Managing Soil Biota-Mediated Decomposition and Nutrient Mineralization in Sustainable Agroecosystems

Figure 4

Ammonia oxidizers absorb from soil pore water and convert it to hydroxylamine and nitrite. Ammonia oxidizers release nitrate into soil pore water, where it is then absorbed by nitrifiers, who convert it to nitrate. Once released into soil pore water, nitrate can undergo other transformations (e.g., immobilization, plant uptake, leaching, and denitrification). Top image: transmission electron micrograph of Nitrosococcus oceani ATCC 19707 (Klotz et al. [18], copyright American Society of Microbiology). Bottom image: transmission electron micrograph of Nitrobacter winogradskyi Nb-255 (Starkenburg et al. [19], image by W. J. Hickey, University of Wisconsin-Madison).