What does the term "compaction" refer to in the context of soils?

In the context of soils, the term "compaction" refers to the process that leads to the reduction of porosity and drainage in soil. When soil is compacted, the individual particles are pressed closely together, which decreases the spaces (or pores) between them. This results in reduced air and water movement through the soil, negatively affecting root growth and the overall health of plants. Compacted soils can lead to problems such as poor drainage, increased runoff, and difficulty for roots to access nutrients and water.

The other choices do not accurately reflect the meaning of compaction. Increasing soil fertility focuses on enriching the soil with necessary nutrients, while loosening soil particles directly counters the effects of compaction. Enhancing soil texture with organic matter also doesn't relate to compaction; instead, it can help improve soil structure and void spaces, encouraging better porosity and drainage.