Soil organic carbon(SOC)plays a key role in improving soil quality and optimizing crop yield.Yet little is known about the fate of macroaggregates(>0.25 mm)under long-term fertilization and their relative importanc...Soil organic carbon(SOC)plays a key role in improving soil quality and optimizing crop yield.Yet little is known about the fate of macroaggregates(>0.25 mm)under long-term fertilization and their relative importance in SOC sequestration in reclaimed calcareous soil.Therefore,the effects of mineral fertilizers and organic manure on the mechanisms of organic carbon(OC)stabilization in macroaggregates were investigated in this study.Four treatments were used:unfertilized control(CK),mineral fertilizer(NPK),compost chicken manure alone(M),and mineral fertilizers plus manure(MNPK).Samples from the 0–20 cm layer of soil receiving 11-year-long fertilization were separated into four fractions based on the macroaggregates present(unprotected coarse and fine particulate organic matter,cPOM and fPOM;physically protected intra-microaggregate POM,i POM;and biochemically protected mineral associated OM,MOM)by the physical fractionation method.Compared with the control,the long-term application of NPK had little effect on SOC content,total nitrogen(TN)content,and OC and TN contents of macroaggregate fractions.In contrast,incorporation of organic manure(MNPK)significantly increased SOC(45.7%)and TN(24.3%)contents.Application of MNPK increased OC contents within macroaggregate-extracted fractions of cPOM(292.2%),fPOM(136.0%)and iPOM(124.0%),and TN contents within cPOM(607.1%),fPOM(242.5%)and iPOM(127.6%),but not the mineral associated organic carbon(MOM-C)and nitrogen(MOM-N)contents.Unprotected C fractions were more strongly and positively correlated with SOC increase than protected C fractions,especially for cPOM-C,indicating that SOC sequestration mainly occurred via cPOM-C in the studied calcareous soil.In conclusion,MNPK increased the quantity and stability of SOC by increasing the contents of cPOM-C and cPOM-N,suggesting that this management practice(MNPK)is an effective strategy to develop sustainable agriculture.展开更多
Calcareous soil contains organic and inorganic carbon(C) pools,which both contribute to CO2 emission during closed-jar incubation. The mineralization of organic C and dissolution of inorganic C are both related to so...Calcareous soil contains organic and inorganic carbon(C) pools,which both contribute to CO2 emission during closed-jar incubation. The mineralization of organic C and dissolution of inorganic C are both related to soil moisture,but the exact effect of water content on CO2 emission from calcareous soil is unclear. The objective of this experiment was to determine the effect of soil water content(air-dried,30%,70%,and 100% water-holding capacity(WHC)),carbonate type(CaCO3 or MgCO3),and carbonate amount(0.0,1.0%,and 2.0%) on CO2 emission from calcareous soil during closed-jar incubation. Soil CO2 emission increased significantly as the water content increased to 70% WHC,regardless of whether or not the soil was amended with carbonates. Soil CO2 emission remained the same or increased slowly as the soil water content increased from 70% WHC to 100% WHC. When the water content was ≤30% WHC,soil CO2 emission from soil amended with 1.0% inorganic C was greater than that from unamended soil. When the soil water content was 70% or 100% WHC,CO2 emission from CaCO3 amended soil was greater than that from the control. Furthermore,CO2 emission from soil amended with 2.0% CaCO3 was greater than that from soil amended with 1.0% CaCO3. Soil CO2 emission was higher in the MgCO3 amended soil than from the unamended soil. Soil CO2 emission decreased as the MgCO3 content increased. Cumulative CO2 emission was 3-6 times higher from MgCO3 amended soil than from CaCO3 amended soil. There was significant interaction effect between soil moisture and carbonates on CO2 emission. Soil moisture plays an important role in CO2 emission from calcareous soil because it affects both biotic and abiotic processes during the closed-jar incubation.展开更多
Hydrocarbon source potential of the Paleogene Pabdeh Formation was studied by means of organic geochemistry and distribution of calcareous nannofossils.Based on the results,an Eoceneaged organic matter(OM)-rich interv...Hydrocarbon source potential of the Paleogene Pabdeh Formation was studied by means of organic geochemistry and distribution of calcareous nannofossils.Based on the results,an Eoceneaged organic matter(OM)-rich interval was identified and traced across different parts of the North Dezful zone and partly Abadan Plain.In order to characterize the OM quality and richness of the studied intervals,Rock-Eval pyrolysis and nannofossils evaluation were performed,and the geochemical data collected along selected wells were correlated to capture the variations of thickness and source potential of the OM-rich interval.Accordingly,remarkable variations were identified within the depth ranges of 2480–2552 m and also 2200–2210 m,which were attributed to the maximum increase in the rate of growth R-selected species.This increase in the productivity rate was found to be well correlated to high Rock-Eval total organic carbon(TOC)and hydrogen index(HI)values.Given that the maturity of Pabdeh Formation in the studied area was found to have reached the oil window,we expect significant hydrocarbon generation(Type II kerogen),making the play economically highly promising.展开更多
基金the National Natural Science Foundation of China(41807102 and U1710255-3)the Shanxi Province Key Laboratory Open Fund of Soil Environment and Nutrient Resources,China(2019003)+1 种基金the Science and Technology Innovation Fund of Shanxi Agricultural University,China(2019004)the Incentive Funding Research Project for Excellent Doctors Settle Down to Work in Shanxi Province,China(SXYBKY201805)。
文摘Soil organic carbon(SOC)plays a key role in improving soil quality and optimizing crop yield.Yet little is known about the fate of macroaggregates(>0.25 mm)under long-term fertilization and their relative importance in SOC sequestration in reclaimed calcareous soil.Therefore,the effects of mineral fertilizers and organic manure on the mechanisms of organic carbon(OC)stabilization in macroaggregates were investigated in this study.Four treatments were used:unfertilized control(CK),mineral fertilizer(NPK),compost chicken manure alone(M),and mineral fertilizers plus manure(MNPK).Samples from the 0–20 cm layer of soil receiving 11-year-long fertilization were separated into four fractions based on the macroaggregates present(unprotected coarse and fine particulate organic matter,cPOM and fPOM;physically protected intra-microaggregate POM,i POM;and biochemically protected mineral associated OM,MOM)by the physical fractionation method.Compared with the control,the long-term application of NPK had little effect on SOC content,total nitrogen(TN)content,and OC and TN contents of macroaggregate fractions.In contrast,incorporation of organic manure(MNPK)significantly increased SOC(45.7%)and TN(24.3%)contents.Application of MNPK increased OC contents within macroaggregate-extracted fractions of cPOM(292.2%),fPOM(136.0%)and iPOM(124.0%),and TN contents within cPOM(607.1%),fPOM(242.5%)and iPOM(127.6%),but not the mineral associated organic carbon(MOM-C)and nitrogen(MOM-N)contents.Unprotected C fractions were more strongly and positively correlated with SOC increase than protected C fractions,especially for cPOM-C,indicating that SOC sequestration mainly occurred via cPOM-C in the studied calcareous soil.In conclusion,MNPK increased the quantity and stability of SOC by increasing the contents of cPOM-C and cPOM-N,suggesting that this management practice(MNPK)is an effective strategy to develop sustainable agriculture.
基金supported by the National Natural Science Foundation of China(40773057)the National Technology R&D Pillar Program in the 12th Five-Year Plan of China(2012BAD15B04)
文摘Calcareous soil contains organic and inorganic carbon(C) pools,which both contribute to CO2 emission during closed-jar incubation. The mineralization of organic C and dissolution of inorganic C are both related to soil moisture,but the exact effect of water content on CO2 emission from calcareous soil is unclear. The objective of this experiment was to determine the effect of soil water content(air-dried,30%,70%,and 100% water-holding capacity(WHC)),carbonate type(CaCO3 or MgCO3),and carbonate amount(0.0,1.0%,and 2.0%) on CO2 emission from calcareous soil during closed-jar incubation. Soil CO2 emission increased significantly as the water content increased to 70% WHC,regardless of whether or not the soil was amended with carbonates. Soil CO2 emission remained the same or increased slowly as the soil water content increased from 70% WHC to 100% WHC. When the water content was ≤30% WHC,soil CO2 emission from soil amended with 1.0% inorganic C was greater than that from unamended soil. When the soil water content was 70% or 100% WHC,CO2 emission from CaCO3 amended soil was greater than that from the control. Furthermore,CO2 emission from soil amended with 2.0% CaCO3 was greater than that from soil amended with 1.0% CaCO3. Soil CO2 emission was higher in the MgCO3 amended soil than from the unamended soil. Soil CO2 emission decreased as the MgCO3 content increased. Cumulative CO2 emission was 3-6 times higher from MgCO3 amended soil than from CaCO3 amended soil. There was significant interaction effect between soil moisture and carbonates on CO2 emission. Soil moisture plays an important role in CO2 emission from calcareous soil because it affects both biotic and abiotic processes during the closed-jar incubation.
基金supported by the Exploration Directorate of National Iranian Oil Company(NIOC)。
文摘Hydrocarbon source potential of the Paleogene Pabdeh Formation was studied by means of organic geochemistry and distribution of calcareous nannofossils.Based on the results,an Eoceneaged organic matter(OM)-rich interval was identified and traced across different parts of the North Dezful zone and partly Abadan Plain.In order to characterize the OM quality and richness of the studied intervals,Rock-Eval pyrolysis and nannofossils evaluation were performed,and the geochemical data collected along selected wells were correlated to capture the variations of thickness and source potential of the OM-rich interval.Accordingly,remarkable variations were identified within the depth ranges of 2480–2552 m and also 2200–2210 m,which were attributed to the maximum increase in the rate of growth R-selected species.This increase in the productivity rate was found to be well correlated to high Rock-Eval total organic carbon(TOC)and hydrogen index(HI)values.Given that the maturity of Pabdeh Formation in the studied area was found to have reached the oil window,we expect significant hydrocarbon generation(Type II kerogen),making the play economically highly promising.
