Nitrogen efficiency of strip-till combined with slurry band injection below the maize seeds

SMN analyses showed an increased proportion (+60%) of ammonium nitrogen (NH4-N) in SMN by addition of NI until 34-40 days after fertilization. Nevertheless, DM yields and N uptakes of STR treatments were not significantly different from CONV treated plots. The largest differences between treatments were observed at the earlier harvest dates compared to main harvest presumably due to the observed high NH4-N concentrations in the slurry band, which are known to positively affect early growth of maize plants and better preservation of soil moisture in the STR system. The addition of NI did not lead to significantly increased DM yields and N uptakes. This was most probably due to negligible nitrate leaching in the early growth stages, i.e. NH4-N stabilization took place but could not display its full potential. The STR treatments (STR and STR + NI) showed the highest N recovery efficiencies (up to 78%) among all treatments indicating the lowest potential N losses of this application system. Significant differences between STR and CONV treatments were found, however, only in 2014 and partially in 2015. Thus it can be assumed that the STR system is beneficial to enhance N efficiency of slurry application but further research is required to prove this.