Dynamics of Soil Organic Matter and Corn Residues Affected by Tillage Practices

摘要: This study was conducted to determine the influence of tillage practices on decomposition corn (Zea mays L.) residues and turnover soil organic matter (SOM). Measurements delta 13C were made whole soil, microbial biomass, two particle-size fractions ( 50 micrometers) in soils that had been under production for 11 yr from an adjacent meadow. Meadow-derived C total SOM (0-24 cm) decreased cropping at same rate all treatments. Corn-derived evenly distributed with depth moldboard plow treatment accumulated surface shallow, reduced-tillage The incorporation residue into 0- 24-cm layer not significantly affected by estimated be approximately 41 g m-2 yr-1, which represents 30% inputs. Both macroorganic (> biomass a greater enrichment (up 35%) corn-derived than either or microorganic (< micrometers), indicating these pools are important recipients plant Nevertheless, also significant sink input, accounting = 50% remaining (0-8 soil. Under conditions this study, influenced vertical distribution but no detectable effect fate when Ap horizon considered.