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a Field Crop Development Centre, Alberta Agriculture, Food and Rural Development, 5030 50th Street, Lacombe, AB, T4L 1W8, Canada
patricia.juskiw{at}agric.gov.ab.ca
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ABSTRACT |
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 TOP ABSTRACT INTRODUCTIONMaterials and methodsResultsDiscussionConclusionsREFERENCES |
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Abbreviations: ADF, acid detergent fiber • A/E, actual/expected yield ratio • DM, dry matter • Im, yield of the mixture • NDF, neutral detergent fiber • NIR, near infrared reflectance • On, yield of the monocrop
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INTRODUCTION |
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TOPABSTRACTINTRODUCTIONMaterials and methodsResultsDiscussionConclusionsREFERENCES |
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The value of high-quality forage for high production rates from ruminant animals was discussed by Waldo and Jorgensen (1981) and Linn and Martin (1989). High-quality forage must have high intake, digestibility, and efficiency of utilization. Cell walls are an important component determining quality. They have a digestible and an indigestible fraction. Neutral detergent fiber content is a measure of the total cell wall fraction. Acid detergent fiber content is a measure of the indigestible fraction. When cell wall content of feed is low, increased intake and digestibility by animals is expected. Protein content is an important feed factor per se, with high-quality feed having a high protein content. Chemical composition and nutritive value of green plant material can give useful information about the quality of the resulting silage (Kjos, 1990).
Compositionally, legumes are known to have higher protein and lower cell wall fractions but higher lignin content than cereals (Waldo and Jorgensen, 1981). Nikkhah et al. (1995) found that chemical composition and digestion characteristics of cereal silage were similar to a medium-quality alfalfa. Most cereals are suitable for ensiling, but the yield and quality of the silage will depend on the species, cultivar, agronomic practices, and environmental conditions during growth. Within the small grain cereals, barley produces a better-quality silage than oat or triticale in terms of feed quality traits (Cherney and Marten, 1982; Khorasani et al., 1997) and intake and rate of gain of heifers (McCartney and Vaage, 1994).
Stage of maturity at harvest has a major effect on biomass yield and quality of cereals (Cherney and Marten, 1982; Twidwell et al., 1987; Bergen et al., 1991; Hadjipanayiotou et al., 1996; Mislevy et al., 1997). Although Schneider et al. (1991) found little effect of stage of maturity at harvest on triticale silage quality, Acosta et al. (1991) and Ben-Ghedalia et al. (1995) found that the quality of silage made from cereals declined with maturity at harvest. Yield increases and quality declines as the crop matures, although in cereals, quality may plateau or improve as grain development takes place (Khorasani et al., 1997). The optimal stage of harvest for barley and oat to maximize yield and quality traits is the soft-dough stage (Bergen et al., 1991); while for triticale and rye it ranges from the boot to early milk stages (Twidwell et al., 1987; Fearon et al., 1990; Schneider et al., 1991; Daccord and Arrigo, 1993).
Baron et al. (1992) found that yield of spring–winter cereal mixtures and intercrops ranged from 84 to 113% of the spring monocrop yield, and that the quality of these mixtures was consistently superior to the spring monocrops. However, Jedel and Salmon (1995) noted that the yield of spring–winter cereal mixtures was lower than the spring monocrop, with no quality difference. Jedel and Salmon (1994) did find that mixtures of spring triticale with barley or oat offered yield stability and better quality across years. Michalski (1994) found that increasing the proportion of triticale in mixtures with barley and oat increased lodging resistance and biomass yields. Jedel and Salmon (1995) found that a seeding rate 1.5x the standard rate of 260 seed m-2, in two of three years of testing, resulted in higher postanthesis biomass yields of cereal mixtures of spring triticale or barley with winter cereals.
The purpose of this study was to determine the influence of production practices (seeding rate, mixtures, and time of harvest) on the yield and quality potential for silage of spring and winter small grain cereals. To test the hypothesis that higher seeding rates may promote higher forage yields for cereal mixtures, addition series tests as outlined by Jokinen (1991) were conducted. A range of seeding rates was used to compare yield and quality potential for silage of barley cultivars and their mixtures, of spring cereals (barley, oat, and triticale) and their mixtures, and of winter cereals (rye and triticale) and their mixtures.
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Materials and methods |
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TOPABSTRACTINTRODUCTIONMaterials and methodsResultsDiscussionConclusionsREFERENCES |
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For Test 1, three subtests were based on `Kasota', an early, semi-dwarf, six-rowed spring barley; `AC Lacombe', a mid-maturing, six-rowed spring barley; and `Seebe', a late, two-rowed spring barley. Within each subtest of Test 1, the nine treatments were each cultivar as a monocrop and the mixtures of the base cultivar of the subtest in the ratios 1:1, 3:1, 1:1:1, and 3:1:1 with the two other cultivars.
For Test 2, the three subtests were based on `Noble', a mid-maturing, six-rowed spring barley; `AC Mustang', a late, spring oat; and `Wapiti', a late, spring triticale. Within each subtest of Test 2, the seven treatments were each species as a monocrop and mixtures of the principal component with the two other species in the ratios 1:1 and 3:1.
For Test 3, the two subtests were based on `Prima', a winter rye; and `Pika', a winter triticale. Within each subtest of Test 3, the treatments were each species as a monocrop and 1:1 mixture for a total of three treatments in 1994-1995, and 1:1, 2:1, and 3:1 mixtures of the principal component with the other species for a total of five treatments in 1995-1996.
The experimental design for each subtest (based on a principal-component cultivar) was a split-plot design with three replicates for Tests 1 and 2, and four replicates for Test 3. A higher replicate number was used for the winter test due to the potential for plot loss due to winterkill. Main plots were the rate of seeding and subplot treatments were the mixture and monocrop treatments. Seeding rate and mixture and monocrop treatments were treated as fixed effects and errors appropriate to this model were used to test effects (Steel and Torrie, 1980). Each subtest was analyzed across years using the GLM procedure (SAS Institute, 1988). Data presented are based on the significance of main or interaction effects from the analyses of variance. Mean separations within subtests were determined using LSMEAN comparisons (SAS Institute, 1988) at 
= 0.05. For comparisons between subtests and tests, means were compared by the method of Steel and Torrie (1980) for independent samples with unequal variances,
, where
with calculation of degrees of freedom.
Field Techniques and Trait Measurements
Plots were established from 1994 to 1996 at Lacombe, AB, on a Penfold loam [orthic Black Chernozem (coarse loamy, frigid Typic Haplustoll)] and for Test 3 only, in 1994 and 1995 at Botha, AB, on a Daysland loam [60% orthic Black Solod (coarse loamy, Typic Argiustoll with a natric horizon) and 40% thin orthic Black Chernozem (coarse loamy, frigid Typic Haplustoll)]. Due to hail in June of 1996 at Botha, data were not collected for that location–year. All seed was mixed in the desired ratios prior to planting. In 1994, seeding dates were 13 May for Test 1 and 5 May (early) and 9 June (late) for Test 2. The second seeding date for Test 2 in 1994 was planted due to a loss of plots from the early seeding when a wild oat herbicide was sprayed down one side of the test. However, although a few plots were lost, damage was not as extensive as first feared, and data were collected from both seeding dates. In 1994 for Test 3, seeding dates were 1 September at Botha and 3 September at Lacombe. In 1995, seeding dates at Lacombe were 9 May for Test 1, 4 May for Test 2, and 1 September for Test 3. In 1996, the seeding date for Tests 1 and 2 was 13 May. Barley seed was treated with Vitavax Single solution (a.i., carbathiin; Gustafson Canada, Calgary, AB, Canada) at 2 mL kg-1 prior to seeding. In all years for Tests 1, 2, and 3, 112 kg ha-1 of a premixed blend of ammonium phosphate and KCl (6-25-30, N-P-K) was incorporated with the seed. In 1996 before planting, additional fertilizer was incorporated as urea (46-0-0, N-P-K) at 112 kg ha-1 and ammonium phosphate (12-51-0, N-P-K) at 112 kg ha-1. In addition for Test 3 in the fall of 1994 at Lacombe, 3.4 kg ha-1 of actual Cu was incorporated before planting. Plot size was 2.52 by 1.12 m with eight rows per plot. Weed control was conducted as required using recommended herbicide treatments and hand weeding. Herbicides were applied as foliar sprays: 6 June 1994, to all tests (first seeding date only), chlorosulfuron {2-chloro-N-[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)amino]carbonyl]-benzenesulfonamide} at 11.1 g a.i. ha-1, and 2,4-D LV ester (2,4-dichloro-phenoxyacetic acid) at 445 g a.i. ha-1; 28 June 1994, to the second date of seeding of Test 2, thifensulfuron {3-[[[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)amino]carbonyl]-amino]sulfonyl-2-thiphenecarboxylic acid} at 9.9 g a.i. ha-1, tribenuron methyl {2-[[[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)methylamino]carbonyl]amino]-sulfonyl]benzoic acid} at 4.4 g a.i. ha-1, and MCPA (2-methyl-4-chlorophenoxyacetic acid) at 371 g a.i. ha-1; 7 June 1995 to Test 1, thifensulfuron was applied at 9.9 g a.i. ha-1, tribenuron methyl at 4.4 g a.i. ha-1, and 2,4-D LV ester at 247 g a.i. ha-1; 11 May 1995 to Test 3 (Botha), 31 May 1995 to Tests 2 and 3 (Lacombe), 4 June 1996 to Test 3 (Lacombe), and 6 June 1996 to Tests 1 and 2, thifensulfuron was applied at 9.9 g a.i. ha-1, tribenuron methyl at 4.4 g a.i. ha-1, and MCPA at 494 g a.i. ha-1; and 4 June 1996 to Tests 1 and 2, a second application of MCPA at 555 g a.i. ha-1 and bromoxynil (3,5-dibromo-4-hydroxybenzonitrile) at 277 g a.i. ha-1.
Subtests were harvested when the principal cultivar was at the soft-dough stage as outlined in Table 1 . Plots were cut with a modified forage chopper-harvester at a cutting height of 13 to 15 cm, a standard height for harvesting of forage. Whole-plot weights of green forage were recorded and a 500-g subsample was retained and dried (<60°C, >24 h) to determine moisture content for calculation of dry matter (DM) yield. Actual/expected yield ratios (A/E) were calculated based on the ratio of the yield of the mixture (Im) to the yields of the monocrops (On) or I1,2;1:1/[(O1 + O2)/2] (for 1:1 mixture of cultivar1 and cultivar2) as described by Jokinen (1991). Protein, ADF, and NDF concentrations were measured on the subsamples at the Soils and Animal Nutrition Laboratory, Alberta Agriculture, Food and Rural Development, Edmonton, using a NIRSystems 6500 (Foss NIRSystems, Silver Spring, MD). Samples were ground with a 1-mm screen in a Wiley hammer mill. Wet chemistry was conducted on samples for validation of the near-infrared reflectance (NIR) calibration. For full explanation of procedures refer to Alberta Agriculture, Food, and Rural Development (1995).
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Results |
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TOPABSTRACTINTRODUCTIONMaterials and methodsResultsDiscussionConclusionsREFERENCES |
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Few differences in protein content were found between treatments (Table 4). The AC Lacombe monocrop had lower protein content than the Kasota or Seebe monocrops in the Kasota- and AC Lacombe-based tests; but for the Seebe-based test, differences were no longer significant. Protein content for the mixtures tended to fall within the range of the monocrops. The effect of seeding rate on protein content was not significant (Table 3).
In all tests, the Seebe monocrop had the lowest ADF and NDF levels, while the AC Lacombe monocrop had higher levels (Table 4). The Kasota monocrop had similar ADF levels to the Seebe monocrop in the Kasota-based test but with the later-harvested tests, levels were similar to the AC Lacombe monocrop. For NDF levels, the Kasota monocrop had intermediate levels to Seebe and AC Lacombe for the Kasota-based test, but similar to, or higher than, levels to AC Lacombe for the later-harvested tests. As for other traits, ADF and NDF levels for the mixtures tended to be intermediate to their component monocrops. Seeding rate effects on NDF were significant for all three tests (Table 3). The higher seeding rates resulted in NDF levels 8 to 13 g kg-1 higher than at the standard seeding rate. Seeding rate effects on ADF were significant only for the Seebe-based test (Table 3). The ADF levels were 8 to 14 g kg-1 higher at the higher seeding rates than at the standard seeding rate. So while higher seeding rates led to higher biomass, the quality of that biomass was reduced.
Test 2 — Spring Cereal Mixtures (Barley, Oat, and Triticale)
In 1994 with the first sowing, no significant differences in biomass yield were found between treatments in the Noble barley-based test (Table 5)
. With the second sowing in 1994, the Wapiti triticale monocrop and the Wapiti mixtures had the highest biomass yields in the Noble barley-based test (Table 5). For the Noble barley-based test, the AC Mustang oat monocrop often had lower yields than the other two monocrops. By the harvest of the oat- and triticale-based tests, the AC Mustang oat monocrop had higher biomass yields than the Noble barley monocrop (Table 5). The AC Mustang and Wapiti had similar biomass yields in the oat- and triticale-based tests. While mixture yields tended to fall within the range of the component cultivars, the barley–oat mixtures (1:1 and 3:1) in the barley-based test often had higher yields than the two components, significantly so in three of six treatment–years (Table 5). By the later harvested subtests, the barley–oat mixtures no longer had superior yields; however, the AC Mustang–Wapiti mixture was performing well, especially the 1:1 mixture. The 1:1 AC Mustang–Wapiti mixture offered some yield stability when the relative yields of the monocrops varied between years. The A/E yield ratios were 1.05 for the Noble-based test, 1.01 for the AC Mustang-based test, and 1.00 for the Wapiti-based tests. No significant effects of seeding rate on yield were found except for the triticale-based test (Table 6)
. For this test a significant environment by seeding rate effect was found, with biomass yield 2.1 Mg ha-1 lower for the standard rate vs. the 1.5 x and 2 x seeding rates; however, this was in only one of the four location–years (data not shown).
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As measured by ADF content, all of the monocrops and mixtures harvested in these tests had relatively good forage quality (Table 7). The Noble monocrop had higher ADF and NDF levels with the later-harvested tests (Table 7). The Wapiti monocrop tended to have the lowest ADF and NDF levels of all the treatments in all of the tests (Table 7). As for other traits, the ADF and NDF levels of the mixtures were intermediate to the component cultivars. For the barley- and triticale-based tests, seeding rate had a significant effect on NDF content, and for the triticale-based test, on ADF content as well (Table 6). For the barley-based test, the 2 x seeding rate resulted in a 5 g kg-1 higher NDF level than the standard seeding rate. For the triticale-based test, the 2 x seeding rate resulted in an 11 g kg-1 higher ADF level and a 9 g kg-1 higher NDF level than the standard seeding rate.
Test 3 — Winter Cereal Mixtures (Rye and Triticale)
No significant differences in biomass yield were found between the rye, triticale, and their mixtures, although the interaction of seeding rate with treatments for the Pika triticale-based test was significant (Table 8)
. The Prima rye monocrop had higher yields than either the Pika monocrop or the 1:1 Pika–Prima mixture at the standard and 2 x seeding rates, while no difference between these treatments was found at the 3 x seeding rate (Table 9) . For the Prima rye-based test, a significant environment x seeding rate effect on yield was found (Table 8). At Botha in 1995, yield was 1.1 Mg ha-1 higher for the 3 x seeding rate than the standard seeding rate. At Lacombe in 1995, yield at the 3 x seeding rate was 0.6 Mg ha-1 higher than the 2 x seeding rate and 1.2 Mg ha-1 higher than the standard rate. At Lacombe in 1996, yield at the 2 x rate was 2.5 Mg ha-1 higher than at the 3 x rate and 1.3 Mg ha-1 higher than at the standard rate. Actual/expected yield ratios for the Prima rye-based test was 1.03 and for the Pika triticale-based test was 0.98.
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Discussion |
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TOPABSTRACTINTRODUCTIONMaterials and methodsResultsDiscussionConclusionsREFERENCES |
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For the spring barley tests, the Seebe monocrop had the best biomass yields across all three subtests, being 3 to 25% higher than the Kasota monocrop. All three of the barley cultivars in the spring barley test continued to accumulate biomass, as shown by higher biomass yields from the early-harvested to the late-harvested subtests.
For the spring cereal tests, the Wapiti monocrop had the best biomass yields across all three subtests, being 5 to 50% higher than the Noble monocrop (although in 1996 the yield was 14% lower in the Noble barley-based test). The oat cultivar, AC Mustang, was high-yielding relative to Noble only in the later-harvested subtests, being 5 to 44% higher than the Noble monocrop. This increase in yield was due to biomass accumulation by the oat, and a decline in biomass yield of Noble with maturation and accompanying loss of leaf material (Juskiw et al., 2000).
Where the Prima rye had higher yields than the Pika triticale, it may have been due to better over-wintering of the rye than the triticale or to an almost 2-wk earlier reinitiation of growth in the spring, a difference reported by Jedel and Salmon (1995). Using fall-planted winter triticale in mixtures may require development of more hardy types that over-winter as well as the rye or the use of higher proportions of triticale in the mixture. However, mixtures of winter rye with other cereals may be ineffective due to an allelopathic effect of the rye (Rice, 1984).
Harvest was timed to cut each test when the base cultivar was in the soft-dough stage. The barley and oat cultivars all tended to have 
650 to 700 g kg-1 moisture content at the soft-dough stage, but for the spring and winter triticale and winter rye, moisture contents at the soft-dough stage were often lower than 650 g kg-1. Harvesting triticale and rye for silage production in the milk stage to ensure optimum moisture for ensiling may be preferable to waiting until the soft-dough stage. Harvesting at the milk stage would be supported by the recommendations of Fearon et al. (1990) and Schneider et al. (1991) to optimize yield and quality of triticale silage. The moisture contents of the mixtures were intermediate to the monocrops. If the cultivars in a mixture are drying-down at the same rate, then a mixture would only shift the period of harvest. However, if the cultivars are drying-down at different rates, then a mixture may extend the window of harvest, at least in comparison with the cultivar that is drying-down at a faster rate. In these tests, there was less moisture loss from subtest to subtest for the oat and triticale than the barley, indicating that the barley was drying-down faster. Therefore, mixtures of these species may lengthen the harvest period compared with that for a barley monocrop. This extension of the harvest window may be particularly important in areas where harvest for silage is hindered by adverse weather conditions or accelerated by hot, dry conditions.
Protein contents for these tests were low compared with contents of 90 to 125 g kg-1 for barley and triticale monocrops and mixtures harvested at the soft-dough stage previously reported by Jedel and Salmon (1995). However, biomass yields for their tests ranged from 2.88 to 15.94 Mg ha-1, while in our test they ranged from 8.86 to 17.37 Mg ha-1, a difference which may have led to a dilution effect on the protein contents reported here. Compared with forage legumes, low protein content of cereals for silage production is one of their undesirable traits. However, when silage is being used as the energy and fiber component of the diet, it may not be critical that it have high protein levels, as the protein is often supplied through a corn (Zea mays L.), canola (Brassica spp.), soybean [Glycine max (L.) Merr.], pea (Pisum sativum L.), or small grain cereal component of the diet. Increased N fertilizer application may be a means to improve protein content in cereal silage (McKenzie et al., 1999); however, it may be at the expense of fiber quality (DiRienzo et al., 1991). The high protein content for the Pika monocrop, compared with the rye monocrop and the mixture, was probably due to the relative immaturity of the Pika compared with the rye.
Acid detergent fiber content of 300 g kg-1 is desirable to prevent diarrhea, but levels higher than this can reduce feed conversion. Generally, all treatments in our study had good fiber quality. Although, an increase in NDF and ADF levels of the early barleys (Kasota and Noble) was observed with the later-cut subtests. For the barley-based tests, Seebe had the lowest fiber content. For the spring cereal tests, Wapiti had the lowest fiber content. With the later-harvested subtests, the fiber content of the AC Mustang monocrop decreased and Wapiti stayed relatively low. Therefore, inclusion of either oat or triticale in a mixture with barley could help to extend the window for silage harvest by maintaining quality as the crop matures. While the Pika triticale had higher protein levels than the Prima rye, it also had higher fiber levels. Despite low moisture content at the soft-dough stage, the winter cereals still maintained low ADF and NDF levels.
Seeding rate had little effect on the yield and quality for silage of the cereals used in these tests. The lack of response to seeding rate was surprising, as Jedel and Salmon (1994, 1995) had earlier found a positive response of cereal biomass yields to higher seeding rates and the general recommendation for silage production is to use a seeding rate of 1.5 x standard. When significant effects of seeding rate were observed, they were associated with a decline in moisture content at harvest and higher fiber content. At the lower seeding rates, there was probably an increase in tillers per plant as plant population per unit area was less. Later tillers would be expected to be less mature at harvest for ensiling, therefore having higher moisture and lower fiber content. Jedel and Helm (1995) had earlier reported little effect of seeding rates from 180 to 320 seeds m-2 on grain yield of barley in this region, so the lack of response to seeding rates in two of the three barley tests was not unexpected.
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Conclusions |
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TOPABSTRACTINTRODUCTIONMaterials and methodsResultsDiscussionConclusionsREFERENCES |
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Seeding rate had little effect on yield and quality potential of cereals for ensiling. When effects of seeding rate were significant, as seeding rate increased, yield increased, moisture content at harvest declined, and fiber content increased. The negative effect on quality would offset to some extent the yield advantage of seeding at the higher seeding rates.
All of the cereals used in these tests had excellent yields and quality, although protein levels were generally low. Cultivar differences were found, with Seebe barley, Wapiti triticale, and Prima winter rye having the best yields and quality in their respective tests.
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ACKNOWLEDGMENTS |
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Received for publication December 22, 1998.
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TOPABSTRACTINTRODUCTIONMaterials and methodsResultsDiscussionConclusionsREFERENCES |
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paszowa pszen
yta jarego w siewie czystym i mieszankach trójgatunkowych z j
czmieniem i owsem. Zeszyty Naukowe Akademii Rolniczej w Szczecinie. 1994;162:169-173.This article has been cited by other articles:
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