Application of manure and straw by deep plough rapidly improves fertility and productivity of brown sandy soil

  Objectives  Ameliorating soil fertility is an effective way to increase crop yields, especially in soils with a coarse sandy loam.

  Methods  We conducted a field experiment in 2018 on the brown soil in southern Liaoning, China, using nine treatments: conventional shallow tillage (0−15 cm, T15) served as the control, and conventional shallow tillage with maize straw return (T15+S), inversion tillage (0−35 cm) without or with straw return (T35 and T35+S), inversion tillage (0−35 cm) with pig manure (T35+M) and pig manure plus maize straw (T35+S+M), no tillage without or with maize straw mulching (NT and NT+S), and no tillage with maize straw ridged-mulching (HT+HS).

  Results  Compared with T15 in the 0−15 cm soil layer, soil organic matter content was increased significantly by 19.2% and 20.4% in T35+M and T35+S+M, while NT and T35 significantly decreased. Soil organic matter content in T35, T35+S, T35+M and T35+S+M was 12.5%, 24.5%, 29.9%, and 35.7% higher than that in T15 in the 15−35 cm soil layer, respectively. In the three experimental years, maize yield showed similar trends among the different treatments, that is, inversion tillage and organic material returning significantly increased maize yield. The average maize yield in T35+S, T35+M and T35+S+M was increased by 10%, 12.3%, and 16.4% in the three experimental years, while the yield in T15+S, NT, NT+S, and HT+HS was decreased compared with T15. The increase in soil organic matter and available nutrient content were the main factors influencing maize yield and contributed significantly to it.

  Conclusions  Inversion tillage with organic materials is a more effective way to improve soil fertility, which could enhance the agricultural productivity of brown soil in the southern part of Liaoning Province.