In fact, decomposition may continue at the highest rates through the winter under the snow in the litter. In systems where moisture becomes limiting in the summer, activity may reach levels even lower than in frozen soil or litter in the winter. When temperatures remains warm enough in the fall, before temperature becomes too low, and rain begins again after the summer drought, such as in Mediterranean climates, a second peak may be observed in the fall. If these peaks are not observed, this suggests inadequate organic matter in the soil. Numbers of total bacteria Just as fungi are the important players in retaining nutrients in forest soil, bacteria are the important players in agricultural and grassland soils.
Bacteria retain nutrients first in their biomass, and second, in their metabolic by-products.
Numbers of total bacteria generally remain the same regardless of soil type or vegetation. Total bacterial numbers range between 10 million and 100 million per gram soil. Bacterial numbers can drop below 1 million in semi-arid agricultural soils. Bacterial numbers can be above 100 million in decomposing logs, in anaerobic soils, and in soil amended with sewage sludge or with high amounts of composted material. In some instances following pesticide treatment, bacterial numbers can fall to extremely low levels, below 100,000 per gram of soil.