Identification of nitrification inhibition in maize to mitigate soil nitrogen loss

Abstract

Nitrogen dynamics in soil produce N2O emissions. To decrease N2O emissions and conserve N, recent studies have focused on chemicals derived from root exudates that inhibit nitrification. However, selective plant breeding could be used to control nitrification activity in soil instead of fertilisers or synthetic nitrification inhibitors. In this study, we investigated the relationship between nitrification rates (NR) and related N dynamics and plant characteristics for 11 maize varieties with varying levels of nitrification inhibition (NI) compared to Brachicaria humidicola (Bh) as the positive control. In a greenhouse experiment, soil concentrations of NI, NR, NH4+-N, and NO3--N and nitrogen uptake by plants were measured. Six maize varieties had a 1.1-1.6 times lower NR than Bh. Low-NR varieties had higher NI and lower root-to-shoot ratios. NI was positively correlated with total N and shoot N content but not with cumulative N2O and NH4+-NO3-. These results show that maize has the capacity to reduce soil nitrification while increasing the total N in the soil and shoot N content in maize.

Keywords

• nitrification inhibition
• maize
• nitrous oxide
• nitrogen
• n2o emission