Certified Crop Advisor Practice Exam

Which factor is most likely to decrease germination percentage?

1. Excess moisture

2. Damp soil

3. Dry soil

4. Warm temperatures

The correct answer is: Dry soil

Dry soil is likely to significantly decrease germination percentage because seeds require a certain amount of moisture to activate metabolic processes necessary for germination. When soil moisture is insufficient, seeds can become desiccated, leading to poor or failed germination. Seeds absorb water through their seed coat, which initiates the germination process, allowing enzymes to activate and the seed embryo to begin growth. In contrast, excess moisture or damp soil can lead to other negative conditions, such as seed rot or fungal diseases, but they generally provide the moisture needed for germination to occur. Warm temperatures can actually enhance germination rates for many species by improving enzyme activity and cellular metabolism, provided that other conditions, like moisture, are also favorable. Therefore, the lack of moisture in dry soil is the primary factor that adversely affects germination rates.