Wheatgrass Response to Seasonal Applications of Two Nitrogen Sources

Abstract

Highlight: Fall, winter, and spring applications of 20 lb. Nfacre as urea or as ammonium nitrate were applied in each of 3 years to two introduced grasses, crested and Siberian wheatgrasses, on Oregon's high desert range. Mature herbage yield increased with fertilizers, but there were no significant interactions with application date. Urea increased mean yield 3% more than did ammonium nitrate, but the increase may not be of practical significance. Crude protein concentration of mature yields, evaluated in 1 year only, was not influenced by either fertilizer or application time. Fall-and winter-applied N fertilizer increased available soil nitrate concentration in mid-April, but differences due to date and source of N were nil.

Effect of Fertilization Date and Litter Removal on Grassland Forage Production

“…Losses, however, appeared to be greatest on the plots fertilized with ammonium nitrate compared to urea. Our results, however, do not agree with Sneva (1973) who found that forage yields were unaffected when urea was applied to deep snow compared to bare soil on rangeland. Wullstein and Gilmour(1964) attributed losses of N, applied on deep snow, to gaseous processes presumably resulting from the dissociation of urea in the snow to ammonia and the rapid evaporation of the snow to the air.…”

Irrigation and Nitrogen Effects on Tall Wheatgrass Yield in the Southern High Plains

“…1) may be due to the distribution of precipitation within each year. Frank and Bauer (1991) and Sneva (1973) mentioned that forage production by cool‐season grasses in semiarid areas was highly correlated with growing season precipitation and stored pre–growing season soil water supply. The lack of rainfall in May and June 1998 probably contributed to poor production in June of that year compared with June 1997 and 1999 (Table 1).…”

“…Others have observed a benefit from fall‐applied N on early spring yields of established perennial cool‐season grasses (Campbell et al, 1986; Sneva, 1973). Cool‐season turfgrasses also are known to benefit from fall‐applied N through stimulation of root growth, which helps in winter and subsequent summer survival and early spring green‐up (Turgeon, 1991).…”

Time of Application and Source of Nitrogen Fertilizer on Yield, Quality, Nitrogen Recovery, and Net Returns for Dryland Forage Grasses

“…Many other studies have been carried out to compare fall applications to spring applications (Jones 1960;Laughlin 1963;Kresge 1965;Stroehlein et al 1968;Sneva 1973;Power et aI. 1972Power et aI.…”