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A field incubation technique with acetylene to inhibit nitrification was used to estimate net N mineralization rates in some grassland soils through an annual cycle. Measurements were made on previously long-term grazed pastures on a silty clay loam soil in S.W. England which had background managements of +/-drainage and +/-fertilizer (200 kg N ha-1 yr-1). The effect of fertilizer addition on mineralization during the year of measurement was also determined. Small plots with animals excluded, and with herbage clipped and removed were used as treatment areas and measurements were made using an incubation period of 7 days at intervals of 7 or 14 days through the year. Soil temperature, moisture and mineral N contents were also determined. Mineralization rates fluctuated considerably in each treatment. Maximum daily rates ranged from 1.01 to 3.19 kg N ha-~, and there was substantial net release of N through the winter period (representing, on average, 27% of the annual release). Changes in temperature accounted for 35% of the variability but there was little significant effect of soil moisture. Annual net release of N ranged from 135 kg ha-1 (undrained soil, no previous or current fertilizer) to 376 (drained soil, + 200 kg N ha-1 yr-1 previous and current fertilizer addition). Addition of fertilizer N to a previously unfertilized sward significantly increased the net release of N but there was no immediate effect of withholding fertilizer on mineralization during the year in which measurements were made.

There is increasing use of barley (Hordeum vulgare L.) forage for swath grazing, bale grazing and silage for back grounding and finishing beef cattle in western Canada. Twelve barley varieties (6 two row and 6 six row) were compared in field trials in the Peace Region of Alberta, from 2009 to 2011, to identify the varieties with superior forage yield and nutritive value. Forage yield dry matter (DM) yield was greatest for Busby, followed by Ponoka, CDC Cowboy, Seebe, CDC Austenson, Vivar, Chigwell, Sundre, Xena, Trochu, AC Lacombe, and AC Ranger. Eight varieties had > 8.0 t ha -1 DM yield, five of which belonged to the two-row barley. The crude protein (CP) content varied from 8.70% for Busby to 10.4% for Seebe. Based on high CP content and low detergent fiber contents, CDC Austenson, Chigwell and Ponoka were the top three varieties. Two of the top three varieties for both forage yield and nutritive value were the two-row type, an indication that the two-row barley type may be better adapted for forage production in this environment. The top rated varieties may therefore be chosen for silage, green feed or swath grazing system in the Peace Region environs.

Seedrow-placed urea minimizes soil disturbance in reduced tillage systems, but it generally decreases emergence at nitrogen (N) rates adequate for optimum crop yield. The objective of this study was to determine the influence of coating urea fertilizer granules with a urease inhibitor or a polymer on the emergence and seed yield of durum wheat (Triticum turgidum L.) and canola (Brassica napus L.) with seedrow-placed urea, and to determine the appropriate rate of Agrotaine coating for seedrow-placement. Protein content and N uptake in wheat seed were also determined. Field experiments were conducted at three locations using durum wheat (Aneroid) and canola (Scott and Swift Current) in Saskatchewan, Canada. The combinations of N rates (28, 56, 84, 112, and 140 kg N ha 21 for durum wheat and 34, 68, 102, and 136 kg N ha 21 for canola) and urea coatings [non-coated urea (NCU)], urea coated with Agrotaine at full rate (Agr1, 5.2 L t 21 ), 2/3 rate (Agr2/3) and 1/3 rate (Agr1/3), and with polymer (Plmr, at 3% by weight) treatments were the main plots. A zero-N check was also included. There were two seed opener types (knife with 1.9 cm wide band and spreader with 7.6 cm wide band) used for the seedrow-placed urea subplots. Agrotaine contained N-(n-butyl)-thiophosphoric triamide (NBPT) urease inhibitor at 25% by weight as active ingredient. With increase in N rate from 28 to 140 kg N ha 21 for wheat, the decline in emergence was greater for NCU (by 59.5 plants m 22 ) than for coated urea treatments (by 23.0 to 29.1 plants m 22 ); the seed yield declined in NCU and Agr1/3 treatments but increased up to 84 or 112 kg N ha 21 in Agr1, Agr2/3 and Plmr treatments. With increasing N rates, the N uptake in wheat seed was not influenced for NCU, slightly increased (by 10.3 kg N ha 21 ) for Agr1/3 and substantially increased (by 31.6 to 34.9 kg N ha 21 ) for Plmr, Agr1 and Agr2/3 treatments. The protein content in wheat seed was increased for all the coated urea treatments up to 140 kg N ha 21 . Compared to the zero-N check, canola emergence with 34 kg N ha 21 declined slightly at Scott (relatively moist area) and substantially at Swift Current (relatively dry area). With an increase in the N rate from 34 to 136 kg N ha 21 , the decline in canola emergence at Scott was much greater with NCU than the coated urea treatments but at Swift Current it was similar for all the urea treatments. With increasing N rate, canola seed yield declined for the NCU treatment at both sites while it increased up to 68 kg N ha 21 for Agr1, Agr2/3 and Agr1/3 at Scott, up to 102 kg N ha 21 for Agr2/3 and Agr1/3 at Swift Current, and up to 136 kg N ha 21 for Plmr at Scott and for Agr1 and Plmr at Swift Current. Both crops responded to higher rates of seedrow-placed N with coated urea compared to NCU. Polymer coating was somewhat more effective than Agrotaine coating at the N rates used in this study. The effectiveness of Agrotaine tended to decline with reduction in coating rate (a trend of Agr1 . Agr2/3 . Agr1/3). The wider spreader opener resulted i...

undulating landscape, yield of wheat was reported to be greater on the upper SL when precipitation was above Successful application of precision agriculture technology requires average and greater on the lower SL when precipitation information on crop response to many factors including fertilization and disease management. Field experiments were conducted on a was below average (Manning et al., 2001c). Reduced hummocky landscape in the northern prairies to determine effects of crop yields on the lower SLs or shallow depressions slope (SL) position, N fertilization, and fungicide (FU) application occur under wet conditions due to water logging, weed on disease incidence, biomass yield, and seed yield, quality, N uptake, infestation, poor root development, and delayed crop and recovery of applied fertilizer N for canola (Brassica napus L.). As maturity (Malo et al., 1974; Colvin et al., 1991; Wibawa N rate was increased, blackleg [Leptosphaeria maculans (Desmaz.) et al., 1993). Ces. & De Not] disease incidence, biomass yield, and seed yield,The potential for N mineralization, immobilization, protein content, N uptake, and percentage green increased while denitrification, and leaching varies because of large difemergence, thousand-seed weight, and seed oil content and recovery ferences in soil moisture availability and the amount of of fertilizer N declined. The response of seed yield to N fertilization organic C across landscape units (Malo and Worcester, Agric. and Agri-Food

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