Labile organic carbon （LOC） is a fraction of soil organic carbon （SOC） with rapid turnover time and is affected by soil fertilization. This investigation characterized the SOC content, LOC content and LOC distribu...Labile organic carbon （LOC） is a fraction of soil organic carbon （SOC） with rapid turnover time and is affected by soil fertilization. This investigation characterized the SOC content, LOC content and LOC distribution in the treatment plots of surface soil erosion at five levels （0-, 5-, 10-, 20- and 30-cm erosion）. The soil had received contrasting fertilizer treatments （i.e., chemical fertilizer or chemical fertilizer ＋ manure） for 6 years. This study demonstrated that both SOC and various LOC fractions contents were higher in the plots with fertilizer ＋ manure than in those with fertilizer alone under the same erosion conditions. The SOC and LOC contents de- creased as the erosion depth increased. Light fraction organic carbon, particulate organic carbon, easily oxidizable organic carbon （KMnO4-oxydizable organic carbon）, and microbial biomass carbon were 27% 57%, 37%-7%, 20%-25%, and 29%-33% higher respectively in the fertilizer ＋ manure plots, than in the fertilizer alone plots. Positive correlations （p 〈 0.05） between SOC content and different fractions contents were observed in all plots except the correlation between total SOC content and water-soluble organic carbon content in the different fertilization treatments. Obviously, fertilizer ＋ manure treatments would be conducive to the accumulation of LOC and SOC in the Black soil of Northeast China.展开更多
The sudangrass (Sorghum sudanense) and ryegrass (Lolium multiflorum L.) rotation is an intensive and new cropping system in Central China.Nutrient management practices in this rotation system may influence soil fertil...The sudangrass (Sorghum sudanense) and ryegrass (Lolium multiflorum L.) rotation is an intensive and new cropping system in Central China.Nutrient management practices in this rotation system may influence soil fertility,the important aspects of which are soil biological properties and quality.As sensitive soil biological properties and quality indicators,soil microbial community activity,microbial biomass,enzyme activities,soil organic matter (SOM) and total N resulting from different fertilization regimes in this rotation system were studied through a four-year field experiment from April 2005 to May 2009.Treatments included control (CK),fertilizer phosphorus and potassium (PK),fertilizer nitrogen and potassium (NK),fertilizer nitrogen and phosphorus (NP) and a fertilizer nitrogen,phosphorus and potassium combination (NPK).Soil microbial community activities in the NK,NP and NPK treatments were significantly lower than those in the CK and PK treatments after the sudangrass and ryegrass trial.The highest microbial biomass C,microbial biomass N,SOM,total N,sucrase and urease activities were found in the NPK treatment,and these soil quality indicators were significantly higher in the NK,NP and NPK treatments than in the PK and CK treatments.Soil microbial biomass and enzyme activities were positively associated with SOM in the sudangrass and ryegrass rotation system,indicating that fertilization regimes,especially N application,reduced microbial community activity in the soil.Proper fertilization regimes will increase microbial biomass,enzyme activity and SOM and improve soil fertility.展开更多
基金Under the auspices of National Natural Science Foundation of China(No.41271313,41172229,41071171)Harbin Bureau of Science and Technology for Outstanding Scientist(No.2010FXYN044)
文摘Labile organic carbon （LOC） is a fraction of soil organic carbon （SOC） with rapid turnover time and is affected by soil fertilization. This investigation characterized the SOC content, LOC content and LOC distribution in the treatment plots of surface soil erosion at five levels （0-, 5-, 10-, 20- and 30-cm erosion）. The soil had received contrasting fertilizer treatments （i.e., chemical fertilizer or chemical fertilizer ＋ manure） for 6 years. This study demonstrated that both SOC and various LOC fractions contents were higher in the plots with fertilizer ＋ manure than in those with fertilizer alone under the same erosion conditions. The SOC and LOC contents de- creased as the erosion depth increased. Light fraction organic carbon, particulate organic carbon, easily oxidizable organic carbon （KMnO4-oxydizable organic carbon）, and microbial biomass carbon were 27% 57%, 37%-7%, 20%-25%, and 29%-33% higher respectively in the fertilizer ＋ manure plots, than in the fertilizer alone plots. Positive correlations （p 〈 0.05） between SOC content and different fractions contents were observed in all plots except the correlation between total SOC content and water-soluble organic carbon content in the different fertilization treatments. Obviously, fertilizer ＋ manure treatments would be conducive to the accumulation of LOC and SOC in the Black soil of Northeast China.
基金supported by the International Plant Nutrition Institute (Grant No. Hubei-22)the National Key Technologies R&D Program of China (Grant No. 2008BADA4B08)the National Department Public Benefit Research Foundation (Grant No. 200803029)
文摘The sudangrass (Sorghum sudanense) and ryegrass (Lolium multiflorum L.) rotation is an intensive and new cropping system in Central China.Nutrient management practices in this rotation system may influence soil fertility,the important aspects of which are soil biological properties and quality.As sensitive soil biological properties and quality indicators,soil microbial community activity,microbial biomass,enzyme activities,soil organic matter (SOM) and total N resulting from different fertilization regimes in this rotation system were studied through a four-year field experiment from April 2005 to May 2009.Treatments included control (CK),fertilizer phosphorus and potassium (PK),fertilizer nitrogen and potassium (NK),fertilizer nitrogen and phosphorus (NP) and a fertilizer nitrogen,phosphorus and potassium combination (NPK).Soil microbial community activities in the NK,NP and NPK treatments were significantly lower than those in the CK and PK treatments after the sudangrass and ryegrass trial.The highest microbial biomass C,microbial biomass N,SOM,total N,sucrase and urease activities were found in the NPK treatment,and these soil quality indicators were significantly higher in the NK,NP and NPK treatments than in the PK and CK treatments.Soil microbial biomass and enzyme activities were positively associated with SOM in the sudangrass and ryegrass rotation system,indicating that fertilization regimes,especially N application,reduced microbial community activity in the soil.Proper fertilization regimes will increase microbial biomass,enzyme activity and SOM and improve soil fertility.
