If an invasive plant that can live in nutrient-poor soil colonizes an abandoned field, and later, after the invasive species is cleared, the soil is found to have an abundance of nitrogen compounds, the best conclusion is: The invasive plant likely increased the nitrogen content of the soil.
Explanation:
- Many invasive plants that thrive in nutrient-poor soils are often nitrogen-fixing species (such as certain legumes or plants with symbiotic bacteria in their roots).
- These plants can convert atmospheric nitrogen into forms usable by plants, enriching the soil with nitrogen compounds.
- Over time, this process improves soil fertility, increasing nitrogen availability even after the invasive species is removed.
Summary:
The invasive plant probably enhanced soil nitrogen through nitrogen fixation or other nutrient-accumulating mechanisms, leading to improved soil fertility in the abandoned field.
