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Cement kiln dust (CKD), a by-product of the cement industry currently being landfilled, may be a beneficial soil amendment. A 2-yr field forage trial compared the effect of surface applications of CKD and lime on forage yield and the concentration and accumulation of N, P, K, Ca, Mg, Mn, Cu, Zn and B in the forage tissue. Seven soil treatments in three blocks were established on three low pH sites: (1) a check plot with neither lime or CKD added; (2) lime application based on the recommendation from soil analysis; (3) lime at 1.5 times the recommended application; (4) CKD applied at the recommended application; (5) CKD at 1.5 times the recommended application; (6) CKD applied on a neutralizing equivalent basis at the recommended application rate; and (7) CKD on a neutralizing equivalent basis at 1.5 times the recommended lime application; equivalence based on CKD’s apparent neutralizing value at 75% that of lime. In 1998, as tissue concentrations of K, Ca, Cu, and Mn increased with CKD application, the concentrations of N, P and Mg decreased, and in 1999, as the concentrations of Ca, K increased, the concentrations of N, P, Mg Mn, Zn decreased. Lime application increased the concentration of Mg (1998) and Ca and Mg (1999). The concentration of the other nutrients either decreased or were not significantly affected. In1998, forage yield and accumulation of Ca, K, Mn, Cu, Zn and B all increased with CKD addition, whereas the accumulation of Mg increased with lime addition. In 1999, forage yield and accumulation of N, P, K, Ca, Cu, Zn and B in the forage tissue all increased with CKD addition. These results were identified by principal component analysis (PCA). Surface applied CKD increased forage yield to a greater extent than lime. It was also a more readily available source of Ca and K than lime.Key words: Cement kiln dust

Changes in the standing crop of Vaccinium corymbosum shrubs were documented over 10 y at six sites throughout eastern North America. Populations in Florida, North Carolina, New Jersey and Nova Scotia showed few significant changes in standing crops over the 10 y of observation. The Ontario population had a significant decrease in standing crop whereas the Maine population increased significantly. Larger shrubs grew proportionately less at the New Jersey site but proportionately more at the Florida site. Seedling recruitment and plant mortality were very low at all sites.

Summary Fresh strawberries were evaluated through a commercial supply chain, from harvest to immediately prior to retail display. These samples were compared with controls that were refrigerated immediately after harvest and kept at a constant temperature for the same period of time. Temperature data were collected throughout all stages of the supply chain. Moisture and vitamin C (ascorbic acid) contents were determined at selected points of the supply chain using recognised methodology. Significant differences were found in the vitamin C concentrations of fresh strawberries at various stages of the supply chain but not in their moisture content. The ascorbic acid concentration decreased with time spent in the supply chain in all trials but the absolute vitamin C content differed from trial to trial. This result indicates that both pre- and post-harvest factors influence the vitamin C content of fresh strawberries available to consumers on the retail market.

The effect of burn-pruning on the flora in a natural stand of lowbush b lueberry was studied over a 24-yr period in Newfoundland and Labrador, Canada. Treatments were: not burned and burn-pruned every 2nd, 3rd, or 4th year. A vegetative survey was conducted before burning and periodically in succeeding years. Following statistical analyses, species were grouped according to their response to burning, as follows: those not significantly affected; those eliminated or whose frequency of occurrence was reduced; and those whose occurrence was increased. Initially, burning virtually eliminated Juniperus communis var. depressa, Empetrum nigrum, Cladina rangiferina, Lycopodium clavatum and Pleurozium schreberi, reduced the frequency of occurrence of nine species by 6 to 69%, and increased 13 others by 1 to 2050%. With burning, Polytrichum commune and Fragaria virginiana ssp. glauca, in particular, increased very early in the study to become two of the most prevalent species. Also, except for some initial effects of burning, the lowbush blueberry and some initially prevalent species (Festuca filiformis, Maianthemum canadense, Danthonia spicata, Cornus canadensis and Luzula multiflora var. acadiensis) remained among the most dominant species. Of the species studied, only seven each of those increased or decreased by burning were affected by the burn-pruning cycle. In both groups, the greatest increases or decreases in the frequency of occurrence were obtained with the 2-yr burn-pruning cycle. Key words: Lowbush blueberry, Vaccinium angustifolium, burning, pruning, plant succession, weeds, fire, flora

This study sought to identify grass/legume mixtures that increase the yield and persistence of forage stands with improved nutritive quality in cold-winter regions, compared with the standard mixture of timothy (Phleum pratense L.)/red clover (Trifolium pratense L.)/alsike clover (Trifolium hybridum L.). Timothy was mixed with either perennial ryegrass (Lolium perenne L.), meadow fescue (Festuca pratensis L.) or Kentucky bluegrass (Poa pratensis L.). The legumes in mixtures were red clover, alfalfa (Medicago sativa L.) or white clover (Trifolium repens L.). Averaged over three production years, the majority of mixtures had greater dry matter (DM) yields than the standard (8.35 t ha -1 ). Timothy, grown alone and in three mixtures, outyielded the standard by 19-30 %. Yield reductions in mixtures over the 3-year period were greatest with red clover, and least with bluegrass. Mixtures with alfalfa were highest in nitrogen (28.4 g kg -1 ), while grasses grown alone (24.6 g kg -1 ) and the standard mixture (25.1 g kg -1 ) were the lowest in N. Mixtures with red clover or alfalfa had the least neutral detergent fibre (NDF), averaging 418 and 429 g kg -1 respectively. Mixtures including white clover were initially low in NDF at 347 g kg -1 in year 1 but increased to 550 g kg -1 in year 3 as white clover composition declined in the sward.

This 2-yr field trial on forage plots compared the relative effectiveness of surface applications of cement kiln dust (CKD) to lime for raising soil pH. Seven soil treatments, in four blocks, were established at four low pH sites, which were: (1) a check plot; (2) lime at the recommended application (L), based on soil test for each site; (3) lime at 1.5 × L; (4) CKD at L; (5 ) CKD at 1.5 ( L; (6) CKD at an equivalent to lime basis; and (7) CKD applied at 1.5 times the equivalent to lime basis, where equivalence was based on CKD’s apparent neutralizing value equal to 75% that of lime. Soil pH was determined before applications and was monitored afterwards for two growing seasons. Two months after surface application, the CKD increased soil pH more than lime, despite its apparent neutralizing value being only 75% that of lime. Effects were greater closer to the soil surface and trends persisted through the following year. The CKD appears to be a quick-acting lime substitute due to its fineness (more than 99% passed through 100-mesh compared with 58% of lime). Key words: Forage, lime, cement kiln dust, pH

Italian ryegrass (Lolium multiflorum Lam.) and perennial ryegrass (L. perenne L.) can be grown for seed and forage in cold winter regions provided the stand persists well over winter. Seed yield and plant characteristics during primary growth, and forage yield during regrowth, were determined for two Italian and one perennial ryegrass cultivars in Atlantic Canada. Establishment methods and dates included sowing ryegrass in cultivated soil alone or with barley in mid-May and, after harvesting the barley crop, by sowing ryegrass following conventional or reduced cultivation and by no-till drilling into barley stubble in mid-August and early September. Despite some winterkill, particularly in Italian ryegrass, seed and forage yields were adequate in post-establishment growing seasons. Seed yield for Italian ryegrass was greatest (1270 kg ha -1 ) when it was sown into cultivated soil in mid-August and least (890 kg ha -1 ) when sown alone in May. Italian ryegrass yielded 15-17 % more seed when plots were established in mid-August rather than in mid-May or early September. Italian ryegrass cv. Lemtal had a greater density of fertile tillers (1030 m -2 ) in the sward than cv. Ajax (860 m -2 ) and its tiller density was greater when seeded into cultivated soil in September than in mid-August. There were fewer spikelets per seed head for sowing Italian ryegrass with barley in May than for the other methods of establishment. Forage yield in regrowth was greater for Italian ryegrass cv. Ajax (2770 kg ha -1 ) than for cv. Lemtal (2480 kg ha -1 ). Seed yield of perennial ryegrass was greater when seeded in mid-May than in mid-August or early September. The seed yield of perennial ryegrass was greater when it was sown with barley in May and harvested for grain, than when it was sown alone or with barley harvested at late milk stage. The establishment methods for mid-August and early September sowing had little effect on seed yield. However, the no-till and reduced tillage methods resulted in a greater tiller density than sowing into the cultivated seedbed. Fertile tillers tended to be denser under reduced cultivation for sowing in August. Forage yield of perennial ryegrass regrowth was not influenced by the sowing method and timing. In conclusion, Italian and perennial ryegrasses produce adequate seed and forage regrowth under different establishment methods and timing. However, the poor persistence of Italian ryegrass may limit commercial production after the establishment year in Atlantic Canada.

Most commercial blueberry growers follow a 2-yr pruning cycle because second-crop yield in a 3-yr cycle is usually too low for an economical harvest. Research was conducted to determine the extent to which second-crop production could be increased by applying fertilizer in the second-crop year. Treatments, consisting of factorial combinations of N (0, 60 kg ha-1), P (0, 26 kg ha-1), and K (0, 50 kg ha-1), were studied over two 3-yr burn-pruning cycles on a natural lowbush blueberry stand. Treatments were applied prior to, or shortly after, flower buds started to swell in the spring of the second-crop year. Nitrogen increased ripe fruit yield by 65% (3410 vs. 2070 kg ha-1) when compared with plots not previously fertilized with N, and by 43% (3410 vs. 2380 kg ha-1) when compared with plots previously fertilized with N. These results indicate that N might make the second crop economical to harvest. Phosphorus did not significantly affect yield, but K applied in combination with N in the second-crop year negatively affected production and Mg uptake. The increase in yield by N was due to more ripe berries resulting from a higher total (ripe + unripe) number of berries and hastened maturity that increased the percentage of ripe fruit. Reduced fruit abortion is suspected to be the reason for higher berry numbers. In contrast, the negative response to K applications with N was due to reduced total berry numbers. Key words: NK interaction, N × K interaction, potassium, nutrition, fertility, fruit abortion

Increased dry matter digestibility and ruminal undegradable protein (RUP) concentration are traits highly ranked to improve the nutritive value of forage legumes. Whole-plant, leaf, and stem samples of 27 alfalfa cultivars grown in eastern Canada were analysed for total nitrogen (TN), in vitro RUP, and in vitro dry matter digestibility (IVDMD). The objectives were to determine if significant variation exists among these cultivars, and to establish the relationship between nutritive value parameters of leaves and stems, and those of whole plants. Cultivars were seeded in triplicate on 2 consecutive years and evaluated during the 2 subsequent production years with two harvests per year. There were significant differences among cultivars in IVDMD of stems and plants in spring growth and summer regrowth. Cultivar differences in leaf IVDMD were significant only in spring growth, but this variation was negligible in practical terms. Cultivars with high forage IVDMD also had high stem IVDMD and this relationship was stronger in summer regrowth. Alfalfa plant IVDMD is a function of stem digestibility and the leaf weight ratio (LWR). Cultivar differences were significant for plant TN in spring growth and summer regrowth, and for stem TN in spring growth only. Leaf (270 to 306 g kg-1 TN) and stem (242 to 287 g kg-1 TN) RUP concentrations varied among cultivars in spring growth. Cultivars with high stem RUP also had high leaf RUP concentration but differences in plant RUP were not always attributed to leaf and stem RUP. The RUP concentration was on average 10% higher in leaves than in stems in spring growth, and this difference reached 15% in summer regrowth. The LWR varied among cultivars in spring growth and summer regrowth, and it was positively related to plant RUP in spring growth. Improved whole-plant RUP concentration is unlikely to be achieved by simply selecting for high RUP in leaves or stems; LWR has a principal role in determining alfalfa plant RUP concentration. Key words: Dry matter digestibility, ruminal undegradable proteins, alfalfa, genetic variation, stems, leaves

During silage fermentation, proteolysis reduces the nutritional value of N, particularly in alfalfa. This study evaluated the proteolysis of 27 alfalfa cultivars seeded in triplicate in 2 consecutive years. Forage from each plot was wilted to a targeted dry matter (DM) content of 250 g kg–1 and ensiled in laboratory silos. Minisilos were made with spring growth and summer regrowth in the first year of production for the first seeding, and with the first 2 yr of production for the second seeding, giving 3 harvest years altogether. Concentrations of NPN, NH3, FAA, DM, TN, and pH were measured in silages, whereas RUP concentration was evaluated in forages. Low NPN concentration indicates low proteolysis during silage fermentation. Spring growth and summer regrowth were analyzed separately by ANOVA as a completely randomized block design replicated over 3 harvest years. A principal component analysis was then performed on the ANOVA means. Silage DM was used as covariate when it was deemed appropriate. There was a significant variation among cultivars for NPN concentration in silages made of summer regrowth; it varied from 612 to 717 g kg–1 of TN. Concentration of NPN was significantly lower for cultivars WL 225, Rangelander, Iroquois, and WL 222, and higher for cultivars Oneida VR, Arrow, Vernal, Spredor 2, and Armor. Oneida VR and Rangelander had respectively high and low silage NPN concentration in both spring growth and summer regrowth. From cultivars with low silage NPN concentration, Rangelander was the only one with high forage RUP concentration in both spring growth and summer regrowth; proteins in this cultivar would be more resistant to microbial degradation during ensiling and in the rumen. Key words: Non protein nitrogen; proteolysis; alfalfa silage; cultivars

Combinations of naphthaleneacetic acid (NAA) and benzyladenine (BA) affected the callus formation from stem, rachis and leaf explants of beach pea. Mature leaf pieces were best for inducing a callus; when cultured on Murashige and Skoog’s (MS) medium supplemented with 4.4μM BA at least 87% of the explants callused regardless of the NAA concentration. Optimal induction was achieved with 5.4 to 10.7μM NAA depending on the explants used. BA at 4.4μM was always more effective than at the lower concentration of 1.1μM. Multiple buds were induced from calli and formed shoots when transferred to MS medium supplemented with 2.7μM NAA + 4.4μM BA.

The quality of alfalfa would be greatly improved by an increase in its ruminal undegradable protein (RUP) concentration. Protein degradation rate (PDR), in vitro dry matter digestibility (IVDMD), leaf weight ratio (LWR), dry matter yield (DMY), total nitrogen (TN), in vitro RUP (expressed on both TN, RUP-TN, and dry matter basis, RUP-DM), acid detergent fiber (ADF), and neutral detergent fiber (NDF) concentrations were determined in 27 alfalfa cultivars. Cultivars were seeded in triplicate on 2 consecutive years and evaluated during the 2 subsequent production years with two harvests per year. Protein degradation rate and RUP-TN were determined using a ruminal inhibitor in vitro system. Data were averaged for spring growth, summer regrowth, and both harvests across 2 production years. Each of the three data sets was analyzed by ANOVA followed by a principal component analysis (PCA) on the ANOVA means. For the four-harvest data, cultivar differences were highly significant (P

Past research has shown that fertilizer applied in the vegetative year can increase yield, but not always. Fertilizer applied in the crop year without weed control also has been shown to increase yield. The present study, conducted on a natural lowbush blueberry stand for 8 yr, compared the effects of factorial combinations of two rates each of N (0, 60), P (0, 26), and K (0, 50 kg ha−1) applied either in the vegetative or crop year, with or without weed control. Greatest production was obtained with weed control, which increased ripe fruit yield by 247% over that from plots without weed control. Nitrogen alone or P and K with N also increased yield, but only when applied in the crop year to weed-controlled plots. Phosphorous or K alone was of little benefit. Nitrogen increased ripe fruit yield from 3910 (unfertilized plots with weed control) to 4440 kg ha−1 and in combination with P and K to 5520 kg ha−1. Yield increases from weed control and N were due to increased berry weight and hastened maturity, but weed control also increased total berry number. The increase by P and K was due to an increase in total and ripe berry numbers. Nitrogen applied in the vegetative year, although producing more flower buds m−2 than when applied in the crop year, gave lower yields. Fruit abortion, due to insufficient nutrients in the crop year, particularly N, is suspected to be the reason for the reduced yield. Key words: Lowbush blueberry, Vaccinium angustifolium, yield flower buds, weed control, fertilizer, herbicide

Late-maturing cultivars of red clover (Trifolium pratense L.) and timothy (Phleum pratense L.) may be grown in short-term rotations with other crops and harvested for hay and silage. Harvesting forage in mid-summer is often advantageous for field curing, but the quality of mature forage may be low. We studied how harvests at different developmental stages affected yield, composition of herbage, and species persistence. The late-maturing single-cut red clover cultivar Altaswede and late timothy cultivar Farol were grown alone and in combination with and without applied N. Total forage, and red clover and timothy dry matter yields, increased between the first (27 June) and third (11 July) dates of harvest. Timothy grown alone or combined with red clover and fertilized with N produced greater forage yields than red clover alone or red clover + timothy without applied N. The in vitro digestibility of dry matter declined from 670 to 625 g kg−1 and crude protein from 134 to 109 g kg−1 between 27 June and 11 July. Water soluble carbohydrates in forage were low (36–66 g kg−1) in cuts 1 and 2. Macronutrient and micronutrient concentrations were generally highest at the first date of harvest on 27 June. Nutrient concentrations in cut 2 were similar for the three harvest schedules. We conclude that growing late-maturing single-cut red clover combined with late timothy produced high yields with good nutritional quality even at advanced stages of maturity. Single-cut red clover persisted for the first production year making this combination suited for short-term rotations that involve late harvesting of the primary growth. Key words: Red clover, Trifolium pratense, timothy, Phleum pratense, composition

In a small target region, it may be possible to exploit local adaptation to increase gains from selection. However, in a large region more extensive testing is usually possible, resulting in more precise estimation of genotype means. A correlated response model was adapted to determine if division of a large target region is likely to increase gains. Genotypic value in a large region and constituent subregions are considered correlated traits. Correlated response in a subregion to indirect selection across the undivided region, relative to direct response to selection within the subregion, is expressed as a function of heritability in the undivided region (H) and in the subregion (H(i)), and of the genotypic correlation between region and subregion means (r(G'). r(G') depends on the magnitude of the genotype x subregion interaction (sigma2GS)) relative to the genotypic variance (sigma2(G)). sigma2(GS) is the portion of the genotype x location interaction (sigma2(GL)) caused by local adaptation, rather than by random site-to-site variability in genotype means. Subdivision can increase heritability through the addition of sigma2(GS) to the numerator of H(i), but this may be offset by reduced replication across locations within the subregion. Modeling using variance estimates from several cereal programs indicated that, unless sigma2(GL) is large relative to sigma2(G) and at least 30% of sigma2(GL) is due to sigma2(GS), subdivision is unlikely to increase response. These results help explain the success of breeding programs that test broadly.

Barley (Hordeum vulgare L.) breeding programs recognize eastern and western Canada as separate target regions, but the extent of local adaptation to regions and subregions within them has not been studied. Genotype × region and subregion interactions were estimated in 145 lines from the two-row barley cross Harrington/TR306 in 22 trials in 1992-1993. The trials were grouped into five subregions (Maritimes-Quebec, Ontario, Manitoba-North Dakota, Saskatchewan, and Alberta) and two regions (eastern Canada and western Canada plus North Dakota). Variance components were estimated by a model in which the genotype × location (σ GL 2 ) variance was subdivided into a genotype × region (or subregion) variance (σ GS 2 ), and a within-region or -subregion σ GL 2 . No σ GS 2 was observed within the eastern or western regions, and genotypic correlations across subregions within regions approached 1.0. Significant σ GS 2 was observed for eastern versus western Canada, but the correlation between genotypic effects across these regions was 0.83. In a selection experiment, subdivision of the eastern or western regions did not increase response. Selection in the east produced greater yields in both the east and west. The same genotype ranked first for yield in both regions. There was little specific adaptation to subregions, and two-row barley genotypes were broadly adapted across northern North America. Further subdivision of the regions is unwarranted, and selection in either region is likely to result in response in the other. The lack of local adaptation indicates that breeding programs that test broadly are likely to outperform ones that are narrowly targeted.

European plum (Prunus domestica L.) cultivars, and selections developed at the Horticultural Research Institute of Ontario, Vineland Station, were evaluated, over a range of rootstocks of differing vigour, in the Annapolis Valley, Nova Scotia. Cultivars and number selections included: Vanette (V66071), Victory (V72331), Voyageur (V63002), V63015, Valerie (V70031), Valor, Veeblue, Vision, Verity, and the standards, Stanley and Italian Prune. The four prunus rootstocks were: Pixy (P. insititia L.), St. Julian A (P. insititia L.), Brompton (P. domestica L.), and Myrobalan B (P. cerasifera Ehrh.). The largest cultivars were Italian Prune, Vision, and Veeblue, particularly on St. Julien A, Brompton, and Myrobalan B. Trees on Pixy were the smallest and had the smallest range of sizes. Yield and efficiency was the greatest for Vision, for all rootstocks. Victory, Voyageur, Valor, and Veeblue performed well with some of the rootstocks. The cultivars Vision, Vanette, Victory, Voyageur, and Valerie were the most precocious. The three cultivars with the largest fruit size were Victory, Valerie, and Vision. Italian Prune produced the smallest fruit. The combination of Stanley/Pixy also produced small fruit. For the Annapolis Valley, Vision is highlighted as a very productive cultivar for which tree size can be contained by the rootstocks Pixy and St. Julien A. Key words: Plum, cultivars, rootstocks, yield, precocity

Four silages were made from the primary growth of an orchardgrass (Dactylis glomerata)/white clover (Trifolium repens) sward in mid-June. Precision chopped (PC) and round bale (RB) silages were made from wilted forage that had been cut either with a regular mower conditioner (CON) or a mower macerator (MAC). Silages were fed to growing steers in a 10-wk feeding trial using a 2 × 2 factorial design. To determine apparent digestibility, silages were fed to wether sheep and ruminally incubated in nylon bags using two canulated cows. The DM concentration of silages ranged between 273 and 362 g kg−1 and was higher in RB than PC silage. Maceration increased fibre concentration in RB silage but had little influence on PC silage. Nitrogen and its fractions were not influenced by treatment. Maceration increased total acid concentration in PC silages but lowered it in RB silage. Lactic acid accounted for a higher proportion of total acids in macerated silages than in control silages. Steers fed RB silage consumed 35% more DM than those fed PC silage (P −1 to 1.09 kg d−1 (interaction; P

Forage chicory (Cichorium intybus L.) was grown alone and in combination with various grasses and legumes for three production years to determine growth, botanical composition, and persistence. Chicory mixed with grasses and legumes produced greater yields than chicory alone. Mixtures of orchardgrass (Dactylis glomerata L.) + white clover (Trifolium repens L.), timothy (Phleum pratense L.) + alfalfa (Medicago sativa L.), and timothy + red clover (Trifolium pratense L.) in combination with chicory produced the highest dry matter yields. Persistence of chicory was adequate; it survived for three production years in the cold-winter region of Atlantic Canada. Including chicory in grass/legume swards improved the seasonal distribution of herbage and increased late season production. Key words: Botanical composition, Cichorium intybus L., combinations, mixtures, persistence, seasonal yield distribution

Protein supplementation for winter-calving beef cows between calving and turnout to pasture was studied in two trials. Changes in cow body weight (BW) and condition and calf BW gains were recorded from calving to weaning in the fall. Reproductive performance was monitored, and in trial 2, milk production was determined. In trial 1, multiparous silage-fed cows were allocated to one of five levels of corn gluten meal (CGM): 0, 200, 400, 600 and 800 g d−1. In the second trial, cows were allocated to either restricted or ad libitum silage feeding in combination with three protein supplements: no protein, 400 g d−1 CGM or 475 g d−1 soybean meal (SBM). In trial 1, cows gained weight during supplementation, but on pasture they lost weight (linear effect, P = 0.10). Calf gains and weights at turnout and weaning showed a quadratic response to protein supplementation (P

Papadopoulos, Y. A., Christie, B. R., McRae, K. B., Gehl, D. and Fillmore, S. A. E. 2015. Pratt timothy. Can. J. Plant Sci. 95: 1047–1048. Pratt timothy (Phleum pratense L.) is an 11-clone synthetic cultivar developed through progeny testing for general combining ability at Agriculture and Agri-Food Canada, Crops and Livestock Research Centre, Charlottetown, Prince Edward Island. Pratt timothy was selected for winter hardiness, plant vigour, plant height, and intermediate maturity (similar to the check cultivar Climax but later than Champ). In Atlantic Canada, Pratt timothy produced more forage than Champ during 3 production years. This cultivar was superior in persistence and re-growth potential with greater production of second-cut herbage.

Field research, conducted for six seasons (1991–1996) on one soil type, compared organic amendments (three formulations of fish bone meal (FBM) and a marine sediment enriched with fish, lobster, and crab meal) with an NPK chemical fertilizer (17–17–17) and a zero-N control (0–17–17). Each fertilizer material was applied pre-plant at 80 kg N ha−1 to the same plot for six seasons that spanned two cycles of a three-crop rotation of seeded carrots, green beans, and transplanted cabbage. In plots receiving the organic amendments, soil pH and Ca increased over time compared with those plots receiving 17–17–17. The increase of soil Mg was greatest in plots receiving the fortified marine sediment treatment. Soil and leaf K values were lowest with the FBM treatment, reflecting its low K composition (6–10–1). Soil and foliar P values from the organic amendment plots were higher than those from the 17–17–17 plots. Foliar N, Ca, Mg, Fe, and B were not consistently affected by 17–17–17 or the organic amendments, but foliar Mn was higher in crops receiving 17–17–17. Marketable yields of cabbage and carrots in plots receiving the organic amendments were comparable with those from 17–17–17, but marketable yields of green beans were consistently higher in plots receiving 17–17–17. Soil and foliar results indicate that the cumulative effect of repeated application of these organic amendments is not detrimental to plant growth, and that these amendments produce marketable yields of cabbage and carrot equivalent to those of the chemical fertilizer. Key words: Fish bone meal, marine sediment, organic amendments, vegetables

In order to assess cold tolerance in V. corymbosum L. in Nova Scotia, 336 even-aged seedlings from 21 locations (representing five different habitats and six eastern North American floristic regions) were set out at the Kentville Research Centre in 1978. Frost damage is largely restricted to Coastal Plain plants and to a lesser extent the Appalachian Mountain plants. Principal component analysis indicates that berry weight co-varies negatively with winter-kill and days from the anthesis until fruit ripening. Hardy plants that flower in early May also need the fewest days to produce ripe fruit. Among the 23 early flowering biotypes, six early fruiting biotypes were identified. Key words: Vaccinium corymbosum, highbush blueberries, frost tolerance, drought tolerance, early flowering and fruiting biotypes

Two cultivated lowbush blueberries (Vaccinium an-gustifolium Ait.) cv Augusta and selection ′70-2 G were grown in adjacent fields that received preplant applications of gypsum, dolomite or calcitic limestone. Calcium (Ca) at 0, 150 and 600 kg/ha (133.8 and 535.2 lbs/ac) was applied 18 months prior to planting ‘Augusta’ and grown for 8 seasons; Ca at 0, 300 and 1,200 kg/ha (267.6 and 1070.4 lbs/ac) was applied 1 month prior to planting ‘70-21’ and grown for 7 seasons. Marketable yield response was similar for ‘Augusta’ and ‘70-21’ in the check (untreated), gypsum and dolomite plots; however, calcite applications reduced yield of both blueberries, compared with the check. Calcite and dolomite application increased soil pH and Ca values and dolomite increased soil Mg values, compared with the check and gypsum treatments, only in ‘70-21.’ Soil pH and Ca values were similar for all treatments in ‘Augusta.’ Although application of both rates of dolomitic limestone increased soil pH (0-7.5cm) (0-3in) to...

Burning is a pruning technique used to improve productivity of lowbush blueberry fields. Growers, however, are concerned that continuing and frequent burning might reduce production and eventually destroy blueberry fields. To assess the effect of long-term spring burn-pruning on blueberry production and the surface organic layer, 2-, 3- and 4-yr burning cycles were studied for 24 yr on a previously unfertilized natural stand of lowbush blueberry. Mean annual yield (averaged over burn and crop years) decreased with increases in the interval between burning due to decreased production in the second and third crop years following burning. Yield in the third crop year was similar to that from the unburned check plots. There was no significant yield decrease between the first 12 yr (period 1) and the second 12 yr (period 2) of production for the 2-yr cycle, but there were declines for the 3- and 4-yr cycles due mainly to lower yields in the second crop. Lower second-crop yields in the second period was attributed to damage by the blueberry leaftier (Croesia curvalana Kft.). Mean annual ripe fruit yields for the 2-, 3- and 4-yr cycles and unburned check were 473, 458, 335 and 109 kg ha−1, respectively, in period 1 and 478, 340, 277 and 38 kg ha−1, respectively, in period 2. Burning did not decrease the depth of the surface organic layer. Key words: Lowbush blueberry, Vaccinium angustifolium, burning, pruning, organic matter, yield, berry weight, flower buds, residual maximum likelihood

Long-term experiments (LTE) are extremely varied in form, and scientists who undertake this type of experiment face many challenges. Aspects of management, design layout, the role of the coordinator and statistician, and computer use are discussed. The important statistical ideas for LTE are reviewed and related to single perennial crops such as wild blueberries, fruit trees and permanent pastures. Key words: Long-term experiments, planning of experiments, experimental design, REML, residual maximum likelihood

The surface color, size, and sugar, titratable acid and anthocyanin contents were measured on samples of various maturities from 72 individual lowbush blueberry clones to determine the relationships between surface color and other ripeness indicators. Among the total 504 berries, the maximum sugar content was approximately 5 times that of the minimum, while the maximum titratable acid and anthocyanin contents were 20 and 11 times those of the minimum contents, respectively. Correlations among variates were generally strongest for samples within clones, and they were weakest among the variate means for the 72 clones. For the total 504 berries, sugar content correlated more strongly with surface color than with berry size, while acid content correlated similarly with surface color and size. Correlations (positive or negative) among berry size and sugar and titratable acid contents did not exceed 0.60. Principal component analysis, which was used to identify groupings of correlated variates, indicated coordinated changes in berry characteristics during ripening, lower sugar and anthocyanin concentrations in large berries, and substantial interclonal variation in wild blueberries. Clonal selections obtained from an experimental trial differed significantly in all the variates measured, while wild clones without a surface bloom were not different from those clones with bloom. Key words: Lowbush blueberry, Vaccinium angustifolium, color, sugar, titratable acid, anthocyanin

Research funding for cooperators in the cereal cultivar testing system in Canada is declining, and cooperators are under pressure to reduce their testing effort. The impact of reducing the number of years, test sites, and replications on the standard error of cultivar means (SE), predicted response to selection (R), and the probability of accepting inferior cultivars in Maritime spring cereal registration trials was examined using variance component estimates. Reducing the number of replications increased SE less than reducing the number of sites or years of testing. Reducing replicates per site from four to two increased SE by no more than 0.02 t ha−1 when the number of sites was three or more. Reducing the number of trial sites from five to three, however, increased SE by up to 0.06 t ha−1 and reduced R by as much as 16%. The probability that a cultivar with a true yield 5% less than that of a standard would equal or exceed the standard in a 3-yr series of trials conducted at five sites ranged from 6% in 2-row barley to 21% in winter wheat. Cost reductions in the Maritime cereal registration trials should be achieved, where possible, by reducing within-site replication rather than reducing the number of trial sites. Some reduction in the risk of registering inferior cultivars can be achieved by comparing test cultivars with the mean of several standards, rather than with a single standard. Key words: Replication, genotype × environment interaction, selection response, acceptance probability, variance components, residual maximum likelihood

Acadia or dykeland soils have produced forages successfully for centuries. The formation of barren areas within very productive forage stands has been noted recently in some land-formed fields, indicating either poor germination or poor growing conditions. A survey was undertaken in 1988 to determine the differences in soil attributes between barren and productive areas, namely: topographical position, resistance to penetration, bulk density, pH, plant-available P2O5, -K2O, Ca, and Mg, salt content (as measured by conductivity and sodium adsorption ratio), and exchangeable and soluble Ca, Mg, K and Na. Barren areas had greater: plant-available P2O5, resistance to penetration (the differential ranged from 480 to 1440 kPa), bulk density (in the top 15 cm), salt and sodium content than the productive ones. The exchangeable and soluble Na:Mg and Na:Ca ratios were higher on barren areas than on productive areas. Organic matter content was lower on barren than on productive areas. Values for topographic position, pH, particle size classes and plant-available K2O, Ca, and Mg were similar between the productivity areas. The results of this survey indicate that the formation of barren areas appears to be mainly due to accumulation of excess salts, especially sodium. Reasons for salt accumulation in these areas are discussed. Key words: Acadia soils, dykeland, salt, sodium, organic matter, resistance to penetration

First growth and regrowth of Trifolium pratense L. ’Florex’ (red clover) were used to study the effect of conditioning on the moisture content (MC = g water g−1 DM) under field conditions. Chemical conditioning using desiccant agents and mechanical conditioning with rollers were applied separately or combined. Swath MC was measured for 52 h after cutting in five trials. In all five trials, the MC of field dried, unconditioned red clover was unsuitable for baling 52 h after cutting (range: 0.25–3.8 MC). In three of the five trials, conditioning failed to lower the MC below that of unconditioned red clover because of rain, even when DM yield was moderate (2.2 t ha−1 in trial 5). Under rain-free weather, the low-rate chemical or mechanical conditioning applied alone or high-rate chemical and mechanical conditionings applied together, to moderate and high-yielding stands of red clover (2.4 and 4.2 t DM ha−1 in trials 4 and 2, respectively), reduced the MC to 0.2 or lower, and provided the practical benefit of storing hay at least a day earlier than unconditioned red clover.Key words: Clover (red), hay, desiccant, roller conditioner, field drying

(1992). Composition of a population of Venturia inaequalis resistant to myclobutanil. Canadian Journal of Plant Pathology: Vol. 14, No. 3, pp. 215-220.

Italian ryegrasses, cultivars Barmultra and Lemtal, and Westerwolds ryegrasses, cultivars Barspectra, Merwester and Promenade, (Lolium multiflorum Lam.) were harvested as first- and second-cut herbages and compared for yield, leafiness and water-soluble carbohydrate content during the 2-yr study. These herbages were conserved as silages and compared for chemical composition and for intake, digestibility, and total-N retention in sheep. First-cut ryegrass yielded more dry matter than second-cut ryegrass (3.3 vs. 2.6 t ha−1). First-cut ryegrass silages contained less dry matter and NDF, and sheep consumed less, but digested better and retained less total-N in comparison with second-cut ryegrass silage. Italian ryegrasses yielded less dry matter, were more leafy, contained less ADF, and were better digested compared with the Westerwolds ryegrasses. The herbage content of water-soluble-N, and the ratio of ammonium-N to total-N in silage were not different between the ryegrasses. Italian Barmultra was more leafy than Lemtal cultivar but no other significant differences were measured between these cultivars. Westerwolds Merwester yielded more dry matter, was less leafy, contained more NDF and ADF, and had lower voluntary intake, digestibility, and its total-N was less retained in sheep as compared with the Barspectra or Promenade Westerwolds ryegrass. Italian ryegrasses were superior in composition, voluntary intake, and digestibility to Westerwolds, but the latter were superior on the basis of yielding ability and efficiency of total-N utilization in sheep.Key words: Silage, ryegrass, intake, digestion, composition, Nitrogen retention

Number of Pratylenchus spp. (primarily P. penetrans) were recorded at planting in experimental potato plots over a 9-year period at one location on Prince Edward Island. Tuber yields of 'Superior' and 'Russet Burbank' potatoes in plots treated with aldicarb were compared with yields in adjacent untreated plots. There was a linear relationship between the number of root lesion nematodes at planting and tuber yield increases after treatment for Superior, but not for Russet Burbank (P < 0.05). When counts of root lesion nematodes were greater than 500/kg dry soil, however, the tuber yields of Russet Burbank increased in treated plots. Additional trials at other locations and the inclusion of other cultivars are needed to make numerical relationships of this type available to a nematode advisory service.

The response to potato late blight of 116 potato cultivars and breeding lines was determined in replicated trials conducted between 1980 and 1988. The index of area under the standardized disease progress curve (ASDPC), based on the cultivar Sebago, was used to rank the cultivars and to identify cultivars that had inconsistent disease responses over years. Most of the cultivars were susceptible to late blight; only 10 cultivars out of 66 currently available (including breeding lines) were judged more resistant than Sebago. Nine cultivars were identified as having inconsistent resistance over years. The index ASDPC was less variable than the relative area under the disease progress curve when the yearly disease conditions differed from the normal.

Two feeding trials were conducted with pigs to determine the effects of blueberry supplementation on plasma lipid levels and other indices of cardiovascular benefit. In the first trial, where basal diets contained a high level of plant-based components (70% soya, oats and barley), supplementation with 1, 2 and 4% blueberries resulted in a decrease in total, LDL- and HDL-cholesterol. The greatest reduction was observed in the 2% blueberry-fed pigs, where total, LDL- and HDL-cholesterol were reduced 11·7, 15·1 and 8·3%, respectively. In the second trial where basal diets contained only 20% (w/w) of soya, oats and barley, the lipid-modulating effect of blueberries was attenuated, so that supplementation with 1·5% blueberries reduced total cholesterol by 8%, which occurred only in pigs whose diets had been supplemented with cholesterol (0·08%), NaCl (0·11%) and fructose (9%). In the first feeding trial, blueberry supplementation had no effect on blood platelet activity. Blueberry supplementation also had no effect on the susceptibility of leucocyte DNA to oxidation in the first trial and no effect on the susceptibility of LDL to oxidation in the second trial. Results of these two feeding trials are discussed in relation to the effects of basal diet composition on lipid-modulating effects of blueberries. Blueberries: Plasma lipids

To investigate the effects of ozone on inactivation of Listeria innocua on solid media.Suspensions of L. innocua ranging from 4.5 x 10(4 )- 6.4 x 10(4) CFU ml(-1) were inoculated onto potato dextrose agar (PDA, pH 5.6 and 6.8) and nutrient agar (NA, pH 6.0 and 6.8), then exposed to gaseous ozone. Variable factors included postinoculation standing time at 20 degrees C before exposure to ozone, ozone concentration, treatment duration and treatment temperature (5 or 20 degrees C). The interaction among ozone concentration, treatment duration, media and temperature in effecting changes in colony-forming units (CFU) was significant. The 100 nl l(-1) ozone treatment for 2 h reduced the microbial populations by 2-3 log CFU ml(-1). Cell viability decreased more rapidly on PDA than on NA. The average time to obtain a 2 log CFU ml(-1) reduction was 1.3 h at 20 degrees C and 2.5 h at 5 degrees C (P0.001).Gaseous ozone effectively inactivates L. innocua at concentrations of 50 and 100 nl l(-1) during short exposure times at both 5 and 20 degrees C. The Gompretz model can be utilized for determining the response of L. innocua to ozone over time.This study provides useful information on ozone inactivating Listeria spp., which may be imposed on ensuring quality and safety of horticultural produce and food products.

Economic control of Rhagoletis mendax was achieved by applying insecticidal sprays to commercial lowbush blueberry vegetative fields, in a biennial production system, rather than to the fruiting fields, when the threshold was exceeded. The viability of this integrated pest management of R. mendax for lowbush blueberries was demonstrated over a 9-yr interval in New Brunswick where three sites were monitored for 2 yr, eight sites for 4 yr, and one site for 9 yr. Control of R. mendax in lowbush blueberry fields was achieved in 2 yr when the fields were isolated, and in 3 yr when there were adjacent lowbush blueberry fields.

Field studies on Prince Edward Island (P.E.I.) loam to fine sandy loam soils from 1977 to 1980 determined the rate of breakdown of atrazine and soil residue effects on crops grown in rotation with silage corn (Zea mays L.). The rate of breakdown was rapid during the first 30 days after application with an estimated half-life of 23 days when averaged over rates and years. Timothy (Phleum pratense L.) and red clover (Trifolium pratense L.) were most sensitive to atrazine residues; yields of red clover were reduced significantly from the 1.13-kg/ha rate and of timothy after the 2.25-kg/ha rate. Yields of winter rye (Secale cereale L.) broadcast seeded in standing corn in August and barley (Hordeum vulgare L.) seeded the next spring were not affected, or reduced only slightly, by atrazine residues from initial applications of 1.13 kg/ha but showed significant yield losses at the 2.25- and 4.50-kg/ha rates. Alfalfa (Medicago sativa L.) seeded the next spring after atrazine use was tolerant of residues showing significant yield losses only at the 4.50-kg/ha rate. In this study, atrazine applied at 1.13 kg/ha in silage corn was sufficiently broken down to permit production of all crops studied except red clover.Key words: Atrazine, residue, clover (red), timothy, alfalfa, rye (winter), barley

A factorial experiment was conducted, with a total of 3168 birds from four commercial meat parent genotypes, to study the cumulative effects of feeding soybean meal (SM) and rapeseed meal (RSM) as protein sources in both juvenile and adult breeder diets. Averaged over all genotypes, general performance was equivalent for all combinations of SM and RSM in the juvenile and adult diets although there was some evidence of second order interactions involving genotypes with juvenile and adult dietary combinations. These interactions affected egg production and related traits such as feed efficiency. It was concluded that some genotypes exhibit a greater responsiveness to rapeseed meal diets than others and that juvenile and adult diets using a combination of different sources of dietary protein supported equal or better performance compared with the same dietary protein source used throughout both periods. Key words: Meat breeders, rapeseed meal, canola, poultry, diets

The effect of soil temperature on urea hydrolysis and subsequent nitrification in an acid Podzolic soil was investigated under laboratory conditions to determine the transformation rate parameters. More than 90% of applied urea was hydrolyzed within 5 d at temperatures between 9 and 18 °C. Subsequent nitrification rates were more temperature dependent and increased from 4 up to 18 °C. Nitrification was limited at 4 °C, was extensive at 9 °C, and it was essentially complete after 48–68 d at 18 °C and 90% complete after 92 d at 9 and 13 °C. The nitrate-N produced during the cropping season from a spring application of urea was predicted, with a model based on the laboratory determined transformation rates, for field conditions at normal soil temperatures. Following spring-applied urea (20 May), the model indicated that nitrification would be virtually complete by 31 July. In a field experiment, total N uptake by Kennebec potatoes (Solanum tuberosum L.) from applied ammonium nitrate was 95% complete within the same period and with a similar seasonal pattern to that predicted for nitrate N produced from urea. It was concluded that urea can be a suitable source of nitrogen fertilizer for the production of potatoes. Key words: Urea hydrolysis, nitrification, potatoes, modelling, prediction

Early-maturing forage corn (Zea mays L.), DK-22, was harvested in Prince Edward Island twice, 3 and 6 wk before the occurrence of the first killing frost, and twice again, 2 and 4 wk after the first killing frost, and ensiled during each of the three experimental years. Each silage was fed to six sheep in order to measure voluntary intake and digestibility. Magnesium content was severely reduced by ensiling fresh forage from prefrost harvest. The postfrost silages were drier and higher in pH than the other silages. Detergent fiber levels were lower in the prefrost than in the postfrost silages (P

A factorial experiment was conducted with 3030 chickens of four maternal dwarf genotypes mated with normal males to estimate the effects of age at a photoperiod change from 8 to 12 h (daily) at 140 or 154 days, and two levels of dietary protein (15 or 17%) on general performance, incidence of Fatty Liver Syndrome and monetary returns. Three of the four maternal genotypes performed similarly for most traits measured but one genotype exhibited better feed efficency of egg production, produced more eggs and, although the eggs were smaller resulted in the highest monetary returns. Delaying the increase in photoperiod change retarded sexual maturity and reduced egg weight at 203 days and egg specific gravity at 406 days. The 17% protein diet improved egg production (including hatching eggs), feed efficiency of egg production, egg weights; and female body weights at 154 and 446 days of age were also heavier. Dietary protein levels had no effect on mortality (P > 0.05). Mean monetary returns from the sale of table eggs, hatching eggs and salvage meat in excess of the costs of day-old breeder stock and feed, averaged $1.07 more per bird fed the 17% diet. The progeny test revealed significant differences among genotypes for male mortality, male and female body weights, and feed conversion; however, monetary returns over feed and chick cost were similar. The time of change in photoperiod and dietary treatments had no significant effect on the overall performance of broiler progeny but there was a genotype × parental diet interaction for 43 day female body weights. Key words: Dwarfs, meat breeders, hens, broilers, photoperiods, diets

A forage system based on timothy (Phleum pratense L.) cultivars of different maturities is recommended in Atlantic Canada. Early and later maturing cultivars are grown to spread the harvesting of timothy, at optimal primary growth maturities, to about 3 wk. At some locations the resulting harvest period has been considerably shorter and for this reason the timothy system was examined in a 4-yr field study. Four timothies, representing very early, early, midseason, and late cultivars, were cut at five dates with primary growth stages ranging from vegetative to full heading. Regrowth was cut about 45 days after cut 1. Total dry matter yield and total N concentration of combined cuts 1 and 2 were generally influenced by cutting schedules but not by cultivars. The in vitro dry matter disappearance (IVDMD) was dependent on both cutting schedule and cultivar. The early-maturing cultivar Clair reached its peak IVDMD earlier than later maturing Champ, Itasca, or Bounty. At termination of the field study, there were fewer timothy tillers per square metre and ground cover by timothy was slightly less for those cuts taken during stem elongation. The results suggest that three out of four cultivars were of similar maturity and had similar total N and IVDMD. We conclude that the currently recommended timothy cultivars in Atlantic Canada do not provide a sufficient range in maturity for the average growing season in the region to warrant multiple cultivars on individual farms. At present, timothy stands may be cut prior to and during stem elongation to lengthen the harvest period.Key words: Timothy, in vitro dry matter digestibility, total nitrogen

The sod seeding of alfalfa (Medicago sativa L.) and bird’s-foot trefoil (Lotus corniculatus L.) was studied in three locations previously cut for conserved feed or used for pasture. At each location an experiment with a split-split-plot design was established with sod-seeded alfalfa and bird’s-foot trefoil as main treatments, methods of drilling as subtreatments, and methods of vegetation control as sub-subtreatments. Drilling was done with a John Deere PowrTill 1500 renovator and Øyjord plot drill equipped with shoe openers. The methods of vegetation control included mowing and spraying with 1:1-′dimethyl-4.4′bipyridinium dichloride (paraquat) or N-(phosphonomethyl) glycine (glyphosate) at the time of drilling. Sod seeding alfalfa resulted in greater dry matter yields than bird’s-foot trefoil. Alfalfa and bird’s-foot trefoil constituted 27 and 17% of total yield in the year after sod seeding and 17 and 4% in the 2nd year after drilling, respectively. Alfalfa performed better in a sward previously cut for conserved feed while bird’s-foot trefoil performed better in a field used for pasture. Both PowrTill and plot drill resulted in satisfactory seedling establishment although the yields of sod-seeded legumes were greater with plot drill than with PowrTill in the year after drilling. Vegetation suppression with paraquat and glyphosate did not improve the growth of sod-seeded alfalfa or bird’s-foot trefoil over the unsprayed treatment. In a heavy sward consisting mainly of Poa pratensis L., sod-seeded alfalfa, and bird’s-foot trefoil failed to establish.

Three experiments, involving 1728 adult Leghorns (Starcross 288), were designed to study the combined effects of grower diet calcium level (3.26 vs. 0.80%) fed from 105 to 147 days and the feeding of supplementary oyster shell and a high protein diet (20.1 vs. 15.1%) from 147 to 497 days of age, on shell strength (egg specific gravity) and other performance traits. In exps. 1 and 2 the hens were housed in individual cages and two birds per cage, respectively, while in exp. 3 birds were housed in floor pens. The feeding of supplementary oyster shell during the laying period had little effect on mortality, egg production, egg weight, body weights or feed consumed per dozen eggs produced. Birds fed the high protein diet were heavier toward the end of the laying period compared with birds fed the low protein diet in the three experiments. Birds fed the high protein diet laid larger sized eggs but this was significant (P

Hatching eggs were collected from two meat parent genotypes (normal and semidwarf) between 200 and 210 days of age and sorted by weight into four quartiles. Eggs from the light and heavy quartiles were retained for a comparative testing of hatching quality and progeny performance. Egg weight differed significantly between the two genotypes. Genotypes and egg size had no significant effect on hatchability. Significant genotypic and egg size effects were observed on fertility and day-old chick weights but not for mortality during rearing. Maternal genotype had no significant effect on the body weights of broiler progeny at either 28 or 49 day s except that at 28 days males from semi-dwarf maternal parents were lighter than males from normal maternal parents. Egg size had a significant effect on both male and female body weights at all ages with broilers hatched from the small eggs being lighter than those hatched from large eggs. Feed conversion was unaffected by genotype, but chickens hatched from large eggs exhibited better feed conversion compared with those hatched from small eggs. The percentage of Grade A carcasses was not affected by genotype but was significantly higher among male broilers hatched from the small sized eggs. Egg size had a significant effect on monetary returns as broiler chickens hatched from the smaller eggs returned approximately 7¢ less per bird compared with broilers hatched from the larger eggs. There was no significant difference between monetary returns from broiler chickens from either normal or semi-dwarf maternal parentage. This strongly supports the future adoption of the semi-dwarf maternal parent by the industry.

Orchardgrass (Dactylis glomerata L.) was grown for 5 yr on a fine sandy loam fertilized with ammonium nitrate at 40–120 kg N∙ha−1 applied in either spring or summer or in combination. Stands were cut two or three times during each growing season. Single N applications in spring increased annual yield by about 11% over equivalent summer applications. For split applications no significant difference in annual yield was found regardless of whether the greater fraction was applied in spring or summer. A second order polynomial was found to explain almost all of the variation in the response curve over time for dry matter yield. Application of 120–165 kg N∙ha−1 were required to maintain a uniform yearly production. There was variation in the mean seasonal N concentration over years but with few clear trends. The N concentrations in cuts 1 and 2 were principally determined by the rate of N applied in the spring and summer but there was a carryover effect from the first to the second cut for the highest rate of applied N in the 4th and 5th years.Key words: Dactylis glomerata L., herbage production, tissue N concentration

The effects of rate and time of N fertilization in the presence of sufficient P and K on seasonal and annual forage yields were studied on timothy, bromegrass, and reed canarygrass for 4 yr. Nitrogen treatments consisted of a control (receiving no N) and two to four split applications of N at the annual rates of 169, 225 and 280 kg N/ha. The annual rates of N application increased spring production of timothy but did not affect the seasonal and annual yields of the other crops. A split application of a portion of 225 or 280 kg N/ha in early summer instead of mid-summer increased timothy production during that season. Bromegrass production in spring was increased with an early spring application of a portion of the annual N rate of 280 kg/ha. Reed canarygrass production was not affected by split treatments of N. Nitrogen fertilization reduced white clover populations in the fields of timothy and reed canarygrass and of broad-leafed weed populations in all the forage crops.