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Evaluation of the Effect of Conventional and Stabilized Nitrogen Fertilizers on the Nutritional Status of Several Maize Cultivars (Zea mays L.) in Critical Growth Stages Using Plant Analysis
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).
Evaluation of the Effectiveness of NBPT and NPPT Application as a Urease Carrier in Fertilization of Maize (Zea mays L.) for Ensiling
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.