Effect of subsoiling depth on soil physical properties and summer maize (Zea mays L.) yield

The present study was carried out in 2016-2017 to assess the effect of subsoiling depth on the soil bulk density, stability of soil structure, soil physical properties and summer maize yield based on a field experiment started in 2015. Four tillage depths were studied: conventional tillage 25 cm (CT25); subsoiling tillage 30 cm (ST30); subsoiling tillage 35 cm (ST35) and subsoiling tillage 40 cm (ST40). The results showed that at the 20-50 cm depth ST30, ST35 and ST40 decreased the mean soil bulk by 4.59, 7.13 and 8.27%, respectively, and at the 0-40 cm depth reduced soil compactness by 17.62, 23.63 and 36.42%, respectively, as compared to CT25. ST40 reduced soil compactness in the 0-40 cm soil layer under conditions of relative drought (during the maize season growing season of 2016), ST35 and ST40 increased macroaggregates (> 0.25 mm), improved the stability of the aggregate structure (geometric mean diameter and mean weight diameter) (20-40 cm), increased soil water storage capacity at 40-60 cm and increased maize yield by 7.89% and 8.91%, respectively. Considering the improvement of soil properties and crop yield, ST35 was the optimum method to increase maize yield and modulate soil physical properties in the North China Plain.