Long – Term Tillage and Manure Effect on Soil Physical and Chemical Properties and Carbon and Nitrogen Mineralization Potentials

The objective of this work was to study the effects of tillage and liquid manureapplications on some physical and chemical properties as well as on the carbon and nitrogenmineralization potential of a meadow soil. Our results indicated that tillage and manureapplications had no effect on the concentration of Cu, Mn, total N and organic C in 0-15 cmlayer of soil after 15 years of treatment. However soil P, Ca, Mg and Zn contents significantlyincreased with manure applications. Soil organic matter and total N significantly decreased in a15-30 cm depth. No significant change was detected in soil structural stability in any of thelayers. Moreover, tillage affected soil soluble C and the C/N ratio significantly. Application of100 t ha-1 manure significantly increased soil soluble C. The results of this study suggest thattillage increased the soil N mineralization rate significantly. The potentially mineralizablenitrogen (N0) was higher in tilled than in no-tilled soil and was at its maximum in the 0-15 cmlayer. Furthermore, a significant positive interaction was observed between tillage and manureapplication on mineralized N after 1.4 wk (Ne). No significant change was detected in Cmineralization rate (Cm) and potentially mineralizable C (C0). The total amounts ofmineralizable carbon (Cm) and nitrogen (Nm) significantly decreased in 15-30 cm depth andwere very closely correlated with the total amounts of C or N and mineralization rate constants(K).