Effect of fertilization date and litter removal on grassland forage production

Abstract

The effects of application dates of urea fertilizer and dormant-season removal of litter were examined on a bluebunch wheatgrass (Pseudoroegneria spicatum [Pursh] A. Love subsp. spicata)- Sandberg's bluegrass (Poa sandbergii Vasey) site in southern British Columbia. Forest grade urea, applied at 100 kg N/ha, increased the yield of both spring (53%) and summer (73%) forage compared to the unfertilized control. Spring forage production was not affected by the application date of urea. Summer forage yields, however, were 20% higher when urea was applied on snow-free (October and March) compared to snow-covered ground (November, January, and February). Dormant-season removal of litter reduced spring forage yields by different amounts (P<0.05) in 1984 (29%) and 1981 (25%). Albiet a small difference, this suggests that removal of litter may interact with annual weather conditions and confound measurements of absolute spring herbage yields in a long-term study. In contrast, dormant-season removal of litter reduced summer forage production consistently by 23% in both 1981 and 1984. This technique might therefore be used to reduce clipping time for summer plots in fertilizer trials. If absolute estimates of above ground herbage production are required, control plots should be clipped each year to account for the losses in yields induced by dormant-season removal of litter.