Optimization of polymerization conditions and thermal degradation of conducting polypyrrole coated polyester fabrics

PET fabric is coated with conducting polypyrrole (PPy) by oxidative polymerization from an aqueous solution of Py using ferric chloride hexahydrate (FeCl₃) as oxidant and p-toluene sulphonate (pTSA) as dopant. The optimum concentrations for Py, FeCl₃ and pTSA were found to be 0.11, 0.857 and 0.077 mol/l respectively, which yielded a conductive fabrics with resistivity as low as 72 Ω/sq. PPy fabric gained resistivity less than one order of magnitude when aged for 18 months at room temperature. The stabilizing effect of the dopant pTSA against thermal degradation was demonstrated; the undoped samples reached resistivity of around 40 kΩ, whereas doped samples reached less than 2 kΩ at the same temperature and time.     

新疆天山一号冰川地衣地理区系与生态特征

初步整理了分布在天山一号冰川的地衣种类,共5目12科24属51种.地衣区系上包括世界广布种、环极北极高山种、环极低北极及北方种、环北方种、两极和大西洋种、温带种、东亚种、东亚-北美西部、北欧-巴基斯坦-北美种、中亚分布种、北半球大陆广布种、两半球广布种、中国特有种等.同时结合地衣的生长环境特征将该地区的地衣分藓丛生、土生、草地生、地面生、石浮土生、岩面生、荒漠风滚、树皮或树枝生、朽木生地衣种等9种生态类型.     

Relationship between rhizosphere acidification and phytoremediation in two acacia species

Purpose

Phytoremediation is the most sustainable and economical strategy for reclamation of the salt-affected soils. In order to investigate the relationship between phytoremediation and rhizosphere acidification, two experiments (greenhouse and field) were conducted using two acacia species viz. Acacia ampliceps and Acacia nilotica.

Materials and methods

In greenhouse experiment, both the species were exposed to 100 and 200 mM NaCl concentrations in solution culture. The release of organic acids from plant roots was determined after 14 and 28 days of the salt treatment. Shoot and root ash alkalinity was determined after harvesting the plants. In field experiment, both the species were grown on a saline sodic soil for 2 years. After every 6 months, plant growth data were recorded and soil samples were collected from different soil depths for physicochemical analyses.

Results and discussion

The results of greenhouse study indicated higher rhizosphere acidification by A. ampliceps than A. nilotica in terms of release of citric acid, malic acid, and tartaric acid along with ash alkalinity. The comparison of both the species in the field indicated higher amelioration in the soil properties like pH_s, EC_e, SAR, bulk density, and infiltration rate by A. ampliceps than A. nilotica.

Conclusions

It is concluded from these studies that A. ampliceps is more suitable species than A. nilotica for the phytoremediation of the salt-affected soils due to its higher rhizosphere acidification potential.

     

The effect of feeding diets containing deoxynivalenol contaminated corn on channel catfish (Ictalurus punctatus) challenged with Edwardsiella ictaluri

Channel catfish were fed practical corn‐soybean meal diets for 10 weeks that contained various weighed amounts of ground, dried field corn contaminated with 20 mg deoxynivalenol (DON) kg⁻¹. Weighed amounts of DON corn were blended with weighed amounts of ground, clean corn that contained no DON (0 mg kg⁻¹) to yield five diets that had 0, 2.5, 5.0, 7.5 and 10.0 mg DON kg⁻¹ of diet. Results show that catfish fed diets that contained DON for 7 weeks did not experience lower weight gains or poorer feed conversion ratios that were significantly (P > 0.05) different from control‐fed fish. Mortality of catfish during the 21‐day post‐challenge period indicate that catfish fed diets containing DON‐contaminated corn that provided at least 5.0 mg DON kg⁻¹ of diet had significantly (P < 0.05) lower mortality than catfish fed the control diet or the diet that provided 2.5 mg DON kg⁻¹ of diet. The presence of DON‐contaminated corn in the experimental diets did not significantly (P > 0.05) alter fish body weight gains and appeared to provide a protective effect for channel catfish challenged with the pathogenic bacterium Edwardsiella ictaluri.     

Supplemental graded levels of neutral phytase using pretreatment and spraying methods in the diet of grass carp,Ctenopharyngodon idellus

A feeding trial was conducted for 8 weeks to evaluate the effects of graded levels of neutral phytase supplementation using pretreatment or spraying method on growth performance, body composition, bone mineral content and serum biochemical parameter in grass carp, Ctenopharyngodon idellus. A control diet without phytase was added and six additional diets were arranged as a 2 × 3 factorial with two methods (pretreatment or spraying) and three levels of phytase (500, 1000 or 1500 U kg^?1). The results showed that supplemental phytase at different levels in the diet and with different application methods all improved weight gain, specific growth rate and protein efficiency ratio of grass carp (P < 0.05). The feed conversion ratio in phytase‐supplemented groups was lower than the control. Dietary phytase addition reduced the lipid content in the whole body of grass carp. Phytase supplementation with different method increased ash and mineral (P, Ca, Mg and Zn) contents in whole‐body and vertebra (P < 0.05). The increase in these mineral contents was also observed in the serum. Based on the results, we may conclude that: 1) supplemental dietary phytase, regardless of the application methodology, improved the growth performance and nutrient utilization in grass carp; 2) the pretreatment mode of phytase application was more effective than spraying at the same phytase level.     

Combined application of biochar with compost and fertilizer improves soil properties and grain yield of maize

A pot study was conducted to assess the combined effect of biochar (B) with compost (Com) and inorganic fertilizers (F) for improving nutrient acquisition and productivity of maize. Seven different treatments, including B (1% w/w), F (Recommended nitrogen, phosphorus and potassium (NPK): 60, 30 and 25 mg kg^─1), Com (1.5% w/w), Com+F (1.5% + NPK), B+F (1% + NPK), B+Com (0.5% + 0.75%), B+Com+F (0.5% + 0.75% + NPK) along with a control (C) without B, Com and F were applied in pots with four replications. The results showed that growth and grain yield of maize increased by the application of B, Com and F compared with C, but B+Com+F was more effective than their sole application (i.e. B, Com and F). Highest leaf chlorophyll content, gas exchange attributes and nutrient concentrations: N, P and K in shoot and grains were observed, where B+Com+F was applied followed by Com+F > B+F > B+Com > F > Com > B > C. Soil properties such as soil organic carbon (SOC), N, P, and K were significantly increased, whereas soil pH was decreased by the combination of B with Com and F. Hence, application of B in combination with Com and F (B+Com+F) could be a good management strategy to enhance crop productivity and improve soil properties.     

Genotypic variation in rice for grain yield and quality as affected by salt-affected field conditions

A field experiment was conducted under two natural field conditions at the Research Farm (normal soil) and Proka Farm (salt-affected soil) of The Institute of Soil and Environmental Sciences (ISES), University of Agriculture, Faisalabad, Pakistan, to evaluate the performance of 11 rice genotypes in normal and salt-affected conditions. The experiment was laid out in randomized complete block design (RCBD) with three replications. The gas exchange attributes were measured at vegetative stage whereas the grain and straw yields and the yield components were recorded at maturity. After harvesting, the ionic parameters including sodium (Na⁺) and potassium (K⁺) were determined. Afterward, grain quality in terms of length, width, milling recovery, broken fraction, and chalkiness was also determined for the selected genotypes. Salt-affected conditions adversely affected the physiology, yield, and quality of the tested genotypes. The genotypes KS-282 followed by Shaheen Basmati showed significantly higher photosynthetic rate, transpiration rate, and stomatal conductance under both normal and salt-affected conditions, whereas the genotypes 99404 followed by 99417 showed minimum values of gas exchange attributes. The grain and straw yields were the highest in the case of KS-282 at both sites, whereas the lowest grain and straw yields were observed in the case of 99440 followed by 99417 under both normal and salt-affected conditions. Regarding the quality attributes, Super Basmati produced longer grains but with higher broken fraction and lower milling recovery, whereas the reverse was observed in the case of KS-282.     

Germination,growth and ions uptake of moringa (Moringa oleifera L.) grown under saline condition

Salinity is the major environmental stress that affects the growth and productivity of plants. The present study was conducted to determine the effect of salinity on growth and ions uptake by moringa (Moringa oleifera L.) plant. The experiment was carried out in two phases. Initially, a germination test was conducted in the laboratory under the different salinity levels (control, 5, 10, 15, and 20 dS m^?1) and found that moringa seeds were germinated only at 5 and 10 dS m^?1 salinity levels, and no germination occurred at higher salinity levels (15 and 20 dS m^?1). The experiment was laid out in a completely randomized design (CRD) with five replications. In the second phase, three-week old nursery grown plants of moringa were shifted in pots under the five salinity levels (control, 5, 10, 15, and 20 dS m^?1). The experiment was laid out in CRD and replicated four times. In pot experiment, the root, shoot length, and dry weights were significantly affected by increasing the salinity levels. The uptake of K⁺ and Ca²⁺ was highly affected at different salinity levels as compared to control and Na⁺ ions accumulation was higher in roots rather than shoot. The results reveal that moringa plant can germinate, survive, and can be cultivated in areas with moderate saline condition.     

Soil Bulk Density Estimation Methods: A Review

Measurement of soil bulk density is important for understanding the physical, chemical, and biological properties of soil. Accurate and rapid soil bulk density measurement techniques play a significant role in agricultural experimental research. This review is a comprehensive summary of existing measurement methods and evaluates their advantages, disadvantages, potential sources of error, and directions for future development. These techniques can be broadly categorised as direct and indirect methods. Direct methods include core, clod, and excavation sampling, whereas indirect methods include the radiation and regression approaches. The core method is most widely used, but it is time consuming and difficult to use for sampling multiple soil depths. The size of the coring cylinder used, operator experience, sampling depth, and in-situ soil moisture content significantly affect its accuracy. The clod method is suitable for use with heavy clay soils, and its accuracy is dependent on equipment calibration, drying time, and operator experience, but the process is complicated and time consuming. Excavation techniques are most commonly used to evaluate the bulk density of forest soils, but have major limitations as they cannot be used in soils with large pores and their measurement accuracy is strongly influenced by soil texture and the type of analysis selected. The indirect methods appear to have greater accuracy than direct approaches, but have higher costs, are more complex, and require greater operator experience. One such approach uses gamma radiation, and its accuracy is strongly influenced by soil depth. Regression methods are economical as they can make indirect measurements, but these depend on good, quality data of soil texture and organic matter content and geographical and climatic properties. Also, like most of the other approaches, its accuracy decreases with sampling depth.     

Nutritional status of Washington Navel orange orchards in arid lands of southern Iran

Nutrient deficiency may be a reason for citrus decline in many countries. In the current investigation, soil and leaf samples of 63 Washington Navel orange orchards in arid lands of southern Iran (Darab region) were analyzed to study the nutritional status of orange orchards and to find relationships between soil properties and nutrients content of soils and orange leaves. The soils differed widely in clay content (3–37%), pH value (7.04–7.95), calcium carbonate equivalent (18–86%), and organic matter content (0.3–12%). These soils represented a wide range of plant nutrients concentration. Majority of the studied soils had sufficient concentrations of all nutrients (except Fe). Results indicated that pH, organic matter, clay, and calcium carbonate contents are the most important characteristics that control the soil nutrients availability. The mean contents of N, K, P, Fe, Mn, Zn, and Cu in leaves were 2.59, 0.84, and 0.14% and 66, 44, 17, and 12?mg?kg^?1, respectively. Most orchards showed K, Fe, and Zn deficiencies. We found no relationships between nutrients content in leaf and soil (except for K, Mn, and Zn); and this indicated that soil analysis may not be a reliable method for most nutrient deficiency diagnosis.