What is the primary factor that should lead to reduced fertilization?

The primary factor that should lead to reduced fertilization is high soil nutrient levels. When soil already has elevated nutrient levels, additional fertilization may not be necessary or beneficial. Over-fertilizing can lead to nutrient runoff, water quality issues, and potential damage to plants due to nutrient toxicity. In contrast, reduced rainfall or drought primarily affects water availability for plants rather than directly influencing the need for fertilization. High temperatures can impact plant growth and water uptake but do not inherently necessitate a reduction in fertilizer application. Pest infestations can damage plants and reduce their ability to uptake nutrients but again are not directly linked to the need for altering fertilization practices. Therefore, the presence of high soil nutrient levels stands as the clear deciding factor warranting reduced fertilization efforts.