The Effect of Organic and Mineral Fertilizers on Silage Maize Biomass Yield and Quality Across Different Soil–Climate Conditions in the Czech Republic

Maize biomass production and quality are influenced by numerous factors, including fertilization, soil characteristics, and climatic conditions. The aim of our study was to evaluate how different fertilization treatments ((1) Control, (2) farmyard manure (FYM), (3) FYM with added mineral nitrogen (FYM + N), and (4) FYM with added NPK mineral fertilizers (FYM + NPK)) affect the biomass yield and quality parameters (crude protein (CP), fiber content (FC), neutral detergent fiber (NDF), starch content (STR), organic matter digestibility (OMD), and neutral detergent fiber digestibility (DNDF)) of silage maize under various soil and climatic conditions in the Czech Republic (Caslav—degraded Chernozem, Ivanovice na Hané–Chernozem, Lukavec–Cambisol). The experiment was conducted from 2020 to 2023. Additionally, the study analyzed the effects of fertilization on soil chemical properties (pH, P, K, Ca, Mg, C, N). The highest average biomass yields were recorded in Ivanovice (23.8 t ha−1, A), followed by Lukavec (19.7 t ha−1, B) and Caslav (18.1 t ha−1, B). Comparing fertilizer treatments, no significant differences were observed among FYM, FYM + N, and FYM + NPK; however, all three treatments significantly outperformed the Control at all sites. Conversely, fertilization did not affect the quality parameters. For silage maize, FYM represents the optimal fertilization strategy, providing yields and quality comparable to the combined application of mineral N, P, and K, which are more costly (in terms of purchase and application) and, under certain conditions, may negatively impact the environment. Nevertheless, the application of mineral fertilizers increased soil nutrient content, thereby improving conditions for subsequent crops.