Deep tillage in the no-till system: Effects on the biological condition of the soil.

The no-tillage system offers the advantages of greater stability and biological diversity, although it may generate soil compaction. This mechanical restriction can be solved with deep tillage, which is able to generate loosening that preserves the superficial covertures. The biological condition of soil is very sensitive to disturbances resulting from tillage. The objective of this study was therefore to evaluate changes in the biological condition of soil that are caused by the use of paratill under no-tillage lots. The experiments were conducted using corn crops in Zavalla, Argentina (60 degrees 53'W and 33 degrees 01'S), in a vertic Argiudoll. The treatments included no-tillage and no-tillage with paratill. The following parameters were assessed: soil organic carbon, nitrates, sulfates and phosphorous: biomass and microbial respiration activity: meso- and macrofauna root Channels; sites with fungi and decomposed organic matter krotovinas and root system depth at the five-leaf stage of cultivation; and aerial and root dry matter. The data were processed by uni- and multivariate analysis. The decompaction generated by paratill was found to impact the soil's biological condition under no-tillage. Paratill promoted the development of root systems without significantly impacting the biomass of the corn. In addition, it created an edaphic environment that conditioned those processes that regulate the microbial population. Moreover, paratill stimulated the dynamics of the organic matter without modifying the fauna of the soil, which settled down during the period of implementation of the no-tillage system. The multivariate methods Were sufficient to integrate the various attributes of the system.