M. Nyborg

Soil chemical properties after long‐term n fertilization of bromegrass: Nitrogen rate

Abstract Nitrogen (N) fertilizers increase yield and quality of grass forage, and may also alter soil chemical properties. A field experiment was conducted in south‐central Alberta to determine the effect of long‐term application of ammonium nitrate to bromegrass on concentration and downward mobility of soluble NO3‐N, extractable NH4‐N, P, Ca, Mg, and K, and total C and N in a Thin Black Chernozemic loam soil. The fertilizer was applied annually in early spring for 16 years at 0 to 336 kg N/ha. There was little accumulation of NO3‐N in the soil at N rates of 112 kg/ha or less. However, at rates higher than 112 kg N/ha there was accumulation of NO3‐N in the 15–30 and 30–60 cm layers, but very little in the 90–120 cm depth. The NH4‐N accumulated in the 0–5 cm layer when the fertilizer was applied at rates between 168 to 280 kg N/ha and in the 5–10 cm layer at N rates exceeding 280 kg/ha. There was a decline in extractable P in soil with N application up to 84 kg N/ha rate, while it increased with high N ra...

Dry matter yield and nitrogen recovery from bromegrass in south‐central Alberta as affected by rate of long‐term nitrogen applications

Abstract A field experiment was conducted on a Thin Black Chemozemic soil at Crossfield in south‐central Alberta to determine the effect of long‐term application of ammonium nitrate on dry matter yield (DMY), protein yield (PY), protein concentration, N use efficiency and recovery of N applied to bromegrass (Bromus inermis Leyss.) grown for hay. The N fertilizer was applied at 0, 56, 112, 168, 224, 280, and 336 kg N/ha in early spring of every year from 1968 to 1986. The DMY increased with applied N achieving a maximum at 224 kg N/ha, though the rate of increase in DMY from N fertilization was greatest with the first two increments applied (i.e. 56 and 112 kg N/ha). Protein yield and protein concentration maximized at 336 kg N/ha. The DMY was greater with a single‐cut system than with a double‐cut system. The DMY varied from year to year, but it was not closely related to precipitation received during the April to August period (R2 = 0.37). However, in some years low DMYs were associated with low precipit...

Dry matter yield and n recovery from bromegrass in south‐central alberta as affected by time of application of urea and ammonium nitrate

Abstract Field experiments were conducted for periods of 14 or 15 years at four sites on Thin Black Chernozemic soils in south‐central Alberta to determine the effect of source and time of N application on dry matter yield (DMY), protein yield (PY), protein concentration, N use efficiency and recovery of N applied to bromegrass (Bromus inermis Leyss.) grown for hay. Two sources of N (urea and ammonium nitrate ‐ A.N.) were applied at four times (early fall, late fall, early spring and late spring) at a rate of 112 kg N ha‐1. Urea was generally less effective in increasing DMY, PY, protein concentration, N use efficiency and % N recovery than A.N. The average, DMY, PY, protein concentration, N use efficiency and % N recovery with A.N. were 4.38 t ha‐1, 445 kg ha‐1, 104 g kg‐1, 21.2 kg DM kg‐1 N ha‐1 and 40.2%, respectively. In the same order, the values with urea were 3.90 t ha‐1, 376 kg ha‐1, 99 g kg‐1, 16.9 kg DM kg‐1 N ha‐1 and 30.2%, respectively. The DMY was greatest with early spring application for A...

Yield response of barley and rapeseed to K fertilizer: Influence of soil test K level and method of placement

Abstract Field experiments were conducted in central Alberta to determine the yield response of barley and rapeseed to KCl on soils varying in soil test K levels and to evaluate three methods of K placement for effectiveness. The soil test K extractant was 1M ammonium acetate solution. Placement methods were incorporation, banding with the seed and banding beside the seed row. The percentage of sites that responded to K fertilizer significantly and yield increase of barley from K fertilizer decreased with increasing soil test K in the soil. Rapeseed responded less often to K than barley and K placement was more critical for barley than for rapeseed. Barley yields were greatest when the K fertilizer was banded in the seed row and least when incorporated into the soil. Rapeseed yields on K‐responsive sites were same when the K fertilizer was incorporated or banded beside the seed row, but tended to be greater when banded with the seed.

Downward movement of surface‐applied P on established forage stands

Abstract Field experiments were conducted on Black Chernozem and Gray Luvisol soils in Alberta to determine the downward movement of long‐term applications of surface‐broadcast P fertilizer on established forage grass or alfalfa stands. The majority of fertilizer P recovered in soil as extractable P remained in the top 5 cm layer. The amount and depth of movement of applied P increased with P rate, but little or none was recovered below 15 cm.

Influence of polymer‐coated urea on mineral nitrogen release, nitrification, and barley yield and nitrogen uptake

Abstract Laboratory incubation [with 200 mg nitrogen (N) kg‐1 added to two soils], and field experiments (in 1989–90 and 1990–91 at three sites in central Alberta) were conducted to determine the influence of polymer coating (9 μm—thin coat and 15 μm—thick coat) and method of placement (incorporated into soil to a depth of 10 cm and banded at 10 cm depth) of urea on mineral N release and nitrification over the winter from autumn application, and yield and N uptake of spring‐sown barley (Hordeum vulgare cv. Leduc) from autumn and spring applications. Rate of N application was 127 kg N ha‐1 in 1989–90 and 50 kg N ha‐1 in 1990–91. In the incubation experiments, mineral N release as percent of applied N on the average was 66% with non‐coated urea and 17% with thick‐coated urea at 15 days. At 30 days incubation, release of mineral N was almost complete for non‐coated urea and was only 37% for thick‐coated urea. Autumn‐applied thin‐ and thick‐coated urea released less mineral N and nitrified more slowly over th...

Effect of phosphorus fertilization on bromegrass hay yield

Abstract A field experiment was conducted on a Black Chernosemic silt loam soil at Lacombe in central Alberta to determine the effect of P applications on dry matter yield and concentration of protein and N03‐N of smooth bromegrass (Bromus inermis Leyss.). Treble superphosphate was applied annually for 5 years at 0, 10, 20, 30, 40, and 60 kg P/ha, and once initially at 60, 120, and 180 kg P/ha. The P fertilizer was incorporated into soil before seeding bromegrass for the initial applications, and the subsequent annual applications were spread on the soil surface. The total dry matter yield (TDMY = cut 1 + cut 2) increased with P rate, but the yield response was proportionately greatest at 10 kg P/ha. The P fertilizer did not affect protein or NO3‐N concentration in hay. The residual effect of P on TDMY lasted for at least 5 years.

Compaction of soils: Yield of barley in greenhouse and field

Abstract The objective of this study was to find the effect of artificial compaction on yield of bailey grain on Black Chernozem and Gray Luvisol soils in greenhouse and field experiments. In the greenhouse experiment, the compaction decreased grain and straw yield of barley in the 0 and 50 kg N ha‐1 rates of urea mixed into soil. Under field conditions, there was a reduction of barley yield in 3 of the 8 experiments and an increase of yield in one experiment due to compaction. On the average of 8 field experiments, the yield differences between compacted and noncompacted treatments were 212, 27) and 428 kg ha‐1 for the zero‐N control, 50 and 100 kg N ha‐1, respectively.

Surface‐applied urea on a black chernozemic soil: Hydrolysis, nitrification, and pH change

Abstract Hydrolysis, nitrification and changes in pH were determined in different soil layers of a Black Chemozemic soil (Udic Boroll) fertilized with surface‐applied prilled urea during incubation of soil columns for 16d. The soil columns were cut into 0–5, 5–10, 10–20, 20–30, 30–40, and 40–50 mm depths. Ura at 75 and 150 kg N/ha resulted in high concentration of urea‐N in the top 5‐mm soil layer for the initial 2 to 4d. The accumulation of NH4‐N was greatest at 4d in the top layer. Nitrification of added fertilizer N did not occur until 5d. Soil pH in the 0–5‐mm layer increased from 6.1 to 7.5 or 8.3 at 4d for the 75 and 175 kg N/ha, respectively, and it was directly related to the NH4‐N concentration in soil. The accumulation of urea‐N and subsequent hydrolysis, elevation of soil pH and NO3‐N increases did not extend beyond the 20‐mm depth. The results indicate that even in a Black Chemozemic soil which had acid pH, high organic C and CEC, the surface‐application of urea‐N at recommended rates can subs...

Changes in extractable phosphorus between fall and spring in some alberta soils

Abstract In the Prairie Provinces of Canada, most soil samples for soil test P are taken in fall, although P fertilization and crop sowing normally occur in spring. Our objective was to compare soil test P values for samples taken in fall and spring. Extractable soil P (in 0.03 N NH4F‐0.03 N H2SO4) was measured in fall and spring samples at 49 sites in central Alberta and 4 sites in northern Alberta. Extractable P was less in fall‐ than ‐spring‐sampled soil at most sites. The average difference was 19.8 kg P/ha for the 49 sites in central Alberta and 34.9 kg P/ha for the 4 northern Alberta sites. In 27 of the 49 sites soil samples were taken in early fall, late fall and spring, with extractable P increasing by 21.9 kg P/ha from early fall to spring, but by only 1.1 kg P/ha from late fall to spring. The linear regression equation to predict the spring extractable P (Y) from early fall extractable P (X) was Y = 5.31 + 1.59X with an R2 value of 0.67 and from late fall extractable P (X) was Y = 6.67 + 0.89X w...