respectively. As a result, the SOC storage was significantly greater in WL than inany of the other three land use patterns, P=0.001, 0.008, and 0.008 as compared with PF, MF, and FF, respectively, whilethere was no significant difference among the other three land uses. It is suggested that woodland has the potential tomake a significant contribution to C storage and environmental quality.
基金National Natural Science Foundation of China(31370613)Research Program of China(973 Program)(2011CB403202)+1 种基金General Administration of Quality Supervision,Inspection and Quarantine of the People’s Republic of China(2009IK177)Fundamental Research Funds for the Central Universities(DL12CA01)~~
文摘Different proportions of A1 and B horizons dark brown forest soils （A1∶B=1∶2） were utilized to set the soil nutrient deficient conditions, and Larix olgensis seedlings were cultivated. By simulating organic acids concentrations in forest litter leachates of northeast China, the effects and mechanism of different concentrations of organic acid solutions on phosphorus （P） availability of dark brown forest soils and P absorption of Larix olgensis seedlings with nutrient deficiency were studied. The results showed that, compared with A1 horizon soils, available P contents of mixed soils in A1 and B horizons decreased, and P accumulation and efficiency of P uptake in root and leaves of Larix olgensis seedlings also decreased, but efficiency of P utilization increased. After treatments of exogenous organic acids, available P contents of mixed soils increased and the impact sequence of different organic acids were succinic acid 〉 citric acid 〉 oxalic acid; the concentration of 5.0 mmol/L had the best function, and the best effect of organic acids was at 20 d. Organic acids also increased P accumulation and efficiency of P uptake in roots and leaves of Larix olgensis seedlings, but decreased efficiency of P utilization. The impact strength of organic acids on P accumulation and efficiency of P uptake varied with treatment time, type and concentration of organic acids. The results of 20 d and 30 d in roots were higher than those of 10 d, however, the results of 10 d and 20 d in leaves were higher than those of 30 d, thus, at the earlier stage of organic acids treatments, more P absorbed were transferred to leaves, and at the later stage, more P would be accumulated in roots. The concentration of 10.0 mmol/L had the best function, and the impact sequence of different organic acids was succinic acid 〉 citric acid 〉 oxalic acid. Therefore, organic acids might contribute to P absorption and accumulation by Larix olgensis seedlings, final y increasing the adaptability and endurance of Larix olgensis seedlings to nutrient deficient soils.
文摘An analysis of the seasonal and vertical distribution of soil nematode communities under three contrasting land uses,i.e.,cropland,abandoned cropland and woodland was conducted in an aquic brown soil.The results showed that different land-use types affected the spatiotemporal distribution of soil nematodes and their dominant genera,and different dominant genera showed different responses to land use.In the abandoned cropland and woodland,most dominant genera were present in the 0–20 cm layers and Chiloplacus was mainly distributed in the 5–30 cm layers,while in the cropland,Pratylenchus exhibited an even distribution from the 0–5 cm to the 40–50 cm depth.Soil environmental parameters under different land use could influence soil nematodes;soil porosity,total organic C,total N and the C/N ratio could positively influence the abundance of some dominant genera.Faunal profiles revealed that environmental stability and the homeostasis in the abandoned cropland and woodland lead to higher levels of community structure,and the soil food web tends to succeed to maturity.Nematode faunal analyses are a useful indicator for interpreting the stress and/or nutrient conditions under different land uses.
文摘A field experiment was carried out at the Shenyang Experimental Station of Ecology (CAS) in order to study the effects of slow-release urea fertilizers high polymer-coated urea (SRU1), SRU1 mixed with dicyandiamide DCD (SRU2), and SRU1 mixed with calcium carbide CaC2 (SRU3) on urease activity, microbial biomass C and N, and nematode communities in an aquic brown soil during the maize growth period. The results demonstrated that the application of slow-release urea fertilizers inhibits soil urease activity and increases the soil NH4+-N content.Soil available N increment could promote its immobilization by microorganisms. Determination of soil microbial biomass N indicated that a combined application of coated urea and nitrification inhibitors increased the soil active N pool. The population of predators/omnivores indicated that treatment with SRU2 could provide enough soil NH4+-N to promote maize growth and increased the food resource for the soil fauna compared with the other treatments.
基金financially supported by the National Natural Science Foundation of China(Nos.41102224,41101259 and 41101206)
文摘This contribution analyzes the similarities and differences between the measured activities of 137Cs and excess 210Pb(210Pbex) in the cultivated brown and cinnamon soils of the Yimeng Mountain area, discusses the influence of soil texture on the measurement of 210Pbex, and presents differences between the two types of soils. Fields A and B were selected to represent the fields that contain cultivated brown and cinnamon soils, respectively. From either study field, one site of sectioned core and six bulk cores were collected to measure 137Cs levels, 210Pbex levels, and the particle-size composition of soil samples. Three undisturbed soil samples were collected to measure capillary and aeration porosities. The 137Cs inventories for the two study fields are very similar. The 137Cs is a man-made radionuclide, which means that its measured levels for soils are unaffected by soil texture. In contrast, levels of the naturally occurring 210Pbex of soils from Field A were lower than those of Field B by about 50%. In contrast to aquatic sediments, levels of 210Pbex in terrestrial surface soils are affected by the emanation of 222Rn from the soils. It can be assumed that the coarser the soils, the greater the emanation of 222Rn; in addition, the lower the measured 210Pbex, the greater the underestimate of this value. The cultivated brown soils in Field A are coarser than the cultivated cinnamon soils in Field B. As a result, 222Rn in Field A will diffuse more easily into the atmosphere than that in Field B. As a consequence, the measured 210Pbex in soils from Field A is much lower than the actual value, whereas the value measured for Field B is much closer to the actual value.
基金Supported by the Special Fund for Agro-scientific Research in the Public Interest of China(201203030,201203050)Special Fund for "Taishan Scholar" Construction Engineering "Agricultural Nonpoint Source Pollution Prevention and Control"~~
文摘[Objective] This study aimed to investigate the effects of long-term differ- ent fertilization in three types of soils on wheat yield and soil nutrient variation in Shandong Province. [Method] A 30-year located experiment in Jinan of Shandong Province was selected and the results of soil nutrient and crop yield in 1984, 1987, 1988, 1989, 1990, 2001, 2005, 2006, 2007 and 2010 were measured and collected. In this study, five treatments： CK, NP, NK, PK and NPK of the located experiment were selected. [Result] The three types of soils in wheat yields decreased signifi- cantly in the first several years and in 2006. Wheat yields of the treatments with P fertilizers were obviously higher than those without P fertilizers; it was shown that phosphorus is the primary nutritional factor for high-yielding of wheat. The highest yield is from cinnamon soil, followed by that from brown soil, and the lowest pro- duction is from fluvo-aquic soil. Under the same fertilization, the influence of other factors on wheat yield of brown soil is the smallest, while cinnamon soil is vulnera- ble to the influence of external conditions, resulting in larger fluctuation of annual wheat yield. The alkali-hydro nitrogen contents of three kinds of soils first de- creased, then raised, and at last reduced apparently. Since 2007, the change of al- kali-hydro nitrogen content appeared rebounded. The available P contents of no- phosphorus treatments decreased over time while those of the treatments with P fertilizers increased at first, then decreased, and after that kept relatively stable. The available K contents of no K treatments decreased slowly. The treatments of PK and NK had higher available K content than NPK treatment. [Conclusion] Thus, it is an effective fertilization measure to improve the wheat yield by supplying reasonable phosphate fertilizer and nitrogen fertilizer and making up potassium fertilizer.
