Frequently the adoption of the system of no tillage is associated with the appearance of the compacting or thickness of the ground surface, either by not revolving or by the traffic of machines, trucks and wagons. With the objective of studying the factors that interfere in the compacting of the ground in the no tillage and its effects in the culture of the maize, this experiment was installed, in a Typical Red Distroférrico Latossolo, in the southwestern region of Paraná, Dois Vizinhos County, in the agricultural year of 1999. The surface of the ground was worked to reach four levels of possible compacting: (1) traffic of loaded harvester with weight of 12.000kgf; (2) traffic of an agricultural tractor with weight of 4.000kgf; (3) subsoiling with subsolador of 4 chainses at 0,40m; (4) one parcel out witness. The development of the radicular system in profiles through trenches opened in all the parcels was evaluated, by counting the number of roots and their depth in the profile, comparing to the productivity. In the end, the analyzed data demonstrated that: (1) the treatment which had suffered traffic from the agricultural tractor presented a compacting of the ground shown by lower productivity; (2) the treatments which had not suffered compression of the ground, the case of the subsoil and the witness, presented higher productivity and density of roots, with more homogeneous distribution in the profile of the ground. Thus, one can conclude that the compacting of the ground through the artificial work produced by the agricultural machines in the parcels had negative effects.
Zea mays; compaction; direct plantation; minimum preparation; rot system
