Wheat and Barley Response to Pre-plant Phosphorus at Safford Agriculural Center, 1999

The economic effect of applying phosphorus at planting of durum wheat is directly correlated to the phosphorus that is available to the plants from the soil. In 1998 a study was done on a field with a bicarbonate soluble phosphorus level of 4.8 ppm, an a sizeable return on the phosphorous fertilizer investment was seen. In 1999 the test field had a phosphorous level of 13.0 ppm and as the University guidelines indicated, returns on phosphoroud expenditures were small. Negative returns were seen with barley and an increase of $61/ac was seen with 400 pounds of 16-20-0 on wheat.