Tillage effects on seasonal nitrate dynamics, leaching and microbial activity in continuous maize production.

A field study was conducted on a loam typic Udifluvent soil to determine th e effects of tillage on NO3-N dynamics during the growing season, on soil p rofile residual NO3-N, on respiratory activity, on mineralization index on microbial biomass. The four tillage treatments examined were minimum tillag e, shallow tillage, ripper subsoiling and conventional deep tillage. Soil s amples were taken periodically in the third year after the introduction of alternative tillage practices. Results showed that the plot under minimum t illage maintained significantly higher NO3-N amounts both in 0-0.6 m depth. during the growing season and in 1 m depth after the harvest. Moreover, th e minimum tillage showed a higher respiratory activity, mineralization inde x and microbial biomass; therefore, it seems to be an alternative managemen t practice in accordance whit sustainable agricultural policy.