The study presents the results of a 3-year field trial aimed at assessing the yield and efficiency indicators of nitrogen application in the cultivation of three maize cultivars differing in agronomic and genetic profile. The advantages of the UltraGrain stabilo formulation (NBPT and NPPT) over ammonium nitrate and urea are apparent if a maize cultivar capable of efficient nutrient uptake in the pre-flowering period and effective utilization during the grain filling stage is selected. Therefore, the rational fertilization of maize with urea-based nitrogen fertilizer with a urease inhibitor requires the simultaneous selection of cultivars that are physiologically profiled for efficient nitrogen utilization from this form of fertilizer (“stay-green” cultivar). The interaction of a selective cultivar with a high genetically targeted potential for nitrogen uptake from soil, combined with a targeted selection of nitrogen fertilizer, is important not only in terms of production, but also environmental and economic purposes.

The study presents the results of a three year field trial aimed at assessing the nutritional status of maize in critical growth stages by means of a plant analysis in the cultivation of three maize cultivars differing in their agronomic and genetic profile. The main research problem was to demonstrate whether the availability of nitrogen from stabilized fertilizers for “stay-green” maize varieties is consistent with the dynamics of the demand for this component. This is very important from both the economic and agronomic aspect of maize cultivation. The research showed a significant response of the maize cultivars to different nitrogen fertilizer formulations, which was observed in the period from the five-leaf stage to the full flowering stage. The advantage of the fertilizer, UltraGran stabilo, over other nitrogen fertilizers in the BBCH 15 stage was demonstrated only for the cultivar, ES Metronom, which produced a greater aerial mass while maintaining the nitrogen concentration at the level of the other two maize cultivars. The nitrogen and potassium content shaped the kernel weight in the ear in the flowering stage, confirming the importance of the interaction of these two elements in forming this feature of maize as the main predictor of the grain yield. This trait (expressed by the R² coefficient) manifested each year of the study, but especially in the years with optimal weather patterns (i.e., the first year). The response of the maize cultivars to nitrogen fertilizers, especially the cultivar, ES Metronom, was manifested by an increase in the content of nutrients and chlorophyll in the ear leaf, that is considered a predictive organ for grain yield. The fertilizers, Super N-46 and UltraGran stabilo, had a positive effect on the chlorophyll content (CCI parameter) and increased its efficiency of excitation energy transfer (the F0 parameter).

The study presents the results of a 3-year field trial aimed at assessing the yield and quality of raw material for ensiling in the cultivation of three maize varieties differing in their agronomic and genetic profile, conditioned by the selection of nitrogen fertilizer. Maize cultivar ES Metronom showed a significant advantage over other cultivars when fertilized with UltraGrain stabile, or alternatively Super N-46. The application of nitrogen-stabilized fertilizers or urea + N-Lock significantly increased the yield of maize green fodder for ensiling. The “stay-green” maize cultivars were characterized by a higher content of non-structural carbohydrates, including starch and water-soluble sugars, and a lower content of structural carbohydrates, compared to the conventional cultivar, which increased their suitability for ensiling. The negative effect of maize fertilization with ammonium nitrate and ammonium nitrate + N-Lock on the chemical composition of green fodder was demonstrated by a reduced starch content and increased structural carbohydrate contents, including crude fiber and NDF. In turn, the positive effect of maize fertilization with urea and urea + N-Lock on the chemical composition of maize fodder was shown by increased starch content and reduced structural carbohydrate contents, including crude fiber and its NDF and ADF fractions. The analysis of the number and weight of leaves may indicate a highly effective utilization of nitrogen (“stay-green” maize hybrids), leading to the faster formation of leaves with a larger assimilation surface, which is the basis for the efficient absorption of solar radiation. The results obtained clearly show that only the correct choice of maize variety for silage cultivation, combined with nitrogen fertilizer guaranteeing access to N during the growing season, can guarantee a high yield for ensiling.

The objective of presented in this paper the results of the 4-year field research was an evaluation of effect of two-component (NP) fertilizer placement depth, the type of nitrogen fertilizer and the date of its application on the occurrence of pests in maize cultivation. Changing weather conditions in the years of performing the field studies significantly differentiated the percentage of maize plants damaged by pests. The depth of NP fertilizer application did not have a significant impact on the number of plants damaged by the European maize borer [Ostrinia nubilalis (Hübner)], frit fly (Oscinella frit L.) and cereal leaf beetle (Oulema melanopus). Frit fly damaged plants fertilized with ammonium nitrate at higher degree than the plants fertilized with urea. In-season sidedress nitrogen application at the BBCH 15/16 growth stage increased the percentage of plants damaged by cereal leaf beetle compared to the pre-sowing N application. Regardless of the years of research and the NP fertilizer placement depth, significantly the smallest damage to plants caused by cereal leaf beetle was recorded for pre-sowing application of ammonium nitrate or urea and significantly the greatest when ammonium nitrate was applied in season at the BBCH 15/16 growth phase. W pracy przedstawiono wyniki 4-letnich badań polowych, których celem była ocena wpływu głębokości umieszczania nawozu mineralnego, dwuskładnikowego (NP) w warstwie gleby, rodzaju nawozu azotowego oraz terminu jego aplikacji na występowanie szkodników w uprawie kukurydzy. Zmienne warunki pogodowe w latach badań, w istotny sposób różnicowały odsetek roślin kukurydzy uszkodzonych przez szkodniki. Głębokość aplikacji nawozu NP nie miała istotnego wpływu na ilość roślin uszkodzonych przez omacnicę prosowiankę [Ostrinia nubilalis (Hübner)], ploniarkę zbożówkę (Oscinella frit L.) i skrzypionkę zbożową (Oulema melanopus). Ploniarka zbożówka w większym stopniu uszkadzała rośliny nawożone saletrą amonową, w porównaniu do mocznika. Pogłówna aplikacja azotu w fazie BBCH 15/16 zwiększała odsetek roślin uszkodzonych przez skrzypionkę zbożową, w stosunku do przedsiewnej aplikacji tego składnika. Niezależnie od lat badań i głębokości aplikacji nawozu NP, istotnie najmniejsze uszkodzenia roślin przez skrzypionkę zbożową odnotowano po zastosowaniu saletry amonowej lub mocznika przed siewem kukurydzy, a istotnie największe, gdy zastosowano saletrę amonową w fazie BBCH 15/16.