Which nutrient is used in large quantities by turfgrass and may be lost through leaching?

• A. Nitrogen
• B. Phosphorus
• C. Potassium
• D. Iron

Answer: (A)

Nitrogen is the nutrient turfgrass uses in the largest quantities, supporting rapid vegetative growth, lush color, and plenty of proteins and enzymes. Because turfgrass needs a lot of nitrogen, it must be replenished frequently, and its form in soil is highly soluble (especially as nitrate). This makes nitrogen prone to moving with water through the soil profile and out of the root zone, a process called leaching. Leaching is more likely with heavy rainfall or irrigation, especially in porous or sandy soils, and can lead to wasted fertilizer and potential water pollution.

Phosphorus tends to bind to soil particles and moves slowly, so it’s less prone to leaching. Potassium is somewhat mobile but not to the same extent as nitrate, and iron is needed in much smaller amounts and doesn’t leach as readily.