Which of the following is a sign of soil compaction that affects irrigation efficiency?

Soil compaction can significantly impact irrigation efficiency, and reduced water infiltration is a critical sign of it. When soil particles are compacted, they become densely packed, leading to a decrease in pore space within the soil structure. This reduced pore space limits the ability of water to move through the soil, creating a barrier for water infiltration. Consequently, water that is applied through irrigation may pool on the surface or run off rather than being absorbed efficiently by the soil.

In contrast, increased water retention, enhanced root growth, and improved drainage do not occur under compacted conditions. In fact, good drainage is hindered by compaction, as the soil structure becomes less capable of allowing excess water to drain away. Similarly, enhanced root growth is impeded because compacted soil restricts root expansion and access to water and nutrients. Therefore, the identification of reduced water infiltration as a sign of soil compaction is essential for maintaining effective irrigation practices.