Biological Nitrification Inhibition in Urochloa Genotypes and Implications for Biomass Production and Nitrogen Uptake

The identification of forage species with Biological Nitrification Inhibition (BNI) capacity is a promising strategy to inhibit soil nitrification and reduce nitrogen (N) losses. This study evaluated the BNI capacity of five Urochloa genotypes (Camello, Cayman, Marandú, Mulato II, Talismán) and their impact on biomass yield and nitrogen uptake (NU). The BNI capacity, biomass yield, N content, and NU of five Urochloa genotypes were compared. Significant differences in BNI capacity were observed between genotypes (p < 0.009). Cayman and Marandú presented the highest BNI values (87.41 and 87.21%, respectively), higher than those of Mulato II, Talismán and Camello (78.20, 81.77 and 82.63%, respectively). Regarding biomass yield, Cayman and Marandú stood out with 3093.5 and 2911.7 kg DM ha−1, respectively. Talismán and Camello showed higher N concentrations in the biomass (1.64 and 1.63%). In terms of NU, Cayman recorded the highest efficiency (47.32 kg N ha−1), surpassing Marandú, Camello, Talisman and Mulato II (42.83, 42.77, 41.53 and 37.23 kg N ha−1, respectively; p < 0.0001). BNI capacity influences biomass yield and nitrogen uptake. The Cayman genotype is positioned as a promising forage alternative for the development of more efficient and sustainable livestock systems by promoting more efficient N use.