A problem with intensive irrigation is
a. Overfertilization.
b. Aquifer depletion.
c. The long-term depletion of soil oxygen.
d. The clogging of waterways by vegetation debris.

Verified step by step guidance

1. Understand the context of intensive irrigation: Intensive irrigation involves the application of large amounts of water to crops, often to maximize agricultural yield.
2. Consider the potential environmental impacts of intensive irrigation: This practice can lead to various environmental issues, such as waterlogging, salinization, and depletion of water resources.
3. Analyze each option: (A) Overfertilization is related to the excessive use of fertilizers, not directly to irrigation. (B) Aquifer depletion occurs when groundwater is extracted faster than it is replenished, which can be exacerbated by intensive irrigation. (C) Long-term depletion of soil oxygen is more related to waterlogging, which can occur with excessive irrigation. (D) Clogging of waterways by vegetation debris is not a direct consequence of irrigation.
4. Focus on aquifer depletion: Intensive irrigation often relies on groundwater sources, leading to the depletion of aquifers as water is extracted at unsustainable rates.
5. Conclude that aquifer depletion is a significant problem associated with intensive irrigation, as it directly relates to the overuse of water resources.

Key Concepts

Aquifer Depletion

Aquifer depletion occurs when water is extracted from underground aquifers faster than it is replenished. This is a common issue with intensive irrigation, as large volumes of water are needed to sustain crops, leading to a significant drop in groundwater levels. Over time, this can result in reduced water availability for future agricultural and personal use.

Soil Oxygen Depletion

Soil oxygen depletion refers to the reduction of oxygen levels in the soil, which can occur due to excessive water saturation from intensive irrigation. When soil is overly saturated, it limits the air spaces within the soil, reducing oxygen availability for plant roots and soil organisms, potentially leading to poor plant growth and soil health.

Waterway Clogging by Vegetation Debris

Clogging of waterways by vegetation debris can happen when irrigation systems wash plant material into nearby streams and rivers. This debris can accumulate, obstructing water flow and affecting aquatic ecosystems. Proper management and filtration systems are necessary to prevent such blockages and maintain healthy waterways.