The effects of different amounts of carbon and nitrogen sources on the soil microbial biomass carbon,dissolved organic carbon and related enzyme activities were studied by the simulation experiment of rice straw retur...The effects of different amounts of carbon and nitrogen sources on the soil microbial biomass carbon,dissolved organic carbon and related enzyme activities were studied by the simulation experiment of rice straw returning to the field,and the mechanism of the decomposition of rice straw returning to the field was discussed.Completely randomized experiment of the two factors of the three levels was designed,and a total of nine treatments of indoor soil incubation tests were conducted.Full amount of rice straw was applied to the soil in this simulation experiment and different amounts of brown sugar and urea were added in the three levels of 0(no carbon source and nitrogen source),1(low levels of carbon and nitrogen sources)and 2(high levels of carbon and nitrogen sources),respectively.The results showed that the addition of different amounts of carbon and nitrogen sources to the rice straw could increase the soil carbon content.Compared with T0N0,the microbial biomass carbon of T2N2 was increased significantly by 170.48%;the dissolved organic carbon content of T1N2 was significantly increased by 58.14%and the free humic acid carbon contents of T0N2,T1N1 and T2N0 were significantly increased by 56.16%and 45.55%and 47.80%,respectively;however,there were no significant differences among those of treatments at later incubation periods.The addition of different carbon and nitrogen sources could promote the soil enzyme activities.During the incubation period,all of the soil enzyme activities of adding sugar and urea were higher than those of T0N0 treatment.Therefore,the addition of different amounts of carbon and nitrogen sources to rice straw returning could improve soil microbial biomass carbon content,dissolved organic carbon and soil enzyme activities.展开更多
Two-factor analysis of variance and redundancy analysis were used to analyze the characte-ristics of soil organic carbon total nitrogen storage in garden land,forestland,grassland,farmland,and bare land in the Dachunh...Two-factor analysis of variance and redundancy analysis were used to analyze the characte-ristics of soil organic carbon total nitrogen storage in garden land,forestland,grassland,farmland,and bare land in the Dachunhe watershed of Jinning District,Kunming City,Yunnan Province,China.The effects of the soil organic carbon,total nitrogen stratification ratio,soil physical and chemical factors on the storage characteristics of organic carbon and total nitrogen of different land-use types were analyzed.The results show that the rates of carbon and nitrogen stratification in soil from 0-20 cm and 40-60 cm of the same land-use types differed are statistically significant(P<0.05).The organic carbon and total nitrogen stratification ratio SR1 of garden land soil are 38.5%and 25.3%,respectively,which are higher than SR^(2).The soil organic carbon and total nitrogen stratification ratio SR^(2) of different land-use types are greater than SR1.There are statistically significant differences in the SR^(2) soil organic carbon and total nitrogen stratification ratios(P<0.05).Soil organic carbon and total nitrogen storage of diffe-rent land-use types gradually decrease with increasing soil depth,with the maximum soil organic carbon and total nitrogen storage in the 0-20 cm soil layer.Soil organic carbon and total nitrogen sto-rage at the same soil depth are significantly different(P<0.05).Soil organic carbon and total nitrogen storage in the garden land are greater than those in the other land-use types.Soil organic carbon and total nitrogen storage in 0-20 cm garden land are 4.96 and 3.19 times than those in bare land,respectively;soil organic carbon and total nitrogen storage are explained by 93.66%and 1.53%in redundancy analysis RDA1 and RDA2,respectively.All physicochemical factors except Available Phosphorus and pH are statistically significance with carbon and nitrogen storage(P<0.05).Soil cationic exchange capacity,Available Phosphorus,C/N ratio,and Moisture Content are positively correlated with organic carbon and total nitrogen storage.In contrast,soil Bulk Density is negatively correlated with organic carbon storage and total nitrogen storage.Available Phosphorus,C/N ratio,and Moisture Content are the main factors promoting soil organic carbon and total nitrogen accumulation.展开更多
A better understanding of soil carbon(C)distribution within aggregate fractions is essential to evaluating the potential of no-till for sustaining productivity and protecting the environment.A meta-analysis on 744 com...A better understanding of soil carbon(C)distribution within aggregate fractions is essential to evaluating the potential of no-till for sustaining productivity and protecting the environment.A meta-analysis on 744 comparisons from 34 studies was conducted to determine the effects of three different tillage treatments(conventional mouldbould ploughing tillage(CT),reduced tillage(RT)and no tillage(NT))on water-stable aggregate size distribution,soil C concentration in aggregate fractions.The meta-analysis indicates that compared with CT treatment,NT/RT significantly(P<0.05)increases macro-aggregate above 20 cm by 20.9%-82.2%(>2.00 mm)and 5.9%-19.1%(0.25-2.00 mm),whereas NT/RT significantly reduces micro-aggregate and silt clay fractions above 20 cm.NT/RT significantly(P<0.05)increases the SOC in macro-aggregate(>0.25 mm)and micro-aggregate(<0.25 mm)size classes above 20 cm soil depth compared with CT.The results suggest that soil sampling depth should be considered to evaluate the influence of tillage systems on the distribution of soil aggregate,and the content of aggregate-associated C content.展开更多
基金Supported by the National Key Research and Development Plan Project(2016YFD0300909-04)。
文摘The effects of different amounts of carbon and nitrogen sources on the soil microbial biomass carbon,dissolved organic carbon and related enzyme activities were studied by the simulation experiment of rice straw returning to the field,and the mechanism of the decomposition of rice straw returning to the field was discussed.Completely randomized experiment of the two factors of the three levels was designed,and a total of nine treatments of indoor soil incubation tests were conducted.Full amount of rice straw was applied to the soil in this simulation experiment and different amounts of brown sugar and urea were added in the three levels of 0(no carbon source and nitrogen source),1(low levels of carbon and nitrogen sources)and 2(high levels of carbon and nitrogen sources),respectively.The results showed that the addition of different amounts of carbon and nitrogen sources to the rice straw could increase the soil carbon content.Compared with T0N0,the microbial biomass carbon of T2N2 was increased significantly by 170.48%;the dissolved organic carbon content of T1N2 was significantly increased by 58.14%and the free humic acid carbon contents of T0N2,T1N1 and T2N0 were significantly increased by 56.16%and 45.55%and 47.80%,respectively;however,there were no significant differences among those of treatments at later incubation periods.The addition of different carbon and nitrogen sources could promote the soil enzyme activities.During the incubation period,all of the soil enzyme activities of adding sugar and urea were higher than those of T0N0 treatment.Therefore,the addition of different amounts of carbon and nitrogen sources to rice straw returning could improve soil microbial biomass carbon content,dissolved organic carbon and soil enzyme activities.
基金Natural Science Foundation of China(51979134,51779113)Yunnan Provincial Education Department Scientific Research Fund Project(2021J0164)+4 种基金Open Fund Project of Yunnan Provincial Key Laboratory of Highland Wetland Protection and Restoration and Ecological Services(202105AG070002)Provincial Innovation Team on Environmental Pollution and Food Safety and Human Health,Southwest Forestry University(2005AE160017)A Study of Terrestrial Animal Habitats in Li Ziping National Nature Reserve,Sichuan Province(2021ZD0125)The Construction Project of Key Disciplines with Advantages and Characteristics(Ecology)in Yunnan UniversitiesResearch Project of Key Laboratory of Soil Erosion and Control in Yunnan University。
文摘Two-factor analysis of variance and redundancy analysis were used to analyze the characte-ristics of soil organic carbon total nitrogen storage in garden land,forestland,grassland,farmland,and bare land in the Dachunhe watershed of Jinning District,Kunming City,Yunnan Province,China.The effects of the soil organic carbon,total nitrogen stratification ratio,soil physical and chemical factors on the storage characteristics of organic carbon and total nitrogen of different land-use types were analyzed.The results show that the rates of carbon and nitrogen stratification in soil from 0-20 cm and 40-60 cm of the same land-use types differed are statistically significant(P<0.05).The organic carbon and total nitrogen stratification ratio SR1 of garden land soil are 38.5%and 25.3%,respectively,which are higher than SR^(2).The soil organic carbon and total nitrogen stratification ratio SR^(2) of different land-use types are greater than SR1.There are statistically significant differences in the SR^(2) soil organic carbon and total nitrogen stratification ratios(P<0.05).Soil organic carbon and total nitrogen storage of diffe-rent land-use types gradually decrease with increasing soil depth,with the maximum soil organic carbon and total nitrogen storage in the 0-20 cm soil layer.Soil organic carbon and total nitrogen sto-rage at the same soil depth are significantly different(P<0.05).Soil organic carbon and total nitrogen storage in the garden land are greater than those in the other land-use types.Soil organic carbon and total nitrogen storage in 0-20 cm garden land are 4.96 and 3.19 times than those in bare land,respectively;soil organic carbon and total nitrogen storage are explained by 93.66%and 1.53%in redundancy analysis RDA1 and RDA2,respectively.All physicochemical factors except Available Phosphorus and pH are statistically significance with carbon and nitrogen storage(P<0.05).Soil cationic exchange capacity,Available Phosphorus,C/N ratio,and Moisture Content are positively correlated with organic carbon and total nitrogen storage.In contrast,soil Bulk Density is negatively correlated with organic carbon storage and total nitrogen storage.Available Phosphorus,C/N ratio,and Moisture Content are the main factors promoting soil organic carbon and total nitrogen accumulation.
基金National Natural Science Foundation of China(31860361)The National Natural Science Foundation of Ningxia Hui Autonomous Region(2019AAC03055)+1 种基金The Science and Technology Young Talent Project of Ningxia Hui Autonomous Region(TJGC2019075)The Young Project from Ningxia University。
文摘A better understanding of soil carbon(C)distribution within aggregate fractions is essential to evaluating the potential of no-till for sustaining productivity and protecting the environment.A meta-analysis on 744 comparisons from 34 studies was conducted to determine the effects of three different tillage treatments(conventional mouldbould ploughing tillage(CT),reduced tillage(RT)and no tillage(NT))on water-stable aggregate size distribution,soil C concentration in aggregate fractions.The meta-analysis indicates that compared with CT treatment,NT/RT significantly(P<0.05)increases macro-aggregate above 20 cm by 20.9%-82.2%(>2.00 mm)and 5.9%-19.1%(0.25-2.00 mm),whereas NT/RT significantly reduces micro-aggregate and silt clay fractions above 20 cm.NT/RT significantly(P<0.05)increases the SOC in macro-aggregate(>0.25 mm)and micro-aggregate(<0.25 mm)size classes above 20 cm soil depth compared with CT.The results suggest that soil sampling depth should be considered to evaluate the influence of tillage systems on the distribution of soil aggregate,and the content of aggregate-associated C content.
