Interaction of Planting Date and Fall Fertilization on Winter Barley Performance 1

Winter survival is a major limiting factor for winter barley ( Hordeum vulgare L.) production in northern areas of the U.S. This field study was conducted on a Honeoye‐Lima silt loam soil (Glossoboric Hapludalf, fine loamy, mesic) to determine the effects of planting date and fall fertilization on winter survival and crop performance in the northeastern U.S. In 1975, ‘Schuyler’ barley was planted in central New York on 8 dates ranging from 21 August to 24 October. In 1976, five plantings of ‘Jefferson’ barley were made from 31 August to 14 October. On each date, treatments of 0 N and 0 P, 22 kg/ha N and 0 P, 0 N and 20 kg/ha P, and 22 kg/ha N and 20 kg/ha P were band‐applied to the soil at planting. A uniform application of 75 kg/ha K was disked into the seedbed prior to planting. At harvest, measurements were taken for grain yield, plant height, grain moisture, test weight, and components of grain yield. Grain yields were highest from early to mid‐September plantings. Winterkilling increased greatly and yields declined as planting was delayed into October. Phosphorus was necessary for best winter survival and highest grain yields. An increase in number of spikes per area was the major reason for increased yield with both P fertilization and proper planting time. Timely planting and P fertilization also increased grain test weight and hastened plant development and grain maturation. Significant interactions between planting date and fertilization were measured for grain yield, test weight, grain moisture, and spikes/m 2 ; as planting date was delayed the need for P fertilization became greater. Nitrogen alone had no effect on barley performance when compared to no fertilizer, and N plus P produced results similar to P alone.