The secondary effect of forecrop green manures on the vitamin C and protein content of red beet has been evaluated. Two forms of forecrop usage was applied, namely the whole biomass and harvest residue. Red beets were cultivated in the third year after organic fertilization. The beets that were grown after the mixture of vetch, oat and field pea as well as after oat was the highest in vitamin C. The ploughing under of the whole biomass of forecrop plants more positively influenced the protein content in beets than the ploughing under of the harvest residue alone.

Over the three-year pot experiment the investigations were made on nickel influence on yielding and mineral composition (K, Ca, Mg, P, Fe and Ni content) of lettuce and spinach leaves as well as zucchini and bean fruits. The experiment was differentiated regarding nickel content (NiSO4·7H2O) introducing: 0 (control); 10; 40 and 60 mg Ni·kg-1 sand, at the same time considering various nutritive requirements of the plant species studied. The obtained results indicate that even the lowest nickel dose applied (10 mg Ni·kg-1 substrate) has caused a significant decrease of yield of the usable parts of lettuce, spinach, zucchini and bean. Further increase of nickel content in the substrate (40–60 mg Ni·kg-1) resulted in more intensive yield drop of lettuce and spinach leaves. Under such conditions due to improper generative development, no generative yield of zucchini and bean was obtained. Nickel at amount 10 mg Ni·kg-1 substrate affected the significant growth of potassium concentration in the leaves of lettuce, phosphorus in spinach leaves, while it decreased phosphorus and potassium concentration in the zucchini and bean fruits causing at the same time significant fall in magnesium content in zucchini fruits and increase in Mg concentration in bean pods. Nickel dose growth in the substrate has differentiated changes in the plant mineral composition to a greater extent. Nickel at amount 10 mg Ni·kg-1 substrate influenced a significant iron growth in spinach leaves, zucchini fruits and bean pods, whereas it decreased Fe content in lettuce biomass. Increased nickel doses have reduced Fe concentration significantly in the usable organs of the vegetable species examined. Generally the growing nickel quantity in substrate affected the successive increase of this metal content in the usable organs of the vegetable species investigated.

The efficiency of protective activities of bacteria and fungi as Glycine max seeds dressing against the soilborne pathogenic fungi was evaluated in presented studies. The microbiological material was prepared from the antagonistic microorganisms strains of Bacillus spp., Pseudomonas spp., Gliocladium spp. and Trichoderma spp. The experiment was established in the field with soybean monoculture with infectious material of fungi naturally accumulated in the soil. Protective activities of applied microorganisms were determined on the ground of the number of grown plants, their healthiness and seeds crop quantity and quality. Obtained results showed that Trichoderma viride 254, T. harzianum 220 and Bacillus sp. 131 were the most effective for soybean protection . Gliocladium roseum 246, Gliocladium catenulatum 49 and Oxafun T Dressing turned out the least effective in their protective activities.

In the years 1999–2001 studies were conducted on the field belonging to the Experimental Station at Czesławice. The field contained naturally accumulated infection material. The subject of the studies was soybean, Poland cv. and chitosan in the form of micro-crystalline gel containing 2.76 of the pure compound. Water solution of this compound with 0.1% chitosan was used in the experiment. Two combinations were considered using chitosan for spraying the seedlings and the plants at the initial stage of anthesis, and the control without any treatments. In each year, field observations were performed which considered the number and healthiness of seedlings and plants at anthesis. After the harvest, the size and quality of the soybean seeds yield were also determined. In the course of field observations the infected seedlings as well as the infected plants at anthesis were taken for laboratory mycological analysis. The studies found out differentiated emergencies and healthiness of plants in particular experimental combinations. Chitosan used for spraying the plants at anthesis slightly improved the healthiness of plants and seeds and contributed to an increase of the yielding as compared to the combination where it was used for the spraying of four weeks old seedlings, and also in comparison to the control. Soybean seedlings were infected by F. solani and R. solani most frequently. On the other hand, plants at anthesis were mostly infected by F. oxysporum f. sp. glycines. The following were isolated from the infected soybean seeds: Phomopsis sojae, Phoma exigua var. exigua, F. oxysporum, R, solani, A. alternata, B. cinerea and S. sclerotiorum.

The influence of organic fertilization as a summer catch crop ploughed as a whole plants or post harvest residues and manuring rye straw on yielding and dry matter and vitamin C content in white cabbage. The highest cabbage crops were obtained when tansy phacelia was ploughed under. Crops of cabbage were higher when the whole catch crop biomass was ploughed under than when the post harvest residues were ploughed under. Among the doses of rye straw used, the best crop-generating effect was displayed by straw dosed at 4 t·ha-1. There wasn’t found any decrease of the dry matter or vitamin C content under the influence of the tested kinds of the organic fertilization.

The aim of the study was to recognise the species composition of beetles (Coleoptera) population occurring on hazel shrubs. Three-year studies were carried out on three ecosystems: on the cultivated hazelnut plantation, on an unprotected one and on shrubs of common hazel in the forest. The presence of 63 species was detected. The smallest number of species (22) and individuals (535) was noted in the protected plantation and the highest number in an unprotected one (46 species and 2787 individuals). In the forest the presence of 46 species and 1317 individuals was observed. The dominant species among beetles on hazel plantation in south-eastern Poland are from weevils’ family (Curculionidae). Curculio nucum and leaf-eaters from Phyllobius sp. genus were most often collected. The remaining species that were observed are non-economic pests of hazelnut, but giving up suitable chemical pest control and horticultural treatment results in an increase of their number. At that situation the number of species characteristic of common hazel growing in the forest increased on large-fruited hazel too. The species composition, number, dominance and the topic and trophic groups of Coleoptera adults are given in this paper.