For each 1% of organic matter in the soil, how many pounds of nitrogen per acre may be available for wheat or small grain use?

The correct answer is based on the understanding of how organic matter in the soil contributes to nitrogen availability for crops such as wheat and small grains. Organic matter is a crucial component of soil health, playing a significant role in nutrient cycling, particularly nitrogen.

For each 1% increase in organic matter, it is estimated that between 8 to 12 pounds of nitrogen per acre can be mineralized and made available for plant uptake. This mineralization process occurs as soil microorganisms break down organic materials, releasing nitrogen in a form that plants can use. This figure reflects the typical contributions from organic matter under ideal conditions for soil biology and fertility.

The ranges mentioned in the answer options highlight the variability in nitrogen availability due to factors such as soil type, climate, and the specific conditions of the agricultural system in question. Understanding this relationship helps agronomists and farmers optimize their nitrogen management practices, aligning fertilizer application with the nitrogen provided naturally by the soil.