Nitrification Slows Sharply Below Soil pH 5.5 and in Cold Soil

… more less Nitrifiers work fastest at about pH 6.5–8 and 25–30 °C; below roughly pH 5.5 and below about 10 °C they slow sharply, and near 5 °C nearly stop, so ammonium from manure spread on a cold, acid bed in March stays ammonium for weeks.