Identification of nitrification inhibition in soil by maize to mitigate nitrogen losses

Abstract

Under aerobic or anaerobic conditions, oxidation and reduction processes of nitrogen dynamics in the soil produce N2 O emissions. To decrease N2 O emissions and conserve nitrogen (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 cultivars 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 cultivars had a 1.1–1.6 times lower NR than Bh. Low-NR cultivars had higher NI and lower root-to-shoot ratios. NI was positively correlated with total N and shot N content but not with cumulative N2 O 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.