Nitrogen Rate and Application Timing Affect the Yield and Risk Associated with Stockpiling Tall Fescue for Winter Grazing

摘要

Stockpiled tall fescue can provide economical winter feed for grazing livestock in the mid-Atlantic of the United States. The effects of N fertilization rate and application timing on the yield of stockpiled tall fescue were evaluated while considering production risk and economic returns. Four N rates ranging from 0 to 120 lb N/acre were applied in mid-August, mid-September, or one-half in mid-August and one-half in mid-September. Accumulated growth was harvested in mid-December. Yield increased with N fertilization for all seven years of the study. However, the response rate, nature of the response, and optimal timing of N fertilization varied among years and was likely related to rainfall. Regression analysis across years showed that yields fromplots fertilized in August or September had linear responses to N rate compared to a quadratic response for the split application. For the moderate N rates (40 and 80 lb N/acre), splitting the N application increased the probability of reaching predetermined yield goals compared to a single application. There was an economic advantage to splitting N applications of less than 80 lb/acre when hay was valued at more than $60 per ton.