Influence of selected factors on the content and properties of starch in the grain of non-food wheat

Three non-food cultivars of winter wheat (Biscay, Clarus, Rapsodia) were grown at four locations in the Czech Republic with different agro-ecological conditions in the years 2005-2008 and two levels of nitrogen fertilization 90 and 120 kg N/ha were used. The influence of growing conditions (year, location, cultivation technology) on grain yield, starch content, protein, gluten, share of amylose in starch, falling number and amylographic characteristics. All qualitative indicators were significantly affected by the weather. Wheat grown in the areas 500 m a.s.l. had lower grain yield of 2.8 t/ha (8.4 t/ha), higher starch content of 2.1% (69.0%) and lower content of proteins by 1.8% (10.2%) in grain than wheat grown in the fertile conditions (below 300 m a.s.l.). The cv. Biscay had the highest starch content of 68%; the proportion of amylose in the starch was in the range 22-27%. The content of proteins was negatively correlated with starch content (r = -0.89). The level of damage of starch a-amylase was most affected by wet weather during ripening falling number was 62 s, with a very low amylographic gelatinization maximum (30-155 Brabender units) and a low gelatinization temperature at the maximum (67-74 degrees C). The respective values recorded in dry conditions were ca 300 s, AU 600 and 90 degrees C. Most damaged starch was recorded in the cv. Clarus.Ministry of Agriculture of the Czech Republic [1G57056, RO0414

Migration of Risk Elements within the Floodplain of the Litavka River, the Czech Republic

Floodplains are one of the most complex sedimentary environments used for the reconstruction of human impacts on fluvial deposition and catchment pollution. Studies of polluted floodplains require an interdisciplinary approach, including tools from geomorphology, geophysics, and geochemistry. The spatial distribution of pollutants can reflect not only pollution history but also post-depositional transfers of pollutants. The Litavka River (SW Czech Republic) was impacted by historical mining and processing of Ag-Pb-Zn-Sb sulfidic ores, which resulted in a severely polluted floodplain. Previous studies revealed that nearly all of the floodplain deposits of the Litavka River downstream from the ore district are polluted, indicating massive floodplain aggradation. Our aim was to decipher the role of aggradation in floodplain development by investigating the pollutant distribution in the floodplain fill. Another important goal was to distinguish polluted (modern) sediments from secondarily polluted sediments (which were previously pristine) caused by extensive lateral and vertical post-depositional chemical migration of risk elements within the floodplain fill. The floodplain topography was characterized via a digital terrain model (DTM); the internal structure of the floodplain was determined by electrical resistivity tomography (ERT). Sediment samples were collected from hand-drilled cores across the floodplain along the ERT line, and their elemental composition and magnetic susceptibility were analysed. Dating of sediments was performed via optically stimulated luminescence (OSL). The concentrations of Zn, Pb and Cd, along with values of magnetic susceptibility decreased with increasing distance from the current river channel. However, the spatial patterns of risk elements were more complicated than expected in a fluvial sedimentary environment. Inter-element relationships of risk elements exhibited a complex pattern, with abundant outliers that required the use of robust regression. The results helped distinguish the geochemical difference between proximal and distal floodplains, and to identify zones of anomalous inter-element ratios attributed to post-depositional element migration. The observed migration was significant, and not only vertical but horizontal, spanning a distance of approximately half the floodplain width. Metal migration explains why unpolluted sediments are practically missing from the floodplain fill of the Litavka River. Use of pollution chemostratigraphy, without considering the possibility of post-depositional migration of risk elements, could lead to overestimation of the volume of younger sediments deposited directly within the floodplain and to overestimation of the role of aggradation processes

Geochemical Mapping in Polluted Floodplains Using in situ X-Ray Fluorescence Analysis, Geophysical Imaging, and Statistics: Surprising Complexity of Floodplain Pollution Hotspot

This study is focused on a pollution hotspot in a floodplain impacted by uranium mining in the second half of the 20th century. To image the internal structure of the hotspot, we performed surface gamma activity mapping, in situ X-ray fluorescence spectroscopic analysis (XRF) using a portable instrument and manually obtained sediment cores, and electric resistivity imaging of the shallow subsurface with the help of electric resistivity tomography (ERT) and dipole electromagnetic profiling (DEMP). We used two approaches aimed at deciphering the origin of the pollution hotspot: (i) surface pollution mapping and (ii) identification of the deeper lying lithogenetic units. The description of the floodplain subsurface was supported by optically stimulated luminescence (OSL) dating. The surface mapping approach was found insufficient to visualise the hotspot and understand its origin. We recognised deposition non-linear in time (or temporally independent) of younger overbank fines, including mining pollutants over considerably older channel sediments. Our work documents the value of dense geochemical mapping for documentation of fluvial pollution (accessible by portable XRF) as well as the need to understand the structure of the floodplain subsurface (accessible by electric resistivity imaging) and thereby rationalise the hotspot internal structure

A Central European Alluvial River Under Anthropogenic Pressure: The Ohře River, Czechia

Detailed geomorphic evaluation, drill coring, and analysis of floodplain sediments, along with geophysical imaging, were used to study the evolution of the youngest terraces and palaeo-meanders in the lower reach of the Ohře River. Floodplain sediment dating was performed by optically simulated luminescence and via the examination of sediment contamination from historical mining of metals in the river catchment. Two river segments were studied. In the upper segment, the Zatec ˇ area, the trunk channel persistently incised from the Early Holocene to ca. 2 ka, and in historical times the meandering channel changed to a low sinuous channel in a narrow channel belt. The terraces and palaeo-meanders in the Zateč area are younger than indicated in the geological maps, by one to two orders of magnitude. In the lower segment, the Písty area, 60 km downstream, approximately half of the sediments in the floodplain transect are the Early to Middle Holocene age and the other half are younger than approximately 1,000 years, in particular from the last five centuries. The deposits of the current channel belt in the Písty area are coarser (mostly sandy in the top metre) than in the rest of the floodplain (mostly silty in the top metre), indicating that the river must have undergone a substantial transformation in the last few centuries. We hypothesise that the trigger of this change was upstream channel straightening and lateral stabilisation, which reduced the amount of river-transported materials. Although the river catchment has been subjected to anthropogenic activity (including intense agriculture in the lower reaches), the river does not show enhanced aggradation