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•pH, EC, and ions were mostly pronounced immediately after burning.•Runoff and erosion were highest 10, and 20–24 months after burn.•Moderate severity burn substantially increased pH, ...Cl¯, SO42¯, Br¯, and K+.•High severity burn increased EC, F¯, Mg2+, and TC in eroded sediments.•Pile-burning should be avoided on slopes.
Slash-pile burning is a frequent land management practice implemented across the Mediterranean. However, the impact of this practice on runoff waters has often been neglected. To address this issue, two experimental burns were conducted: one with moderate (MS) severity, and another with high (HS) severity, to evaluate the impact of different types of slash–pile on the quality of runoff waters. An unburned (UB) treatment was also considered in this study, to evaluate the impacts of slash–pile burning per se. Treatments were established on a slope terrain (∼18°) characteristic of the Adriatic coast. During the two-year study, runoff and erosion samples were collected 22 times after major rainfall events. Aside from runoff, erosion, and total carbon in sediments (TC) were determined, as well as various water quality parameters, including, pH, electrical conductivity (EC), and Br¯, Cl¯, SO42¯, PO43¯, F¯, K+, Na+, Ca2+, and Mg2+. Overall, water quality parameters were more affected shortly after burning, while runoff and erosion were more dependent on precipitation patterns. TC in sediments was higher in HS than in MS, the highest values being observed in the last sampling events for both burned treatments. Regarding runoff water quality, the effects were more pronounced at HS, even if the hydrological response was stronger at the MS. The UB treatment showed significant changes in runoff water quality following major rain events, which was attributed to soil saturation. Our results suggest that slash pile burning has adverse effects on runoff waters, so it is recommended for biomass to be used in other ways, especially in the context of soil and water conservation.
Changes in C and nutrient cycling during succession are well studied, however, results can be contrasting for different nutrients and successional sequences. We analyzed soil chemical differences ...between early and late succession of oak-hornbeam forest. Late forest succession efficiently retained plant-available P, and total Mn, Zn, Fe, Cu, and Ni pools in the soil, as their concentrations were similar to those of early-successional grasslands. Available K, soil organic C, and organic matter content, as well as C:N and C:S ratios were higher in late than in early succession. Soil organic N and S concentrations did not differ between the stages.
In this local-scale synecological study, we investigated the changes in plant community composition throughout secondary succession occurring after cessation of agricultural land use (i.e. grassland ...abandonment). The successional sequence studied had the following pathway: Avenula pubescens (Huds.) Dumort. haypastures → Brachypodium pinnatum (L.) P.Beauv. successional grassland → Cornus sanguinea L. scrubs → late-successional Populus tremula L. forest → late-successional oak-hornbeam (Quercus-Carpinus) forest. The last forest stage was represented by the association Epimedio-Carpinetum betuli (Horvat 1938) Borhidi 1963. Occurrence of plant species throughout secondary succession was mostly stage-specific; only Fragaria vesca L., Ajuga reptans L., Cornus sanguinea, Prunus spinosa L., and Viola hirta L. showed survival ability throughout almost all stages.
Abstract
Changes in soil chemistry after invasion by bracken (Pteridium aquilinum) have been studied in heathlands, but comparable studies in meadows are lacking. We investigated if bracken invasion ...into P-deficient meadows alters the soil nutrient-resource pool, as well as the mechanisms behind it linked to soil processes and bracken nutrition. Furthermore, we investigated how community composition responds to differences in soil chemistry before and after the invasion. Soil and plant material sampling, along with vegetation survey, were performed during bracken peak biomass. Data analyses included analysis of variance and canonical correspondence analysis (CCA). Bracken invasion increased soil P availability, soil organic C concentration, as well as C:N, C:S and N:S ratios, while decreasing Fe and Co concentrations. Bracken pinnae were rich in P, and its rhizomes were rich in K, whereas N:P of pinnae and rhizomes was low. CCA showed contrasting abundance patterns of frequent meadow species related to P and K availability. Holcus lanatus exhibited competitive advantage under extremely low P availability. Increase in P availability under bracken may have occurred through promoting the leaching of Fe and Al. By increasing P availability for its growth and increasing N limitation for other species, bracken can gain a competitive advantage from the soil resource-niche perspective. Its ability to increase soil P availability, along with the physiological mechanisms behind its high P acquisition efficiency, seem to differentiate bracken from other species of competitive ecological strategy, which are mainly confined to nutrient-rich environments. This enabled bracken to invade P-deficient meadows.
The objective was to evaluate the ability of visible and near-infrared (NIR) spectroscopy to predict winter wheat grain yield, according to the performance of different prediction models. In situ ...reflectance measurements (350–1050 nm) were acquired from winter wheat flag leaves grown under nine mineral nitrogen (N) fertilization treatments (0–300 kg N ha
−1
), during stem extension developmental stage. Linear statistical models (MLR—multiple linear regression, PLSR—partial least squares regression) and non-linear prediction (ANN—artificial neural networks) were generated to estimate grain yield, based on derived variables from hyperspectral data as input features (first derivative of reflectance in form of principal components—PCs and vegetation indices—VIs). The expected influence of variable N fertilization on agronomic and spectral variables was recorded. The red and NIR reflectance contributed most to development of PCs, while VIs were calculated from 704 nm (
λ
RED
) and 785 nm (
λ
NIR
). Very strong positive relationship was determined between grain yield and VIs. ANN models were the most efficient in capturing the complex link between grain yield and leaf reflectance compared to the corresponding VIs, MLR and PLSR models, indicating good learning performance. In terms of N stress and non-N-limited environment, it can be concluded that the prediction methods used in this study can provide in-season estimates of winter wheat yield at a field scale based on hyperspectral data. Key spectral features and algorithms defined in this study should help to support site-specific and real-time yield forecasting in winter wheat production.
Some species intrinsically have a high invasiveness capacity, shown by high phenotypic plasticity and rapid growth, enabling a wide distribution across their native habitats and successful invasion ...in the introduced range. For such species, information from native habitats is critically important. An example is Glechoma hederacea, native to Eurasia but introduced and widespread in the USA. Our main objective was to investigate variation in traits of native G. hederacea populations across contrasting habitats: open, forest edge and understory. Vegetation was sampled and the ecophysiological and morphological traits were measured with accompanying environmental parameters. Results showed that in native habitats environmental conditions cover wide gradients of light and soil moisture. Plants had the highest cover in nutrient-rich, shaded habitats, representing the optimal habitat, indicating shade tolerance of G. hederacea. Plants from forest understory exhibited strong similarities in investigated traits to plants from the forest edge, even though this was a drier, sunnier habitat. Plants from open, sunny habitats experienced stress as indicated by the quantum efficiency of PSII and significantly higher sexual reproduction. Results show that G. hederacea is moderately tolerant simultaneously to shade and drought, a characteristic that has been reported for numerous invasive species, while at the same time it shares some characteristics with weedy plants.
Heavy metals accumulation in crops and soils poses a significant threat to the human health. A study was carried out in 2016 in order to assess hemp (Cannabis sativa L.) ability to accumulate heavy ...metals and to reveal its possibility as a phytoaccumulator or phytostabilizer. Two soil types from Croatia were used in experimental pots: Gleysoils (alkaline soil) and Stagnic Luvisol (acid soil). Majority of the varieties accumulated more heavy metals in roots than in above-ground biomass. Removal of Cd, Ni, Pb, Hg, Co, Mo and As was higher in acid soil. Potential ability for phytostabilization was observed in alkaline soil in order Cu > Cr > Cd > Mo > Hg > Zn > Ni > Co > As > Pb, while for acid soil in order Zn > Cd > Cr > Ni > Hg > Cu > Mo > As > Co > Pb. Some varieties exhibited a translocation coefficient (TC) more than 1 and shown the ability of hyper-accumulation for Zn, Hg, Mo and Cd. Higher accumulation of heavy metals in some varieties could lead to their general application for phytoaccumulation of heavy metals from polluted soils.
Accumulated copper (Cu) in agricultural soils is non-biodegradable and persists in the environment, which imposes the need for its regular monitoring by selective, rapid, simple, and low-cost ...analytical techniques. The performance of portable X-ray fluorescence spectrometers (pXRF) has significantly improved in the last ten years, and they are increasingly applied for environmental, agronomic, and soil science purposes. This study aims to compare the total Cu content determined in agricultural soil samples using three analytical methods (inductively coupled plasma mass spectrometry, (ICP-MS), atomic absorption spectrophotometry (AAS), and pXRF). The research was based on analyses of thirty-five soil samples collected from two vineyards, arable land, and a meadow located in North-West Croatia. In air-dried, milled, and homogenized soil samples, Cu content was detected using a hand-held XRF analyzer under laboratory conditions, while ICP-MS and AAS analysis were performed after open digestion by aqua-regia. Determined Cu content varied in very similar ranges from 51.2 mg/kg to 444.3 mg/kg with an average of 138.9 mg/kg for AAS; from 48.6 mg/kg to 446.4 mg/kg and an average of 139.7 mg/kg for ICP-MS and from 54.0 mg/kg to 435.3 mg/kg with an average of 141.3 mg/kg for pXRF. A high positive correlation between Cu content determined by pXRF and ICP-MS (R2 = 0.996), as well as between pXRF and AAS (R2 = 0.997), along with the results of Bland-Altman statistical analysis indicate that pXRF can be applied as a reliable tool for analyses of Cu-contaminated agricultural soil.
Coal ash deposited in open landfills is a potential source of environmental pollutants due to the contained toxic element content. The weathered coal ash used in this study additionally contains ...enhanced activity concentrations of 238U series radionuclides. This study aimed to determine the physiological effects of enhanced ionizing radiation and toxic elements on five plant species (smilo grass, sticky fleabane, blackberry, mastic and pine tree) inhabiting the coal ash disposal site. Among the potentially toxic measured elements, contents of Sb, As and especially V significantly exceeded their respective levels at the control site, as well as the content of 238U and its progenies. Significant changes in photosynthetic pigments were recorded following chronic exposure to the plants growing on the coal ash site. Different responses were also observed in the plant species regarding the activity of catalase and glutathione-S-transferase (GST). The level of lipid peroxidation markedly increased in plants from the disposal site, except in blackberry, wherein GST activity was the strongest, indicating an important role of that enzyme in the adaptation to coal ash pollutants. The results of this study suggest that the modulation of the studied biochemical parameters in plants growing on coal ash is primarily species-dependent.
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•The studied coal ash is a source of both radionuclides and stable toxic elements.•Photosynthetic pigments increased in shrubs and decreased in grasses and pine tree.•Lipid peroxidation markedly increased in most of the plants from the disposal site.•Variable response in antioxidative enzyme activity in different plant species.•Plant species is a decisive factor in response to multiple stressors in coal ash.
The study aimed to determine the effect of different slope positions on selected chemical properties of Pseudogley in the vineyard. The study was conducted in Zagreb, central Croatia. A total of 15 ...top-soil samples (0-30 cm) were collected from a hilltop, backslope, and footslope and analysed for pH, hydrolytic acidity (Hy), soil organic carbon (SOC) content, P2O5, K2O, and potentially toxic elements (As, Cu, Ni, Pb, and Zn). A slight increase in mean pH value from the hilltop to the footslope and a decrease in Hy were observed, although differences were not statistically significant. The SOC content was low and uniform along the entire slope. A significantly higher concentration of P2O5 at the footslope compared to the hilltop was established (10.4 and 3.4 mg/100 g of soil, respectively). The K2O concentration at the footslope (29.7 mg/100 g of soil) was significantly higher than at the backslope (21.2 mg/100 g of soil). The Cu, Pb, and Zn concentrations were significantly affected by slope positions in terms of download accumulation. The studied soil was contaminated by As, Ni, and Zn at the hilltop and the footslope and partly at the backslope, according to the Ordinance on the Protection of Agricultural Land from Pollution. The Cu concentrations exceeded the maximum allowed concentrations only on the backslope and footslope. The minor differences in studied soil properties between slope positions can be attributed to a short length, low and uneven inclination, and relatively short-term anthropogenic influence.
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