Effect of Reduced Nitrogen Fertilization on the Chemical and Biological Traits of Soils under Maize Crops

Abstract

The European Commission’s “Farm to Folk” strategy recommends reducing fertilizers by at least 20% by 2030. In this context, the aim of this study was to verify whether a 20 and 40% reduction of nitrogen (N) fertilization rate will be sufficient to maintain soil chemical features, fertility, and yields in monoculture maize cultivation in the no-tillage (NT) system versus the traditional plowing (PL) system. We also examined which tillage system (PL, NT) allows the reduction of fertilization while maintaining good yields of the tested soils. Two fields (10 ha each) were established for PL and NT maize cultivation, and soils (0–20 cm) were sampled twice per year—before maize sowing and after maize harvesting. A broad range of chemical and biological parameters were monitored (i.e., pH, forms of nitrogen, phosphorus and carbon, content of selected macronutrients and humic substances, and respiration activity). It was concluded that the 20% reduction in N fertilization (after 4 years of use) did not have an adverse effect on the soil’s chemical and biological features, which mainly depended on the season of the year. The maize yield seemed to be higher in the PL system, which was mostly the result of the tillage system rather than the N dose. The study will be continued in the next vegetation season to further verify our findings, especially with regard to the maize tillage system and yields.