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1.
Understanding of the landscape response to agricultural practices mainly in relation to soil trace metals requires particular attention. Consistent with this, the trend and possible pollution of total and DTPA fraction of Mn, Zn, Cu, and Cd in the agricultural soils developed on different landscape positions involving piedmont alluvial plain (PAP), river alluvial plain (RAP), plateau (PL), and lowland (LL) were investigated. The content of the metal in different soil profiles, grouped by landscape positions, varied in the following orders: total and DTPA-Mn as LL > PAP > RAP > PL, total Zn and Cu as PAP > RAP > LL > PL, total Cd as RAP > PAP > PL > LL, DTPA-Zn as RAP > PAP > PL > LL, and DTPA-Cu as RAP > LL > PL > PAP. A wide variation in the total fraction of Mn (89–985 mg kg?1), Zn (24–152 mg kg?1), Cu (8–27 mg kg?1), and Cd (0.6–1.7 mg kg?1) and in the DTPA fraction of Mn (1.2–11 mg kg?1), Zn (0.3–4.4 mg kg?1), Cu (0.3–3 mg kg?1), Cd (0.03–0.09 mg kg?1) observed as a result of the effects of agricultural practices and landscape properties. The values of both total and DTPA-extractable Mn, Zn, and Cu were enriched in the AP horizon probably due to anthropogenic activities particularly successive use of agrochemical compounds and manure during numerous years. Using soil pollution indices [single pollution (PI) and comprehensive pollution (PIN)], the study soils were categorized mainly as low to moderate pollution and Zn was identified as the major element affecting on the yield of these indices.  相似文献   
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Monitoring general variability of soil attributes is a fundamental requirement from the point of view of understanding and predicting how ecosystems yield. In order to monitor impact of different land use types on the combination of morphological, clay mineralogical and physicochemical characterizes, 42 soil samples (0–30 cm) were described and analyzed. Soil samples belonging to Cambisols and Vertisols reference soil groups collected from three neighboring land use types included cropland (under long-term continuous cultivation), grassland, and forestland. The soils were characterized by high pH (mean of 7.1–7.5) and calcium carbonate equivalent (CCE) (mean of 35–97 g kg?1) in the three land use types. The weakening in soil structure, hardening of consistency, and lighting of soil color occurred for the cropland under comparable condition with grassland and forest. Changes in land use types produced a remarkable change in the XRD patterns of clay minerals containing illite and smectite due the dynamic and removal of potassium. Continuous cultivation resulted in an increase in sand content up to 35 % while silt and clay content decreased up to 22 and 18 %, respectively, as compared to the adjoining grassland and forest mainly as a result of the difference of dynamic alterational and erosional process in the different land use. Long-term cultivation caused a negative and degradative aspects on soil heath as is manifested by the increasing in soil pH (a rise of 0.3–0.46 unit), electrical conductivity (EC) (a rise of 1.78–5.5 times), sodium absorption ration (SAR) (a rise of 10–51 %), exchangeable sodium percentage (ESP) (a rise of 3–46 %), and the decrease in soil organic C (a drop of 12–41 %), along with soil fertility attributes. Overall, the general distribution of soil organic C, total N, available P and K, cation exchange capacity (CEC), and exchangeable cations (Ca, Mg, and K) followed the order: forestland > grassland > cropland. The general distribution of EC, SAR, ESP, and exchangeable Na, however, followed the order: cropland > grassland > forestland. Soil quality index (SQI), calculated based on some physicochemical properties, specified that cultivation led to a negative effect in SQI for both Cambisols (a drop of 10–17 %) and Vertisols (a drop of 17 %) as compared to those of under grassland and forestland.  相似文献   
4.
Rezapour  Salar  Taghipour  A.  Samadi  A. 《Natural Hazards》2013,65(3):1951-1966
Droughts are expected to become more common in Mediterranean urban contexts during the next decades. Water conservation campaigns are a crucial part of drought management actions but doubts remain regarding their effectiveness once the drought period has finished. In this paper and taking the example of the Metropolitan Area of Barcelona, we present the results of a survey on drought perception and behaviour undertaken for 437 households of this area. Conservation messages were compared with household perception and conservation behaviours. Results indicate that conservation campaigns were successful in raising awareness about the drought, but messages failed to target specific uses (indoor/outdoor). Against a backdrop of decreasing consumption per capita in the compact urban areas, future conservation campaigns must be aware of these factors if the conservation burden is not to fall on those already consuming very little water.  相似文献   
5.
The aim of this study was to evaluate a computer-based method to find a new inhibitor for polyphenol oxidase (PPO) in banana, apple, and mushroom. First, the sequence of PPOs was separately obtained from Protein Data Bank, and their homology was investigated. Next, the same structure of their active site was found, and it was interacted with various phenolic and benzoic compounds by a molecular dynamic software. Moreover, the inhibition of enzymatic browning was also investigated at different laboratory conditions. This study showed that histidine–leucine–phenylalanine–histidine was in all types of PPOs. Also, molecular dynamic simulation showed that (3S)-2-(3,4-dihydroxyphenyl)-3,5,7-chromanetriol (DHPC) is the best compound to interact with PPOs. Based on experimental tests, DHPC had the highest efficacy at 4 °C. The decrease in inhibition of enzymatic browning was seen with the increase in temperature. Also, the decrease in pH led to increase in enzymatic browning. It could be concluded that DHPC is a good inhibitor for enzymatic browning. It seems that this compound can be used in different fruits and vegetables to inhibit enzymatic browning.  相似文献   
6.
Twelve soil profiles and 62 soil cores were described from two neighboring landscapes in the northwest of Iran to understand whether long-term wastewater irrigation has caused variations in morphological, physicochemical, and DTPA-heavy metals contents in soils. Along a gradual slope, different positions reflected heterogeneous response to flooding wastewater irrigation. Upper slope and mainly midslope were subject to gradual soil loss as characterized by thin Ap-horizons and shallow soil depth, whereas periodic cycles of soil accumulation and sediment along with local reducing condition were highlighted in lower slope. Compared to different positions of control land, wastewater irrigation increased significantly (P????0.05) soil fertility attributes (N, P, K, and organic matter) along with electrical conductivity. Significant correlations were observed between soil fine particles fraction and available P and also with available K, indicating that spatial distribution pattern of these elements is mainly dependent on distribution of the <0.002?mm fractions along the landscape as it is affected by wastewater irrigation. Midslope position was found to be more degraded compared to the other position regarding soil loss and available nutrients (N, P, and K) as a result of the processes of soil redistribution and soil transport in wastewater irrigation system. Mean concentrations of DTPA-extractable Zn, Cu, Cd, and Pb in the different geomorphological positions were 3.8?C7.8, 2.5?C3, 3?C4, and 1.7?C3.5 times greater, respectively, when compared to the adjacent control soil. With the exception of lower slope position, which indicated a remarkable increasing pattern of smectite in response to wastewater irrigation and unfavorable drainage condition, the relative abundances of clay minerals in view of the peak position and intensity followed almost the same pattern in both wastewater-irrigated and control landscape.  相似文献   
7.
Groundwater is a valuable natural resource for drinking, domestic, livestock use, and irrigation, especially in arid and semi-arid regions like the Garmiyan belt in Kurdistan region. The Awaspi watershed is located 50 km east of Kirkuk city, south Kurdistan, Iraq; and covers an area of 2146 km2. The paper presents result of a study aimed at: (1) mapping and preparing thematic layers of factors that control groundwater recharge areas, and (2) determination of sites suitable for groundwater recharge. We used available data such as geological map, groundwater depth map, digital elevation model (DEM), Landsat 8 imagery, and tropical rainfall measuring mission (TRMM) data for this study. These data, supplemented by slope features, lithology, land use land cover, rainfall, groundwater depth, drainage density, landform, lineament density, elevation and topographic position index, were utilized to create thematic maps to identify suitable areas of groundwater recharge, using GIS and remote sensing techniques. Analytic hierarchy process (AHP) was applied to weight, rank, and reclassify these maps in the ArcGIS 10.3 environment, to determine the suitable sites for groundwater recharge within the Awaspi watershed. Fifty-five percent of the total area of the watershed was found to be suitable for groundwater recharge; whereas 45% of the area was determined to have poor suitability for groundwater recharge, but can be used for surface water harvesting.  相似文献   
8.
Earthquake Engineering and Engineering Vibration - In this paper, the potential of utilizing improved metaheuristic approaches in optimal design of building structures is concerned. In this regard,...  相似文献   
9.
The concentration and dynamic of soil trace metals in natural ecosystems, in particularly, is dependent on the lithology of parent rock as well as topography and geopedological processes. To ascertain more knowledge for this dependency, soils on three parent rocks involving peridotite, pegmatite, and dolerite in two contrasting topography aspects were investigated. The total values of Fe, Mn, Zn, Cu, and Ni were determined and compared for different soil pedons. The concentration of Fe, Mn, and Ni were highest in soils developed from peridotite (127, 1.8 g kg?1, and 218 mg kg?1, respectively), intermediate in soils derived from dolerite (81, 1.3 g kg?1, and 166 mg kg?1, respectively), and least in soil developed from pegmatite (50, 0.23 g kg?1, and 20 mg kg?1, respectively). The values of Zn and Cu, originated from different parent rocks, were in order of dolerite (78 mg kg?1) > peridotite (77 mg kg?1) > pegmatite (28 mg kg?1) and pegmatite (121 mg kg?1) > peridotite (111 mg kg?1) > dolerite (28 mg kg?1), respectively. For most of the studied pedons, profile metals distribution differed among the soils: The values of Fe, Cu, and Ni were enriched in the cambic horizons mainly as result of release, mobilization, and redistribution of the studied metals during geopedological processes, whereas those of Zn and Mn were concentrated in the surface horizons. Probably due to greater weathering rate of trace metal-bearing rocks on north-facing slope, the content of the trace metals along with the geoaccumulation index (I geo) and the degree of soil contamination (C d) were higher than on south-facing slope. Based on assessment of soil pollution indices, the soils were categorized as unpolluted [I geo ≤ 0 (class 0)], unpolluted to moderately polluted levels [0 < I geo < 1 (class 1)], and very low [C d < 1.5 (class 0)] to low degree of contamination [1.5 < C d < 2 (class 1)].  相似文献   
10.
In order to investigate changes caused in clay mineralogy and potassium (K) status by different land-use types, 42 soils samples (0–30 cm) were monitored and analyzed. Soil samples belonging to Reference Soil Groups of Cambisols and Vertisols were collected from three neighboring land uses involving cropland (under long-term continuous cultivation), grassland, and forestland. The soils reflected an alkaline and calcareous aspect as were characterized by high pH (mean of 7.1 to 7.5) and calcium carbonate equivalent (mean of 35 to 97 g?kg?1) in the three land-use types. X-ray diffraction patterns of the clay fraction showed that the soils were mainly composed of illite, smectite, chlorite, and kaolinite. Chlorite and kaolinite remained unweathered irrespective of land use and soil types, soil processes, and physicochemical attributes assessed. Some changes in the XRD diffractograms of illite and smectite (the intensity or the position of peaks) were observed in the cultivated soils compared to those of the adjoining grassland that may explain the dynamics of the K trapped in illite interlayer sites. Potassium issues reflected a heterogeneous response to changes in land-use types. In light of this, a pronounced variation in soluble K (4–22 mg?kg?1), exchangeable K (140–558 mg?kg?1), and non-exchangeable K (135–742 mg?kg?1) appeared among the land-use types for both Cambisols and Vertisols, corresponding to variability in clay content, nature and type of clay mineral (mainly illite and smectite), cation exchange capacity (CEC), and soil organic carbon (SOC). In general, the largest amounts of soluble K and exchangeable K were recorded in the forestland, whereas the highest contents of non-exchangeable K were found in the grassland for both Cambisols and Vertisols. Exchangeable K, available K, CEC, and clay contents in the soils with higher smectite values (25–50 %) were significantly different (P?≤?0.05) compared to those of the lower smectite values (10–25 %). This suggests that smectite is a major source for surface sorption of K in the studied soils.  相似文献   
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