Single and competitive adsorption isotherms of some heavy metals onto a light textured calcareous soil amended with agricultural wastes-biochars

This study investigated the adsorption behavior of selected heavy metals (Pb, Cu, and Ni) under single and multi-metal conditions by a light textured calcareous soil amended with plant residue biochars (corn straw, wheat straw, rice husk and licorice root pulp each at 3% w/w). The Freundlich isotherm best described the heavy metal adsorption suggesting multilayer adsorption. For all treatments under both adsorption conditions, the heavy metal adsorption capacity followed the order of Pb > Cu > Ni, which was associated with the hydrolysis constant, ionic radius, and electronegativity of these metals. Simultaneous presence of multiple metals decreased the adsorption capacity for each metal and the sequence was in the order of Ni > Pb > Cu. The corn straw biochar (CSB) had the highest adsorption capacity (Freundlich K_f (mg g^?1) for Ni = 0.23, Cu = 1.41 and Pb = 2.73) and medium distribution coefficient (K_{d medium}(L kg^?1) for Ni = 59.30, Cu = 1961.00 and Pb = 2602.00), indicating the CSB is the best treatment for stabilization of heavy metals in the soil. This was associated with the chemical characteristics of the CSB (high amounts of CaCO₃ and P) and the greatest increase in soil pH value.     

焉耆盆地耕地数量时空变化驱动力及生态环境效应分析

利用1988-2011年统计资料,采用多元统计分析与文献调查方法,分析焉耆盆地近20多年来耕地时空变化情况及其驱动机理,并讨论耕地动态变化对研究区生态环境的影响。结果表明：（1）1988-2011年间,焉耆盆地耕地面积动态变化存在着明显的波动状态,大体上呈增加趋势。耕地面积从1988年的76．25×104 hm2增加至2011年的135．70×104hm2,增加幅度为178％,净增加59．45×104hm2,各县耕地面积变化趋势基本相同;（2）影响焉耆盆地耕地动态变化的驱动因子可归纳为政策变动、经济发展、人口增长、农业科技进步等四大因素;（3）耕地动态变化在某种程度上改善焉耆盆地生态环境同时,导致了绿洲外围沙漠化,绿洲内部土壤盐渍化,湖泊、湿地减少等一系列生态环境问题,威胁了绿洲稳定性。     

Effect of dietary phospholipid sources and levels on growth performance,enzymes activity,cholecystokinin and lipoprotein fractions of rainbow trout (Oncorhynchus mykiss) fry

This study was conducted to evaluate the effect of soybean lecithin (SBL) and chicken egg lecithin (EGL) on growth performance; pancreatic and intestine enzymes, cholecystokinin (CCK) and lipoprotein fractions of rainbow trout, Oncorhynchus mykiss (Walbaum) fry. Seven isonitrogenic and isolipidic diets were prepared by replacing 0 (as a control), 2%, 4% and 6% soybean and chicken egg lecithin instead of soybean oil in diets. Trout fry with initial average weight of 120 ± 4.08 mg, were randomly distributed in 21 90 L tanks. Triplicate groups (165 fish for each tank) of fry were fed each diet to visual satiation at six meals per day for 40 days. Dietary supplements of 2% and 4% chicken egg lecithin led to increase in fry final weight, weight gain and specific growth rate suggesting that moderate PL levels are needed during this stage of rainbow trout. Also 2% chicken egg lecithin caused significantly higher activity of amylase, lipase, phospholipase A₂, alkaline phosphatase (AP), aminopeptidase‐N (AN) and lower activity of leucine alanine peptidase (leu‐ala) in the digestive tract of fry than those in control group. Furthermore, fry fed 2% chicken egg lecithin had a higher ratio of AN/leu‐ala and AP/leu‐ala than that in the control group. Chicken egg lecithin increased significantly cholecystokinin (CCK) and chylomicron fractions of fry compared to control group. It is noteworthy that soybean lecithin had moderate effect on final growth, weight gain and specific growth rate of fry and induced significantly higher activity of amylase, lipase, phospholipase A₂ and secretion of CCK compared to control group. The results of this study indicate that dietary supplementation 2% chicken egg lecithin indirectly through some biochemical parameters improves growth performance of rainbow trout fry.     

Temperature influences postdispersal predation of weed seeds

Temperature is a key factor for the living organisms on earth. It influences weed management practices, either directly or indirectly. Field experiments were conducted to determine the effect of temperature on the postdispersal seed predation of four important weed species (Cuscuta compestris, Stellaria media, Taraxacum officinale and Veronica persica) in two lucerne fields in Mashhad and Chenaran, north‐eastern Iran. These two cities have the same climate: temperate and cold alpine but the temperature varies between them. Wire mesh cages were used to determine the relative importance of birds in predation and pitfall traps were used to detect the species and the activity density of invertebrate predators. The results showed that the predation preference of different weed species was significantly different between and within fields. Seed predation fluctuated widely throughout the sampling periods, matching the periodic forage harvest and regrowth cycle of lucerne. Despite the level of seed predation fluctuating, it declined toward the last sampling periods. Using wire mesh exclusion cages showed no significant effect of birds on weed seed predation in both fields. Ants, crickets and carabid beetles were the invertebrate seed predators that were caught in the pitfall traps. There were significant correlations between the mean temperature and predator activity densities and also between the predated seeds and the mean air temperature in both locations. The results of this study indicate the significant effect of temperature on postdispersal weed seed predation. Therefore, with respect to climate change and increasing global warming, it would be possible to focus on postdispersal seed predation in weed management in the future.     

GIS-based forest fire susceptibility mapping in Iran: a comparison between evidential belief function and binary logistic regression models

The aim of this research was to produce forest fire susceptibility maps (FFSM) based on evidential belief function (EBF) and binary logistic regression (BLR) models in the Minudasht Forests, Golestan Province, Iran. At first, 151 forest fire locations were identified from Moderate-Resolution Imaging Spectero Radiometer data, extensive field surveys, and some reports (collected in year 2010). Out of these locations, 106 (70%) were randomly selected as training data and the remaining 45 (30%) cases were used for the validation goals. In the next step, 15 effective factors such as slope degree, slope aspect, elevation, plan curvature, Topographic Position Index, Topographic Wetness Index, land use, Normalized Difference Vegetation Index, distance to villages, distance to roads, distance to rivers, wind effect, soil texture, annual temperature, and rainfall were extracted from the spatial database. Subsequently, FFSM were prepared using EBF and BLR models, and the results were plotted in ArcGIS. Finally, the receiver operating characteristic curves and area under the curves (AUCs) were constructed for verification purposes. The validation of results showed that the AUC for EBF and BLR models are 0.8193 (81.93%) and 0.7430 (74.30%), respectively. In general, the mentioned results can be applied for land use planning, management and prevention of future fire hazards.     

伞伐更新法对赫卡尼亚(Hyrcanian)森林系统中森林再生和林分结构的影响

研究伞伐更新法对赫卡尼亚森林系统中森林再生和林分结构的影响。在伊朗北部优势种为山毛榉（Fagus orientalisLipsky）的硬木林,采取伞伐更新法和非伞伐更新法方法设计实验区。结果表明,在山毛榉（F orientalis Lipsky）林中采用伞伐更新法处理,明显影响林下草本植物种的频度和密度。伞伐更新法处理后,林堇菜（Viola silvestris Lam.）、车叶草（Asperula odorata L.）、苔草（Carex spp.）和悬钩子（Rubushyrcanus Juz）的种频度明显增加。在对照区,树种的胸高直径（57.50±2.15cm）大于被处理区（50.67±1.88cm）的树种的胸高直径（50.67±1.88 cm）,但对照区和处理区的树种的高度值相似。在1995-2005年间,波斯铁木（Parrotia persica）苗木数量增加到13.2%,而山毛榉（F orientalis）和欧洲鹅耳枥（Carpinus betulus）的苗木数量却明显减少。总之,应该利用其它育林方法,如,带状择伐作业,而不是伞伐更新法培育赫卡尼亚森林中山毛榉林。     

Symptoms and fungi associated with elm trees decline in Iran

Elm (Ulmus, Ulmaceae) is one of the most popular and important trees in urban and landscape areas in Iran. A severe decline of elm trees has recently been observed in some areas of Kerman and Shiraz cities. However, the identity of the causal agents has not yet been investigated. The purpose of this study, carried out in the years 2012–2014, was to isolate and identify fungal trunk pathogens associated with decline symptoms observed in elm trees. Samples were collected from trunks and branches of trees showing various disease symptoms and internal wood lesions. Fungal isolations were made from discolored or decayed wood tissue. In Kerman some elm trees were attacked by the beetle Aeolesthes sarta; therefore, samples were also collected from larvae and adults of beetles associated with trees showing wood damage. Fungal isolates were identified by morphological, cultural and molecular characteristics. Thirteen fungal species, Phaeoacremonium (P.) minimum, P. parasiticum, P. sicilianum, P. alvesii, P. fraxinopennsylvanicum, Spencermartinsia viticola, Dothiorella (Do.) sarmentorum, Neoscytalidium hyalinum, Diatrype (Di.) whitmanensis, Cosmospora viridescens, Phoma (Pho.) herbarum, Phellinus (Phe.) tuberculosus and Inonotus levis were identified. Phaeoacremonium parasiticum was the only species isolated from both larvae and adult beetles. Pathogenicity trials were performed on detached shoots of elm under greenhouse conditions. Dothiorella sarmentorum was the most virulent species based on the length of wood necrosis. This study is the first report of P. sicilianum, C. viridescens and Phe. tuberculosus in Iran. In addition, most of the isolated species are reported for the first time on elm trees in the world.     

The Effects of Cow Manure and Vermicompost on Availability and Desorption Characteristics of Zinc in a Loamy Calcareous Soil

The application of organic fertilizers in soils not only increases soil organic matter but also introduces essential nutrients to soil. Therefore, applying these fertilizers can affect the availability and desorption characteristics of nutrients. The main objective of this research is to study the effects of cow manure (CM) and vermicompost (VC) on availability and desorption characteristics of zinc (Zn) in a loamy calcareous soil. In this study, concentration of available Zn (using DTPA-TEA, AB-DTPA, and Mehlich 3) and desorption characteristics of Zn (using successive extraction with DTPA-TEA For 1–504 h at 25 ± 1°C) in amended soil with 0, 0.5, and 1% (w/w) of CM and VC were investigated in a completely randomized design. Results of this research showed that concentration of Zn extracted by using three methods was higher in amended soils with 1% CM and VC than those with 0.5% of these fertilizers. Furthermore, the difference between concentration of available Zn in amended soils with CM and VC was not found to be significant (p > 0.05). The results of kinetics study illustrated that the effect of organic fertilizers on Zn desorbed after 504 h was found to be significant (p < 0.01). Amount of cumulative of Zn desorbed in amended soils was significantly (p < 0.05) higher than unamended soil. Concentration of Zn desorbed after 504 h in 0.5 and 1% of CM and VC compared with unamended soil increased 26, 54, 12, and 46%, respectively. In addition, Zn desorption rate in amended soils with CM was higher than those with VC. It can be concluded that organic fertilizers applied to loamy calcareous soils enhance source of available Zn for the plant. Moreover, the results of this study showed that the ability of amended soils with VC to supplying Zn for plants was lower than those with CM.     

Physiological responses of pepper plant (Capsicum annuum L.) to drought stress

Water shortage is the most important factor constraining agricultural production all over the world. New irrigation strategies must be established to use the limited water resources more efficiently. This study was carried out in a completely randomized design with three replications under the greenhouse condition at Shahrekord University, Shahrekord, Iran. In this study, the physiological responses of pepper plant affected by irrigation water were investigated. Irrigation treatments included control [full irrigation (FI) level] and three deficit irrigation (DI) levels—80, 60, and 40% of the plant's water requirement called DI₈₀, DI₆₀, and DI₄₀, respectively. A no plant cover treatment with three replications was also used to measure evaporation from the soil surface. Daily measurements of volumetric soil moisture (VSM) were made at each 10-cm intervals of the soil column, considered as a layer. The differences between the measured VSM and the VSM in the next day and evaporation rate at the soil surface at the same layer of the bare soil with no plant cover treatment were calculated. Eventually, by considering the applied and collected water in each treatment, evapotranspiration (ET_C) and root water uptake in each layer per day were estimated. Furthermore, fruit number per plant, fresh fruit weight/day, root fresh/dry weights, shoot fresh/dry weights, root zone volume, root length and density, crop yield, and water use efficiency (WUE) were measured under different water treatments. The results showed that the maximum and minimum of all the studied parameters were found in the FI and DI₄₀ treatments, respectively. ET_C in the DI₈₀, DI₆₀, and DI₄₀ treatments were reduced by 14.2, 37.4, and 52.2%, respectively. Furthermore, applying 80, 60, and 40% of the plant's water requirement led to the reduction in crop yield by 29.4, 52.7, and 69.5%, respectively. The averages of root water uptakes in the DI₈₀, DI₆₀, and DI₄₀ treatments reduced by 17.08, 48.72, and 68.25%, respectively. WUE and crop yield also showed no significant difference in the FI and DI₈₀ treatments. Moreover, in the DI₈₀ treatment, the reduced rate of water uptake was less than the reduced rate of plant's applied water. According to these results, it can be concluded that 20% DI had no significant reduction on the yield of pepper, but above this threshold, there was an adverse effect on the growth and yield. Therefore, for water management in the regions with limited water resources, rate of plant's applied water can be decreased by around 20%.     

Effects of coated and non-coated ZnO nano particles on cucumber seedlings grown in gel chamber

Zinc oxide-engineered nanoparticles (ZnO ENPs) have received the most attention in recent years. This increasing interest has been directed towards studying the environmental fate and effects of ZnO ENPs on ecological terrestrial species. In this study, ZnO NPs were synthesized by atmospheric pressure solution evaporation method and were coated or uncoated with humic acid (HA). The root uptakes of uncoated and HA-coated ZnO NPs and zinc (Zn) were investigated by gel-grown cucumber. Two ZnO levels (1 and 200 µM) were applied in the form of coated (T₃) and non-coated (T₂) NPs or bulk particles (T₁). The results showed that coating NPs by HA increases zeta potential of NPs and decreases their aggregation size due to the increase in the repulsion forces among the particles. Addition of 1 mgL^?1 ZnO into gel chamber enhanced root and shoot biomass; however, the shoot growth was higher in the presence of NPs compared to its bulk counterpart. Moreover, greater phytotoxicity of ZnO from the source of NPs than bulk particles in shoot was observed. Scanning electron microscopy results showed a clear evidence of the penetration of NPs into root cells.