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
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
【目的】研究秸秆配施化肥对暗棕壤团聚体组成、团聚体碳氮含量、土壤微生物量特征及小麦产量的影响,揭示长期秸秆配施化肥下土壤肥力和生产力的协同提升机制。【方法】依托长期定位40年施肥试验,选取4个处理:单施化肥(NP)、秸秆配施化...【目的】研究秸秆配施化肥对暗棕壤团聚体组成、团聚体碳氮含量、土壤微生物量特征及小麦产量的影响,揭示长期秸秆配施化肥下土壤肥力和生产力的协同提升机制。【方法】依托长期定位40年施肥试验,选取4个处理:单施化肥(NP)、秸秆配施化肥(S+NP)、秸秆配施1/2化肥(S+1/2NP)、秸秆配施1/4化肥(S+1/4NP),其中秸秆为麦秸隔年还田,用量为3000 kg·hm^(-2),氮磷化肥用量为150 kg N·hm^(-2)、150 kg P2O5·hm^(-2)。采集0—20 cm土层土样,利用湿筛法得到不同粒级的水稳性团聚体,测定团聚体中有机碳(SOC)、氮含量及土壤微生物量碳(SMBC)、微生物量氮(SMBN)含量。【结果】(1)长期秸秆配施化肥显著降低土壤容重并提高了团聚体稳定性,和NP相比,S+NP处理土壤容重降低4.7%,>2 mm团聚体含量、平均重量直径(MWD)和几何重量直径(GWD)分别提升254.4%、76.5%和91.3%。(2)S+NP、S+1/2NP处理>2 mm团聚体百分含量、MWD和GWD显著高于S+1/4NP,分别增加了49.1%—52.4%,19.43%—22.4%和24.2%—33.3%。(3)S+NP、S+1/2NP、S+1/4NP和NP相比增加了>2 mm和>0.25 mm团聚体对土壤有机碳、全氮贡献率,并显著提高全土SOC、SMBC和SMBN含量;其中,SOC含量在S+NP中最高,比S+1/2NP、S+1/4NP高6.3%和12.6%。(4)产量表现为S+NP>NP>S+1/2NP>S+1/4NP处理,S+NP比减施化肥处理提高小麦产量28.6%—47.5%。(5)土壤团聚体稳定性、SOC含量及小麦产量之间有较好的相关性,>2 mm和>0.25 mm团聚体含量、MWD和GWD分别与全土SOC含量及小麦产量呈显著或极显著正相关。【结论】暗棕壤地区在长期秸秆还田条件下,配施化肥量150 kg N·hm^(-2)、150 kg P2O5·hm^(-2)时能提高土壤团聚体稳定性、有机碳含量、微生物生物量和小麦产量,最大化实现土壤结构改良、肥力提升和作物增产的协同效应。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.
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.
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【目的】研究秸秆配施化肥对暗棕壤团聚体组成、团聚体碳氮含量、土壤微生物量特征及小麦产量的影响,揭示长期秸秆配施化肥下土壤肥力和生产力的协同提升机制。【方法】依托长期定位40年施肥试验,选取4个处理:单施化肥(NP)、秸秆配施化肥(S+NP)、秸秆配施1/2化肥(S+1/2NP)、秸秆配施1/4化肥(S+1/4NP),其中秸秆为麦秸隔年还田,用量为3000 kg·hm^(-2),氮磷化肥用量为150 kg N·hm^(-2)、150 kg P2O5·hm^(-2)。采集0—20 cm土层土样,利用湿筛法得到不同粒级的水稳性团聚体,测定团聚体中有机碳(SOC)、氮含量及土壤微生物量碳(SMBC)、微生物量氮(SMBN)含量。【结果】(1)长期秸秆配施化肥显著降低土壤容重并提高了团聚体稳定性,和NP相比,S+NP处理土壤容重降低4.7%,>2 mm团聚体含量、平均重量直径(MWD)和几何重量直径(GWD)分别提升254.4%、76.5%和91.3%。(2)S+NP、S+1/2NP处理>2 mm团聚体百分含量、MWD和GWD显著高于S+1/4NP,分别增加了49.1%—52.4%,19.43%—22.4%和24.2%—33.3%。(3)S+NP、S+1/2NP、S+1/4NP和NP相比增加了>2 mm和>0.25 mm团聚体对土壤有机碳、全氮贡献率,并显著提高全土SOC、SMBC和SMBN含量;其中,SOC含量在S+NP中最高,比S+1/2NP、S+1/4NP高6.3%和12.6%。(4)产量表现为S+NP>NP>S+1/2NP>S+1/4NP处理,S+NP比减施化肥处理提高小麦产量28.6%—47.5%。(5)土壤团聚体稳定性、SOC含量及小麦产量之间有较好的相关性,>2 mm和>0.25 mm团聚体含量、MWD和GWD分别与全土SOC含量及小麦产量呈显著或极显著正相关。【结论】暗棕壤地区在长期秸秆还田条件下,配施化肥量150 kg N·hm^(-2)、150 kg P2O5·hm^(-2)时能提高土壤团聚体稳定性、有机碳含量、微生物生物量和小麦产量,最大化实现土壤结构改良、肥力提升和作物增产的协同效应。
