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Greenhouse research was conducted to determine the effects of foliar application of humic acid on dry matter and some nutrient element uptake of maize grown under calcareous soil conditions. Agricultural lime was used to obtain five calcium carbonate (CaCO 3 ) doses (0, 5, 10 20, and 40%) and three foliar application doses of humic acid (0, 0.1, and 0.2%) sprayed at 20 and 35 days after emergence. Although the dry weight and mineral element uptake of maize were affected negatively, especially at 20 and 40% of lime levels, foliar application of humic acid had a statistically significant positive effect on dry weight and copper (Cu), zinc (Zn), and manganese (Mn) uptakes (P < 0.01) of maize plants. The greatest dry weight and Cu and sodium (Na) uptakes were obtained from the 0.01% humic acid treatment. The interaction of lime and humic acid was also statistically significant on dry weight, nitrogen (N), phosphorus (P), calcium (Ca), magnesium (Mg), Cu, Zn, and Mn uptake (P < 0.01).

The aim of this study was to examine the effects of the soil application of humus substances on the dry weight and the nutrient uptake of selected elements in maize grown under salt stress in greenhouse conditions. Sodium chloride was added to the soil to obtain 0, 15, 30, 45 or 60 mM NaCl. Three different doses of solid humus (0, 1 or 2 g kg -1) were applied to the soil one month prior to planting. High levels of salt (45 and 60 mM NaCl) had negative impacts on the dry weight and the N, P, K, Ca, Mg, Fe, Cu, Zn and Mn uptake of the maize plants. The highest mean dry weight, Mg and Mn uptake were observed for the 1 g humus kg -1 treatment and the highest mean Cu content was in the 2 g humus kg -1 treatment. On the contrary, the highest mean uptakes of N and P were found in the soils in which humic substances was not added. The interactions of NaCl and the soil humus content were significant for the uptake of Cu (p≤ 0.01), and we found that adding humus increased the content of Cu in maize plants under slight salt stress (15 mM NaCl) (p≤0.01).

Green apple peels, (25.06 ± 0.06 g) with the moisture content of 3.05 ± 0.02 [kg (moisture) kg–1 (dry matter)], were dried using two dehydration methods, microwave, and natural drying until moisture content of apple peels was reduced to 0.092 ± 0.001 [kg (moisture) kg–1 (dry matter)]. Microwave drying periods at 1,000, 800, 600, and 400 W lasted for 17, 21, 27, and 33 min, respectively; whereas, natural drying lasted for 66 hr. The scope of this study, a comparison of measurements of moisture with that of the predicted results was made, obtained from 21 thin layer drying models. For both 600 and 800 W microwave drying, Modified Henderson and Pabis's model; whereas, at 1,000 W, Alibas's model, and at 400 W, Modified Jena and Das's model were considered to be the most appropriate models. The most suitable drying process according to color parameters, chlorophyll content, and nutrients was obtained at 400 W microwave drying. Practical applications The herbal tea industry is growing globally and it is constanrly looking for new flavors that can attact consumers' attention. Herbal teas, in addition to being delicious, are required to meet the daily nutritional needs of the consumers. One of the drawbacks of drying is the loss of aroma and nutrients, moreover, drying operations carried out in open fields, such as sun drying, leads to contamination and can cause more harm than benefit. Thus, for food safety, it is very essential for herbal tea production facilities to use appropiriate methods to produce high‐quality products. The present study on drying of apple peels for herbal tea contains important data on the selection of the most suitable drying method for the preservation of nutrients.

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