Passage:
In agricultural science, soil structure plays a vital role in determining crop yields. During periods of heavy, continuous rainfall, non-compacted clay soils absorb excessive moisture, filling the microscopic pore spaces between soil particles. When these pore spaces become completely saturated with water, oxygen is effectively displaced from the root zone. Deprived of oxygen, plant roots are unable to perform cellular respiration, a crucial biological process necessary for absorbing essential nutrient ions like potassium and nitrogen from the surrounding dirt. Consequently, plants growing in waterlogged fields exhibit severe stunting and leaf yellowing, not because the soil lacks mineral nutrients, but because root cell damage directly prevents nutrient uptake. To mitigate this issue, farmers often cultivate cover crops such as deep-rooting radishes during the off-season. As these taproots penetrate dense clay layers and decay, they create stable macro-channels. These channels dramatically increase soil drainage and aeration, thereby ensuring that oxygen remains available to crop roots even during torrential rainstorms.
Based on the passage, what explicitly causes plants in waterlogged soil to stop absorbing essential mineral nutrients?
- The displacement of oxygen from the root zone prevents root cells from performing cellular respiration.Answer
- BThe absorption of nitrogen and potassium displaces oxygen from the microscopic pore spaces between soil particles.
- CThe surrounding clay soil becomes completely depleted of essential mineral nutrients during heavy rainstorms.
- DDeep-rooting cover crops consume the available potassium and nitrogen in the upper soil layers.