Soil compaction alleviation by deep non-inversion tillage and crop yield responses in no tilled soils of the Pampas region of Argentina. A meta-analysis

Abstract No till is considered part of the good management practices recommended in conservation agriculture. Regardless of the benefits of this practice, shallow compaction or soil hardening by farm machinery traffic can lead to soil constraints to crop growth. Deep non-inversion tillage could be proposed together with other practices to alleviate this soil compaction. In this meta-analysis, we reviewed experimental results (32 field studies) obtained throughout the Pampas Region focused on the immediate effects and duration of soil mechanical alleviation measured by relevant soil physical properties and by the impact on maize and soybean yield. Treatments were classified in: a) Control (no tilled soils), and b) Subsoiled (no tilled soil subjected to mechanical compaction alleviation by deep non-inversion tillage). Data were analyzed by comparing pairs of the same experiment (t-paired test). The response to compaction alleviation (Δ Subsoiled - Control) for different soil variables was related to soil and climate and agricultural history management. Deep non-inversion tillage significantly decreased soil bulk density (0−0.20 m; P