This tells us that factors other than fertilizer have an effect on yield. Pollination, moisture and winter injury affect yield. Fertilizer Rates Be sure to have good weed management if you use fertilizer. Use MAP if plants have extra growth or have winter injury. T he form of N provided should be ammonium nitrogen not nitrate nitrogen.
Every field is different.
Keep records of leaf P and N values, fertilizer rates and yields to help you track when production is leveling off or declining. Leave an untreated strip in your field to compare to fertilized areas. David E. Yarborough, Extension Blueberry Specialist and John M. Smagula, Professor of Horticulture, University of Maine, Orono, ME 04469. Homepage For more information, contact your University of Maine Cooperative Extension county office . This information is provided purely for educational purposes.