Protection and Modeling in the Use of S, Ca, and Mg Alternatives for Long-Term Sustainable Fertilization Systems

The complexity of NP and NPK fertilizers in stationary and long-term system yields is proven to determine substantial changes in soil fertility, revealing interaction possibilities related to the chemistry and requirements of other nutrients (S, Ca, Mg, and microelements), while sustainable fertilization can exert control over them through rational fertilization practices and complex nutritive management. Revealing the extent of the modifying effects in the application of S, Ca, and Mg correlated to the soil-plant system conditions relates to the hypothesis of the present research in the context of long-term experiments in Romania at the Office of Pedological and Agrochemical Studies Alba (OSPA Alba) and the Turda Agricultural Research and Development Station (SCDA Turda) with 55 years of a fertilizing effect over the 1967–2022 period, but not solely. This study shows that for sustainable fertilization systems, the complementary application of S, Ca, and Mg with NP and NPK has proven to be effective and unitarily constitutes a measure for the sustainable protection and enhancement of soil fertility.