What does field capacity indicate about soil?

Field capacity refers to the amount of moisture that soil can retain after excess water has drained away and the rate of downward movement has slowed. At this point, the soil contains enough water for plants to take up while also having sufficient air spaces for root respiration. This balance is crucial for plant health, ensuring that roots have access to both water and oxygen, which are vital for growth.

The other options do not accurately reflect the concept of field capacity. When soil is completely dry, it does not have any available water for plants, which would not be described as field capacity. Saying that the soil can hold excess water implies that it has surpassed its point of field capacity and is waterlogged, which can lead to anaerobic conditions. Finally, indicating that soil's particles are too tightly packed refers to compaction issues, which do not connect to the balance of water and oxygen availability that field capacity describes. Thus, the best understanding of field capacity is that it represents an ideal condition where soil can support plant life effectively.