Phosphorus (P) is an expensive nutrient but critical for good crop production. Phosphorus is the backbone to the plants genetic code, for ATP (energy transfer/storage) in plants, and for cell division and enlargement. When P is severely limited, plants turn a purple color, which is common on cold wet soils in the spring. However, plants often have a hidden hunger for P which may limit yields. Chad Penn, Research Soil Scientist for USDA from West Lafayette, Indiana at the Ohio No-till conference; shared recent research on corn P nutrition. Available P in soil varies by soil type and weather conditions. Farmers try to optimize P application, but it varies so much, even within a few inches or feet. Even with extensive soil testing and grid soil sampling, P is often either under applied or over applied. The ARS-USDA research is trying to find a way to put on just the right amount of P so that it maximizes yield. Chad discussed the two main sources of soil P. The first fraction is the...