Runoff from agricultural land results in reduced availability of water for crop growth and delivery of nutrients to surface waters. Available soil phosphorus (P) in the surface layer can reach extremely high levels, especially with manure application, which adds to the potential of P delivery to surface waters in runoff. Occasional tillage for improvement of no-till systems is proposed as a single, one-time tillage conducted once in 12 or more years intended to invert the surface layer with less improved deeper soil. We hypothesize that occasional tillage will result in decreased P loads in runoff water, even though water infiltration of tilled soils may decrease due to macro-pore disruption. The objective is to measure and collect runoff under a simulated rainfall, and compare P loads from manured vs. non-manured treatments and contrasting tillage options. Two experiments in long-term NT fields were installed under rainfed corn or sorghum rotated with soybeans in Eastern Nebraska. Tillage treatments were done in spring or fall and include: continuous no-till, tandem disk, 10-cm wide twisted shank-chisel, moldboard plow and mini-moldboard plow. Subplots were applied with 200 kg phosphate per hectare (as composted feedlot manure) previous to tillage to examine how occasional tillage could help when applying such high P rates. A Cornell Sprinkle Infiltrometer was used to simulate a 15-min rainfall event with a recurrence period of 50 years. Runoff collected during the first 15 minutes was analyzed for total and dissolved P fractions. Rainfall was continued at the same intensity, until runoff rate became steady. Measurements allow for estimation of Sorptivity (S) and field-saturated infiltrability (I_fs), which are used to describe the effects of treatments on soil hydraulic properties, and to explain the differences in runoff P loads.