Short-term effect of different doses of sewage sludge on soil physical and hydraulic properties with different irrigation regimes in a silage maize field

Soil physical and hydraulic properties may be affected significantly from stabilized sewage sludge, and irrigation regimes may change the magnitude of these effects. Therefore, we examined the effects of different sewage sludge doses (D0: 0 t/ha, D1: 30 t/ha, D2: 60 t/ha, D3: 90 t/ha) and irrigation regimes (S1, S2, S3) on the soil physical and hydraulic properties with two-year study in a silage maize cultivated soil. The experiment was carried out in a completely random factorial design with three replications. In the S1, S2 and S3 irrigation regimes, when the sum of estimated crop evapotranspiration by FAO-Penman-Monteith approach and effective precipitation difference were 25 mm, 50 mm and 75 mm, respectively, irrigations were carried out and the moisture deficit in the soil was completed to field capacity. While moisture regimes did not have significant effects on soil physical and hydraulic properties, sewage sludge doses resulted in significant effects. Compared to D0, 3.1% lower bulk density, 1.9% lower particle density, 14.9% higher wet aggregate stability and 2.6% higher gravimetric field capacity values were determined at the D3 treatment. It was determined that these improvements were due to the high organic matter content of the sewage sludge, which increased the organic matter content in the soil with increasing doses, and it was also supported by significant linear relationships between the organic matter and these parameters. As a conclusion, although the importance of the positive effects of increasing dose can be emphasized, it can be stated that longer-term studies are needed to see more permanent and effective results.