Organic matter accumulation in lacustrine shale of the Permian Jimsar Sag,Junggar Basin,NW China

The lacustrine organic-rich shale in the Permian Lucaogou(LCG)Formation of the Jimsar Sag,Junggar Basin,is one of the main shale oil plays in China.In this paper,geological and geochemical research techniques were employed to evaluate the geochemical variability of the lacustrine shale and the pro-duction of organic matter and its preservation conditions.The LcG Formation is characterized by its complex mineral compositions and a wide range of organic matter richness and quality.The presence of high proportions ofβ-carotane and C2g steranes,indicates that the organic matter mainly originated from phytoplankton and aquatic algal-bacterial organisms,especially cyanobacteria.This study found that the productivity of the Lower LCG Member(P2li)was highest,and the Middle LCG Member(P_(2)l_(2))was the lowest.During the deposition of the Lower LCG Member,the lake's bottom water was predominantly a reducing environment,and the degradation of organic matter was largely a result of bacterial sulfate reduction.During the deposition of the Middle and Upper LCG members,the lake's bottom water was mainly oxidizing,and the degradation of organic matter was likely to be caused by aerobic processes.Based on a comprehensive analysis of the origin and production of organic matter,as well as its depo-sitional environment and preservation conditions,two organic matter accumulation models were pro-posed to explain the distribution of the organic-rich shale.In model A,the high influx of volcanic ash released nutrients and brought abundant sulfate into the water,the accumulation of organic matter was mainly controlled by the preservation of organic matter,which was mainly controlled by BsR.In the model B,the influx of volcanic ash was small,organic matter was mainly degraded by oxygen and the accumulation of organic matter is mainly determined by the production of organic matter.

Effects of soil potassium levels on dry matter and nutrient accumulation and distribution in cotton

Background Potassium(K)is an essential nutrient for plant growth and development.However,plant fertilization ignoring the soil K level is very likely to cause excessive fertilizer use,and further arouse a series of side effects.This study investigated the response of cotton growth to different soil K levels and the uptake of major nutrients,aiming to evaluate the appropriate K supply level for cotton growth.Using a random block design with 6 soil K levels,we conducted 18 micro-zones field experiments over two continuous years.The soil available K concentration of each treatment was K1(99.77-100.90 mg·kg^(-1)),K2(110.90-111.26 mg·kg^(-1)),K3(123.48-128.88 mg·kg^(-1)),K4(140.13-145.10 mg·kg^(-1)),K5(154.43-155.38 mg·kg^(-1)),and K6(165.77-168.75 mg·kg^(-1)).Cotton nutrient contents,soil nutrient contents,accumulation and distribution of dry matter in cotton were determined,and the relationships between K content in soil and plants and dry matter accumulation were analyzed.Results The soil K content had a significantly positive relationship with dry matter and K accumulation in cotton plants.There were significant differences in dry matter accumulation,single-plant seed cotton yield,mineral nutrient uptake and the proportion of K accumulation in reproductive organs among different soil K levels.The results showed that there was significant difference between K4 and lower K level treatments(K1 and K2),but no significant difference between K4 and higher K level treatments(K5 and K6)in dry matter,single-plant seed cotton yield,or accumulation,distribution and seed cotton production efficiency of N,P and K.Conclusion The soil K level of K4 was able to provide sufficient K for cotton growth in our experiment.Therefore,when the soil K level reached 140.13 mg·kg^(-1),further increasing the soil K concentration no longer had a significant positive effect on cotton growth.

Effects of a Dehydrating Agent on Dry Matter Accumulation and Nutritional Quality of Different Maize Varieties

The high water content of corn grain at harvest is a challenge in Northeast China,where the growing season is short.Using a dehydrating agent before harvest can help corn seeds dehydrate quickly.The dry matter accumulation and nutrient quality of maize were systematically studied by field experiments and instrumental analysis using maize varieties of different maturities as test materials.The results showed that the accumulation of dry matter was enhanced by an increased dosage of a dehydrating agent.When the dehydrating agent dosage reached 1800 mL•hm-2,the dry matter accumulation of early-maturing varieties increased by 24.1 g,and the water content decreased by 8.08%.Different maize varieties were treated with the same dose;early-maturing varieties showed significant effects on grain dry matter accumulation,and kernel dry matter accumulation increased by 7%.The effects of different doses on grain dehydration were obvious,and the effects on different maize varieties varied.Medium-ripening maize varieties showed the most significant effect,with a 19.5%reduction in water content.The effects of dehydrating agent doses on maize yield,grain nutrient quality and seed germination rate were not significant.Therefore,a dehydrating agent promoted the accumulation of dry matter in grain and accelerated the rapid dehydration.

Soil conditioners improve Cd-contaminated farmland soil microbial communities to inhibit Cd accumulation in rice

The addition of silicon(Si)and organic fertilizers to soil conditioners can inhibit the transfer of heavy metal ions from soil to crops.However,it is not clear how Si and organic fertilizers affect soil properties and the micro-ecological environment and thereby reduce cadmium(Cd)accumulation in rice.In this study,the effects of L-type soil conditioners containing Si and organic fertilizers on bacterial and fungal community diversity,soil pH,organic matter,and available Si were analyzed with field experiments at two sites in Liuzhou City and Hezhou City,respectively,in Guangxi,China.With the increase of Si and organic fertilizer content in soil conditioner,rice yield respectively increased by 16.8–25.8 and 6.8–13.1%,and rice Cd content decreased significantly by 8.2–21.1 and 10.8–40.6%,respectively,at the two experimental sites.Soil microbiome analysis showed that the increase in abundance of Firmicutes and Actinobacteriota bacteria associated with Cd adsorption and sequestration,and Basidiomycota fungal populations associated with degradation of macromolecules favored the inhibition of soil Cd activity(soil exchangeable Cd decreased by 14.4–14.8 and 18.1–20.6%).This was associated with an increase in organic matter and Si content caused by applying soil conditioners.In conclusion,L-type soil conditioners,rich in Si and organic fertilizer,can reduce soil Cd bioavailability by regulating the dominant Cd passivating flora in the soil and ultimately reduce Cd accumulation in rice.

Tectonic evolution and accumulation characteristics of Carboniferous shale gas in Yadu-Ziyun-Luodian aulacogen, Guizhou Province, South China

The Yadu-Ziyun-Luodian aulacogen(YZLA) developed into being NW-trending in the Late Paleozoic,and was considered as an important passive continental margin aulacogen in Guizhou Province, South China. This tectonic zone is considered a large intracontinental thrust-slip tectonic unit, which has undergone a long period of development. It was ultimately determined in the Yanshanian, where the typical Upper Paleozoic marine shales were deposited. In 2021, Well QSD-1 was deployed in the Liupanshui area at the northwest margin of the aulacogen, and obtained a daily shale gas flow of 11011 m3in the Carboniferous Dawuba Formation. It thus achieved a breakthrough in the invesgation of shale gas in the Lower Carboniferous in South China, revealing relatively good gas-bearing properties and broad exploration prospects of the aulacogen. Being different from the Lower Paleozoic strata in the Sichuan Basin and the Yichang area of the Middle Yangtze, the development of the Carboniferous Dawuba Formation in the aulacogen exhibits the following characteristics:(1) The Lower Carboniferous shale is thick and widely distributed, with interbedded shale and marlstone of virous thickness;(2) The total organic carbon(TOC) content of the shale in the Dawuba Formation ranges from 1% to 5%, with an average of 2%, and the thermal maturity of organic matter(Ro) varies from 1% to 4%, with an average of2.5%, indicating good hydrocarbon generation capacity;(3) The main shale in the aulacogen was formed during the fault subsidence stage from the Middle Devonian to the Early Permian. Although the strong compression and deformation during the late Indosinian-Himalayan played a certain role in destroying the formed shale gas reservoirs, comparative analysis suggests that the area covered by the current Triassic strata has a low degree of destruction. It therefore provides good conditions for shale gas preservation,which can be regarded as a favorable area for the next exploration.

Photosynthesis and Dry Matter Accumulation in Different Chlorophyll-Deficient Rice Lines

Three different chlorophyll-deficient rice isogenic lines chl,fgl and pgl,and their recurrent parent zhefu802 （zf802） were used to study effects of leaf color on photosynthesis,dry matter accumulation,yield,and quality in early season indica rice.Analysis showed that the chlorophyll （Chl.） a/b ratio of isogenic lines chl-8,pgl and fgl was 5.35,10.00 and 15.46,respectively,among them,line fgl had higher leaf area index （LAI）,higher net photosynthetic rate and higher grain-filling rate than its recurrent parent zf802 at the later period of grain filling stage;while LAI,net photosynthetic rate and dry matter accumulated in lines chl-8 and pgl were lower than in zf802.Differences were found in the grain yield and quality among chlorophyll deficient isogenic lines,lines fgl,chl-8 and zf802 had similar grain yield,which was significantly higher than that of pgl;the highest milling quality was observed in isogenic line fgl,with relatively high protein content.This study showed that isogenic line fgl would become a unique material for the development of high yield rice with high grain quality because of its slow aging process and relative steady grain-filling rate.

Orbital control on cyclical organic matter accumulation in Early Silurian Longmaxi Formation shales

High resolution(939 samples)total organic carbon content(TOC)analyses were conducted on the Shuanghe Section of^152.6 m in the Changning area,Sichuan Basin.The sampling section was divided into two units considering the distinct-different deposit environment and sediments accumulation rate.The lower part(Unit 1)and the peer part(Unit 2)with high resolution sample spacing(0.08–0.4 m)enables the identification of the precession cycle in two sedimentary sequences with distinct different sedimentary accumulation rate.MTM Power spectral analyses on untuned TOC series reveals significant peaks exceeding above the 95%confidence level and shows that both Unit 1 and Unit 2 have recorded Milankovitch cycles of 405 kyr long eccentricity,short eccentricity,obliquity and precession.The floating astronomical time scale(ATS)was constructed on the Shuanghe Section in the Early Silurian(~439.673–444.681 Ma),and which was calibrated by 405 kyr long eccentricity cycles.The total duration of the Wufeng and Longmaxi shales is 5.01 Myr.The floating ATS used for estimating the duration of the graptolite zones and each stage in the study interval.Finally,we postulated two models that could verify the linkage between orbital cycle and organic accumulation.To make sure whether productivity or preservation is the main factor that under long eccentricity control,the phase correlation between the obtained filtered signal and the theoretical orbital solution should be made clear in the further research.

Preliminary study on nanopores,nanofissures,and in situ accumulation of Gulong shale oil

The Qingshankou Formation shale oil in the Gulong Sag is an important oil and gas reservoir in the Daqing oilfield,with geological resources of 15.1 billion tons.The fabric of shale can reflect not only its genesis but also the nature of the reservoir space,its physical properties,oil content,and development value.Here,the characteristics of clay minerals in the Gulong shale oil reservoir were studied via electron microscopy,with the primary focus on the microfabrics and reservoir space;thereafter,the in situ accumulation was studied and discussed.Electron backscattering patterns revealed that nanometer pores and fissures were well developed in the Gulong shale oil reservoir.The nano pores were mostly 20-50 nm in diameter(median 20-30 nm),irregularly shaped,mostly,polygonal,and connected with nanofissures.The widths of nanofissures ranged mostly between 10-50 nm(median 20-30 nm);moreover,these fissures were mainly formed by F-F condensation of clay sheets(clay domains).The coagulation of clays was closely related to organic matter,especially algae.The clay colloids were negatively charged due to isocrystalline replacement;hence,metal cations were absorbed around the clay,forming a positive clay group.The positively charged clays subsequently adsorbed negatively charged humic acid(organic matter)and initially degraded algae to form an organic clay flocculant.When the organic clay flocculates reached the threshold for hydrocarbon generation and expulsion,the volume of organic matter decreased by 87%;thereafter,the generated and expelled hydrocarbon filled the nearby pores formed by this contraction.Moreover,the discharged hydrocarbon could not migrate due to capillary resistance(~12 MPa)of the nanopores;hence,the nanopores formed a unique continuous in situ reservoir within the Gulong shale oil.This study demonstrated that the Gulong shale oil reservoir is an actual clay-type shale reservoir with numerous nanopore and fissures.During coagulation,a large amount of organic matter(including layered algae)was absorbed by the clay,forming an organic clay condensate that could have provided the material foundation for hydrocarbon generation at a later stage.Thermal simulation experiments revealed that the volume of organic matter decreased sharply after hydrocarbon generation and expulsion.

Organic matter accumulation in hill forests of Chittagong region, Bangladesh

Litter fall and its effect on forest soil properties at each decomposition stages were investigated in tropical monsoon climatic conditions of three plantations （7-year acacia plantation, 15-year acacia plantation and 18-year mixed plantation） and one natural forest （Si- tapahar forest） from Chittagong hilly region of Bangladesh. Results showed that total accumulation of organic matter increased with plantation age, accompanying with a decrease of annual accumulation rate. Within the same vegetation type, the organic accumulation of both fresh and partially decomposed litter with humus varied significantly （p≤0.05） on hill positions, being highest on bottom slope and decreased gradually towards hilltop in the forest. Reverse trend in accumulation of soil organic matters was shown in 15-year Acacia auriculiformis plantation, from where fuel wood collected. In 7- and 15-year acacia and 18-year mixed broadleaved plantations, rates of total organic matter production consisting of fresh, partially and completely decomposed litter as well as incorporated organic matter in soil were 2554.31, 705.79 and 1028.01 kg.ha^-1.a^-1, respectively, and the corresponding contribution from fresh litter were 38.23, 19.40 and 30.48 kg-ha^-1.a^-1, respectively. In the three plantations and the natural forest, on an average fresh litter constituted 32.45%, partially decomposed litter with humus 13.50% and incorporated organic matter in soil 54.56% of the total organic matter production with mean litter thickness of 0.90 cm. Soil acidity increased with the increase of decomposition stage of organic matter.

Dynamic Simulating to the Accumulation and Distribution of Dry Matter for Black Walnut(Juglans hindsii) Seedlings

It is very important to study eco-physiological processes of plants and to determine quantitative relations between accumulation, distribution of dry matter and environmental factors for regionalization, standardization and precision agriculture. Meanwhile, global changes, e.g., atmospheric CO2 concentration rising, global warming, and climate abnormity, have been effecting on agricultural productivity. This study provides a theoretical basis for predicting productive potentials and development trends in different agricultural regions. One-year-old black walnut （Juglans hindsii） seedlings were employed as subjects for setting up the dynamic models of dry matter accumulation and distribution, based on mechanistic models of photosynthesis, matter conservation and concentration gradient. Under optimum conditions of soil moisture and mineral nutrient, during the period of the canopy construction, the dry matter accumulation of the canopy conformed to logistic curves; but the accumulation of both total biornass and dry matter of stem-root could be divided into two phases： the first phase was exponential increase, the second was linear increase. The total biomass, dry matter of canopy and stem-root all presented a fluctuant increase, which was affected by the environmental factors. Ratio of daily increase of dry matter in the canopy and the steem-root （dWJdWs） was changeable along with growth periods and environmental factors. At the initial stage of the canopy forming, dW/dWs was larger, about 3.2 on average, which indicated that the photosynthetic product was mainly used to develop leaves; in the midterm, it was about 1.9, which indicated that the distribution of dry matter in the canopy and in the stem-root was relatively balanced; when the plant tended to stop growing, dWl/dWs decreased linearly, and the main distribution of dry matter moved to the roots.

Influence of Straw Incorporation on Maize Yield,N Accumulation and Remobilization on Slope Farmland in Northeast China

Slope farmland is a main type of agricultural land throughout northeast China.Long-term high intensity utilization and unreasonable farming have caused the deterioration of soil resources and a decrease in crop production.Here,it was hypothesized that crop straw incorporation might help to reduce nutrient losses and increase maize yields across time and space.A field experiment for testing straw management practices on maize across three slope positions(top,back and bottom slopes)was conducted in Northeast China in 2018 and 2019.In this study,the dry matter accumulation(DMA),N accumulation(NA),N remobilization,postsilking N uptake and grain yield were measured under SI(straw incorporation)and NSI(no straw incorporation)across three slope positions of 100-m-long consecutive black soil slope farmland during the maize(Zea mays L.)growth stages.Compared with NSI,SI significantly increased DMA and NA at the silking and maturity stages.SI typically increased the N remobilization in all slope positions,and significantly increased N remobilization efficiency and contribution of N remobilization to grain on the back and bottom slopes.However,post-silking N uptake was only increased by SI on the top slope.SI generally increased the crop yield in three slope positions.In the SI treatments,the bottom slope was the highest yield position,followed by the top,and then the back slopes,suggesting that the bottom slope position of regularly incorporated straw might have increased the potential for boosting maize yield.Overall,the study demonstrated the outsized potential of straw incorporation to enhance maize NA and then increase the grain yield in black soil slope farmland.

Effects of Calcium Application Rate on Dry Matter Accumulation and Yield of Peanut

The effects of calcium application rate on dry matter accumulation and yield of peanut were studied under high-yielding field condition. The variety used for the study was Tang A8252( Spanish peanut). The results showed that number of full fruit,dry weight per plant,kernel yield,and pod yield all increased with calcium application increased,and they decreased when calcium application rate was more than150 kg/ha. Both the height of main stem and the length of side shoot decreased with calcium application increased. Therefore,to obtain the optimal agronomic character index and the highest yield benefit,the suggested calcium application rate would be 150 kg/ha for peanut.

The Enhancement of Soil Fertility,Dry Matter Transport and Accumulation,Nitrogen Uptake and Yield in Rice via Green Manuring

Readily available chemical fertilizers have resulted in a decline in the use of organic manure(e.g.,green manures),a traditionally sustainable source of nutrients.Based on this,we applied urea at the rate of 270 kg ha−1 with and without green manure in order to assess nitrogen(N)productivity in a double rice cropping system in 2017.In particular,treatment combinations were as follows:winter fallow rice-rice(WF-R-R),milk vetch rice-rice(MV-R-R),oil-seed rape rice-rice(R-R-R)and potato crop rice-rice(P-R-R).Results revealed that green manure significantly(p≤0.05)improved the soil chemical properties and net soil organic carbon content increased by an average 117.47%,total nitrogen(N)by 28.41%,available N by 26.64%,total phosphorus(P)by 37.77%,available P by 20.48%and available potassium(K)by 33.10%than WF-R-R,however pH was reduced by 3.30%across the seasons.Similarly,net dry matter accumulation rate enhanced in green manure applied treatments and ranked in order:P-R-R>R-R-R>MV-R-R>WF-R-R.Furthermore,the total leaf dry matter transport(t ha−1)for the P-R-R in both seasons was significantly higher by an average 11.2%,7.2%and 36%than MV-R-R,R-R-R,and WF-R-R,respectively.In addition,net total nitrogen accumulation(kg ha−1)was found higher in green manure applied plots compared to the control.Yield and yield attributed traits were observed maximum in green manure applied plots,with treatments ranking as follows:P-R-R>R-R-R>MV-R-R>WF-R-R.Thus,results obtained highlight ability of green manure to sustainably improve soil quality and rice yield.

Effect of Nitrogen Fertilizer on the Accumulation and Distribution of Dry Matter in Broomcorn Millet

[Objective] To understand the effect of nitrogen application on dry matter accumulation and allocation dynamics in broomcorn millet. [Method] The accumulation and distribution of dry matter were studied using cultivars Jin Shu 7 and Huang Mizi at different levels of nitrogen fertilizer at the jointing stage. [Result] The results showed that increasing N application led to the increase of green leaf area and the delay of leaf senescence, which was beneficial to the accumulation of dry matter.Appropriate nitrogen application(90 kg/hm2) could coordinate the translocation rate of dry matter among different plant parts, thereby enhancing the yield of broomcorn millet; among different organs, the contribution rate of stem to kernel was greater than that of leaf to kernel; there was obvious correlation between dry matter and yield. For Jin Shu 7, leaf area and dry weight of spike showed significant negative correlation with yield. [Conclusion] The formation of grain yield of broomcorn millet involved the accumulation and allocation of dry matter, the appropriate amount of nitrogen application(90 kg/hm2) could improve the rates of translocation and contribution of dry matter, thereby promoting the yield of broomcorn millet.

Effects of Limited Water Supply and Ridge Plotted Field on Soybean Yield and Dry Matter Accumulation

The drought in spring leads to the lack of soil water, which influents sprout and bud of crops, which furthermore affects growth and yield of crops. Studying the technology integration of bed-irrigating sowing, the mending irrigation of seedling stage and the effect of water-saving of ridge plotted field, analyzing the finger of yield and dry matter accumulation, water-saving technology integration have good effects on water-saving, water storage and increasing moisture on soil and enhancement of soybean yield.

Geochemistry and heterogeneous accumulation of organic matter in lacustrine basins:A case study of the Eocene Liushagang Formation in the Fushan Depression,South China Sea

Determining the spatial distributions of organic-rich mudstones in hydrocarbon-bearing lacustrine basins is crucial for targeting exploration wells and discovering commercially viable petroleum accumulations.However,the strong heterogeneity of sedimentary systems and organic matter(OM)input and accumulations make it difficult to identify OM-rich mudstones in lacustrine deposits.This paper takes the Eocene Liushagang Formation,in the Fushan Depression,South China Sea,as an example to clarify the relationship between the geochemical characteristics of OM and sedimentary facies.A practical approach is proposed for predicting the spatial distribution of good-quality source rocks with high OM contents.The method used is a combination of logging-based surface fitting and the mudstone to stratum thickness ratio(M/S ratio)of different depositional systems.It was found that this approach improved TOC content prediction both vertically and laterally.The results suggest that semi-deep lacustrine mudstones with predominantly aquatic organism input,deposited in suboxic-anoxic saline stratified water,contain more preserved OM than other mudstones.Using this method,limited areas on the southern slope of the lower Liushagang sequence(SQls3),the central part of the Huangtong Sag in the middle Liushagang sequence(SQls2),and the northern part of the Huangtong Sag in the upper Liushagang sequence(SQls1)are determined to be the best-quality source rocks in the development area.

Pattern of Growth and Dry Matter Accumulation in Some Improved Cowpea Varieties (<i>Vigna unguiculata</i>) Exposed to Alpha Nano Spin

Ten (10) cowpea varieties exposed to alpha nano spin were evaluated during the 2019 cropping season to access the role of alpha nano spin in their growth and dry matter accumulation at the Botanical garden of Federal University, Lafia. A Randomized Complete Block Design (RCBD) with four replications was used. The fourth replication was used for the destructive sampling over time. The seed was exposed to alpha nano spin before planting at 0, 20, 40 and 60 minutes respectively. Results of the study showed that the varieties differed significantly with respect to morphological traits studied (P < 0.05) as exposed to the alpha nanoparticles. Morphological traits such as vine length, number of leaves and above ground stems were significantly influenced by alpha nano spin bombardment. 40 mins alpha nano spin resulted in maximum accumulation of dry matter, leaf area and leaf area index. The traits evaluated were stable under alpha nano spin exposure, suggesting that they could be useful indices in creating genetic variability in each of the varieties.

Clogging processes caused by biofilm growth and organic particle accumulation in lab-scale vertical flow constructed wetlands

The accumulation of organic matter in substratum pores is regarded as an important factor causing clogging separately in the subsurface flow constructed wetlands.In this study,the developing process of clogging caused by biofilm growth or organic particle accumulation instead of total organic matter accumulation was investigated in two groups of lab-scale vertical flow constructed wetlands（VFCWs）,which were fed with glucose（dissolved organic matter） and starch（particulate organic matter） influent.Results showed that the growth of biofilms within the substratum pores certainly caused remarkable reduction of effective porosity,especially for the strong organic wastewater,whereas its influence on infiltration rate was negligible.It was implied that the most important contribution of biofilm growth to clogging was accelerating the occurrence of clogging.In comparison with biofilm growth,particles accumulation within pores could rapidly reduce infiltration rate besides effective porosity and the clogging occurred in the upper 0-15 cm layer.With approximately equal amount of accumulated organic matter,the effective porosity of the clogged layer in starch-fed systems was far less than that of glucose-fed systems,which indicated that composition and accumulation mode in addition to the amount of the accumulated organic matter played an important role in causing clogging.

Unconventional Petroleum Sedimentology:A Key to Understanding Unconventional Hydrocarbon Accumulation

The commercial exploitation of unconventional petroleum resources(e.g.,shale oil/gas and tight oil/gas)has drastically changed the global energy structure within the past two decades.Sweet-spot intervals(areas),the most prolific unconventional hydrocarbon resources,generally consist of extraordinarily high organic matter(EHOM)deposits or closely associated sandstones/carbonate rocks.The formation of sweet-spot intervals(areas)is fundamentally controlled by their depositional and subsequent diagenetic settings,which result from the coupled sedimentation of global or regional geological events,such as tectonic activity,sea level(lake level)fluctuations,climate change,bottom water anoxia,volcanic activity,biotic mass extinction or radiation,and gravity flows during a certain geological period.Black shales with EHOM content and their associated high-quality reservoir rocks deposited by the coupling of major geological events provide not only a prerequisite for massive hydrocarbon generation but also abundant hydrocarbon storage space.The Ordovician-Silurian Wufeng-Longmaxi shale of the Sichuan Basin,Devonian Marcellus shale of the Appalachian Basin,Devonian-Carboniferous Bakken Formation of the Williston Basin,and Triassic Yanchang Formation of the Ordos Basin are four typical unconventional hydrocarbon systems selected as case studies herein.In each case,the formation of sweet-spot intervals for unconventional hydrocarbon resources was controlled by the coupled sedimentation of different global or regional geological events,collectively resulting in a favorable environment for the production,preservation,and accumulation of organic matter,as well as for the generation,migration,accumulation,and exploitation of hydrocarbons.Unconventional petroleum sedimentology,which focuses on coupled sedimentation during dramatic environmental changes driven by major geological events,is key to improve the understanding of the formation and distribution of sweet-spot intervals(areas)in unconventional petroleum systems.

Influences of climate change on dry matter accumulating velocity of spring wheat and numerical simulation in arid and semi-arid regions

The influences of climate change on the velocity of dry matter accumulation of spring wheat and numerical simulation in arid and semi-arid regions under the condition of rainfalled agriculture or irrigated agriculture were quantitatively analysed by using the field experimental data. The results showed that the velocity of dry matter accumulation of spring wheat was declined with the temperature rising. The accumulating velocity would be declined 4.9 - 14.0% in irrigated agriculture area when air temperature rose in 0.5-4.0℃ ; but in rainfalled agriculture regions, the velocity of dry matter accumulation would be increased with the soil moisture increasing when air temperature rose in 0.5-1.0℃ and decreased when the air temperature rose in 3.0-4.0 ℃ .