TILLAGE MACHINERY AND COMPACTION LEVEL INFLUENCE ON SOIL PHYSICAL PROPERTIES AND CORN AGRONOMIC ASPECTS

Soil tillage and increased traffic in farming areas have contributed to a higher soil compaction and decreased crop yields. Thus, we aimed at assessing the influence of tillage implement types and compaction levels on physical properties of a Yellow Argisol (Ultisol) and further effects on corn agronomic traits. The treatments consisted of three tillage implements (IP1 = disc harrow, IP2 = moldboard plow and IP3 = chisel plow) and four levels of compaction (NC0 = no traffic soil; NC3 = 3 passes; NC6 = 6 passes and NC9 = 9 passes by a tractor). We evaluated the following soil properties: soil bulk density, total porosity and mechanical resistance to penetration at the depth ranges of 0.00-0.10; 0.10-0.20; 0.20-0.30 and 0.30-0.40 m. Regarding the corn plants, we assessed plant and root dry matter as well as grain yield. The results showed that tillage implements had influence on soil density and total porosity at the layer of 0.00-0.10 m. Furthermore, the compaction levels increased soil mechanical resistance to penetration at a depth of 0.30 m. We also observed that an increase above 1.53 MPa in soil resistance to penetration reduced linearly plant dry matter and grain yield; and when it was above 2.18 MPa, root dry matter was reduced too.