Inter-microbial competition for N and plant NO3− uptake rather than BNI determines soil net nitrification under intensively managed Brachiaria humidicola

Abstract Brachiaria humidicola (syn. Urochloa ) has been acknowledged to control soil nitrification through release of inhibitors (NI), a phenomenon conceptualized as biological inhibition (BNI). Liming and N fertilization features agricultural intensification may suppress BNI performance, due decrease in NI exudation, increased NH 3 availability promotion ammonia oxidizing bacteria (AOB) over archaea (AOA). A 2-year three-factorial pot trial was conducted investigate the influence pH microbial background (ratio bacteria) on performance B. . The study verified capacity reduce net rates by 50 85% compared non-planted control, irrespective background. reduction nitrification, however, largely dependent immobilization efficient plant uptake. gross could not be confirmed for AOA dominated soil, but possibly contributed reduced AOB-dominated soil. However, this putative attributed plant-facilitated inter-microbial competition between bacterial heterotrophs nitrifiers rather than BNI. It concluded that play dominant role extensive pasture systems, while uptake display factors controlling under intensively managed