Agarista salicifolia is the wild tree and has been used as important medicinal plants in South Ethiopia since a long time ago. The aim of this work was to carry out a chemical analysis focusing on secondary metabolites, particularly phenolic compounds, which have several roles in the plant physiological processes and have demonstrated significant capacity in the prevention of human health diseases. Phenolic acids, flavonols, flavan-3-ols, and dihydrochalcones were characterized and quantified using ultra high-performance liquid chromatography coupled with diode array and electrospray ionization mass spectrometric detection (LC-MS), FTIR, and UV-Visible spectroscopy techniques. After extraction with ethanol, compounds were characterized and quantified based on retention time, molecular ions, and the comparison with reference compounds. Six flavan-3-ols, four phenolic acids, five flavonols, and two dihydrochalcones were identified and quantified in the extract. Chlorogenic (279.23 ± 28.75 µg/g of dried leaf) acid, Quercetin-3-O-rhaminoside (97.24 ± 4.07 µg/g of dried leaf), and epicatechin (304. 57 ± 20.88 µg/g of dried leaf), were the most abundant phenolic acid, flavonol, and flavanols, respectively. This is the first study on the phenolic composition of A. salicifolia, highlighting the importance of these natural products as a source of medicinal applications in pharmaceutical industries by herbal drug manufacturers.

The application of phosphogypsum (PG) on sodic soils provides nutrients to the soil, reduces the toxic effect of Na+, and improves soil properties. Laboratory experiments were performed to evaluate the effects of PG on the chemical properties of sodic soils. The treatments were arranged in a completely randomized design with five replications. The treatments included 0% GR (control), 50% GR (28.18 g·kg−1), 100% GR (56.37 g·kg−1), 150% GR (84.50 g·kg−1), and 200% GR (112.74 g·kg−1) rates that were thoroughly mixed with soil under incubation, whereas PG was mixed with topsoil before leaching at the same application rates under the leaching experiment. Soil and leachate samples from each pot were collected in 7, 14, 21, 28, and 35 days and subjected to spectrometric analysis. Results indicated that there was a highly significant ( p < 0.001 ) effect on soil pH, exchangeable sodium percentage (ESP), available P, exchangeable Na+, and Ca+2 under 35-day incubation compared with control. In a closed incubation system, most of the nutrients were released after 7 days of incubation and inconstantly released after 14 days of incubation. Furthermore, the removal of Na+ and SAR increased in initial leachate collection and decreased with the subsequent application of irrigation water (PV). Because of the high contents of Ca+2 released from PG and the residual effect of H2SO4, soil pH and ESP were rapidly reduced compared with control. Post leachate analysis also revealed that available P and extractable S-SO4−2 were significantly ( p < 0.001 ) increased in soil solutions. However, available P was decreased during incubations compared with the value of post leachate analysis. During a closed incubation, displaced Na+ replaces Ca+2 on exchange sites, resulting in increased Ca-P precipitation. Thus, the combined application of PG and irrigation water in 7 to 14 days would allow chemical reaction with the soils and reduce sodicity problems to crop planting.

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Aims Effect of phosphogypsum (PG) level and its application method on the performance of wheat and the chemical properties of sodic soils. Methods The field experiment was arranged as a split-plot design with three replications. Two methods of PG application (band and broadcast) were allocated as the main plot, and five PG levels (0, 50, 100, 150, and 200% GR) were randomly assigned as subplots. The experiments were repeated on plots and pots that were used for growing haricot beans using the same treatments and design. After two successive harvestings, soil samples (0–20 cm) were collected from each plot to compare treatment effects and analyzed for chemical properties. Results Results revealed that PG levels significantly reduced soil pH, ESP, and exchangeable Na+, whereas exchangeable Ca, SO4 − 2, and available P were significantly increased compared with control in both methods of PG application. Grain and straw yields, P uptake, and protein contents were also significantly increased with increasing levels of PG. However, yields were significantly decreased when growing the crop on plots and pots previously used for haricot beans. Yield reduction during the second growing might be due to the reduction of available P in the soil solution. Soil chemical properties and wheat yield better under band PG application than broadcasted plots. Conclusions The study showed that the PG amendment offers twin benefits in reclaiming the sodic soil and providing P and SO4 − 2 for growing crops. Repeating the experiment using higher levels of PG and at other sites on sodic soil is recommended to draw sound conclusions.