Nutrient Losses In Surface Runoff From Claypan Soil Receiving Turkey Litter and Fertilizer.

Runoff losses of nutrients and sediment pose significant threats to surface water quality.  Little information is available on relative losses of nutrients from animal wastes as compared to commercial fertilizers, especially for claypan soils in southeastern Kansas.  The objectives of this study were: i) to compare surface runoff losses of nutrients and sediment from turkey litter manure and fertilizer and ii) to determine the influence of tillage on nutrient and sediment losses in surface runoff from the use of turkey litter.  The experiment was conducted from 2005 through spring 2008 near Girard, KS.  The soil was a Parsons silt loam overlying a claypan B horizon.  The treatments were: 1) control – no fertilizer or turkey litter applied, 2) fertilizer – only commercial fertilizer to supply N and P with no turkey litter, 3) turkey litter (N based) – turkey litter applications to supply all N [that also provides excess P], 4) turkey litter (P based) – turkey litter applications to supply all P with supplemental fertilizer N, and 5) turkey litter (P based) – same as treatment #4 but with incorporation of litter and fertilizer.  Treatments 1 through 4 were planted with no tillage, but treatment #5 was planted after chisel and disk incorporation of the litter and fertilizer.  A high litter rate (treatment #3) resulted in high flow-weighted concentrations of N and P in runoff, and also resulted in carry-over P losses.  N losses were inorganic and organic, whereas P losses were mainly the soluble, ortho-P form.  Incorporation appeared to reduce nutrient losses in runoff, but was not always significant.  A high litter rate built up soil P levels, and annual P runoff losses appeared to accelerate when soil P values exceeded 30 mg/kg in a 0-15 cm sample.