Fig. 4. Effect of spring-applied dairy manure and tillage on dissolved reactive P (DRP) concentration and load in runoff (histograms) and soil test P (line) values (0- to 2-cm depth), September 1999. CP = chisel plow; ST = shallow till; NT = no till. Where P > F is 0.05, mean values followed by the same letter are not significantly different at the 0.05 probability level; NS, not significant.