In term of fertilization, what is 'leaching'?

Leaching refers to the process through which nutrients in the soil are dissolved and washed away by water movement, typically due to rainfall or irrigation. This phenomenon occurs when water percolates through the soil, carrying away soluble nutrients such as nitrogen, potassium, and other minerals, which can then be lost from the root zone of plants.

Understanding leaching is crucial for effective nutrient management in agriculture. It highlights the importance of timing and method of fertilization to minimize nutrient loss. High levels of leaching can lead to nutrient deficiencies in crops and can also contribute to environmental problems if those nutrients end up in water bodies, causing issues like eutrophication.

The other choices do not accurately describe leaching. The absorption of nutrients by crops refers to the uptake of essential elements through plant roots and does not involve loss. The runoff of soil into nearby water bodies focuses on soil erosion rather than nutrient loss specific to leaching. The process of nitrogen fixation involves converting atmospheric nitrogen into a usable form for plants and is distinct from the loss of nutrients due to water movement.