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
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
[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
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.
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[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.
