This article demonstrates the influence of the method using application of 100 kg N/ha of nitrogen fertilizer and hybrid types of maize (Zea mays L.) on selected efficiency indicators used for this macroelement. It was shown that in comparison to traditional broadcast fertilization, fertilization in rows or fertilization in rows combined partly with top dressing increased the values of such characteristics as nitrogen uptake and use, percentage of fertilizer nitrogen in the total nitrogen uptake as well as the agricultural and physiological effectiveness of the nitrogen. All the studied nitrogen effectiveness factors for maize (apart from physiological effectiveness) were significantly higher for the stay-green cultivar. In relation to a traditional cv. ES Palazzo, the cv. ES Paroli stay-green was characterised by poorer use of the nitrogen uptake regardless of the nitrogen fertilizer application method, which was visible in the lower values of physiological effectiveness.

Studies were carried out in the two years in Trzcianka near Nowy Tomyśl, on brown soil, IIIa-IVa with pH 7.1-7.2. Plants of five maize cultivars were cut at the height of 15 cm and 55 cm. The lower parts of stems with leaves which remain on the field in case of high cutting, were characterized by a smaller content of protein and by a greater content of fibre, in comparison with the higher parts of plants. The energetic value of 1 kg of dry matter of the lower 40 cm part with leaves expressed in MJ NEL, in spite of significant differences in the chemical composition, was only insignificantly lower than the upper part. The content of dry matter, the chemical composition and the energetic value of both parts differed, depending on the cultivar.

Field experiments showed the occurrence of such agrophages as the frit fly (Oscinella frit L.) and the European maize borer (Pyrausta nubilalis Hbn.). Identified diseases included fusariosis (Fusarium ssp.) and maize smut (Ustilago maydis Corda). The incidence of the frit fly was influenced by weather conditions, mainly temperature, in the period from sowing to the BBCH 15–16 phase. Moderate temperature conditions contributed to the occurrence of the pest. The significantly highest percentage of plants damaged by larvae of this pest was recorded on maize fertilised only with potassium (K) and phosphorus with potassium (PK). In turn, the lowest percentage of plants damaged by frit fly larvae was recorded for maize fertilised with nitrogen and potassium (NK). The percentage of plants damaged by the European maize borer was influenced by temperature and humidity conditions in individual years of the study. The highest percentage of plants damaged by larvae of the pest was found in the vegetation season characterised by the highest amount of rainfall with the lowest mean daily air temperature. The presence of potassium in a given fertiliser combination, the application of manure or combined application of manure and mineral fertilisation resulted in an enhanced resistance of maize plants to Fusarium ssp. fungi. The significantly greatest infestation of maize plants by the fungus Ustilago maydis Corda was recorded in the treatment in which only nitrogen was applied. In turn, the lowest percentage of plants with symptoms of this disease was recorded in the treatment with the application of potassium alone and in the application of potassium together with phosphorus.

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