03067naa a2200193 a 450000100080000000500110000800800410001910000200006024501160008026000090019630000140020550000480021952024250026770000150269270000180270770000190272570000210274477301080276514696532008-03-19       2006    bl uuuu     u00u1 u    #d1 aPICCININ, J. L.  aCrop yield and physical attributes of a clayey oxisol under diferent soil management systems and crop rotation.  c2006  c1 CD-ROM.  aNome correto do quarto autor SARAIVA, O. F.  aTillage and plant species that compose the soil management and crop rotation systems have a pronounced effect on soil physical quality, especially on aggregate stability and soil bulk density. This study aimed to evaluate the degree of aggregate stability in water, bulk density, soil porous space (total, macro e micro porosity) under cultivated no-tillage with chiseling every three years and disk plowing plus harrow disking soil management. Two crop systems were evaluated in each tillage system, with wheat/soybean succession and crop rotation systems, including soybean and/or maize in the summer, and wheat as crop, black oat and/or white lupins as green-manure, in the winter; soil samples under natural vegetation were taken as reference. The field experiment was was carried out from 1999/2000 to 2003/2004 at Embrapa Soybean Research Center in Londrina (Paraná State), Brazil in a Red Latosol (Rhodic Ferralsol). Soil sample were taken at 0-10; 10-20; 20-30 and 30-40 cm depth layer, during each crop flowering season. Compared to the native forest, areas under crop cultivation had soil physical properties degraded, mainly under disk plowing plus harrow disking. Soil ploughing reduced the aggregate stability and organic carbon concentration under with wheat/soybean crop succession. In the four studied depth layers the soil bulk density and micro porosity was higher under treatments with less soil mobilization (no-tillage with chiseling every three years under two crop succession), while the total porosity and macro porosity showed an opposite behavior. The crop rotation systems under no-tillage showed constant values for aggregate stability, bulk density values, total porosity and macro porosity during three consecutive years, indicating no soil compaction tendency over time. The soybean and corn yields did not differ significantly between the management systems, demonstrating that for these crops the soil structure did not affect the yield. Wheat was sensitive to the structural conditions of the soil since the management systems under disk plowing plus harrow disking, this treatment provided more appropriate conditions. The results evidenced no need to mobilize the soil each year or every three years in the areas operated under no tillage systems. The use of crop rotation systems improved the soil physical quality of clayey hapludox, especially due to the increment organic carbon.1 aTORRES, E.1 aZOTARELLI, L.1 aSARANVA, O. F.1 aESPINDOLA, C. R.  tIn: WORLD CONGRESS OF SOIL SCIENCE, 18., 2006, Philadelphia. Abstracts... Madison: ASA-CSSA-SSSA, 2006.