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maturing, six-rowed spring barley; 'AC Mustang', a late, spring yields. Jedel and Salmon (1995) found that a seeding oat; and 'Wapiti', a late, spring triticale.
CROP ECOLOGY, PRODUCTION, & MANAGEMENT Forage Yield and Quality for Monocrops and Mixtures of Small Grain Cereals P. E. Juskiw,* J. H. Helm, and D. F. Salmon ABSTRACT

that sufficient compaction occurs for exclusion of O2, that the fermentation processes of ensiling occur, and that overheating does not occur. However, moisture contents ⬎700 g kg⫺1 can lead to seepage problems from the silo or pit, nutrient loss due to leakage, dilution of acid levels, and poor preservation of the silage. Ensiling does not increase the quality of the feedstuffs, so it is important that high-quality material is put into the silo. 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). Highquality 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 highquality 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

Cereals are an important substrate for silage production in the short growing season of the northern Prairies. Our objectives were to determine the effects of seeding rate, species, and harvest date on the forage yield and quality of cereals. Three field studies were conducted to evaluate the productivity of barley (Hordeum vulgare L.), oat (Avena sativa L.), triticale (⫻ Triticosecale rimpaui Wittm.), and rye (Secale cereale L.) grown as monocrops or in various mixtures. Seeding rates ranged from 250 to 750 seeds m⫺2. Harvest times were based on the maturity of the principal cereal in each mixture. Few effects of seeding rate on yield or quality were found, but when effects were found, higher seeding rates were associated with higher yields, lower moisture content, and higher fiber content. All treatments produced high quality forage as measured by neutral detergent fiber (NDF), from 515 g kg⫺1 for early-harvested tests to 656 g kg⫺1 for late-harvested tests, and acid detergent fiber (ADF) contents, from 310 g kg⫺1 for early-harvested tests to 387 g kg⫺1 for late-harvested tests. Protein was low, ranging from 61.5 to 101.0 g kg⫺1. Biomass yields ranged from 10.1 to 16.5 Mg ha⫺1 in the barley cultivar tests, 7.0 to 18.5 Mg ha⫺1 in the spring cereal tests, and 10.8 to 12.2 Mg ha⫺1 in the winter cereal tests. Although, some exceptions occurred, forage yield and quality of cereal mixtures were generally intermediate to monocrop production, especially for moisture and fiber content, suggesting that planting species mixtures could extend the harvest period and result in higher-quality silage.

A

nnual cereals are a major substrate for silage production on the northern Prairies. They complement or are used as an alternative to silage made from alfalfa (Medicago sativa L.) and other perennial grasses and legumes. Cereal silage is predominantly used as cattle feed in feedlots and dairies, but some is used for sheep and horse feed. The ensiling process involves swathing the cereal while immature, wilting the material in the field if necessary (material may be allowed to dry-down in the swath) and cutting the material into small 0.5- to 3.5-cm lengths. This field operation is followed by packing the cut material into an upright silo or horizontal trench or bunker silo. Air is excluded from silos by packing the material with heavy machinery and covering with plastic or soil. During the ensiling process, fermentation occurs, releasing organic acids, preferably lactic acid. The high acid content lowers the pH to a desirable 4.2 to 4.5 range, thereby preserving proteins and carbohydrates. Adequate moisture content (⬎650 g kg⫺1) of the green plant material is essential to ensure Field Crop Development Centre, Alberta Agriculture, Food and Rural Development, 5030 50th Street, Lacombe, AB, T4L 1W8, Canada. Received 22 Dec. 1998. *Corresponding author (patricia.juskiw@ agric.gov.ab.ca).

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.

Published in Crop Sci. 40:138–147 (2000).

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JUSKIW ET AL.: MONOCROPS AND MIXTURES OF SMALL GRAIN CEREALS: FORAGE YIELD AND QUALITY

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 1.5⫻ 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. MATERIALS AND METHODS Test Treatments and Design This study consisted of three tests: Test 1, spring barley cultivar mixtures; Test 2, spring cereal mixtures of barley, oat,

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and triticale; and Test 3, winter cereal mixtures of rye and triticale. Seeding rates used for Tests 1 and 2 were 250 (standard), 375 (1.5 ⫻), and 500 (2 ⫻) seeds m⫺2. Seeding rates used for Test 3 were 250 (standard), 500 (2 ⫻), and 750 (3 ⫻) seeds m⫺2. Due to the potential for winter kill, higher seeding rates were used for the winter tests than the spring-planted tests. Germination tests were conducted on all seed lots prior to seed setup, and seeding rates were adjusted so rates were based on a live-seed basis. Within Tests 1 and 2, three subtests were run based on the principal cultivar of the test, while within Test 3, two subtests were run. The subtests were run to facilitate harvesting of the crop when the principal component was at the soft-dough stage (Zadoks growth stage 85). For Test 1, three subtests were based on ‘Kasota’, an early, semi-dwarf, six-rowed spring barley; ‘AC Lacombe’, a midmaturing, six-rowed spring barley; and ‘Seebe’, a late, tworowed 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 midmaturing, 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 In-

Table 1. Harvest dates for biomass and quality determinations of cereal forage and total precipitation (May–July) for growth period. Test

Subtest

1994

1995

1996

Harvest dates Test 1 Spring barleys

Test 2 Spring cereals†

Test 3 Winter cereals

Kasota-based AC Lacombe-based Seebe-based

3 Aug. 4 Aug. 8 Aug.

28 July 31 July 4 Aug.

29 July 1 Aug. 7 Aug.

Noble barley-based AC Mustang oat-based Wapiti triticale-based

23 Aug. (2 Aug.) 6 Sept. (18 Aug.) 6 Sept. (18 Aug.)

24 July 14 Aug. 16 Aug.

1 Aug. 19 Aug. 21 Aug.

21 26 17 19

– 15 July – 22 July

Prima rye-based at Botha Prima rye-based at Lacombe Pika triticale-based at Botha Pika triticale-based at Lacombe Total precipitation

– – – –

July July July July

mm Lacombe Botha

148 –

168 166

† In 1994 for the spring cereals tests, two dates were planted. The date of harvest for the first seeding date is in parentheses.

110 –

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stitute, 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, t ⫽ (x1 ⫺ x2)/s(x1⫺x2), where s(x1⫺x2) ⫽ (s21/n1 ⫹ s22/n2)1/2 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-chloroN-[[(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-2yl)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 500g 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).

RESULTS Test 1 — Spring Barley Mixtures The Kasota monocrop was continually the lowestyielding treatment, while the Seebe monocrop was one Table 2. Biomass yield (dry matter basis) of barley monocrops and mixtures when harvested at the soft-dough stage of the base cultivar, at Lacombe, AB from 1994 to 1996. Biomass yield Treatment

1994

1995

1996

Mean

ha⫺1

Mg Kasota-based test Kasota AC Lacombe Seebe 1:1 Kasota–AC Lacombe 3:1 Kasota–AC Lacombe 1:1 Kasota–Seebe 3:1 Kasota–Seebe 1:1:1 Kasota–AC Lacombe–Seebe 3:1:1 Kasota–AC Lacombe–Seebe SE‡

12.74d† 14.14ab 14.22a 13.21d 13.39cd 13.43bcd 12.86d

11.01e 11.15de 12.53a 11.79bcd 11.20de 12.27ab 12.00abc

Kasota AC Lacombe Seebe 1:1 AC Lacombe–Kasota 3:1 AC Lacombe–Kasota 1:1 AC Lacombe–Seebe 3:1 AC Lacombe–Seebe 1:1:1 AC Lacombe–Kasota– Seebe 3:1:1 AC Lacombe–Kasota– Seebe SE

12.22e 15.15a 14.66ab 13.89cd 14.40bc 14.88ab 14.59ab

10.70f 11.77de 13.36a 11.29ef 11.77de 12.45bc 12.95ab

10.38c 10.90abc 11.44a 10.41bc 10.74bc 10.99abc 11.02ab

11.10g 12.61bcd 13.15a 11.87f 12.31d 12.77bc 12.85ab

13.73d

12.08cd

10.46bc

12.09ef

14.36bcd 12.05cd 10.94abc 0.22 0.22 0.22 Seebe-based test§

12.45cde 0.13

Kasota AC Lacombe Seebe 1:1 Seebe–Kasota 3:1 Seebe–Kasota 1:1 Seebe–AC Lacombe 3:1 Seebe–AC Lacombe 1:1:1 Seebe–Kasota–AC Lacombe 3:1:1 Seebe–Kasota–AC Lacombe SE

12.58d 15.49a 14.38bc 15.13ab 15.34a 14.04c 14.67abc

14.10f 15.25cde 16.21ab 16.48a 16.17abc 15.14de 15.49bcde

11.81b 12.51ab 12.81a 13.07a 13.00a 12.44ab 12.87a

12.83e 14.41abcd 14.47abc 14.89a 14.84ab 13.87d 14.34bcd

14.34bc

14.81ef

12.67ab

13.94cd

13.98abc 12.19ab 13.08d 0.26

10.26a 10.49a 10.54a 10.10a 10.14a 10.44a 10.47a

11.34e 11.93bcd 12.43a 11.70cde 11.58de 12.05abc 11.78cde

10.67a

12.28ab

11.45cde 10.48a 11.67cde 0.26 0.26 0.15 AC Lacombe-based test

14.66abc 15.76abcd 13.06a 0.33 0.33 0.33

14.49ab 0.19

† Within a subtest and column, means followed by the same letter are not significantly different at ␣ ⫽ 0.05 using LSMEAN comparisons (SAS Institute, 1988). ‡ SE is for the comparison of treatment means within and between years within a subtest. § The interaction of year ⫻ treatment for the Seebe-based test was not significant by GLM.

JUSKIW ET AL.: MONOCROPS AND MIXTURES OF SMALL GRAIN CEREALS: FORAGE YIELD AND QUALITY

of the highest-yielding treatments in all three spring barley subtests (Table 2). The yields of the AC Lacombe monocrop were more variable depending on year and test. The mixtures tended to yield between the yields of the component monocrops. However, the Kasota– Seebe mixtures harvested at the soft-dough stage of Seebe tended to have higher yields than either monocrop (Table 2). The three-way mixtures did not outperform the two-way mixture, although in the Kasotabased test, especially the 1:1:1 mixture had higher yields. The mixtures with Seebe tended to out-perform the Kasota–AC Lacombe mixtures. When A/E ratios were calculated, treatment effects were not significant (Table 4). Average A/E ratios were 1.01 for the Kasota-based test, 1.00 for the AC Lacombe-based test, and 1.02 for the Seebe-based test. The only significant seeding rate effect on yield was for the Kasota-based test (Table 3), with yields at the 2 ⫻ seeding rate being 0.51 Mg ha⫺1 more than the standard rate and at the 1.5 ⫻ rate, 0.45 Mg ha⫺1 more. The Seebe monocrop had the highest moisture content for all tests (Table 4). For the Kasota-based test, increasing the Kasota portion of the mixtures significantly reduced moisture content. For the AC Lacombebased test, moisture content of the mixtures was very similar to the AC Lacombe monocrop. For the Seebe-

141

based test, treatment effects on moisture content depended on year (Table 3), but the mixtures generally had moisture contents similar to the Seebe monocrop. There was a significant seeding rate effect on moisture content for the AC Lacombe-based test (Table 3) with the standard seeding rate resulting in 8 to 10 g kg⫺1 higher moisture content at harvest than the 1.5 ⫻ and 2.0 ⫻ rates. 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 Kasotabased 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-

Table 3. Mean squares from the analysis of variance for biomass yield, moisture, protein, acid detergent fiber (ADF), neutral detergent fiber (NDF), and actual/expected yield ratio (A/E) of barley monocrops and mixtures when harvested at the soft-dough stage of the base cultivar, at Lacombe, AB from 1994 to 1996. Source of variation

df

Biomass yield Mg

Moisture

ha⫺1

Protein

ADF

NDF

df

A/E

kg⫺1†

(⫻100) g Kasota-based test

Year (y) Error a Seeding rate (r) y⫻r Error b Treatment (t) y⫻t r⫻t y⫻r⫻t Error c

2 6 2 4 12 8 16 16 32 143

189.547** 0.759 6.391** 0.762ns 0.464 3.236** 1.246* 0.472ns 0.595ns 0.595

434.7** 14.0 6.4ns 2.3ns 3.5 24.9** 3.0ns 2.0ns 1.4ns 2.0

264.12** 384.1** 9.09 3.7 1.91ns 6.2ns 1.40ns 5.5ns 1.56 3.4 2.24** 14.9** 1.22ns 2.3ns 0.72ns 3.4ns 0.97ns 2.4ns 0.80‡ 2.4‡ AC Lacombe-based test

1822.8** 3.4 7.3* 1.4ns 1.5 35.9** 4.7** 1.1ns 1.8ns 2.2‡

2 6 2 4 12 5 10 10 20 89

0.027ns 0.008 0.000ns 0.014ns 0.012 0.003ns 0.004ns 0.002ns 0.005ns 0.004

Year (y) Error a Seeding rate (r) y⫻r Error b Treatment (t) y⫻t r⫻t y⫻r⫻t Error c

2 6 2 4 12 8 16 16 32 144

238.584** 5.939 4.361ns 1.393ns 2.063 10.184** 1.789** 0.449ns 0.512ns 0.445

267.8** 5.3 21.7* 10.8ns 4.7 30.3** 3.0ns 3.0ns 4.0* 2.3

38.03* 348.4** 6.11 8.2 1.53ns 13.3ns 0.39ns 7.3ns 1.78 5.0 1.71* 7.3** 0.80ns 6.1** 0.55ns 3.2ns 0.86ns 2.7ns 0.82 2.0 Seebe-based test

1615.2** 4.8 19.0* 7.3ns 4.1 18.1** 11.9** 2.0ns 1.9ns 2.1

2 6 2 4 12 5 10 10 20 90

0.022ns 0.023 0.024ns 0.016ns 0.019 0.004ns 0.004ns 0.001ns 0.002ns 0.003

Year (y) Error a Seeding rate (r) y⫻r Error b Treatment (t) y⫻t r⫻t y⫻r⫻t Error c

2 6 2 4 12 8 16 16 32 144

162.914** 4.080 0.129ns 2.454ns 3.270 10.622** 1.407ns 0.877ns 1.375ns 1.004

459.7** 6.6 12.3ns 5.8ns 3.4 62.6** 6.62* 3.05ns 3.61ns 3.37

2402.2** 4.0 35.4** 1.7ns 2.6 27.8** 9.5** 1.3ns 2.3ns 2.8

2 6 2 4 12 5 10 10 20 90

0.013ns 0.010 0.012ns 0.069* 0.020 0.003ns 0.004ns 0.006ns 0.004ns 0.005

215.30** 7.44 2.84ns 1.68ns 1.61 1.08ns 1.44ns 0.87ns 1.51ns 1.21

*, ** Significant at 0.05 and 0.01 levels of probability, respectively; ns is not significant. † Actual values equal reported values times the indicated factor. ‡ Degrees of freedom ⫽ 142, due to missing plot.

564.7** 10.6 37.8** 3.7ns 3.1 12.8** 6.2* 3.3ns 3.8ns 3.2

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Table 4. Moisture, protein, acid detergent fiber (ADF), and neutral detergent fiber (NDF) content of barley monocrops and mixtures when harvested at the soft-dough stage of the base cultivar, at Lacombe, AB from 1994 to 1996. Treatment

Moisture

Protein

ADF

NDF

g kg⫺1 Kasota-based test Kasota AC Lacombe Seebe 1:1 Kasota–AC Lacombe 3:1 Kasota–AC Lacombe 1:1 Kasota–Seebe 3:1 Kasota–Seebe 1:1:1 Kasota–AC Lacombe–Seebe 3:1:1 Kasota–AC Lacombe–Seebe SE

701e† 724b 735a 720bc 710d 720bc 714cd 724b 715cd 2.7 AC

Kasota AC Lacombe Seebe 1:1 AC Lacombe–Kasota 3:1 AC Lacombe–Kasota 1:1 AC Lacombe–Seebe 3:1 AC Lacombe–Seebe 1:1:1 AC Lacombe–Kasota–Seebe 3:1:1 AC Lacombe–Kasota–Seebe SE

691c 710b 727a 704b 707b 724a 711b 712b 710b 2.9

Kasota AC Lacombe Seebe 1:1 Kasota–Seebe 3:1 Kasota–Seebe 1:1 AC Lacombe–Seebe 3:1 Seebe–AC Lacombe 1:1:1 Kasota–AC Lacombe–Seebe 3:1:1 Seebe–Kasota–AC Lacombe SE

641c 667b 691a 675b 684a 668b 686a 674b 685a 3.5

96.0a 312c 540d 86.2b 330a 564a 93.3a 311c 529e 92.3a 327ab 561a 92.2a 317bc 548bc 93.6a 310c 535de 94.5a 313c 538d 92.1a 322ab 550b 96.1a 312c 541cd 1.7 3.0 2.9 Lacombe-based test 101.0a 330ab 93.0d 335a 98.9abc 317c 94.8cd 330ab 97.2abcd 332ab 97.2abcd 328ab 96.9abcd 326b 95.5bcd 327b 99.9ab 325bc 1.7 2.7 Seebe-based test 94.0 92.3 96.9 93.9 95.8 93.0 98.3 93.4 96.0 NS

341a 341a 323c 325bc 329bc 334ab 324c 333abc 330bc 3.4

574a 573a 548d 572ab 569abc 562c 564bc 562c 562c 2.8 589a 586a 561d 567bcd 564cd 572bc 561d 575b 572bc 3.2

† Within a subtest and column, means followed by the same letter are not significantly different at ␣ ⫽ 0.05 using LSMEAN comparisons (SAS Institute, 1988).

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 Wa-

piti had similar biomass yields in the oat- and triticalebased 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 ⫻ and 2 ⫻ seeding rates; however, this was in only one of the four location–years (data not shown). Moisture contents of the mixtures fell between that of the component cultivars (Table 7). For the barleybased test in 1994 and the oat- and triticale-based tests in all years (data not shown), moisture content of the base cultivar was often ⬍650 g kg⫺1. Significant seeding rate effects on moisture content were found for the barley-based test, and for the interaction of rate with treatment for the oat-based test (Table 6). For the barley-based test, the moisture content at the standard seeding rate was 10 g kg⫺1 higher than at the 2 ⫻ rate. The interaction effect in the oat-based tests was due to the oat monocrop having a 20 g kg⫺1 higher moisture content at the standard seeding rate than the oat– triticale mixtures, while at the 1.5 ⫻ and 2 ⫻ seeding rates, the monocrop and oat–triticale mixtures had similar moisture contents. The Noble and Wapiti monocrops had higher protein contents than the AC Mustang monocrop in the barleybased test, but by the harvest of the oat- and triticalebased tests, the AC Mustang monocrop often had protein content similar to the barley monocrop, and higher than the triticale monocrop (Table 7). The protein content of the mixtures was generally intermediate to the monocrop components (Table 7). No significant effects of seeding rate on protein content were found (Table 6). 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 triticalebased 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 ⫻ seeding rate resulted in a 5 g kg⫺1 higher NDF level than the standard seeding rate. For the triticale-based test, the 2 ⫻ 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.

JUSKIW ET AL.: MONOCROPS AND MIXTURES OF SMALL GRAIN CEREALS: FORAGE YIELD AND QUALITY

143

Table 5. Biomass yield (dry matter basis) of barley, oat, and triticale monocrops and mixtures when harvested at the soft-dough stage of the base species, at Lacombe, AB from 1994 to 1996. Biomass yield Treatment

1994a†

1994b

1995

1996

Mean

10.66a 9.38b 9.12b 10.90a 11.16a 10.47a 10.69a 0.30

11.03b 10.52c 11.22b 11.75a 11.34ab 11.16b 11.33ab 0.16

12.88d 15.80a 15.19ab 14.40bc 14.17c 14.83bc 14.96abc 0.34

10.97c 13.85a 14.11a 12.66b 13.12b 13.98a 13.70a 0.18

13.27c 15.40a 14.10bc 14.64ab 14.94ab 15.11ab 14.10bc 0.42

10.82d 13.41b 14.07a 12.49c 13.54ab 13.70ab 13.42ab 0.23

Mg ha⫺1 Noble barley-based test Noble AC Mustang Wapiti 1:1 Noble–AC Mustang 3:1 Noble–AC Mustang 1:1 Noble–Wapiti 3:1 Noble–Wapiti SE§

14.79a‡ 14.29a 15.18a 15.27a 14.82a 14.58a 14.78a 0.36

9.50c 9.55c 10.90a 10.48ab 9.95b 10.41ab 10.23abc 0.30

9.16b 8.87b 9.66ab 10.34a 9.43b 9.18b 9.64ab 0.30 AC Mustang oat-based test

Noble AC Mustang Wapiti 1:1 AC Mustang–Noble 3:1 AC Mustang–Noble 1:1 AC Mustang–Wapiti 3:1 AC Mustang–Wapiti SE

13.47d 14.53cd 17.86a 15.19c 15.04c 16.83ab 15.66bc 0.42

8.52d 12.26a 11.24bc 10.33c 11.55ab 11.79ab 11.51ab 0.34

9.01d 12.81a 12.17ab 10.74c 11.70bc 12.47ab 12.66ab 0.34 Wapiti triticale-based test

Noble AC Mustang Wapiti 1:1 Wapiti–Noble 3:1 Wapiti–Noble 1:1 Wapiti–AC Mustang 3:1 Wapiti–AC Mustang SE

14.40d 15.21cd 18.51a 15.79cd 17.37ab 15.76bcd 16.27bc 0.55

8.61c 12.22a 12.72a 10.15b 12.29a 12.28a 12.20a 0.42

6.99c 10.80a 10.95a 9.39b 9.56b 11.63a 11.09a 0.42

† In 1994, the early planting date is denoted by “a” and the second planting date that year by “b”. ‡ Within a subtest and column, means followed by the same letter are not significantly different at ␣ ⫽ 0.05 using LSMEAN comparisons (SAS Institute, 1988). § SE is for the comparison of treatment means within and between years within a subtest.

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 ⫻ seeding rates, while no difference between these treatments was found at the 3 ⫻ seeding rate (Table 9). For the Prima rye-based test, a significant environment ⫻ seeding rate effect on yield was found (Table 8). At Botha in 1995, yield was 1.1 Mg ha⫺1 higher for the 3 ⫻ seeding rate than the standard seeding rate. At Lacombe in 1995, yield at the 3 ⫻ seeding rate was 0.6 Mg ha⫺1 higher than the 2 ⫻ seeding rate and 1.2 Mg ha⫺1 higher than the standard rate. At Lacombe in 1996, yield at the 2 ⫻ rate was 2.5 Mg ha⫺1 higher than at the 3 ⫻ 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. Harvest at the soft-dough stage for these winter cereals resulted in a lower than desired moisture content of 650 to 700 g kg⫺1 (Table 10). As expected due to relative maturity, the Pika monocrop was more moist at harvest than the Prima, while the mixture was intermediate (Table 10). Protein content of these winter cereals were 65 g kg⫺1 for the rye-based tests and 56 g kg⫺1 for the triticale-

based test. Seeding rate effects on treatments were significant for the rye-based test (Table 9), with the Pika monocrop having higher protein than the Prima monocrop and the 1:1 mixture at the standard and 2 ⫻ seeding rates than at the 3 ⫻ seeding rate (Table 11). The mixture had a lower protein content than the Prima monocrop at the 3 ⫻ seeding rate (Table 11). Where treatment effects were significant, the Pika monocrop had higher ADF and NDF levels than the Prima monocrop (Table 10). Generally the mixture had ADF and NDF levels intermediate to the monocrops. While seeding rate had no significant effect on ADF content, it did on NDF content for both subtests (Table 9). The 3 ⫻ seeding rate resulted in a 10 g kg⫺1 higher NDF level in the rye-based test and 13 g kg⫺1 higher NDF level in the triticale-based test compared with the standard seeding rate.

DISCUSSION Based on the A/E, mixtures offered little yield advantage over high-yielding monocrops. The mixtures of the spring cereals were about the same as growing pure stands of the monocrops on the same land basis. However, the barley–oat mixtures harvested when the barley component was at the soft-dough stage and the Seebe– Kasota mixtures harvested when the Seebe component was at the soft-dough stage tended to be higher-yielding than the component monocrops, although not always significantly so. The mixtures of the winter cereals had

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Table 6. Mean squares from the analysis of variance for biomass yield, moisture, protein, acid detergent fiber (ADF), neutral detergent fiber (NDF), and actual/expected yield ratio (A/E) of barley, oat, and triticale monocrops and mixtures when harvested at the softdough stage of the base cultivar, at Lacombe, AB from 1994 to 1996. Source of variation

df

Biomass yield

Moisture

Mg ha⫺1

Protein

ADF

NDF

df

A/E

(⫻100) g kg⫺1† Noble barley-based test

Year (y) Error a Seeding rate (r) y⫻r Error b Treatment (t) y⫻t r⫻t y⫻r⫻t Error c

3 7 2 6 14 6 18 12 36 126

276.122** 2.558 3.114ns 1.237ns 1.111 4.414** 1.918** 1.118ns 0.799ns 0.789

557.7** 11.4 17.27* 5.8ns 4.0 311.1** 9.4** 3.8ns 5.7ns 3.8

109.22** 193.4** 4.22 4.1 1.76ns 1.8ns 0.71ns 1.7ns 0.77 2.4 5.01** 115.4** 3.73** 22.3** 1.70ns 3.6ns 1.33ns 2.4ns 1.35 3.3 AC Mustang oat-based test

882.2** 5.4 8.3* 1.4ns 2.1 238.9** 33.4** 2.4ns 2.2ns 2.3

2 6 2 4 12 3 4 6 8 66

0.006ns 0.052 0.033ns 0.021ns 0.020ns 0.048ns 0.009ns 0.016ns 0.014ns 0.038

Year (y) Error a Seeding rate (r) y⫻r Error b Treatment (t) y⫻t r⫻t y⫻r⫻t Error c

3 7 2 6 14 6 18 12 36 126

262.212** 10.288 1.856ns 2.416ns 1.335 39.332** 3.460** 1.435ns 1.153ns 1.077

576.0** 3.4 20.2ns 7.7ns 7.3 583.8** 30.3** 7.2** 3.0ns 2.9

241.65** 30.3* 5.30 6.4 0.06ns 3.9ns 0.78ns 11.8ns 1.47 6.8 1.79** 163.7** 2.03** 19.7** 0.84ns 6.4ns 0.79ns 4.9ns 0.56 4.3 Wapiti triticale-based test

768.1** 8.7 2.4ns 14.8ns 8.1 453.7** 22.3** 5.2ns 6.1ns 5.9

1 4 2 2 8 3 3 6 6 60

0.009ns 0.001 0.056ns 0.022ns 0.013 0.001ns 0.007ns 0.004ns 0.005ns 0.032

Year (y) Error a Seeding rate (r) y⫻r Error b Treatment (t) y⫻t r⫻t y⫻r⫻t Error c

3 7 2 6 14 6 18 12 36 123

388.656** 4.391 1.239ns 6.089* 1.706 38.064** 5.958** 1.943ns 2.105ns 1.573

368.9** 12.8 15.0ns 2.5ns 4.5 756.9** 35.9** 3.0ns 4.2ns 3.0

384.5** 1.8 27.6** 2.3ns 1.4 499.7** 24.2** 3.4ns 2.2ns 2.1

2 6 2 4 12 3 4 6 8 63

0.083ns 0.151 0.025ns 0.027ns 0.843 0.013ns 0.136ns 0.129ns 0.146ns 0.034

224.55** 2.83 3.44ns 0.48ns 1.20 1.00ns 2.47** 0.58ns 0.39ns 0.85

69.8** 5.8 13.7** 0.5ns 1.8 176.9** 10.5** 3.2ns 3.0ns 2.0

*, ** Significant at 0.05 and 0.01 levels of probability, respectively; ns is not significant. † Actual values equal reported values times the indicated factor.

a slight yield disadvantage compared with the higheryielding monocrop. As the proportion of the principal component in the mixture increased, the mixture performance was more like that monocrop. Three-way mixtures did not generally out-perform two-way mixtures, and relative performance of any mixture was dependent on when it was harvested. 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 barleybased test). The oat cultivar, AC Mustang, was highyielding 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

JUSKIW ET AL.: MONOCROPS AND MIXTURES OF SMALL GRAIN CEREALS: FORAGE YIELD AND QUALITY

Table 7. Moisture, protein, acid detergent fiber (ADF), and neutral detergent fiber (NDF) content of barley, oat, and triticale monocrops and mixtures when harvested at the soft-dough stage of the base species, at Lacombe, AB from 1994 to 1996. Treatment

Moisture

Protein

ADF

NDF

Table 9. Seeding rate effects on biomass yield (dry-matter basis) of winter rye and triticale monocrops and mixtures when harvested at the soft-dough stage of the base species for the Pikabased test, grown at Lacombe, AB from 1994 to 1996 and Botha, AB in 1994–1995. Biomass yield

g kg⫺1 Noble barley-based test

Seeding rate (250 seeds m⫺2)

Noble AC Mustang Wapiti 1:1 Noble–AC Mustang 3:1 Noble–AC Mustang 1:1 Noble–Wapiti 3:1 Noble–Wapiti SE

667f 762a 694c 706b 691cd 684de 677ef 3.5

80.2ab 349b 70.1c 364a 78.9ab 310e 76.2ab 355b 75.4bc 348bc 81.3a 322d 80.4ab 339c 2.1 3.2 AC Mustang oat-based test

594a 579c 516e 587b 585bc 554d 579c 2.7

Noble AC Mustang Wapiti 1:1 AC Mustang–Noble 3:1 AC Mustang–Noble 1:1 AC Mustang–Wapiti 3:1 AC Mustang–Wapiti SE

541f 665a 629d 615e 643c 654b 660ab 3.0

66.9a 372a 67.1a 321c 62.3bc 304d 62.8bc 347b 60.9c 344b 65.0ab 319c 63.0bc 329c 1.3 3.6 Wapiti triticale-based test

642a 550d 528e 591b 578c 547d 558d 4.3

Noble AC Mustang Wapiti 1:1 Wapiti–Noble 3:1 Wapiti–Noble 1:1 Wapiti–AC Mustang 3:1 Wapiti–AC Mustang SE

534e 667a 645b 587d 617c 664a 661a 3.1

64.4 63.2 60.1 64.4 64.0 63.2 60.6 NS

387a 326c 319d 345b 329c 324cd 324cd 2.6

145

656a 559cd 540e 594b 566c 554d 551d 2.6

† Within a subtest and column, means followed by the same letter are not significantly different at ␣ ⫽ 0.05 using LSMEAN comparisons (SAS Institute, 1988).

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

Treatment

Standard

2⫻

3⫻

Mean

ha⫺1

Mg Pika triticale-based test Pika monocrop Prima monocrop 1:1 Pika–Prima SE‡

10.75b† 12.07a 11.07b 0.31

11.03b 12.25a 11.15b 0.31

11.40a 11.34a 11.51a 0.31

11.06b 11.89a 11.25b 0.18

† Within a subtest and column, means followed by the same letter are not significantly different at ␣ ⫽ 0.05 using LSMEAN comparisons (SAS Institute, 1988). ‡ SE is for the comparison of treatment means within and between seeding rates.

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

Table 8. Mean squares from the analysis of variance for biomass yield, moisture, protein, acid detergent fiber (ADF), neutral detergent fiber (NDF), and actual/expected yield ratio (A/E) of winter rye and triticale monocrops and mixtures when harvested at the softdough stage of the base species, at Lacombe, AB from 1994 to 1996 and Botha, AB in 1994–1995. Source of variation

df

Biomass yield

Moisture

Mg ha⫺1

Protein

ADF

NDF

df

A/E

62.9* 11.4 10.1* 4.5ns 2.3 100.1** 6.4* 4.3ns 4.0ns 2.4

2 9 2 4 17 2 – 4 – 18

0.009ns 0.019 0.017ns 0.010ns 0.044 0.010ns – 0.004ns – 0.013

63.5** 2.7 15.2* 2.7ns 2.9 22.9* 20.9** 2.3ns 1.4ns 2.9

2 9 2 4 17 2 – 4 – 19

0.003ns 0.017 0.002ns 0.015ns 0.012 0.003ns – 0.020ns – 0.010

(⫻100) g kg⫺1† Prima rye-based test

Environment (e) Error a Seeding rate (r) e⫻r Error b Treatment (t) e⫻t r⫻t e⫻r⫻t Error c

2 9 2 4 18 4 4 8 8 71

1057.331** 8.356 0.240ns 13.770** 2.512 3.401ns 4.085ns 2.060ns 1.969ns 2.576

431.7** 3.1 4.3ns 4.8ns 3.8 52.4** 4.2ns 1.5ns 0.9ns 3.9

Environment (e) Error a Seeding rate (r) e⫻r Error b Treatment (t) e⫻t r⫻t e⫻r⫻t Error c

2 9 2 4 18 4 4 8 8 72

345.848** 4.124 0.979ns 2.275ns 2.376 2.778ns 0.929ns 2.778* 1.449ns 1.130

39.3ns 10.1 6.5ns 2.8ns 4.9 16.2** 2.9ns 2.3ns 5.3ns 3.5

104.54** 411.5** 6.31 11.9 6.37ns 8.3ns 4.92ns 2.6ns 1.40 4.0 0.76ns 44.5** 0.76ns 3.3ns 3.38** 2.4ns 2.10ns 1.3ns 1.07 1.7 Pika triticale-based test 100.26** 1.74 3.13ns 0.16ns 2.06 0.91ns 1.74ns 2.67ns 1.81ns 1.69

*, ** Significant at 0.05 and 0.01 levels of probability, respectively; ns is not significant. † Actual values equal reported values times the indicated factor.

334.7** 3.0 8.1ns 0.9ns 3.3 12.6** 19.0** 6.3* 2.2ns 2.7

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CROP SCIENCE, VOL. 40, JANUARY–FEBRUARY 2000

Table 10. Moisture, protein, acid detergent fiber (ADF), and neutral detergent fiber (NDF) content of winter rye and triticale monocrops and mixtures when harvested at the soft-dough stage of the base species, at Lacombe, AB from 1994 to 1996 and Botha, AB in 1994–1995. Treatment

Moisture

ADF

NDF

kg⫺1

g Prima rye-based test Pika monocrop Prima monocrop 1:1 Prima–Pika SE

641a† 588c 598b 3.3

Pika monocrop Prima monocrop 1:1 Pika–Prima SE

649a 625c 636b 3.1

358a 316c 333b 2.2 Pika triticale-based test 333a 331a 336a 2.8

583a 523c 546b 2.6 555a 544b 551ab 2.8

† Within a subtest and column, means followed by the same letter are not significantly different at ␣ ⫽ 0.05 using LSMEAN comparisons (SAS Institute, 1988).

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 conTable 11. Seeding rate effects on protein content of winter rye and triticale monocrops and mixtures when harvested at the soft-dough stage of the base species of the Prima-based test at Lacombe, AB from 1994 to 1996 and Botha, AB in 1994–1995. Protein content Seeding rate (250 seeds m⫺2) Treatment

Standard

2⫻

3⫻

Mean

kg⫺1

g Prima rye-based test Pika monocrop Prima monocrop 1:1 Prima–Pika mixture SE‡

81.5a† 64.5b 69.6b

66.9a 63.7a 63.6a 3.0

69.7ab 71.7a 61.5b

72.7a 66.6b 64.9b 1.7

† Within a subtest and column, means followed by the same letter are not significantly different at ␣ ⫽ 0.05 using LSMEAN comparisons (SAS Institute, 1988). ‡ SE is for the comparison of treatment means within and between seeding rates.

tent 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 ⫻ 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.

CONCLUSIONS These small grain cereal mixtures were generally intermediate to the monocrops for all traits measured. Because of this intermediate nature, especially in reference to moisture and fiber, species mixtures could be a means for producers to extend their window of harvest for silage, while improving the quality of that harvest. The interspecific mixture of oat and barley, when harvested at the soft-dough stage of the barley, gave higher yields and quality than the barley or oat monocrops. The intraspecific mixture of Kasota and Seebe barley, when harvested at the soft-dough stage of Seebe, tended to have higher yields than the monocrops. 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. ACKNOWLEDGMENTS The technical assistance of Donna Westling, Dave Dyson, Susan Lajeunese, Deanna Runge, and Tom Zatorski is gratefully acknowledged. Discussion of this work with Drs. Robert Wolfe, Solomon Kibite, and George Clayton were greatly

JUSKIW ET AL.: MONOCROPS AND MIXTURES OF SMALL GRAIN CEREALS: FORAGE YIELD AND QUALITY

appreciated. A portion of this research was funded by Alberta Agricultural Research Institute.

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