N and P Fertilization of Bromegrass in the Dark Brown Soil Zone of Saskatchewan

Abstract

UKRAINETZ, H. aNo CarvrpnlLL, C. A. 1988. N and P fertilization of bromegrass in the Dark Brown soil zone of Saskatchewan. Can J. Plant Sci. 68: 457-470. A 5-yr study was conducted on a Dark Brown Ioam at Scott, Saskatchewan to determine the effect of rate of ammonium nitrate-N (34-0-0) and urea-N (46-0-0) on bromegrass (Bromus inermis Leyss.) production and quality, N recovery and N use efficiency when the N was applied either annually or as a single application at the start of the experiment. The effect of phosphorus (P) on the above listed parameters was also assessed. Each N source was applied at once-only rates of 0, 100, 200, 400, and 800 kg ha-t and annual rates were 0, 50, 100 and 200 kg ha-r. Phosphorus was applied in 1976, 1979 and 1981 at 100 kg ha-r P2O5. Forage dry matter was positively related to precipitation received in April-June (r:0.91**) and in April of the crop year plus the previous September (r:0.80**). Dry matter response to N rates generally increased at a decreasing rate in early years but linearly in later years. Over the first 4 yr, annual applications of N resulted in up to 31% more dry matter than the single applications. Dry matter production was generally greater when ammonium nitrate was applied than when urea was used; these differences were more consistent at medium N rates-Dry matter was increased by P only when N was applied. Nitrogen concentration in forage was directly related to N rate in years ofgood precipitation, was greater in dry than wet years, and when N was applied annually, but was unaffected by N source. Phosphorus fertilization increased P concentration of forage but heavy dry matter production reduced P concentration. Annual N applications increased P concentration in forage only in the first year and N source had no effect. Toxic concentrations of NO3-N in the forage occurred in the first year only at N rates > 200 kg ha-r and were directly related to the amount of N applied. Except for the 800 kg ha I N rate in the second year, there were no further indications of NO3-N toxicity. Accumulated N use efficiency decreased linearly with increasing N rate and was greater for ammonium nitrate than for urea except at very high N rates. Accumulated N recovery was inversely related to N rate for the single method of application but unaffected by N rate applied annually. Over the first 4 yr, accumulated N recovery was greater for the single application at low N rates, but was greater for annual applications of N at high N rates. P fertilization increased N recovery.

The Economics of Fertilizing Bromegrass in Saskatchewan

“…In general, N fertilization of bromegrass was highly profitable for most economic situations, except at the higher rates of N application when forage prices were low and fertilizer costs high. Fufiher, NPV was generally higher when N was applied as ammonium nitrate as opposed to urea, reflecting the greater loss ofurea-N by volatilization (Ukrainetz and Campbell 1988). This concurs with the findings of an earlier study at Scott (Campbell et al 1986 (1977)(1978)(1979)(1980)(1981)(1982)(1983)(1984)(1985).…”

“…3). These results parallel the 4-yr total dry matter yield increases over check reported by Ukrainetz and Campbell (1988). The additional economic benefit from annual compared to single N applications at the two higher N rates averaged $1ll and $196 ha-I at forage prices of $0.05 and $0.09 kg-r, respectively, and $79 ha-I when price was adjusted for forage nu- [1977][1978][1979][1980] and 8 yr (1977)(1978)(1979)(1980)(1981)(1982)(1983)(1984) at Loon Lake for base fertilizer costs.…”

Effect of crop rotations and cultural practices on soil organic matter, microbial biomass and respiration in a thin Black Chernozem

“…(h) Assumed %N in bromegrass roots = I.l0% each year based on average of Scott and Loon Lake data of Ukrainetz et al (1988) Ukrainetz and Campbell (1988);and Campbell et al (1977a (Campbell et al l99la) as an index of soil organic matter quality.…”

Harvest management and N-fertilization effects on yield and regrowth of smooth bromegrass, crested wheatgrass, and meadow bromegrass in the eastern prairies

“…a-< Different letters denote signihcant differences (P < 0.05) between species using tukey's multiple comparison test. (Table l) (Malhi et al 1986(Malhi et al ,1993Penney et al 1990) and on Graywooded soils in Saskatchewan (Ukrainetz et al 1988) A harvest management x N-rate interaction occurred on the sandy loam soil in 1993 (Fig. 2) A species x harvest management x N-rate interaction occurred on the clay loam soil in 1992 and on the sandy loam soil in 1993 (Fig.…”