Placement of Banded Liquid Fertilizer Affects Corn Rooting Patterns.

Banding liquid fertilizer is allows crop plants to make more efficient use of nutrients.  This is particularly true in the case of less soluble and less mobile nutrients such as phosphorus and potassium.  Plant roots have been shown to respond physiologically to chemical gradients in soil.  Root growth toward a concentrated zone of nutrients allows for less energy to be expended by the whole plant by reducing the need to explore a large volume of soil.  However, when nutrients are placed too near the surface, periods of drought may result in limited nutrient availability due to increases in energy required to extract solution from the soil.  Crop plants must shift energy to producing more root mass to explore deeper portions of the soil volume for nutrients and water.  By placing banded liquid fertilizer more deeply, it is possible that root growth may be stimulated to concentrate near the banded zone where both water and nutrients are more likely to be available during periods of water stress.  Thus, the plant may conserve energy required for stress response mechanisms other than root growth.  This study examines the response of corn rooting patterns, nutrient uptake, stress, and yield to the placement of liquid fertilizer at three depths.