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The study aimed to explore how phosphoric acid-modified rice husk biochar (PBC) affects the growth and concentrations of essential and non-essential elements in two crops: lettuce as the primary crop and arugula as the secondary crop. The treatments consisted of a no P fertilized control and 250 mg P kg−1 sourced either from PBC, triple super phosphate (TSP) or phosphoric acid (PA). When subjected to phosphorus (P) sources, both lettuce and arugula exhibited a noteworthy rise in their dry weights compared to the control plants. PBC treatments significantly increased P concentration in both plants. Although the PBC treatment decreased lettuce nitrogen (N) concentration, it had no impact on arugula N concentration. Phosphorus treatments resulted in a decrease in lettuce K concentration, whereas it increased in arugula. Calcium (Ca), magnesium (Mg) and sulfur (S) concentrations in both plants were not affected by P sources. The zinc (Zn) concentrations of the plants notably decreased with P treatments. Moreover, P treatments led to a reduction in manganese (Mn) concentration specifically in arugula. PBC significantly increased the silicon (Si) concentrations of lettuce plants. The application of PA significantly increased the vanadium (V) concentration in arugula. Phosphoric acid treatments resulted in an increase in the plant bromine (Br) concentrations. To conclude, PBC may serve as an alternative P source, potentially being as effective as or even more effective than other P sources in influencing plant nutrition, without causing an undesirable elevation of non-essential elements in plants. [ABSTRACT FROM AUTHOR]

Salt plays a vital role in many body functions. Humans must consume a well-balanced amount of salt to remain healthy as deficiency or excess of it causes many health problems. The major oxide element's values are only evaluated while processing for production; however, the type and amount of the trace elements in the salt are also important as they may entail risks for human health. This study concerns the mineralogy and geochemistry of salt samples which are taken from several salt mines and localities in Turkey. In addition, these local samples are compared with well-known samples from Himalayas and Asal Lake (Djibouti Southeast Africa) salt mines. The X-Ray Diffraction (XRD) and Confocal Raman Spectroscopy (CRS) analysis reveal that the most of Turkish salts are mainly composed of halite with minor amounts of thenardite and gypsum as well as the low concentrations of some potentially toxic elements (PTEs) such as As, Cd, Co, Hg, Mn, Ni, Pb and Zn. The samples from Tuz Lake have significant contents of As, Co, Cu, Mn, Ni, U and Zn. The mineralogy and geochemistry of the samples reveal a mixture of residual seawaters with the redissolving of the crystalized salt minerals in the region. Although the quality of the salts is mostly evaluated with the content of NaCl, the significant contents of the PTEs in the salt may be accumulated by time and danger human health. [ABSTRACT FROM AUTHOR]

The use of nanotechnology in agriculture has become an area of great interest for soil scientists. Therefore, it is important and necessary to investigate the effects of nanoparticles on plant growth and its nutritional interactions. The aim of this study was to investigate the effects of acid modified rice husk (MRH) and nano-Silicon (Si) derived from rice husk on the growth and phosphorus uptake and phosphorus use efficiency in Si accumulator wheat and non-accumulator lettuce plants. MRH and nano-Si were applied at 200 mg kg−1 and P was applied 100 mg kg−1 for wheat and 200 mg kg−1 for lettuce plants. The highest dry weight was obtained with the application of nano Si + P treatment; while both MRH and nano-Si had no significant effect over the applied 100 mg P kg−1. Phosphorus fertilization significantly reduced Si concentrations in both plants of wheat and lettuce. However, the decrease in Si concentration was partly compensated by nano-Si treatment. When P was applied together with nano-Si, its uptake and phosphorus use efficiency (PUE) significantly increased in wheat plants as compared to other treatments. Nano-Si derived from rice husk is a sustainable waste biomass and is an important alternative Si fertilizer source, which can be a valid strategy for the effective use of P fertilizers. The depletion of available Si in soil can be recovered by applying nano-Si as a fertilizer. The overall results obtained from the current research were promising. [ABSTRACT FROM AUTHOR]

We obtained a gold nanomaterial/graphene oxide-modified glassy carbon electrode and characterized it using transmission electron microscope, scanning electron microscope, cyclic voltammetry (CV), and X-ray photoelectron spectroscopy techniques. A response of the electrode using square wave anodic stripping voltammetry for [Pb.sup.2+], [Cu.sup.2+], and [Hg.sup.2+] was found linear in the range from 1 x [10.sup.-7] to 1 x [10.sup.-11] M. The detection limits of [Pb.sup.2+], [Cu.sup.2+] and [Hg.sup.2+] were 0.14, 0.5 and 1.2 pM, respectively. The method was applied to the simultaneous determination of [Pb.sup.2+], [Cu.sup.2+] and [Hg.sup.2+] in seawater samples from a coastal region of Anatolia, and the results corresponded well with the values obtained by inductively coupled plasma-optical emission spectroscopy. Keywords: seawater sample, voltammetry, gold nanomaterial, graphene oxide, heavy metal determination, modified electrode, Determining the chemical composition of seawater is highly important as it is largely related to geological and geochemical processes. Heavy metals and metalloids have great importance in terms of human [...]

In this study, the effect of different calcium sources on calcium carbonate deposition by the ureolytic Paenibacillusfavisporus U3 was investigated. Calcium lactate, calcium nitrate, and calcium chloride were used as organic and inorganic calcium sources. In addition, the activity of urease and carbonic anhydrase enzymes required for calcium carbonate mineralization by U3 was determined. Results showed that the highest amount of CaCO.i was reached at lOOOmM CaCE concentration. Enzyme activity studies proved that U3 contains urease and carbonic anhydrase enzymes. Also, calcite and vaterite forms of calcium carbonate were produced by the U3 strain. The calcite and vaterite crystals of calcium carbonate were verified by XRD, XRF, CRS, EPMA, and FESEM-EDX. Lastly, P. favisporus U3 can precipitate large amounts of calcium carbonate by tolerating high CaCE concentration, demonstrating its potential for use in soils with high calcium chloride concentrations. [ABSTRACT FROM AUTHOR]

AbstractSalt stress, which impairs plant growth and induces oxidative stress, presents a major challenge in agriculture. In response, biochar has emerged as a promising soil amendment, capable of enhancing plants’ stress tolerance mechanisms. This study investigated the impact of rice husk biochar (RBC), derived from rice husks, on enhancing salt stress tolerance in lettuce plants grown under greenhouse conditions. Molecular and chemical characterization of the biochar samples was performed using Scanning Electron Microscopy (SEM) and Raman spectroscopy. Salinity reduced the fresh and dry weights of the plants from 25.0 g plant−1 and 1.83 g plant−1 to 20.4 g plant−1 and 1.42 g plant−1, respectively. The application of RBC recovered the growth decline caused by salinity, increasing the fresh and dry weights of the plants to 28.1 g plant−1 and 1.83 g plant−1, respectively. While the concentrations of sodium and chloride in plants decreased with RBC application, potassium and silicon concentrations significantly increased. As a result of salt stress, hydrogen peroxide levels (H2O2) increased in plant tissues, and a decrease in H2O2 levels was observed with an increase in superoxide dismutase, catalase, and ascorbate peroxidase activities. Consequently, RBC proved to be effective in enhancing salt tolerance in lettuce plants. In conclusion, while RBC demonstrates significant potential for enhancing salt tolerance, its successful application depends on several factors such as biochar dosage, application method, soil type, and plant species, underscoring the need for further research to elucidate the mechanisms at play and optimize its use for sustainable soil management in saline conditions. [ABSTRACT FROM AUTHOR]