The residual effects of historical broiler litter applications on soybean productivity is currently being evaluated. Between 1997 to 2002, annual broiler litter application treatments were: 0, 2.2, 4.5, 6.7, 9.0, 11.2, 13.4, and 15.7 Mg/ha.� In 2003, the broiler litter application was reduced to a half the above rate. In 2004, no broiler litter applications were made.� Throughout this period,� corn was grown on these plots with only broiler litter applications and no fertilizer.� During the 2005 and 2006 season, soybeans were grown on these historic plots with no further broiler litter applications. In these soybean experiments, extra phosphorus (258 kg/ha of P₂O₅) and potassium (280 kg/ha of K₂O) was applied to the low fertility plots that had received the historical low broiler litter rates (2.2 or 4.5 Mg/ha). In these two years, the soybeans receiving the extra supplemental phosphorus and potassium did not yield as well as the plots with historic high broiler litter rates.� Overall, the soybean yields were significantly higher in the plots with the high historic broiler litter application rates compared with plots that had received lower broiler litter rates.� In 2007, a soybean experiment has been conducted to investigate reasons for this effect. Because of the severe drought during 2007, the experiment was irrigated using drip lines.� At the R6 stage, the total above-ground portion of the plants �within a 0.5-meter of row was harvested and is being analyzed for 13 elements.� Additionally, soil fertility, soil quality, and soybean yields are being measured.