Salvaged cow horns from slaughterhouses have been transformed into fine particles for a physical characterization that has led us to determine the humidity rate (2.34% ± 0.054%), the actual density situated betwe...Salvaged cow horns from slaughterhouses have been transformed into fine particles for a physical characterization that has led us to determine the humidity rate (2.34% ± 0.054%), the actual density situated between 0.586 g/cm<sup>3</sup> and 0.732 g/cm<sup>3</sup>, the swelling rate (12%), and one chemical characterization that permitted us to determine the rate of dry matters (97.05%), of mineral matters (2.5%), of protein matters (94.52%). From these weak values, it can easily be seen that cow horn case doesn’t absorb much water and improve the mechanical characteristics of the composite;the high rate of protein shows that keratin which is the structural molecule favors its gripping as reinforcing element in the manufacturing of composite materials.展开更多
The accurate assessment of soil properties is a crucial factor for composing and implementing reclamation plans. The main objective of this study was to evaluate soil chemical and physical properties and calculate the...The accurate assessment of soil properties is a crucial factor for composing and implementing reclamation plans. The main objective of this study was to evaluate soil chemical and physical properties and calculate the chemical and fertility index for assisting land reclamation in Toshka area. The Toshka area is located between latitudes 31°32'N and 31°36'N and longitudes 32°40'E and 32°60'E. GIS was used to select 16 sites. The results revealed the soil has undesirable characteristics. The soil pH ranged from slightly alkaline to moderately alkaline. Furthermore, it was characterized as saline (with a ECe of 4.65 - 11.45 dS⋅m<sup>−1</sup>) and moderately calcareous soil (with CaCO<sub>3</sub> at 11.85% - 17.20%). The soil had a low soil organic matter content which did not exceed 0.18%. The soil was dominated by a sandy loam texture (62.50%) followed by a sandy clay loam texture (18.75%). The bulk density, total soil porosity and saturated hydraulic conductivity values varied with 1.38 - 1.55 Mg⋅cm<sup>−3</sup>, 41.85% - 48.45% and 1.20 - 3.34 cm⋅h<sup>−1</sup>, respectively. The chemical index ranged from low to moderate quality. The correlations between the parameters osculated between negative and positive. Therefore, the soil may be reclaimed if the soil properties are improved and crop selection is optimized for this soil.展开更多
The in-situ oxidation of manganese sulfate solution with H2O_(2),sodium hypochlorite,potassium permanganate and oxygen as oxidants was investigated by means of SEM,EDS,XRD,BET and infrared analysis,and the effects of ...The in-situ oxidation of manganese sulfate solution with H2O_(2),sodium hypochlorite,potassium permanganate and oxygen as oxidants was investigated by means of SEM,EDS,XRD,BET and infrared analysis,and the effects of different oxidants on the morphology,phase composition,surface properties and specific surface area of manganese oxides were investigated.The experimental results show that the diameter of manganese oxide particles prepared with H_(2)O_(2)is the smallest,about 50 nm,and the specific surface area is the largest,63.8764 m^(2)/g.It has the advantages of abundant surface hydroxyl groups,no introduction of other impurities and large adsorption potential.It is most suitable to be used as an oxidant for oxidizing manganese sulfate solution to prepare manganese oxide by in-situ oxidation.Nano manganese oxide prepard by H_(2)O_(2)in-situ oxidation method is used as adsorbent to adsorb cobalt and nickel impurities in manganese sulfate.When the reaction pH is 6,the reaction time is 30min and the amount of adsorbent is 1.0 g,the adsorption rates of cobalt and nickel impurities in 100ml manganese sulfate solution are 97.59%and 97.67%,respectively.The residual amounts of cobalt and nickel meet the industrial process standard of first-class products(Co,Ni w/%≤0.005)of high-purity manganese sulfate(Hg/t4823-2015)for batteries.The study plays a guiding role in the preparation and regulation of manganese oxide,and provides a new method with high efficiency,purity and adsorbent availability for the preparation of high-purity manganese sulfate solution.展开更多
In order to clarify the influence of liquid sulfur deposition and adsorption to high-H2S gas reservoirs,three types of natural cores with typical carbonate pore structures were selected for high-temperature and high-p...In order to clarify the influence of liquid sulfur deposition and adsorption to high-H2S gas reservoirs,three types of natural cores with typical carbonate pore structures were selected for high-temperature and high-pressure core displacement experiments.Fine quantitative characterization of the cores in three steady states(original,after sulfur injection,and after gas flooding)was carried out using the nuclear magnetic resonance(NMR)transverse relaxation time spectrum and imaging,X-ray computer tomography(CT)of full-diameter cores,basic physical property testing,and field emission scanning electron microscopy imaging.The loss of pore volume caused by sulfur deposition and adsorption mainly comes from the medium and large pores with sizes bigger than 1000μm.Liquid sulfur has a stronger adsorption and deposition ability in smaller pore spaces,and causes greater damage to reservoirs with poor original pore structures.The pore structure of the three types of carbonate reservoirs shows multiple fractal characteristics.The worse the pore structure,the greater the change of internal pore distribution caused by liquid sulfur deposition and adsorption,and the stronger the heterogeneity.Liquid sulfur deposition and adsorption change the pore size distribution,pore connectivity,and heterogeneity of the rock,which further changes the physical properties of the reservoir.After sulfur injection and gas flooding,the permeability of TypeⅠreservoirs with good physical properties decreased by 16%,and that of TypesⅡandⅢreservoirs with poor physical properties decreased by 90%or more,suggesting an extremely high damage.This indicates that the worse the initial physical properties,the greater the damage of liquid sulfur deposition and adsorption.Liquid sulfur is adsorbed and deposited in different types of pore space in the forms of flocculence,cobweb,or retinitis,causing different changes in the pore structure and physical property of the reservoir.展开更多
Plant derived natural fibers have been widely investigated as alternatives to synthetic fibers in reinforcing polymers.Researchers over the years have explored many plant fibers using different extraction processes to...Plant derived natural fibers have been widely investigated as alternatives to synthetic fibers in reinforcing polymers.Researchers over the years have explored many plant fibers using different extraction processes to study their physical,chemical,and mechanical properties.In this context,the present study relates to the extraction,characterization,and optimization of Typha angustata L.stem fibers.For this purpose,desirability functions and response surface methodology were applied to simultaneously optimize the diameter(D),linear density(LD);yield(Y),lignin fraction(L),and tenacity(T)of Typha stem fibers.Typha stems have been subjected to both alkali(NaOH)and enzymatic(pectinex ultra-SPL)treatments.Three levels of process variables including enzyme concentration(10,15,and 20 ml/L)and treatment duration(10,15,and 20 days)were used to design the experiments according to the factorial design.Experimental results were examined by analysis of variance and fitted to second order polynomial model using multiple regression analysis.The Derringer’s desirability function released that the values of process variables generating optimized diameter,linear density,yield,lignin ratio and tenacity are 20 ml/L and 20 days for concentration of pectinex ultra-SPL enzyme and treatment duration,respectively.Confirmation was performed and high degree of correlation was found between the experimental and statistical values.Moreover,the morphological structure has been investigated by the scanning electron microscope,showing a crenelated structure of ultimate fiber bundles of cellulose composing the Typha fiber.Compared to Typha stem non-treated fibers(TSNTF),Typha stem combined treated fibers(TSCTF),brings to improve mechanical properties.This change in mechanical properties is affected by modifying the fiber structure showing alpha cellulose of(66.86%)and lignin ratio of(10.83%)with a crystallinity index of(58.47%).展开更多
[Objective] The aim was to study on changing rules of physical and chemical properties of Eucalyptus uraphylla spp. forest at different ages in Southwest of Yunnan Province. [Method] In the research, field survey and ...[Objective] The aim was to study on changing rules of physical and chemical properties of Eucalyptus uraphylla spp. forest at different ages in Southwest of Yunnan Province. [Method] In the research, field survey and laboratory analysis were adopted to study on physical and chemical properties of soils for the Eucalyptus uraphylla spp. at the first cutting ages in Lancang County. [Result] With the increasing of forest ages, for physical properties of soils, soil bulk density was increasing, and soil structure became poor; water contents in soils and capillary porosity were improving, but total soil porosity and non-capillary porosity were decreasing. For chemical properties, pH of soil dropped, but soil acidity improved; organic matter, total N, hydrolysable nitrogen, available phosphorus, and available potassium all declined; exchangeable Ca and Mg were improving due to fertilization and Ca and Mg lower consumption. The results showed that plays important roles in water absorption of soils and vegetation growth were improved with age increase by Eucalyptus uraphylla spp. forest, but ventilation and fertility declined accordingly. [Conclusion] The research indicated that dry branches and fallen leaves should be preserved and nutrient cycling should be protected during introduction and management of Eucalyptus uraphylla spp. to guarantee the nutrients in dry branches and leaves are back to soils, providing theoretical references for management of forest plantation and environment protection.展开更多
With 5 types of typical forests as research object, the physical and chemical properties of different types of forests were analyzed by sample plot investigation method. The results showed that: the soil total porosi...With 5 types of typical forests as research object, the physical and chemical properties of different types of forests were analyzed by sample plot investigation method. The results showed that: the soil total porosity was the highest in the Casuarina equisetifolia forest (46.168%), but the lowest in the Encalyptus robusta forest (39.46%). The soil capillary porosity was the highest in the Acacia mangium forest (22.57%), but the lowest in the secondary forest (18.95%). The soil water content was the highest in the C. equisetifolia forest, with a mean value of 27.85%, but the lowest in the secondary forest, with a mean value of 4.34%. The soil pH values were in the range of 4.81-6.59, the soils in the A. mangium forest, C. equisetifolia forest and E. robusta forest were strongly acidic (pH 4.5-5.5), and the soils in the secondary forest and C. nucifera forest were weakly acidic. The soils had organic matter contents in the range of 0.34-28.68 g/kg, and showed an order of A. mangium forest〉C. equisetifolia forest〉E. robusta forest〉secondary forest〉C. nucifera forest, with a decreasing trend with the soil depth increasing. The soil total N contents were in the range of 0.10-1.63 g/kg, the A. mangium forest showed the highest soil total N contents, while the C. nucifera forest exhibited the lowest soil total N contents; the soil total P contents were in the range of 0.21-1.74 g/kg, and the E. robusta forest had the highest soil total P contents; and the soil total K contents were in the range of 0.16-2.15 g/kg, and the A. mangium forest exhibited the highest soil total K contents. The soil available P contents were in the range of 0.98-132.46 mg/kg; and the secondary forests had the highest soil available P contents; and the soil rapidly available K contents were in the range of 3.03-27.35 mg/kg, and the C. nucifera forest exhibited the highest soil rapidly available K contents. The soil ammonium N contents were in the range of 1.38-5.15 mg/kg, and the nitrate N contents were in the range were in the range of 0.56 -3.51 mg/kg. The A. mangium forest showed the highest soil nitrate N contents (with a mean value of 2.29 mg/kg) and ammonium N contents (with a mean value of 3.93 mg/kg). For the same forest type, with the increase of soil depth, the nitrate nitrogen and ammonium nitrogen content also showed a decreasing trend.展开更多
[Objective] This study was aimed to find a new method for the classification of common aroma components in tobacco leaves. [Method] Sixty-four common aroma components in tobacco leaves were classified by cluster analy...[Objective] This study was aimed to find a new method for the classification of common aroma components in tobacco leaves. [Method] Sixty-four common aroma components in tobacco leaves were classified by cluster analysis based on their relative molecular weight. The contents and distribution of aroma components in another 71 C3F and 64 B2F tobacco leaf samples were analyzed by using the new method. [Result] The 64 common aroma components were divided into three categories trough the cluster analysis based on their molecular weight. CategoryⅠ consisted of 12 aroma components which had high molecular weight(281.308±21.536on average) and high boiling point(371.311±29.904 ℃ on average). Category Ⅱ included 27 components which had low molecular weight(103.722 ± 13.115 on average) and low boiling point(176.132±42.342 ℃ on average). Category Ⅲ included 25components which had middle molecular weight(175.393 ± 24.906 on average) and middle boiling point(250.562±45.431 ℃ on average). The content of high-molecularweight aroma components in middle leaves(547.344±224.391 μg/g) was much higher than that in upper leaves(477.549±182.066 μg/g). The content of low-molecularweight aroma component in middle leaves(17.468±3.459 μg/g) was also significantly higher than that in upper leaves(15.936±3.456 μg/g). The content of middle-molecular-weight aroma component in middle leaves(44.931 ±8.953 μg/g) was extremely significantly higher than that in upper leaves(37.997±6.042 μg/g). [Conclusion] This study proposed a new way to classify the aroma components in flue-cured tobacco leaves using the relative molecular weight as the index, which will provide theoretical reference for developing special tobacco leaves.展开更多
[Objective] The aim was to clear the suitable green manure cropping pat- terns in Xiangxi tobacco-planting areas. [Method] 8 treatments were set to study the effects of the monoculture and mixed cropping of common vet...[Objective] The aim was to clear the suitable green manure cropping pat- terns in Xiangxi tobacco-planting areas. [Method] 8 treatments were set to study the effects of the monoculture and mixed cropping of common vetch (Vicia gigantea Bge.), perennial ryegrass (Lofium) and rapeseed (Brassica campestris L.) on physi- cal and chemical properties of soil and economic characters of flue-cured tobacco. [Result] (1) Green manure turnover can reduce soil bulk density by 1.08%-8.62%, and the effect of green manure mixed cropping pattern was the best. (2) Green manure turnover also can increase the soil nutrient, soil organic matter, total nitro- gen (N), total phosphorus (P), total potassium (K), alkali-hydrolyzale N, rapidly available P and rapidly available K by 1.44%-6.10%, 0.01-0.12 g/kg, 1.89%- 11.32%, 0.12%-3.56%, 1.06%-11.76%, 0.04%-18.93% and 0.98%-23.12%, respec- tively, and the effect of the monoculture of common vetch was the best.(3) The overall change of soil pH was not obvious.(4)Green manure turnover can increase the yield and output of flue-cured tobacco, and the effect of the monoculture of common vetch was the best. [Conclusion] The monoculture of common vetch can be generalized in the dry land of Xiangxi tobacco-planting areas.展开更多
Fire affects the physical and chemical properties and soil biological activity of natural ecosystems. This study was conducted in the Miyan Tang region, Ilam Province in western Iran. The study site was 110 hectares, ...Fire affects the physical and chemical properties and soil biological activity of natural ecosystems. This study was conducted in the Miyan Tang region, Ilam Province in western Iran. The study site was 110 hectares, where we sampled soils in areas that were classified by fire severity: low (LS), high (HS) and medium severity (MS), and unburned (UB), which served as the control. In each severity class, 25 transect points were randomly selected for measurement. Around each transect plot center, 3 soil samples were selected randomly and soils collected from the 0 to 20 cm depth were combined into a composite sample that was used in laboratory analysis to represent conditions at that point. Plots in the UB and LS fire classes had similar soil conditions and had higher values of factors such as saturated moisture, organic carbon, carbon dioxide, and silt and clay content. In contrast, plots in the HS and MS fire severity classes were clustered in the positive direction along the first axis that represented gradients in soil acidity, electrical conductivity, cation exchange capacity, accessible phosphorus, accessible potassium, bulk density, and sand. Soil attributes were similar in areas of HS and MS fire severity classes, whereas soil conditions in the LS class and UB controls were most similar. Fire in the LS areas either did not significantly alter the physicalchemical soil properties and microbial basal respiration, or soils were able to recover quickly after being burned.展开更多
Large oilfields are often coincidentally located in major river deltas and wetlands,and potentially damage the structure,function and ecosystem service values of wetlands during oil exploration.In the present study,th...Large oilfields are often coincidentally located in major river deltas and wetlands,and potentially damage the structure,function and ecosystem service values of wetlands during oil exploration.In the present study,the effects of crude oil contamination during oil exploration on soil physical and chemical properties were investigated in marshes of the Momoge National Nature Reserve in Jilin Province,China.The concentrations of total petroleum hydrocarbons in the marsh soil near the oil wells are significantly higher than those in the adjacent control marsh.Soil water contents in oil-contaminated marshes are negatively correlated with soil temperature and are significantly lower than those in the control area,especially in fall.Crude oil contamination significantly increases the soil pH up to8.0,and reduces available phosphorus concentrations in the soil.The concentrations of total organic carbon are significantly different among sampling sites.Therefore,crude oil contamination could potentially alkalinize marsh soils,adversely affect soil fertility and physical properties,and cause deterioration of the marshes in the Momoge National Nature Reserve.Phyto-remediation by planting Calamagrostis angustifolia has the potential to simultaneously restore and remediate the petroleum hydrocarbon-contaminated wetlands.Crude oil contamination affects the soil physical and chemical properties,so developing an effective restoration program in the Momoge wetland is neccesary.展开更多
The results of a system analysis of the efficiency of nitrous oxide(N_2O) as a propellant component for small space vehicles(SSV) were presented. A criterion for mass efficiency of the SSV propulsion system(PS) is det...The results of a system analysis of the efficiency of nitrous oxide(N_2O) as a propellant component for small space vehicles(SSV) were presented. A criterion for mass efficiency of the SSV propulsion system(PS) is determined. The current global state-of-the-art of SSV PSs is shown. The application field of nitrous oxide in SSV PSs is calculated and mass efficiency of N_2O application is quantitatively determined. An overview of physical and chemical as well as operational properties of nitrous oxide as a promising, non-toxic component of rocket propellant is provided. Main physical and chemical constants of gaseous and liquid nitrous oxide; chemical properties of N_2O, thermal stability of N_2O, catalytic decomposition of N_2O, a mechanism of decomposition of N_2O, catalysts for decomposition of N_2O, ballast additives to N_2O, application of nitrous oxide, nitrous oxide as a rocket propellant, production of nitrous oxide, toxicity of nitrous oxide, fire hazard of N_2O, requirements to equipment when handling N_2O; storage and transportation of N_2O are considered. It is demonstrated that nitrous oxide is a chemical compound meeting the requirements to rocket propellants, including those related to the environmental friendliness of propellants. With 75 references.展开更多
Application of nitrogen (N) fertilizer is one of the most important approaches on improving maize grain yield. However, as is known to all, overuse N fertilizer not only leads to decline of N use efficiency and maize ...Application of nitrogen (N) fertilizer is one of the most important approaches on improving maize grain yield. However, as is known to all, overuse N fertilizer not only leads to decline of N use efficiency and maize yield, but also leads to potential risk to environment pollution. This experiment was conducted to determine the effects of N fertilizer applications with nine different treatments on soil physical-chemical characters and maize grain yield using hybrid variety Zhengdan 958 in 2011 and 2012. Results indicated that the soil bulk densities of T2 (CK) and T1 were the lowest compared to other treatments in 2011 and 2012, respectively, whereas the soil bulk density of T5 in 2011 and T3 in 2012 were higher than other treatments. The soil porosity and field capacity of T5 in 2011 and T3 in 2012 were lower than other treatments, but those of CK in 2011 and T1 in 2012 were higher than other treatments. The pH values of T3 to T7 were lower than other treatments. These results indicated that the soil bulk densities were increased, whereas the soil porosity, field capacity and values pH were decreased by N application at different stages. N application could increase the N contents of leaf and stem, whereas less or excess N application should not significant improve maize yield. Although the soil organic matter and total N contents of T3 were the highest in both 2011 and 2012, the yield of T4 is the highest in both 2011 and 2012. The application amount, period and times of N fertilizer were important to maize yield.展开更多
Biological soil crusts (BSCs) are capable of modifying nutrient availability to favor the establishment of biogeochemical cycles. Microbial activities serve as critical roles for both carbon and nutrient transformat...Biological soil crusts (BSCs) are capable of modifying nutrient availability to favor the establishment of biogeochemical cycles. Microbial activities serve as critical roles for both carbon and nutrient transformation in BSCs. However, little is known about microbial activities and physical-chemical properties of BSCs in the Gurbantunggut Desert, Xinjiang, China. In the present research, a sampling line with 1-m wide and 20-m long was set up in each of five typical interdune areas selected randomly in the Gurbantunggut Desert. Within each sampling line, samples of bare sand sheet, algal crusts, lichen crusts and moss crusts were randomly collected at the depth of 0-2 cm. Varia- tions of microalgal biomass, microbial biomass, enzyme activities and soil physical-chemical properties in different succession of BSCs were analyzed. The relationships between microalgal biomass, microbial biomass, enzymatic activities and soil physical-chemical properties were explored by stepwise regression. Our results indicate that micro- algal biomass, microbial biomass and most of enzyme activities increased as the BSCs developed and their highest values occurred in lichen or moss crusts. Except for total K, the contents of most soil nutrients (organic C, total N, total P, available N, available P and available K) were the lowest in the bare sand sheet and significantly increased with the BSCs development, reaching their highest values in moss crusts. However, pH values significantly decreased as the BSCs developed. Significant and positive correlations were observed between chlorophyll a and microbial biomass C. Total P and N were positively associated with chlorophyll a and microbial biomass C, whereas there was a significant and negative correlation between microbial biomass and available P. The growth of cyanobacteria and microorganism contributed C and N in the soil, which offered substrates for enzyme activities thus increasing enzyme activities. Probably, improvement in enzyme activities increased soil fertility and promoted the growth of cyanobacteria, eukary- otic algae and heterotrophic microorganism, with the accelerating succession of BSCs. The present research found that microalgal-microbial biomass and enzyme activities played important roles on the contents of nutrients in the successional stages of BSCs and helped us to understand developmental mechanism in the succession of BSCs.展开更多
The improvement of the soil physical and chemical properties is the most important foundation for mine ecological restoration.The experiment is aimed at undisturbed area,restored area,and damaged area of abandoned Yon...The improvement of the soil physical and chemical properties is the most important foundation for mine ecological restoration.The experiment is aimed at undisturbed area,restored area,and damaged area of abandoned Yongledian Quarry in Beijing.Through determination and analysis of soil physical and chemical properties,it shows that there are significant differences in the composite effects of soil physical and chemical properties between restored area,and undisturbed area,damaged area,and engineering restoration effectively improves the composite effects of soil physical and chemical properties in the restored area.The single factor hypothesis test shows that soil pH value,organic matter,alkali-hydrolyzable nitrogen,and total nitrogen traits are the key targets to be restored in this mining area.展开更多
Six forest stands of 59,34 and 24 year-old Pinus massoniana forests and their mixed forests were selected at the Experimental Center of Tropical Forestry of Chinese Academy of Forestry,and 20 m × 20 m plot was se...Six forest stands of 59,34 and 24 year-old Pinus massoniana forests and their mixed forests were selected at the Experimental Center of Tropical Forestry of Chinese Academy of Forestry,and 20 m × 20 m plot was set up and soil samples were taken from 0-60 cm soil layers,to analyze the changes of soil nutrient content under different forest stands and forest ages. The results showed that soil moisture and the bulk density in the mesophytic forest land were higher than those of other forest lands. The highest soil porosity value was observed in the early forest land. Soil p H of different forest was 4. 45-4. 75,indicating the variation was small. Besides,it indicated that the mixed forest was more able to increase the soil fertility than the pure forest because that the variation of soil acidity,organic matter content and total P and K in 34 and24 year-old mixed forests were higher than those in pure forests of the same year old. However,the content of soil available P and K decreased with the increase of soil depth,and varied in terms of forest ages. From the changes of soil indicators in different forest lands,soil nutrients in the 34 year-old P. massoniana forest was superior to that of other forest stands.展开更多
Most of the seeds produced by neem (Azadirachta indica A. Juss) trees in Nigeria are currently underutilized. Hence, relevant literature provides only limited information conceming many of the seed oils from this co...Most of the seeds produced by neem (Azadirachta indica A. Juss) trees in Nigeria are currently underutilized. Hence, relevant literature provides only limited information conceming many of the seed oils from this country, especially where it concems the potential applications of these oils as preservatives for ligno-cellulose against bio-deterioration. Using standard procedures therefore, this study was carried out to evaluate and document selected physical and chemical properties of neem seed oil (NSO), mechanically extracted using a cold press at 31.03 N-mm^-2 pressure and a room temperature of 25 ± 2℃. The results show that oil yield was 38.42% with a specific gravity of 0.91 ± 0.01. The amount of acid was 18.24 ± 1.31 mg KOH.g^-1 and that of iodine 93.12 ± 2.01 g-100 g^- 1, while saponification and peroxide values were 172.88 ± 2.06 and 1.42 ± 0.04 mg·g^-1 respectively. The implication of the values obtained, particularly those for the chemical properties, as they concern the potential application of NSO as a preservative for ligno-eellulose, is likely that it may be useful in this regard since the values may support some of the documented anti-microbial properties of the oil, although other physical and chemical properties that may affect this potential are recommended for investigations. Conclusions and other recommendations follow in line with the results of the study.展开更多
Five kinds of greenhouse vegetables( eggplant,loofah,tomato,cucumber and pepper) were selected in summer uprooting stage from greenhouse in Shouguang area,Shandong Province. Total nitrogen,ammonium nitrogen,nitrate ni...Five kinds of greenhouse vegetables( eggplant,loofah,tomato,cucumber and pepper) were selected in summer uprooting stage from greenhouse in Shouguang area,Shandong Province. Total nitrogen,ammonium nitrogen,nitrate nitrogen,available phosphorus,available potassium,organic matter content and p H,EC value of three soil layers were measured,respectively. The results showed that the total nitrogen,ammonium nitrogen,nitrate nitrogen,available phosphorus and available potassium in the soil were mainly accumulated in the upper soil,which made the soil acidification trend,because different farmers adopted different cultivation practices for different greenhouse vegetables in Shouguang region,but there was no significant effect on soil EC value. The input of ammonium nitrogen and nitrate nitrogen and other related fertilizers to greenhouse cucumber was higher than that of other greenhouse vegetables,but the amount of available potassium fertilizer and organic matter input to greenhouse tomato under different cultivation practices was lower than other greenhouse vegetables. In Shouguang area,the input of organic matter into greenhouse vegetables should be increased by increasing the proportion of manure input to increase the content of soil organic carbon,so as to achieve the balance of carbon and nitrogen ratio,and to provide a scientific basis for the establishment of an evaluation system for the environmental benefits brought about by chemical fertilizer reduction in greenhouse vegetables in Shouguang area.展开更多
In order to investigate the variation in soil physical and chemical properties and nutrients in the mountainous areas in southern Ningxia, and to provide a theoretical basis for fertilization management in local farml...In order to investigate the variation in soil physical and chemical properties and nutrients in the mountainous areas in southern Ningxia, and to provide a theoretical basis for fertilization management in local farmland, the soil p H, total salt content,crop root length, root weight, soil organic matter, available nitrogen, total nitrogen, total phosphorous and total potassium in different fertilization treatments were measured from 2010 to 2016. Multiple comparisons of the data were performed using Duncan's new multiple range test. The results indicated that in the 0-20 cm soil layer, soil p H value and total salt content changed in different patterns, and varied greatly from 2010 to 2016(P<0.05). The changes of both root length and root weight of millet over time fitted S-shaped curves. The root length and root weight in the four fertilization treatments(Treatment 2 to Treatment5) increased faster than those in the control(Treatment 1). The soil organic matter content in all the five treatments gradually increased from 2010 to 2016. The content of alkaline hydrolyzable nitrogen in soil rapidly increased in the first two to three years of the experiment, followed by a slow increase or decrease in 2013, and then raised rapidly again from 2014 to 2016.The soil total nitrogen content varied significantly from 2010 to 2016. The total phosphorus content in soil changed in a different pattern from that of total nitrogen content. The seven-year field trails revealed that soil p H, total salt content, root length, root weight and soil nutrient all changed with the increase of fertilizer level, and that long-term fertilization is of significance for maintaining soil fertility, improving soil quality and reducing soil salinization.展开更多
The concern of this study is determine the quality of soil when irrigation used treated water and wastewater in comparison with soil irrigated with tap water on some chemical and physical soil properties. The experime...The concern of this study is determine the quality of soil when irrigation used treated water and wastewater in comparison with soil irrigated with tap water on some chemical and physical soil properties. The experiment components were three trials carried out under greenhouse conditions, 10 pots for each trial. The first trial irrigated with tap water, the second trial irrigated by treated water and the third trial irrigated with wastewater. The experiment conducted to study the impact of water types on some soil physical and chemical properties. The experiment included important analysis for water and soil before and after irrigation. The results showed that the values for electrical conductivity (EC) were 0.850, 308 and 324 μs/cm for the treated soil with tap water, treated water and wastewater, respectively. The variation of pH values seems to be approximately constant between the different of water used. The percent of organic matter (OM) in soils receiving treated water and wastewater 4.7% and 5.2% respectively were higher than values in soil treated with tap water 3%. The same trend was in organic carbon (OC) in soils receiving treated water and wastewater 58.5% and 89% respectively, while soil treated with tap water showed the lowest value 27.7%. Soil particle density (SPD) increased significantly in both water treatments were the values was 2 g/cm<sup>3</sup> in tap water but increased value 2.8 g/cm<sup>3</sup> and 3.3 g/cm<sup>3</sup> in treated water and wastewater used respectively. The Bulk Density (BD) values range 1.1 g/cm<sup>3</sup> in soil irrigated with tap water 1.5 g/cm<sup>3</sup> in soil irrigated with treated water and 1.85 g/cm<sup>3</sup> in soil irrigated with treated water. The results of soil analysis before and after planting showed that most of the values increased for the physical and chemical soil properties.展开更多
文摘Salvaged cow horns from slaughterhouses have been transformed into fine particles for a physical characterization that has led us to determine the humidity rate (2.34% ± 0.054%), the actual density situated between 0.586 g/cm<sup>3</sup> and 0.732 g/cm<sup>3</sup>, the swelling rate (12%), and one chemical characterization that permitted us to determine the rate of dry matters (97.05%), of mineral matters (2.5%), of protein matters (94.52%). From these weak values, it can easily be seen that cow horn case doesn’t absorb much water and improve the mechanical characteristics of the composite;the high rate of protein shows that keratin which is the structural molecule favors its gripping as reinforcing element in the manufacturing of composite materials.
文摘The accurate assessment of soil properties is a crucial factor for composing and implementing reclamation plans. The main objective of this study was to evaluate soil chemical and physical properties and calculate the chemical and fertility index for assisting land reclamation in Toshka area. The Toshka area is located between latitudes 31°32'N and 31°36'N and longitudes 32°40'E and 32°60'E. GIS was used to select 16 sites. The results revealed the soil has undesirable characteristics. The soil pH ranged from slightly alkaline to moderately alkaline. Furthermore, it was characterized as saline (with a ECe of 4.65 - 11.45 dS⋅m<sup>−1</sup>) and moderately calcareous soil (with CaCO<sub>3</sub> at 11.85% - 17.20%). The soil had a low soil organic matter content which did not exceed 0.18%. The soil was dominated by a sandy loam texture (62.50%) followed by a sandy clay loam texture (18.75%). The bulk density, total soil porosity and saturated hydraulic conductivity values varied with 1.38 - 1.55 Mg⋅cm<sup>−3</sup>, 41.85% - 48.45% and 1.20 - 3.34 cm⋅h<sup>−1</sup>, respectively. The chemical index ranged from low to moderate quality. The correlations between the parameters osculated between negative and positive. Therefore, the soil may be reclaimed if the soil properties are improved and crop selection is optimized for this soil.
基金Funded by the National Natural Science Foundation of China(No.51864012)the Key Projects Supported by Science and Technology in Guizhou Province(No.[2002]KEY020)+2 种基金the Major Special Projects in Guizhou Province(No.[2022]003)the Guizhou Provincial Science Cooperation Program(Nos.[2016]5302,[2017]5788,[2018]5781,[2019]1411,and[2019]2841)the Major Special Projects in Tongren City,Guizhou Province(No.[2021]13)。
文摘The in-situ oxidation of manganese sulfate solution with H2O_(2),sodium hypochlorite,potassium permanganate and oxygen as oxidants was investigated by means of SEM,EDS,XRD,BET and infrared analysis,and the effects of different oxidants on the morphology,phase composition,surface properties and specific surface area of manganese oxides were investigated.The experimental results show that the diameter of manganese oxide particles prepared with H_(2)O_(2)is the smallest,about 50 nm,and the specific surface area is the largest,63.8764 m^(2)/g.It has the advantages of abundant surface hydroxyl groups,no introduction of other impurities and large adsorption potential.It is most suitable to be used as an oxidant for oxidizing manganese sulfate solution to prepare manganese oxide by in-situ oxidation.Nano manganese oxide prepard by H_(2)O_(2)in-situ oxidation method is used as adsorbent to adsorb cobalt and nickel impurities in manganese sulfate.When the reaction pH is 6,the reaction time is 30min and the amount of adsorbent is 1.0 g,the adsorption rates of cobalt and nickel impurities in 100ml manganese sulfate solution are 97.59%and 97.67%,respectively.The residual amounts of cobalt and nickel meet the industrial process standard of first-class products(Co,Ni w/%≤0.005)of high-purity manganese sulfate(Hg/t4823-2015)for batteries.The study plays a guiding role in the preparation and regulation of manganese oxide,and provides a new method with high efficiency,purity and adsorbent availability for the preparation of high-purity manganese sulfate solution.
基金Supported by the National Natural Science Foundation of China(U19B6003)Sinopec Technology Research Project(P20077kxjgz)。
文摘In order to clarify the influence of liquid sulfur deposition and adsorption to high-H2S gas reservoirs,three types of natural cores with typical carbonate pore structures were selected for high-temperature and high-pressure core displacement experiments.Fine quantitative characterization of the cores in three steady states(original,after sulfur injection,and after gas flooding)was carried out using the nuclear magnetic resonance(NMR)transverse relaxation time spectrum and imaging,X-ray computer tomography(CT)of full-diameter cores,basic physical property testing,and field emission scanning electron microscopy imaging.The loss of pore volume caused by sulfur deposition and adsorption mainly comes from the medium and large pores with sizes bigger than 1000μm.Liquid sulfur has a stronger adsorption and deposition ability in smaller pore spaces,and causes greater damage to reservoirs with poor original pore structures.The pore structure of the three types of carbonate reservoirs shows multiple fractal characteristics.The worse the pore structure,the greater the change of internal pore distribution caused by liquid sulfur deposition and adsorption,and the stronger the heterogeneity.Liquid sulfur deposition and adsorption change the pore size distribution,pore connectivity,and heterogeneity of the rock,which further changes the physical properties of the reservoir.After sulfur injection and gas flooding,the permeability of TypeⅠreservoirs with good physical properties decreased by 16%,and that of TypesⅡandⅢreservoirs with poor physical properties decreased by 90%or more,suggesting an extremely high damage.This indicates that the worse the initial physical properties,the greater the damage of liquid sulfur deposition and adsorption.Liquid sulfur is adsorbed and deposited in different types of pore space in the forms of flocculence,cobweb,or retinitis,causing different changes in the pore structure and physical property of the reservoir.
文摘Plant derived natural fibers have been widely investigated as alternatives to synthetic fibers in reinforcing polymers.Researchers over the years have explored many plant fibers using different extraction processes to study their physical,chemical,and mechanical properties.In this context,the present study relates to the extraction,characterization,and optimization of Typha angustata L.stem fibers.For this purpose,desirability functions and response surface methodology were applied to simultaneously optimize the diameter(D),linear density(LD);yield(Y),lignin fraction(L),and tenacity(T)of Typha stem fibers.Typha stems have been subjected to both alkali(NaOH)and enzymatic(pectinex ultra-SPL)treatments.Three levels of process variables including enzyme concentration(10,15,and 20 ml/L)and treatment duration(10,15,and 20 days)were used to design the experiments according to the factorial design.Experimental results were examined by analysis of variance and fitted to second order polynomial model using multiple regression analysis.The Derringer’s desirability function released that the values of process variables generating optimized diameter,linear density,yield,lignin ratio and tenacity are 20 ml/L and 20 days for concentration of pectinex ultra-SPL enzyme and treatment duration,respectively.Confirmation was performed and high degree of correlation was found between the experimental and statistical values.Moreover,the morphological structure has been investigated by the scanning electron microscope,showing a crenelated structure of ultimate fiber bundles of cellulose composing the Typha fiber.Compared to Typha stem non-treated fibers(TSNTF),Typha stem combined treated fibers(TSCTF),brings to improve mechanical properties.This change in mechanical properties is affected by modifying the fiber structure showing alpha cellulose of(66.86%)and lignin ratio of(10.83%)with a crystallinity index of(58.47%).
基金Supported by National Natural Science Foundation of China (40961031)Applied Basic Research Programs of Yunnan Province (2009CD022)Young and Middle-aged Teachers Training of Yunnan University (XT412003)~~
文摘[Objective] The aim was to study on changing rules of physical and chemical properties of Eucalyptus uraphylla spp. forest at different ages in Southwest of Yunnan Province. [Method] In the research, field survey and laboratory analysis were adopted to study on physical and chemical properties of soils for the Eucalyptus uraphylla spp. at the first cutting ages in Lancang County. [Result] With the increasing of forest ages, for physical properties of soils, soil bulk density was increasing, and soil structure became poor; water contents in soils and capillary porosity were improving, but total soil porosity and non-capillary porosity were decreasing. For chemical properties, pH of soil dropped, but soil acidity improved; organic matter, total N, hydrolysable nitrogen, available phosphorus, and available potassium all declined; exchangeable Ca and Mg were improving due to fertilization and Ca and Mg lower consumption. The results showed that plays important roles in water absorption of soils and vegetation growth were improved with age increase by Eucalyptus uraphylla spp. forest, but ventilation and fertility declined accordingly. [Conclusion] The research indicated that dry branches and fallen leaves should be preserved and nutrient cycling should be protected during introduction and management of Eucalyptus uraphylla spp. to guarantee the nutrients in dry branches and leaves are back to soils, providing theoretical references for management of forest plantation and environment protection.
基金Supported by Special Fund for Technological Development and Research of Provincial Scientific Research Institutions(KYYS-2015-16)~~
文摘With 5 types of typical forests as research object, the physical and chemical properties of different types of forests were analyzed by sample plot investigation method. The results showed that: the soil total porosity was the highest in the Casuarina equisetifolia forest (46.168%), but the lowest in the Encalyptus robusta forest (39.46%). The soil capillary porosity was the highest in the Acacia mangium forest (22.57%), but the lowest in the secondary forest (18.95%). The soil water content was the highest in the C. equisetifolia forest, with a mean value of 27.85%, but the lowest in the secondary forest, with a mean value of 4.34%. The soil pH values were in the range of 4.81-6.59, the soils in the A. mangium forest, C. equisetifolia forest and E. robusta forest were strongly acidic (pH 4.5-5.5), and the soils in the secondary forest and C. nucifera forest were weakly acidic. The soils had organic matter contents in the range of 0.34-28.68 g/kg, and showed an order of A. mangium forest〉C. equisetifolia forest〉E. robusta forest〉secondary forest〉C. nucifera forest, with a decreasing trend with the soil depth increasing. The soil total N contents were in the range of 0.10-1.63 g/kg, the A. mangium forest showed the highest soil total N contents, while the C. nucifera forest exhibited the lowest soil total N contents; the soil total P contents were in the range of 0.21-1.74 g/kg, and the E. robusta forest had the highest soil total P contents; and the soil total K contents were in the range of 0.16-2.15 g/kg, and the A. mangium forest exhibited the highest soil total K contents. The soil available P contents were in the range of 0.98-132.46 mg/kg; and the secondary forests had the highest soil available P contents; and the soil rapidly available K contents were in the range of 3.03-27.35 mg/kg, and the C. nucifera forest exhibited the highest soil rapidly available K contents. The soil ammonium N contents were in the range of 1.38-5.15 mg/kg, and the nitrate N contents were in the range were in the range of 0.56 -3.51 mg/kg. The A. mangium forest showed the highest soil nitrate N contents (with a mean value of 2.29 mg/kg) and ammonium N contents (with a mean value of 3.93 mg/kg). For the same forest type, with the increase of soil depth, the nitrate nitrogen and ammonium nitrogen content also showed a decreasing trend.
基金Supported by the Fund from Hongyun Honghe Tobacco(Group)Co.Ltd.(HYHH2012YL01)~~
文摘[Objective] This study was aimed to find a new method for the classification of common aroma components in tobacco leaves. [Method] Sixty-four common aroma components in tobacco leaves were classified by cluster analysis based on their relative molecular weight. The contents and distribution of aroma components in another 71 C3F and 64 B2F tobacco leaf samples were analyzed by using the new method. [Result] The 64 common aroma components were divided into three categories trough the cluster analysis based on their molecular weight. CategoryⅠ consisted of 12 aroma components which had high molecular weight(281.308±21.536on average) and high boiling point(371.311±29.904 ℃ on average). Category Ⅱ included 27 components which had low molecular weight(103.722 ± 13.115 on average) and low boiling point(176.132±42.342 ℃ on average). Category Ⅲ included 25components which had middle molecular weight(175.393 ± 24.906 on average) and middle boiling point(250.562±45.431 ℃ on average). The content of high-molecularweight aroma components in middle leaves(547.344±224.391 μg/g) was much higher than that in upper leaves(477.549±182.066 μg/g). The content of low-molecularweight aroma component in middle leaves(17.468±3.459 μg/g) was also significantly higher than that in upper leaves(15.936±3.456 μg/g). The content of middle-molecular-weight aroma component in middle leaves(44.931 ±8.953 μg/g) was extremely significantly higher than that in upper leaves(37.997±6.042 μg/g). [Conclusion] This study proposed a new way to classify the aroma components in flue-cured tobacco leaves using the relative molecular weight as the index, which will provide theoretical reference for developing special tobacco leaves.
基金Supported by Key Project of Hunan Tobacco Monopoly Bureau-"Study an Demonstration of Tobacco-planting Soil Maintenance and Improvement in Xiangx Autonomous Prefecture Tobacco-growing Area"(13-14ZDAa03)the Project o China Tobacco Zhejiang Industrial Co.,Ltd.-"Demonstration and Extension o Tobacco-planting Soil Improvement Using Green Manure"(ZJZY2013B003)~~
文摘[Objective] The aim was to clear the suitable green manure cropping pat- terns in Xiangxi tobacco-planting areas. [Method] 8 treatments were set to study the effects of the monoculture and mixed cropping of common vetch (Vicia gigantea Bge.), perennial ryegrass (Lofium) and rapeseed (Brassica campestris L.) on physi- cal and chemical properties of soil and economic characters of flue-cured tobacco. [Result] (1) Green manure turnover can reduce soil bulk density by 1.08%-8.62%, and the effect of green manure mixed cropping pattern was the best. (2) Green manure turnover also can increase the soil nutrient, soil organic matter, total nitro- gen (N), total phosphorus (P), total potassium (K), alkali-hydrolyzale N, rapidly available P and rapidly available K by 1.44%-6.10%, 0.01-0.12 g/kg, 1.89%- 11.32%, 0.12%-3.56%, 1.06%-11.76%, 0.04%-18.93% and 0.98%-23.12%, respec- tively, and the effect of the monoculture of common vetch was the best.(3) The overall change of soil pH was not obvious.(4)Green manure turnover can increase the yield and output of flue-cured tobacco, and the effect of the monoculture of common vetch was the best. [Conclusion] The monoculture of common vetch can be generalized in the dry land of Xiangxi tobacco-planting areas.
文摘Fire affects the physical and chemical properties and soil biological activity of natural ecosystems. This study was conducted in the Miyan Tang region, Ilam Province in western Iran. The study site was 110 hectares, where we sampled soils in areas that were classified by fire severity: low (LS), high (HS) and medium severity (MS), and unburned (UB), which served as the control. In each severity class, 25 transect points were randomly selected for measurement. Around each transect plot center, 3 soil samples were selected randomly and soils collected from the 0 to 20 cm depth were combined into a composite sample that was used in laboratory analysis to represent conditions at that point. Plots in the UB and LS fire classes had similar soil conditions and had higher values of factors such as saturated moisture, organic carbon, carbon dioxide, and silt and clay content. In contrast, plots in the HS and MS fire severity classes were clustered in the positive direction along the first axis that represented gradients in soil acidity, electrical conductivity, cation exchange capacity, accessible phosphorus, accessible potassium, bulk density, and sand. Soil attributes were similar in areas of HS and MS fire severity classes, whereas soil conditions in the LS class and UB controls were most similar. Fire in the LS areas either did not significantly alter the physicalchemical soil properties and microbial basal respiration, or soils were able to recover quickly after being burned.
基金Under the auspices of National Natural Science Foundation of China(No.31170476)Chinese Academy of Sciences/State Administration of Foreign Experts Affairs International Partnership Program for Creative Research Teams(No.KZZD-EW-TZ-07)+1 种基金Major Program of Science and Technology of Jilin Province(No.20075014)Fundamental Research Funds for the Central Universities of China(No.11GJHZ002)
文摘Large oilfields are often coincidentally located in major river deltas and wetlands,and potentially damage the structure,function and ecosystem service values of wetlands during oil exploration.In the present study,the effects of crude oil contamination during oil exploration on soil physical and chemical properties were investigated in marshes of the Momoge National Nature Reserve in Jilin Province,China.The concentrations of total petroleum hydrocarbons in the marsh soil near the oil wells are significantly higher than those in the adjacent control marsh.Soil water contents in oil-contaminated marshes are negatively correlated with soil temperature and are significantly lower than those in the control area,especially in fall.Crude oil contamination significantly increases the soil pH up to8.0,and reduces available phosphorus concentrations in the soil.The concentrations of total organic carbon are significantly different among sampling sites.Therefore,crude oil contamination could potentially alkalinize marsh soils,adversely affect soil fertility and physical properties,and cause deterioration of the marshes in the Momoge National Nature Reserve.Phyto-remediation by planting Calamagrostis angustifolia has the potential to simultaneously restore and remediate the petroleum hydrocarbon-contaminated wetlands.Crude oil contamination affects the soil physical and chemical properties,so developing an effective restoration program in the Momoge wetland is neccesary.
文摘The results of a system analysis of the efficiency of nitrous oxide(N_2O) as a propellant component for small space vehicles(SSV) were presented. A criterion for mass efficiency of the SSV propulsion system(PS) is determined. The current global state-of-the-art of SSV PSs is shown. The application field of nitrous oxide in SSV PSs is calculated and mass efficiency of N_2O application is quantitatively determined. An overview of physical and chemical as well as operational properties of nitrous oxide as a promising, non-toxic component of rocket propellant is provided. Main physical and chemical constants of gaseous and liquid nitrous oxide; chemical properties of N_2O, thermal stability of N_2O, catalytic decomposition of N_2O, a mechanism of decomposition of N_2O, catalysts for decomposition of N_2O, ballast additives to N_2O, application of nitrous oxide, nitrous oxide as a rocket propellant, production of nitrous oxide, toxicity of nitrous oxide, fire hazard of N_2O, requirements to equipment when handling N_2O; storage and transportation of N_2O are considered. It is demonstrated that nitrous oxide is a chemical compound meeting the requirements to rocket propellants, including those related to the environmental friendliness of propellants. With 75 references.
文摘Application of nitrogen (N) fertilizer is one of the most important approaches on improving maize grain yield. However, as is known to all, overuse N fertilizer not only leads to decline of N use efficiency and maize yield, but also leads to potential risk to environment pollution. This experiment was conducted to determine the effects of N fertilizer applications with nine different treatments on soil physical-chemical characters and maize grain yield using hybrid variety Zhengdan 958 in 2011 and 2012. Results indicated that the soil bulk densities of T2 (CK) and T1 were the lowest compared to other treatments in 2011 and 2012, respectively, whereas the soil bulk density of T5 in 2011 and T3 in 2012 were higher than other treatments. The soil porosity and field capacity of T5 in 2011 and T3 in 2012 were lower than other treatments, but those of CK in 2011 and T1 in 2012 were higher than other treatments. The pH values of T3 to T7 were lower than other treatments. These results indicated that the soil bulk densities were increased, whereas the soil porosity, field capacity and values pH were decreased by N application at different stages. N application could increase the N contents of leaf and stem, whereas less or excess N application should not significant improve maize yield. Although the soil organic matter and total N contents of T3 were the highest in both 2011 and 2012, the yield of T4 is the highest in both 2011 and 2012. The application amount, period and times of N fertilizer were important to maize yield.
基金financially supported by the National Natural Science Foundation of China (41071041, U1203301)the West Light Foundation of Chinese Academy of Sciences (RCPY201101)
文摘Biological soil crusts (BSCs) are capable of modifying nutrient availability to favor the establishment of biogeochemical cycles. Microbial activities serve as critical roles for both carbon and nutrient transformation in BSCs. However, little is known about microbial activities and physical-chemical properties of BSCs in the Gurbantunggut Desert, Xinjiang, China. In the present research, a sampling line with 1-m wide and 20-m long was set up in each of five typical interdune areas selected randomly in the Gurbantunggut Desert. Within each sampling line, samples of bare sand sheet, algal crusts, lichen crusts and moss crusts were randomly collected at the depth of 0-2 cm. Varia- tions of microalgal biomass, microbial biomass, enzyme activities and soil physical-chemical properties in different succession of BSCs were analyzed. The relationships between microalgal biomass, microbial biomass, enzymatic activities and soil physical-chemical properties were explored by stepwise regression. Our results indicate that micro- algal biomass, microbial biomass and most of enzyme activities increased as the BSCs developed and their highest values occurred in lichen or moss crusts. Except for total K, the contents of most soil nutrients (organic C, total N, total P, available N, available P and available K) were the lowest in the bare sand sheet and significantly increased with the BSCs development, reaching their highest values in moss crusts. However, pH values significantly decreased as the BSCs developed. Significant and positive correlations were observed between chlorophyll a and microbial biomass C. Total P and N were positively associated with chlorophyll a and microbial biomass C, whereas there was a significant and negative correlation between microbial biomass and available P. The growth of cyanobacteria and microorganism contributed C and N in the soil, which offered substrates for enzyme activities thus increasing enzyme activities. Probably, improvement in enzyme activities increased soil fertility and promoted the growth of cyanobacteria, eukary- otic algae and heterotrophic microorganism, with the accelerating succession of BSCs. The present research found that microalgal-microbial biomass and enzyme activities played important roles on the contents of nutrients in the successional stages of BSCs and helped us to understand developmental mechanism in the succession of BSCs.
文摘The improvement of the soil physical and chemical properties is the most important foundation for mine ecological restoration.The experiment is aimed at undisturbed area,restored area,and damaged area of abandoned Yongledian Quarry in Beijing.Through determination and analysis of soil physical and chemical properties,it shows that there are significant differences in the composite effects of soil physical and chemical properties between restored area,and undisturbed area,damaged area,and engineering restoration effectively improves the composite effects of soil physical and chemical properties in the restored area.The single factor hypothesis test shows that soil pH value,organic matter,alkali-hydrolyzable nitrogen,and total nitrogen traits are the key targets to be restored in this mining area.
基金Supported by Project of National Natural Science Foundation(31270681)
文摘Six forest stands of 59,34 and 24 year-old Pinus massoniana forests and their mixed forests were selected at the Experimental Center of Tropical Forestry of Chinese Academy of Forestry,and 20 m × 20 m plot was set up and soil samples were taken from 0-60 cm soil layers,to analyze the changes of soil nutrient content under different forest stands and forest ages. The results showed that soil moisture and the bulk density in the mesophytic forest land were higher than those of other forest lands. The highest soil porosity value was observed in the early forest land. Soil p H of different forest was 4. 45-4. 75,indicating the variation was small. Besides,it indicated that the mixed forest was more able to increase the soil fertility than the pure forest because that the variation of soil acidity,organic matter content and total P and K in 34 and24 year-old mixed forests were higher than those in pure forests of the same year old. However,the content of soil available P and K decreased with the increase of soil depth,and varied in terms of forest ages. From the changes of soil indicators in different forest lands,soil nutrients in the 34 year-old P. massoniana forest was superior to that of other forest stands.
文摘Most of the seeds produced by neem (Azadirachta indica A. Juss) trees in Nigeria are currently underutilized. Hence, relevant literature provides only limited information conceming many of the seed oils from this country, especially where it concems the potential applications of these oils as preservatives for ligno-cellulose against bio-deterioration. Using standard procedures therefore, this study was carried out to evaluate and document selected physical and chemical properties of neem seed oil (NSO), mechanically extracted using a cold press at 31.03 N-mm^-2 pressure and a room temperature of 25 ± 2℃. The results show that oil yield was 38.42% with a specific gravity of 0.91 ± 0.01. The amount of acid was 18.24 ± 1.31 mg KOH.g^-1 and that of iodine 93.12 ± 2.01 g-100 g^- 1, while saponification and peroxide values were 172.88 ± 2.06 and 1.42 ± 0.04 mg·g^-1 respectively. The implication of the values obtained, particularly those for the chemical properties, as they concern the potential application of NSO as a preservative for ligno-eellulose, is likely that it may be useful in this regard since the values may support some of the documented anti-microbial properties of the oil, although other physical and chemical properties that may affect this potential are recommended for investigations. Conclusions and other recommendations follow in line with the results of the study.
基金Supported by National Key R&D Program(2016YFD0201206)Youth Research Fund of Beijing Academy of Agriculture and Forestry Sciences(QNJJ201831)+1 种基金Special Technology Innovation Capacity Building Project-Regional Synergetic Innovation of Beijing Academy of Agriculture and Forestry Sciences(KJCX20180708)Youth Research Fund of Beijing Academy of Agriculture and Forestry Sciences(QNJJ201809)
文摘Five kinds of greenhouse vegetables( eggplant,loofah,tomato,cucumber and pepper) were selected in summer uprooting stage from greenhouse in Shouguang area,Shandong Province. Total nitrogen,ammonium nitrogen,nitrate nitrogen,available phosphorus,available potassium,organic matter content and p H,EC value of three soil layers were measured,respectively. The results showed that the total nitrogen,ammonium nitrogen,nitrate nitrogen,available phosphorus and available potassium in the soil were mainly accumulated in the upper soil,which made the soil acidification trend,because different farmers adopted different cultivation practices for different greenhouse vegetables in Shouguang region,but there was no significant effect on soil EC value. The input of ammonium nitrogen and nitrate nitrogen and other related fertilizers to greenhouse cucumber was higher than that of other greenhouse vegetables,but the amount of available potassium fertilizer and organic matter input to greenhouse tomato under different cultivation practices was lower than other greenhouse vegetables. In Shouguang area,the input of organic matter into greenhouse vegetables should be increased by increasing the proportion of manure input to increase the content of soil organic carbon,so as to achieve the balance of carbon and nitrogen ratio,and to provide a scientific basis for the establishment of an evaluation system for the environmental benefits brought about by chemical fertilizer reduction in greenhouse vegetables in Shouguang area.
基金Supported by National Grain and Sorghum Industry Technical System(CARS-06-13.5-A18)Program for the Integrated Development of the Primary,Secondary and Tertiary Sectors in Rural Area of Ningxia(YES-06-08)
文摘In order to investigate the variation in soil physical and chemical properties and nutrients in the mountainous areas in southern Ningxia, and to provide a theoretical basis for fertilization management in local farmland, the soil p H, total salt content,crop root length, root weight, soil organic matter, available nitrogen, total nitrogen, total phosphorous and total potassium in different fertilization treatments were measured from 2010 to 2016. Multiple comparisons of the data were performed using Duncan's new multiple range test. The results indicated that in the 0-20 cm soil layer, soil p H value and total salt content changed in different patterns, and varied greatly from 2010 to 2016(P<0.05). The changes of both root length and root weight of millet over time fitted S-shaped curves. The root length and root weight in the four fertilization treatments(Treatment 2 to Treatment5) increased faster than those in the control(Treatment 1). The soil organic matter content in all the five treatments gradually increased from 2010 to 2016. The content of alkaline hydrolyzable nitrogen in soil rapidly increased in the first two to three years of the experiment, followed by a slow increase or decrease in 2013, and then raised rapidly again from 2014 to 2016.The soil total nitrogen content varied significantly from 2010 to 2016. The total phosphorus content in soil changed in a different pattern from that of total nitrogen content. The seven-year field trails revealed that soil p H, total salt content, root length, root weight and soil nutrient all changed with the increase of fertilizer level, and that long-term fertilization is of significance for maintaining soil fertility, improving soil quality and reducing soil salinization.
文摘The concern of this study is determine the quality of soil when irrigation used treated water and wastewater in comparison with soil irrigated with tap water on some chemical and physical soil properties. The experiment components were three trials carried out under greenhouse conditions, 10 pots for each trial. The first trial irrigated with tap water, the second trial irrigated by treated water and the third trial irrigated with wastewater. The experiment conducted to study the impact of water types on some soil physical and chemical properties. The experiment included important analysis for water and soil before and after irrigation. The results showed that the values for electrical conductivity (EC) were 0.850, 308 and 324 μs/cm for the treated soil with tap water, treated water and wastewater, respectively. The variation of pH values seems to be approximately constant between the different of water used. The percent of organic matter (OM) in soils receiving treated water and wastewater 4.7% and 5.2% respectively were higher than values in soil treated with tap water 3%. The same trend was in organic carbon (OC) in soils receiving treated water and wastewater 58.5% and 89% respectively, while soil treated with tap water showed the lowest value 27.7%. Soil particle density (SPD) increased significantly in both water treatments were the values was 2 g/cm<sup>3</sup> in tap water but increased value 2.8 g/cm<sup>3</sup> and 3.3 g/cm<sup>3</sup> in treated water and wastewater used respectively. The Bulk Density (BD) values range 1.1 g/cm<sup>3</sup> in soil irrigated with tap water 1.5 g/cm<sup>3</sup> in soil irrigated with treated water and 1.85 g/cm<sup>3</sup> in soil irrigated with treated water. The results of soil analysis before and after planting showed that most of the values increased for the physical and chemical soil properties.