Mechanical and Biological Soil Decompaction for No-Tillage Maize Production

Soil structural quality in areas under a no-tillage system is altered after successive crops, where compaction is a recurrent problem. The objective of this study was to evaluate the effect of different forms of soil decompaction on maize grain production. A randomized split-plot block design with four replications was used, in a 5 x 3 x 2 factorial arrangement, consisting of five forms of mechanical soil decompaction: ripping to a depth of 0.3 m, ripping to a depth of 0.5 m, subsoiling to a depth of 0.3 m, and subsoiling to a depth of 0.5 m, and no-tillage; three crop seasons: 2014/2015, 2015/2016, and 2016/2017; and two cover crops: sunn hemp and pearl millet. The soil resistance to root penetration (RP, 0.0-0.40 m), density (0.0-0.40 m), moisture (0.0-0.40 m), fresh (FB), and dry (DB) above-ground biomass of cover crops, and maize yield were evaluated. The subsoiling to a depth of 0.3 or 0.5 m results in higher production of sunn hemp biomass but has no effect on millet. Mechanical and biological soil decompaction improved maize grain yield throughout the seasons by at least 28% above the average yield in the study area region. The RP of up to 3.3 MPa did not negatively affect cover crop biomass production and maize grain. The association between the mechanical and biological decompaction method using cover crops provided greater resilience to the preparation carried out up to three years after the application of the treatments, resulting in greater corn grain productivity.