Abstract： Physical, chemical and biological soil properties in surface （0-5 cm） and subsurface soil （5-15 cm） were determined in a field experiment conducted with seven treatments consisted of different combinati...Abstract： Physical, chemical and biological soil properties in surface （0-5 cm） and subsurface soil （5-15 cm） were determined in a field experiment conducted with seven treatments consisted of different combinations of fertilizer N （0, 100 and 200 kg N ha^-1）, P （0, 22 and 44 kg P2O5 ha^-1） and K （0, 41 and 82 kg K2O ha^-1） applied both to summer-grown maize （Zea mays L.） and winter-grown wheat （Triticum aestivum L.） crops continuously for 37 years under irrigated subtropical conditions. Application of N, P and K significantly increased water stable aggregates and had profound effects in increasing the mean weight diameter as well as the formation of macro-aggregates, which were highest in both surface （81%） and subsurface （74%） soil layers with application of 100 kg N ＋ 22 kg P2O5 ＋ 41 kg K2O ha^-1 （N100P22K41）. The N100P22K41 treatment also enhanced total organic C （TOC） from 4.4 g kg^-1 in no-NPK control to 4.8 g kg^-1in surface layer and from 3.3 to 4.1 g kg1 in subsurface layer leading to the 20% higher TOC stocks in 0-15 cm soil. The labile C and N fractions such as water soluble C, particulate and light fraction organic matter, potentially mineralizable N and microbial biomass were also highest under the optimized balanced application of N100P22K41. Relatively higher increase in all labile fractions of C and N as proportion of TOC and total N, respectively suggested that these are potential indicators to reflect changes in management practices long before changes in TOC and TN are detectable. These results demonstrated that optimized balanced application of N, P and K is crucial for improving soil health ensuring long-term sustainability of farming systems in semiarid subtropical soils.展开更多
Organic matter(OM) is preserved as different occurrences in mudstones, which can affect the hydrocarbon generation process. However, little research has focused on hydrocarbon generation as a function of different occ...Organic matter(OM) is preserved as different occurrences in mudstones, which can affect the hydrocarbon generation process. However, little research has focused on hydrocarbon generation as a function of different occurrences of OM. This study collected a suite of mudstones in the Dongying Sag, Bohai Bay Basin, and conducted Rock-Eval Ⅵ pyrolysis after Soxhlet extraction and Na_(2)S_(2)O_(8) oxidation, aiming to quantify the OM with different occurrences and figure out the contributions of each occurrence of OM to the hydrocarbon generation. There are three types of occurrences of OM: soluble organic matter(SOM),mineral-bound organic matter(MOM), and particulate organic matter(POM). MOM is the most abundant among the three occurrence types of OM. SOM and MOM are the main hydrocarbon precursors, and their hydrocarbon contributions alternate with different kerogen types and layers. Additionally, MOMcontributed hydrocarbons are numerous at shallow depths;SOM-contributed hydrocarbons mainly occur at deep depths;and POM-contributed hydrocarbons change little with depth. These results demonstrate that MOM should be the main hydrocarbon precursor in shallow formations and that SOM is the main hydrocarbon contributor at deep depths.展开更多
Water-soluble organic matter（WSOM） represents a critical fraction of fine particles（PM2.5）in the air, but its changing behaviors and formation mechanisms are not well understood yet, partly due to the lack of fast...Water-soluble organic matter（WSOM） represents a critical fraction of fine particles（PM2.5）in the air, but its changing behaviors and formation mechanisms are not well understood yet, partly due to the lack of fast techniques for the ambient measurements. In this study,a novel system for the on-line measurement of water-soluble components in PM2.5, the particle-into-liquid sampler（PILS）–Nebulizer–aerosol chemical speciation monitor（ACSM）, was developed by combining a PILS, a nebulizer, and an ACSM. High time resolution concentrations of WSOM, sulfate, nitrate, ammonium, and chloride, as well as mass spectra, can be obtained with satisfied quality control results. The system was firstly applied in China for field measurement of WSOM. The mass spectrum of WSOM was found to resemble that of oxygenated organic aerosol, and WSOM agreed well with secondary inorganic ions. All evidence collected in the field campaign demonstrated that WSOM could be a good surrogate of secondary organic aerosol（SOA）. The PILS–Nebulizer–ACSM system can thus be a useful tool for intensive study of WSOM and SOA in PM2.5.展开更多
Two types of soluble organic matter, the free and adsorbed, were obtained and quantified from the brack- ish to saline lake source rocks. The adsorbed type was ex- tracted with chloroform, solvent mixtures of methanol...Two types of soluble organic matter, the free and adsorbed, were obtained and quantified from the brack- ish to saline lake source rocks. The adsorbed type was ex- tracted with chloroform, solvent mixtures of methanol: acetone:chloroform (MAC) and CS2:N-methyl-2-pyrroli- dinone (CS2/NMP). The total amounts of the two types of soluble organic matter from some immature source rocks are >830 mg/g TOC, more than 63% of the total organic matter in these samples. This result indicates that the majority of the organic matter in the immature source rocks in the brackish to saline lake basin is soluble, and is significant for study of petroleum formation and helpful for petroleum exploration in the brackish to saline lake basin.展开更多
A brief discussion is given to the thermal-induced polycondensation of soluble organic matter (SOM) in coal during lower maturation stage, based on laboratory simulation on hydrocarbon generation from coal and on corr...A brief discussion is given to the thermal-induced polycondensation of soluble organic matter (SOM) in coal during lower maturation stage, based on laboratory simulation on hydrocarbon generation from coal and on correlation with natural maturation of coal. An essential relationship between the retrogressive variation of SOM and thermal-induced polycondensation during the lower maturation stage has been established.展开更多
文摘Abstract： Physical, chemical and biological soil properties in surface （0-5 cm） and subsurface soil （5-15 cm） were determined in a field experiment conducted with seven treatments consisted of different combinations of fertilizer N （0, 100 and 200 kg N ha^-1）, P （0, 22 and 44 kg P2O5 ha^-1） and K （0, 41 and 82 kg K2O ha^-1） applied both to summer-grown maize （Zea mays L.） and winter-grown wheat （Triticum aestivum L.） crops continuously for 37 years under irrigated subtropical conditions. Application of N, P and K significantly increased water stable aggregates and had profound effects in increasing the mean weight diameter as well as the formation of macro-aggregates, which were highest in both surface （81%） and subsurface （74%） soil layers with application of 100 kg N ＋ 22 kg P2O5 ＋ 41 kg K2O ha^-1 （N100P22K41）. The N100P22K41 treatment also enhanced total organic C （TOC） from 4.4 g kg^-1 in no-NPK control to 4.8 g kg^-1in surface layer and from 3.3 to 4.1 g kg1 in subsurface layer leading to the 20% higher TOC stocks in 0-15 cm soil. The labile C and N fractions such as water soluble C, particulate and light fraction organic matter, potentially mineralizable N and microbial biomass were also highest under the optimized balanced application of N100P22K41. Relatively higher increase in all labile fractions of C and N as proportion of TOC and total N, respectively suggested that these are potential indicators to reflect changes in management practices long before changes in TOC and TN are detectable. These results demonstrated that optimized balanced application of N, P and K is crucial for improving soil health ensuring long-term sustainability of farming systems in semiarid subtropical soils.
基金financially supported by the National Natural Science Foundation of China (Grant Nos. 41672115 and 41972126)the National Science and Technology Major Project of China(Grant No. 2016ZX05006001-003)。
文摘Organic matter(OM) is preserved as different occurrences in mudstones, which can affect the hydrocarbon generation process. However, little research has focused on hydrocarbon generation as a function of different occurrences of OM. This study collected a suite of mudstones in the Dongying Sag, Bohai Bay Basin, and conducted Rock-Eval Ⅵ pyrolysis after Soxhlet extraction and Na_(2)S_(2)O_(8) oxidation, aiming to quantify the OM with different occurrences and figure out the contributions of each occurrence of OM to the hydrocarbon generation. There are three types of occurrences of OM: soluble organic matter(SOM),mineral-bound organic matter(MOM), and particulate organic matter(POM). MOM is the most abundant among the three occurrence types of OM. SOM and MOM are the main hydrocarbon precursors, and their hydrocarbon contributions alternate with different kerogen types and layers. Additionally, MOMcontributed hydrocarbons are numerous at shallow depths;SOM-contributed hydrocarbons mainly occur at deep depths;and POM-contributed hydrocarbons change little with depth. These results demonstrate that MOM should be the main hydrocarbon precursor in shallow formations and that SOM is the main hydrocarbon contributor at deep depths.
基金supported by the National Natural Science Foundation of China(Nos.U1301234,21277003)the Ministry of Science and Technology of China(No.2014BAC21B03)the Science and Technology Plan of Shenzhen Municipality
文摘Water-soluble organic matter（WSOM） represents a critical fraction of fine particles（PM2.5）in the air, but its changing behaviors and formation mechanisms are not well understood yet, partly due to the lack of fast techniques for the ambient measurements. In this study,a novel system for the on-line measurement of water-soluble components in PM2.5, the particle-into-liquid sampler（PILS）–Nebulizer–aerosol chemical speciation monitor（ACSM）, was developed by combining a PILS, a nebulizer, and an ACSM. High time resolution concentrations of WSOM, sulfate, nitrate, ammonium, and chloride, as well as mass spectra, can be obtained with satisfied quality control results. The system was firstly applied in China for field measurement of WSOM. The mass spectrum of WSOM was found to resemble that of oxygenated organic aerosol, and WSOM agreed well with secondary inorganic ions. All evidence collected in the field campaign demonstrated that WSOM could be a good surrogate of secondary organic aerosol（SOA）. The PILS–Nebulizer–ACSM system can thus be a useful tool for intensive study of WSOM and SOA in PM2.5.
文摘Two types of soluble organic matter, the free and adsorbed, were obtained and quantified from the brack- ish to saline lake source rocks. The adsorbed type was ex- tracted with chloroform, solvent mixtures of methanol: acetone:chloroform (MAC) and CS2:N-methyl-2-pyrroli- dinone (CS2/NMP). The total amounts of the two types of soluble organic matter from some immature source rocks are >830 mg/g TOC, more than 63% of the total organic matter in these samples. This result indicates that the majority of the organic matter in the immature source rocks in the brackish to saline lake basin is soluble, and is significant for study of petroleum formation and helpful for petroleum exploration in the brackish to saline lake basin.
文摘A brief discussion is given to the thermal-induced polycondensation of soluble organic matter (SOM) in coal during lower maturation stage, based on laboratory simulation on hydrocarbon generation from coal and on correlation with natural maturation of coal. An essential relationship between the retrogressive variation of SOM and thermal-induced polycondensation during the lower maturation stage has been established.
