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A study on the influence of doses nitrogen on salt concentration, yield, biological value, and chemical composition of butterhead lettuce, kale, and leafy celery was carried out under greenhouse conditions in 2006-2008. The experiment was set up as a completely randomized design. A single experimental unit consisted of one pot with a plant. Increasing rates of nitrogen in the form of ammonium nitrate (34% N): 0.3; 0.6; 0.9; 1.2 g N·dm⁻³ of growing medium, were applied in all investigations, while the other macronutrients were the same for all plants. The obtained results revealed that the salt concentration in the growing medium depended both on the rate of nitrogen and the plant grown. Significantly lower crop yield was recorded when the highest nitrogen rate was applied (1.2 g N·dm⁻³), although this relationship was shown when there was high variation in EC in particular types of medium. It was found that excessive salt concentration in the growing medium due to increasing nitrogen rates significantly reduced vitamin C content in butterhead lettuce and leafy celery. An opposite relationship was observed for kale leaves. It was found that the protein levels in the tested plants increased with an increase in nitrogen rates. As compared to the lowest rate, the increase was 32.2% for butterhead lettuce, 30.6% for kale, and 41.2% for leafy celery.
The examinations were aimed at determining the dependence between form and rate of applied nitrogen fertilizer vs. yield and chemical composition of leaves of Swiss chard cultivated in greenhouse in spring. Nitrogen was applied in a form of urea, potassium nitrate, and ammonium nitrate at three amounts: 0.2; 0.4; 0.6 g N·dm⁻³ of substrate. Following items were assessed: yield, nutrients contents, as well as chemical analyses of substrate after plant harvest were made. Increase of nitrogen rate in objects with potassium nitrate and ammonium nitrate resulted in the decrease of fresh matter yield, while in objects with urea, the yield remained at constant level. The highest yield of above ground parts (356 g·plant⁻¹) was achieved by fertilizing the plants with the lowest nitrogen rate (as ammonium nitrate). Contents of nitrates in leaf dry matter was within the range of 0.59–1.27% depending on nitrogen rate and form. The highest nitrate levels were found when potassium nitrate was applied as fertilizer, whereas the lowest – when applying ammonium nitrate; however, regardless the fertilizer type, higher rates caused the increase of nitrate contents. Studies revealed that at increasing nitrogen concentration in a substrate, level of vitamin C also increased. Contents of N, P, K, Ca, and Mg in Swiss chard’s leaves depended on nitrogen fertilizer type. Comparison of studied factors influence on potassium concentration in plants indicated that increasing nitrogen rates in objects with urea and ammonium nitrate was accompanied by the decrease of this element content. An inverse dependence was recorded in objects with potassium nitrate, where content of potassium in Swiss chard’s leaves increased along with the nitrogen level increase. Application of 0.2 g N· dm⁻³ substrate appeared to be the most profitable in spring cultivation of Swiss chard, because the largest yields of fresh matter and the lowest share of nitrates in dry matter of studied plant were found.
The experiments on celery, curly kale and lettuce reported in this paper were carried out in a greenhouse, with plants grown in 2 dm3 pots filled with peat substrate. The trials were established in a completely randomized design. The aim was to determine the effect of increasing nitrogen doses (0.3, 0.6, 0.9, 1.2 g N dm-3 of substrate) on N-tot., NO3-N, concentrations of P, K, Ca, Mg, Fe, Zn, Mn and Cu as well as ratios between these elements in three vegetable species such as curly kale, lettuce, and celery, distinguished by different degrees of sensitivity to salinity. An increase in the content of total nitrogen and NO3-N in lettuce, curly kale and celery appeared to be parallel to the increasing doses of nitrogen, while the average total nitrogen content was similar in all the tested species, and the content of N-NO3 in kale was about five-fold lower than in lettuce and celery. The level of nitrogen fertilization influenced the content of potassium and magnesium in lettuce as well as the content of phosphorus, potassium, calcium and magnesium in celery. The nitrogen doses significantly differentiated proportions between the nutrients in plants, mostly the K:Mg and Zn:Cu ratios. The increasing doses of nitrogen modified the content of microelements and proportions between various components in the tested plant species.
The aim of the study was to determine the effect of pH and soil chemical composition on morphological traits of common tansy (Tanacetum vulgare L.). A two-year study was conducted based on observations, measurements and analyses of material collected from 24 stands in the following regions: Równina Włocławska (Włocławek Plain), Wyżyna Lubelska (Lublin Upland), Padół Zamojski (Zamość Depression), Działy Grabowieckie (Grabowiec Divide) Płaskowyż Suchedniowski (Suchedniów Plateau), Wysoczyzna Siedlecka (Siedlce High Plain) and Niecka Połaniecka (Połaniec Basin). Morphological traits of tansy shoots were determined: number of plants per clump, stem length, number of leaves per plant, total leaf length, petiole length, number of branches from the main stem, number of flower heads per corymb and fl ower head diameter. A soil analysis was performed determining the content of magnesium, potassium and phosphorus available for plants. The soil pH was also determined. The collected results indicate significant differentiation of the investigated samples, both in terms of morphological traits of the shoots and the chemical composition of the soils. A negative correlation was found between soil pH and number of leaves per shoot as well as number of branches per corymb. A positive correlation was noted between soil pH and total leaf length as well as between magnesium content and number of flower heads per corymb. The increased content of available phosphorus in the soil was associated with petiole shortening. A growth trend in the tansy shoot length was observed at larger amounts of available magnesium in the soil. On soils with low nutrient availability and a low pH, a reduced population density of the species in question was observed.
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