Impact of tillage practices on seasonal nitrate dynamics, leaching and microbial activity in a crop rotation

Publisher Summary The study discussed in this chapter determines the effect of different tillage practices on nitrate dynamics during the growing season and on residual nitrogen level in the soil over a three year period and measures the changes in the organic carbon content, in same microbial activities, after six years of reduced tillage on a typical crop rotation in a Mediterranean region. A field study was conducted on a loam typic Udifluvent soil to determine the effects of tillage on N–NO 3 − and N–NH 4 dynamics during the growing season, on soil profile residual N–NO 3 − , on organic carbon, on respiratory activity, on mineralization index, and on microbial biomass. Conventional tillage was compared with shallow tillage in a three-year crop rotation. Soil samples were taken periodically for a three-year period for nitrate and ammonium determination and in the sixth year, after the introduction of alternative tillage practices, for organic carbon (OC) and microbial activity. Results showed that the plots under minimum tillage maintained significantly higher N–NO 3 − amounts both in 0–20 and 0–60 cm depth during the growing season. The N–NH 4 content proved not to be influenced by tillage practices. Moreover, the minimum tillage plots showed high respiratory activity, mineralization index, and microbial biomass.