Effect of nitrogen source, rate and time of application on fruit yields of the Micmac strawberry

Rate and source of nitrogen application significantly increased total yields from Micmac strawberry plants, but only in the first of 3 successive cropping seasons. Early harvest yields of marketable and total fruit from control plots were equal to or higher than those from the nitrogen treatments in all seasons, but these differences were not reflected in significant total yield responses in the 2— and 3— cropping seasons. Early season soil NO3‐N and NH4‐N values, in the planting year, reflected nitrogen application but the effect decreased as the season progressed and there was no consistent effect of any subsequent nitrogen treatment on soil or leaf N levels, marketable or total yields. A leaf N range of 1.5–2.0% at full bloom and spring soil NH4‐N, NO3‐N and mineralizable N levels of 4, 10 and 25 ppm, respectively, were adequate for optimum yields.