Soybeans, Corn and Phosphorus

By James Hoorman, Hoorman Soil Health Services

Soybeans and corn require a steady supply of phosphorus (P) for early seedling vigor, root development and stalk growth. The nutrient is a key component of cell membranes, serves as the backbone of DNA and RNA, and plays a critical role in energy transfer through ATP. Although P is required in smaller amounts than some other nutrients, it is considered one of the three primary crop nutrients, along with nitrogen and potassium, because of its significant impact on yield. Recommended soil test levels for corn and soybeans range from 20 to 40 parts per million using the Mehlich test.

Soybeans require only about 1 lb. of P during the first 30 days of growth, compared with roughly 15 lb. for wheat. However, demand increases substantially later in the season as plants support energy transfer, root development and pod set. At harvest, approximately 70% to 80% of the plant’s accumulated P ends up in the grain, leading to high nutrient removal rates.… Continue reading