The objective of the presented studies carried out in the Department of Horticultural Plant Fertilization, University of Life Sciences in Poznań was the investigation of the influence of the introduced doses of cadmium and lead (soil pollution) on the yield of the particular organs of selected cultivars of Marigold (Tagetes erecta L.) and to check whether these plants are suitable to be planted on soils polluted with the mentioned metals. Plants used in the experiment were planted in individual outflowless containers in plastic tunnel. The studied cultivars of Marigold were planted in a substrate artificially polluted with cadmium and lead. The two heavy metals were introduced in the following doses: Cd – 0 (control); 1; 5; 10 mg dm^-3, Pb – 0 (control); 100; 500; 1000 mg dm^-3. Statistical analyses carried out in the present paper refer to the analysis of variance for leaf, stalk and inflorescence matters and the number of inflorescences. Analysis of the mean total yield of the particular cultivars grown in all substrates has shown that the highest total yield was reached by ‘Titania’ cultivar, in the second place was ‘Hawaii’ and the smallest yield was obtained from ‘Mann im Mond’. The smallest amounts of cadmium and lead, regardless of the applied dose, remained in the substrate in which ‘Hawaii’ cultivar was grown.

In the Department of Plant Fertilization, University of Life Sciences in Poznań, a vegetation experiment (in plastic tunnel) was carried out in which the substrate was artificially contaminated with cadmium and lead and three cultivars of Tagetes erecta L. were planted in it: ‘Mann im Mond’, ‘Hawaii’ and ‘Titania’. The substrate was artificially contaminated with increasing doses of metals: Cd – 0 (control); 1; 5; 10 mg dm^-3; Pb: 0 (control); 100; 500; 1000 mg dm^-3. The objective of studies was to investigate which organs of Tagetes erecta L. cumulated the greatest amounts of cadmium and lead, what amounts of Cd and Pb move from the substrate to the organs of the studied cultivars and whether the studied cultivars of Marigold are suitable for the remediation of soils polluted with cadmium and lead. The metals contained in the particular plant organs, after dry mineralization, were identified by the method of atomic spectrophotometer AAS-3 of Zeiss Company. In all studied cultivars, the highest contents of cadmium were found in leaves, smaller amounts were shown in stalks, while inflorescences contained the smallest Cd amounts. The highest amounts of lead in all studied cultivars were found in the stalks, smaller amounts in the leaves and the least amount was shown in the inflorescences The greatest contents of cadmium and lead were found in the organs of ‘Hawaii’ cultivar, both in the leaves, stalks and inflorescences. The studied cultivars of Tagetes erecta can be utilized for the remediation of soils polluted by heavy metals.

The field experiment was carried out in 2006–2008 on lessive soil developed from medium dusty loams. Salsify (Tragopogon porrifolius L.) of ‘Mamut’ cv. was the experimental species. The experimental design included three intercrop plants: common vetch, lace phacelia, and oats; two soil tillage ways: a) set of pre-sowing tillage operations, sowing the intercrop plants (mid of August), pre-winter ploughing, mixing the green matter with soil, b) set of pre-sowing tillage operations, sowing the intercrop plants (mid of August), spring ploughing, mixing the plant matter with soil; as well as two plant cultivation manners: on ridges and on flat soil. It was found that spring ploughing made to mix the intercrop biomass with the soil as well as cultivation of plants on ridges significantly increased the total salsify root yields. Significantly positive influence of intercrop plants on salsify root yields, inulin content, inulin yield, and dry matter content was also recorded. Considering the roots yield and their nutritional value, plants cultivated on ridges after spring ploughing and mulching with lace phacelia appeared to be the most beneficial salsify cultivation combination.

In 2-year seasonal experiments (cultivation in peat), the effect of chelated and mineral forms of zinc on the yield of greenhouse lettuce and on the content of zinc, copper, manganese and iron in lettuce leaves were compared. The following zinc doses were applied: 10, 20, 30, and 60 mg dm^-3 of substrate. Using both forms of zinc in the studied range, good and similar yields were obtained. Zinc application in the mineral form caused a twice greater zinc concentration in lettuce leaves and a higher concentration of manganese, while copper and iron showed smaller concentrations.

In the years 2006–2007 radish ‘Opolanka’ cv. was grown in 60 × 40 × 20 cm containers, placed in the open field under a shade providing fabric. A loamy clay soil was used as a substrate. The following foliar nutrition treatments were applied twice: 1 – control (spray with water), 2 – urea, 3 – urea + Mo, 4 – urea + Mo + BA, 5 – urea + Mo + BA + sucrose, 6 – BA (benzyladenine) and 7 – sucrose. There were used the following concentrations of tested compounds: urea 20 g∙dm^-3, sucrose 10 g∙dm^-3, molybdenum (Mo) 1 mg∙dm^-3 and BA 5 mg∙dm^-3. Foliar nutrition treatments had a significant effect on average mass of plant leaves and on concentration of soluble sugars and ascorbic acid in radish roots. Plants treated with a mixture of urea + Mo + BA + sucrose featured the highest average mass of plant leaves. Radish roots of control plants and those sprayed solely with BA contained significantly more soluble sugars than roots of plants from other treatments. Spraying the plants with solutions containing only sucrose or only BA (treatments: 6 and 7) caused a significant reduction of ascorbic acid content in radish roots in comparison to other treatments. All the solutions used for foliar nutrition had no effect on radish roots mass and on mass of whole plants (roots + leaves). There were also not observed any significant changes in dry matter content of leaves and roots likewise in the content of phenolic compounds, phenylpropanoids, flavonols or anthocyanins in radish roots.