Which factor is not typically involved in natural control of plant populations?

Fertilization is not typically involved in the natural control of plant populations. In natural ecosystems, plant population dynamics are influenced by factors that occur without human intervention. Weather patterns can affect growth conditions, such as temperature and precipitation, which in turn impact plant health and competition. Soil nutrients are critical as they determine the availability of essential elements for plant growth and can influence the prevalence or scarcity of various plant species. Natural predators, including herbivores, can keep plant populations in check by consuming them, thus playing a key role in maintaining balance within the ecosystem.

In contrast, fertilization is a human-assisted process that involves adding nutrients to the soil to promote plant growth, usually for agricultural purposes. It alters the natural nutrient balance and can lead to changes in plant dynamics that would not occur under natural conditions. Therefore, it does not fit into the category of factors that operate in the natural control of plant populations.