Journal of Agricultural Science and Technology, cilt.27, sa.5, ss.1061-1077, 2025 (SCI-Expanded)
The surge in biogas energy production has resulted in an accumulation of Liquid Digestate (LD), a byproduct with possible agricultural utility. To discern its benefits and shortcomings, a field trial was conducted to evaluate the effects of different doses of LD on maize yield, soil salinity, leaf and grain Nitrogen (N) content. The study included both single-year and consecutive two-year applications of LD at doses of 10, 30, 50, and 70 t ha-1. Based on maize N requirements, any N deficit was supplemented with chemical fertilizers. For the one-year experiment, the highest grain yield was obtained from the chemical fertilization treatment and 70 t ha-1 dose of LD. In the two consecutive years, 70 t.ha-1 dose gave the highest grain yield. LD provided N to the soil as effectively as chemical fertilization and stabilized the soil pH within approximately 1 month. However, high doses of digestate resulted in increased soil salinity and decreased N Use Efficiency (NUE). Consecutive two-year application increased Electrical Conductivity (EC) and pH stabilization in the soil to a greater extent than single-year applications. However, there was no difference in the N content of the plant between single-year and two consecutive applications. In summary, LD provides significant agricultural benefits such as pH stabilization and increased inorganic N levels. However, our findings indicate that overuse can lead to soil salinity and N losses, underscoring the importance of balanced application to maximize its benefits while minimizing potential drawbacks.