Effects of Soil Moisture Content and p H on Residual Dynamics of Chlorothalonil in Acidified Soil

[Objective] This study aimed to investigate the residual dynamics of chlorothalonil in acidified soil under different conditions of soil moisture content and pH. [Method] By simulation tests, the effects of different soil moisture content and pH on chlorothalonil residues in acidified soil were analyzed. [Result] Under different conditions of soil moisture content and pH, the residual quantity of chlorothalonil in acidified soil was reduced gradually with the extension of incubation time. To be specific, the reduction rate of chlorothalonil residues in soil was extremely high within the first three days and slightly declined at 3-7 d; after 7 d, the residual quantity of chlorothalonil in soil was reduced slowly and steadily. [Conclusion] This study provides the reference for soil environmental remediation and maintenance of a health cultivation system.

对三水合乙酸钠和无水乙酸钠试剂国家标准一些问题的商榷

本文通过对GB/T 693—1996《化学试剂三水合乙酸钠(乙酸钠)》和GB/T 694—1995《化学试剂无水乙酸钠》两份国家标准的采标、主含量测定和pH值指标等方面问题的剖析,和化学试剂标准领域的人士进行商榷,指出对这些标准进行修订的必要性。

A novel model to assess soil productivity in the dry-hot valleys of China

Accurate evaluation of soil productivity has been a long-standing challenge. Although numerous models for productivity assessment exist, most are cumbersome to use and require substantial parameter inputs. We developed a new empirical soil productivity model based on field investigations of soil erosion, soil physieoehemieal properties, and crop yields in the dry-hot valleys （DHVs） in China. We found that soil pH, and organic matter and available potassium contents significantly affected crop yields under eroded conditions of the DHVs. Moreover, available potassium content was the key factor affecting soil productivity. We then modified an existing soil productivity model by adding the following parameters： contents of effective water, potassium, organic matter, and clay, soil pH, and root weighting factor. The modified soil productivity model explained 63.5% of the crop yield. We concluded that the new model was simple, realistic, and exhibited strong predictability. In addition to providing an accurate assessment of soil productivity,our model could potentially be applied as a soil module in comprehensive crop models.

Effects from changes in pulp nature after ultrasonic conditioning on high-sulfur coal flotation

A study of the effects of the pulp nature on desulphurization and de-ashing during high-sulfur coal flotation is described in this paper. Highlighted are the use of a solution oxygen gauge, a pH value gauge and a surface tension gauge to investigate changes in the pulp nature related to changes in the oxygen content, the pH value and the interfacial tension. The temperature be- fore and after ultrasonic conditioning was also investigated. The results showed that ultrasonic conditioning resulted in a decrease in the oxygen content and the interracial tension and an increase in the pH value and the temperature of the pulp. The perfect index of flotation and the perfect index of desulphurization of fine coal increased by 25.19% and 18.03%, respectively, after the pulp was ultrasonically conditioned. This study shows that ultrasonic conditioning can change the pulp nature and enhance the degree of desulphurization during high-sulfur coal flotation.

Heavy Metal Contamination of Well Water in the Kipushi Mining Town （Democratic Republic of Congo）

Concentrations of eleven heavy metals （AI, Cd, Co, Cu, Cr, Fe, Mn, Mo, Ni, Pb and Zn） and pH determination in water from nine spade-sunk wells of 2-15 meter depth, five drilled wells of 30-72 meter depth, and two water supply faucets in the Kipushi mining town, south-east of the Democratic Republic of Congo, were investigated from February to July 2011. The results were compared with the World Health Organization （WHO） drinking water pH and heavy metal guidelines. Mean concentrations of Pb in water from four spade-sunk wells and three drilled wells, those of A1 and Fe in water from four and two spade-sunk wells, and those of Cd in water from four drilled wells were higher than the WHO drinking water maximum permissible contaminant limits of 0.01 mg/L, 0.2 mg/L, 0.3 mg/L and 0.003 mg/L respectively, probably due to the mining activities carried out in Kipushi for about 90 years. The pH mean values of water from five spade-sunk wells and three drilled wells were lower than the WHO drinking water pH optimum of 6.5-9.5, suggesting that the water from those eight wells was not conform to the chemical quality of water for human consumption.

Effects of curing age on compressive and tensile stress-strain behaviors of ecological high ductility cementitious composites

To obtain the design parameters of the structure made by ecological high ductility cementitious composites(Eco-HDCC),the effects of curing age on the compressive and tensile stress-strain relationships were studied.The reaction degree of fly ash,non-evaporable water content and the pH value in pore solution were calculated to reveal the mechanical property.The results indicate that as the curing age increases,the peak compressive strength,peak compressive strain and ultimate tensile strength of Eco-HDCC increase.However,the ultimate compressive strain and ultimate tensile strain of Eco-HDCC decrease with the increase in curing age.Besides,as the curing age increases,the reaction degree of fly ash and non-evaporable water content in Eco-HDCC increase,while the pH value in the pore solution of Eco-HDCC decreases.Finally,the simplified compressive and tensile stress-strain constitutive relationship models of Eco-HDCC with a curing age of 28 d were suggested for the structure design safety.

The Effect of Different Levels of Sunflower Head Pith Powder on Some Emulsion Attributes of Mechanically Deboned Chicken Meat

In this study, the effect of sunflower head pith powder at various concentrations （0.0, 0.5, 1.0, 1.5, 2.0%） on the emulsion properties of mechanically deboned chicken meat （MDCM） was investigated in a model system. For this purpose, fresh and frozen MDCM samples were used for preparing the oil/water （O/W） model emulsion systems, pH values of slurries and emulsions, emulsion capacity （EC）, stability （ES） and viscosity （EV） of the prepared model system emulsions were analyzed. Protein, fat, ash, dry matter contents and pH value of MDCM were 14.85, 14.93, 0.99, 30.45% and 6.7, respectively. It was found that the pith powder addition significantly （P 〈 0.01） decreased the pH values of slurries. On the other hand, the effect of pith powder addition on pH values of emulsions was insignificant （P 〉 0.01）. The highest EC value was reached when 1% of pith powder added. ES values of the emulsions reached a maximum level at 1.5% pith powder level. Fresh MDCM emulsions had higher EV values than did frozen MDCM emulsions at 10, 20, 50 rpm.

The Kinetic Study of Adsorption of Copper Metal Ion in Selected Contaminated Red Soil Samples in Palestine

Heavy metals are persistent pollutants in the environment. Problems associated with the cleanup of sites contaminated by metals have demonstrated the need to develop remediation technologies that are feasible, quick, and effective in a wide range of physical settings. In this study we have investigated the adsorption of Cu（lI）, onto red soil in single and multi-element systems as a function of soil and heavy metal concentrations. Before contamination, soils were characterized to determine particle size, pH, organic matter content and heavy metal contents. The results of experimental sorption data fitted very well the Freundlich isotherm model with n = 1.4 and k = 1.25 and first order kinetics model. The best pH for adsorption of Cu^2＋ on red soil was found to be 4.0. Adsorption of metals on soil increased in the order Cu 〉 Pb 〉 Zn ≈ Cd. This trend might be related to the increase in the electronegativity of the metal ion.

Study on the Effects of Probiotics on the Growth of Cyprinus carpiod and Water Quality

[Objective] The aim was to discuss the effects of probiotics on the growth of Cyprinus carpiod and water quality. [Method] Taking C. carpiod as the research object, probiotics were supplemented in the fodder and water to study their effects on the growth of C. carpiod and water quality. [Result] Probiotics had promoting effects on the growth of C. carpiod and its optimum dosage was 6%. pH, ammonia nitrogen content and nitrite content in water body in experimental groups were all lower than those in control group. [Conclusion] Compound probiotics had a broad application foreground in the aquatic breeding industry.

Long-Term Effect of Industrial Waste Water Irrigation on Soil Chemical Properties

A laboratory experiment was conducted in Soil Science Division of BRRI during 2011 aimed to determine the vertical distribution of soil chemical properties under long-term industrial waste water irrigated rice field. Waste water irrigated rice field seemed to create some differences in soil pH profile. The pHW and pHKCl in all soil depth was higher with waste water irrigated rice field. The surface charge of both the soils was considerably negative. Waste water irrigated rice field developed more negative charges in soils. Irrigation with waste water increased Electrical Conductivity （EC） in rice soils profile. The organic carbon content （%） started to decrease sharply with the increase in soil depth. Organic carbon content was higher with waste water irrigated rice soils Total nitrogen （%） was high with underground water irrigated rice soils in surface but at deeper, total N was similar in both soils. Olsen P （mg/kg） was higher with underground water irrigated soil at 0-5 cm depth but at 5-100 cm soils profile, it was higher with waste water irrigated rice soils. Micronutrients （Zn, Fe, Cu and Mn） and heavy metals （Pb, Cd, Ni and Cr） in soils were increased significantly through irrigation with waste water in rice-rice cropping pattern.

Catalytic dechlorination of chlorinated methanes by nanoscale Pd/Fe bimetallic particles

This paper examined the potential of using laboratory-synthesized nanoscale Pd/Fe bimetallic particles to dechlorinate chlorinated methanes, including dichloromethane (DCM), trichloromethane (CF) and tetrachloromethane (CT). Nanoscale Pd/Fe bimetallic particles were characterized in terms of surface area, morphology, size and structure. The parameters affecting the dechlorination efficiency were studied through batch experiments. Effects of Pd content, Pd/Fe addition, and the initial pH value of reaction system on the dechlorination efficiency of chlorinated methanes were determined systematically. Results show that nanoscale Pd/Fe bimetallic particles play a prominent role in the dechlorination of chlorinated methanes. The change of pH value and ferrous ion concentration during dechlorination reaction were also investigated in this study. It is found that the dechlorination efficiency of chlorinated methanes is in the order of CT>CF>DCM.

Using Organic Matter and pH to Estimate the Bulk Density of Afforested/Reforested Soils in Northwest and Northeast China

Regression models for predicting soil bulk density(BD) have usually been related to organic matter content, but it remains unknown whether soil acidity modifies this relationship, particularly for afforested/reforested soils. We measured soil BD along with organic matter content and pH in an afforested/reforested area in Northwest and Northeast China. Using these measurements, we parameterized and validated three BD models: the Adams equation, and exponential and radical models. Model validation showed that the Adams equation failed to predict the BD of the afforested/reforested soils, producing a large overestimation. Incorporation of soil pH into the Adams equation significantly improved its performance. The exponential and radical models parameterized by the measured data simulated soil BD quite well, particularly when soil pH was incorporated. However, incorporation of soil texture variables into these models did not improve model performance compared with the pH-modified models. This led to the conclusion that the Adams equation, exponential, and radical models with pH modification are applicable to afforested/reforested soils with various acidities.

Nitrous Oxide Emission by Agricultural Soils: A Review of Spatial and Temporal Variability for Mitigation

This short review deals with soils as an important source of the greenhouse gas N2O. The production and consumption of N2O in soils mainly involve biotic processes: the anaerobic process of denitrification and the aerobic process of nitrification. The factors that significantly influence agricultural N2O emissions mainly concern the agricultural practices (N application rate, crop type, fertilizer type) and soil conditions (soil moisture, soil organic C content, soil pH and texture). Large variability of N2O fluxes is known to occur both at different spatial and temporal scales. Currently new techniques could help to improve the capture of the spatial variability. Continuous measurement systems with automatic chambers could also help to capture temporal variability and consequently to improve quantification of N2O emissions by soils. Some attempts for mitigating soil N2O emissions, either by modifying agricultural practices or by managing soil microbial functioning taking into account the origin of the soil N2O emission variability, are reviewed.

Predicting Cadmium Safety Thresholds in Soils Based on Cadmium Uptake by Chinese Cabbage

Cadmium(Cd), a common toxic heavy metal in soil, has relatively high bioavailability, which seriously threatens agricultural products. In this study, 8 different soils with contrasting soil properties were collected from different regions in China to investigate the Cd transfer coefficient from soil to Chinese cabbage(Brassica chinensis L.) and the threshold levels of Cd in soils for production of Chinese cabbage according to the food safety standard for Cd. Exogenous Cd(0–4 mg kg^(-1)) was added to the soils and equilibrated for 2 weeks before Chinese cabbage was grown under greenhouse conditions. The influence of soil properties on the relationship between soil and cabbage Cd concentrations was investigated. The results showed that Cd concentration in the edible part of Chinese cabbage increased linearly with soil Cd concentration in 5 soils, but showed a curvilinear pattern with a plateau at the highest dose of exogenous Cd in the other 3 soils. The Cd transfer coefficient from soil to plant varied significantly among the different soils and decreased with increasing soil p H from 4.7 to 7.5. However, further increase in soil pH to > 8.0 resulted in a significant decrease in the Cd transfer coefficient. According to the measured Cd transfer coefficient and by reference to the National Food Safety Standards of China, the safety threshold of Cd concentration in soil was predicted to be between 0.12 and 1.7 mg kg^(-1) for the tested soils. The predicted threshold values were higher than the current soil quality standard for Cd in 5 soils, but lower than the standard in the other 3 soils. Regression analysis showed a significant positive relationship between the predicted soil Cd safety threshold value and soil p H in combination with soil organic matter or clay content.

Synergistic Effects of Biochar and NPK Fertilizer on Soybean Yield in an Alkaline Soil

Biochar effects on legume growth and biological nitrogen fixation have been studied extensively, mostly in acidic soils with laboratory produced biochar. In the present study, a pot experiment in a full factorial experimental design was performed to examine soybean yield and nodulation of three genotypes grown with or without biochar and NPK fertilizers in an alkaline soil. We observed synergistic effects of biochar and NPK fertilizer applications on biomass and seed yields for all three soybean genotypes. Total biomass production and seed yield increased on average by 67% and 54%, respectively, with biochar and by 201% and 182% with NPK fertilizer application compared to the control. When applications of biochar and NPK fertilizer were combined, the increases were 391% and367%, respectively. However, the biomass production in the control was very low(692 kg ha-1) due to a high soil p H(8.80). The nodulation increased with biochar and NPK fertilizer applications, and was largest with the combined application. A correlation was found between leaf chlorophyll content(single photon avalanche diode value) and nodule number. We suggested that the synergistic increase in yield was due to a decrease in soil p H caused by biochar and NPK fertilizer applications thereby increasing P availability in this alkaline soil.

Adsorption and Desorption of Methiopyrsulfuron in Soils

Methiopyrsulfuron is a new low-rate sulfonylurea herbicide for weed control in wheat; however, there is a lack of published information on its behavior in soils. In this study, methiopyrsulfuron adsorption and desorption were measured in seven soils sampled from Heilongjiang, Shandong, Jiangxi, Sichuan, Anhui, and Chongqing provinces of China using a batch equilibrium method. The Freundlich equation was used to described its adsorption and desorption. Adsorption isotherms were nonlinear with the values of Kf-ads, the Freundlich empirical constant indicative of the adsorption capacity, ranging from 0.75 to 2.46, suggesting that little of this herbicide was adsorbed by any of the seven soils. Soil pH and organic matter content (OM) were the main factors influencing adsorption; adsorption was negatively correlated with pH and positively correlated with OM. Methiopyrsulfuron desorption was hysteretic on the soils with high OM content and low pH.