Frequent Irrigation of Silage Maize in Soil Containing Sewage Sludge Reduces Co2 Emissions Per Unit Yield By Increasing Productivity

Abstract

Although organic fertilization improves soil health and productivity, a sustainable food supply also requires reducing environmental carbon emissions. The aim of this field study was to reduce CO₂ emissions from soil per unit biomass yield of silage maize. The experiment was conducted in a total of 36 plots with three replicates with three irrigation regimes (R1, R2, and R3) with varying wetting–drying durations in soil containing four doses of stabilized sewage sludge (0, 30, 60 and 90 Mg ha⁻¹; D0, D1, D2 and D3). Irrigation was applied when the ∑ (estimated evapotranspiration – effective precipitation) value reached 25, 50 and 75 mm in R1, R2 and R3, respectively. A steady change in carbon emissions was also detected with a steady loss of organic carbon throughout the vegetation period. R1 and D3 led to the highest cumulative CO₂ emissions per unit production area of 9821.4 kg CO₂ ha⁻¹ and 11514.9 kg CO₂ ha⁻¹, respectively; these values were also 11.5% and 40.8% higher than the R3 and D0 values, respectively. The changes in CO₂ emissions per unit of water use were similar to the changes in cumulative emissions. However, while R1 provided the lowest CO₂ emission per unit biomass yield with the highest yield, the highest values were determined in D0 with a lower yield and in D3 with a higher emission. Therefore, frequent irrigation with 30 and 60 Mg ha⁻¹ doses of sewage sludge can decrease CO₂ emissions per unit yield in silage maize.