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Forages

Prairiegrass–Brassica Hybrid Swards for Autumn Dry Matter Production

USDA-ARS, Appalachian Farming Syst. Res. Cent., 1224 Airport Rd., Beaver, WV 25813-9423

^* Corresponding author (david.belesky{at}ars.usda.gov)

Received for publication February 9, 2006.

	ABSTRACT

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS NOTES RESULTS AND DISCUSSION REFERENCES

 
Stockpiling herbage can redistribute nutrient availability and supplement quantity for livestock, depending on production objectives. Brassicas (Brassica spp.) and improved prairiegrass (Bromus catharticus Vahl.) cultivars are adapted to growing conditions occurring in the Appalachian region and provide nutritionally valuable herbage in autumn; however, highly digestible brassica herbage may require supplementation with a fibrous companion species for efficient rumen microbe function and nutrient use by grazers. A prairiegrass–brassica hybrid [B. rapa L. x B. rapa subsp. pekinensis (Lour.) Hanelt.] mixture and pure stands of each were established to determine productivity and nutritive value of stockpiled stands in autumn. Field plots were established in late June of 2003 and 2004, and clipping began 74 and 63 d after planting, respectively. Prairiegrass co-established with brassica hybrid and could be harvested in the establishment year. Sown species and year interacted to influence stand composition, dry matter productivity, and nutritive value. Dry conditions occurred shortly after planting in 2003 and slowed brassica hybrid establishment and productivity. Total dry matter varied for monospecific and mixed stands of prairiegrass and brassica hybrid each year, as did distribution during the season. Nutritive value varied with years and met or exceeded values suggested for efficient rumen microbe function. Herbage growth continued for about 80 d after the first clip in early September for all sward types and demonstrated the compatibility of co-seeded prairiegrass and brassica hybrid as well as the suitability of the mixture to provide adequate herbage mass and nutritive value when stockpiled in autumn.

Abbreviations: CP, crude protein • DAP, days after planting • DM, dry matter • RNY, relative nutrient yield • RY, relative yield • RYM, relative yield of mixture • TDN, total digestible nutrients • TNC, total nonstructural carbohydrate

	INTRODUCTION

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS NOTES RESULTS AND DISCUSSION REFERENCES

 
HERBAGE GROWTH is slow in autumn and ceases during winter in much of the central Appalachian region ofthe eastern USA, creating a potential shortfall of herbage in forage-based livestock production systems. Stockpiling, or accumulating herbage for later use, can supplement quantity, redistribute availability, reduce the need for purchased feed, and help meet livestock nutrient requirements when gaps occur. Important considerations when designing stockpile components of forage–livestock systems include dry matter production and nutritive value needs. Careful management is required to achieve the desired herbage mass and nutritive value. Trade-offs between herbage yield and nutritive value determine when stockpiling should begin and accumulated herbage used (Matches and Burns, 1995).

Plants that resist the destructive effects of weather (e.g., frost and wind) and retain herbage nutritive value in late autumn or early winter {e.g., tall fescue [Lolium arundinaceum Schreb. Darbyshire (formerly Festuca arundinacea Schreb.)} are ideal for late-season stockpiling. Much of what is known about autumn stockpiled herbage focuses on tall fescue with tough, resilient leaves and orchardgrass (Dactylis glomerata L.), which is common in pastures throughout the Appalachian region (Baker et al., 1988).

Alternative species that could be used for autumn stockpile include grasses with strong late-season production (e.g., Bromus spp.). For example, ‘Matua’ prairiegrass (Bromus willdenowii Kunth.) grew vigorously during autumn in central Appalachia (Belesky and Stout, 1994), but persistence was compromised by susceptibility to diseases. A stockpiled mixture of smooth bromegrass (Bromus inermis L.) and red clover (Trifolium pratense L.) was comparable to a mixture of tall fescue and alfalfa (Medicago sativa L.) in terms of productivity, nutritive value, and livestock performance (Hitz and Russell, 1998). New prairiegrass (Bromus catharticus Vahl.) cultivars with disease resistance, upright growth habit (‘Dixon’) (Rumball and Miller, 2003a), or ability to tolerate cold weather (‘Lakota’) (Rumball and Miller, 2003b) are suited to growing conditions in many parts of the USA. The new prairiegrass cultivars could prove to be useful components of systems requiring high quality herbage in autumn (Belesky and Cassida, 2004; Belesky and Ruckle, 2005).

Forage brassicas are fast-growing, cold-tolerant annuals that can provide herbage mass and quality needed to sustain livestock late in the year. Brassicas planted in midsummer are productive in autumn and retain high nutrient concentrations when stockpiled (Guillard et al., 1988; Cassida et al., 1995). The high soluble nutrient content of brassica species should be supplemented with a source of fiber for efficient rumen function and nutrient use (Cassida et al., 1994). One means of achieving this in pasture would be to establish brassica along with a companion grass. Information demonstrating the compatibility of grass–brassica mixtures sown at the same time is scarce. Our objective was to determine the seasonal pattern of herbage production and nutritive value of a prairiegrass–brassica hybrid mixture sown in midseason and stockpiled in autumn.

	MATERIALS AND METHODS

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS NOTES RESULTS AND DISCUSSION REFERENCES

 
Plots were established on an upland site of the Allegheny Plateau in southern West Virginia (37°46' N, 81°00' W; 870 m elevation above sea level). Soil was a Clymer series, channery loam (coarse-loamy, siliceous, active, mesic Typic Hapludult) on a hilltop site with <5% slope. Two glyphosate [N-(phosphono-methyl) glycine] applications (2.5 kg a.i. ha^–1 each) and tillage eliminated existing cool- and warm-season grasses. Soil fertility supplied moderate amounts of P (about 15 kg ha^–1) and ample K (about 250 kg ha^–1), at an initial pH of 7.03 in the surface 15 cm of soil.

Plots were sown 30 June 2003 and on an adjacent site on 29 June 2004 to Dixon prairiegrass, ‘Tyfon’ brassica hybrid [turnip (Brassica campestris var. rapa L.)–Chinese cabbage (B. pekinensis (Lour.) Rupr.)], or a mixture with both species. Main plots (3 by 9 m) were sward type (pure or mixed) in replicated (three) blocks with main plots divided to accommodate seven 1- by 3-m harvest strips. Stands were broadcast or no-till seeded (Tye¹ pasture seeder) to prairiegrass (45 kg seed ha^–1), brassica hybrid (9 kg Tyfon seed ha^–1), and the mix at 45 kg prairiegrass seed ha^–1 and 5 kg Tyfon seed ha^–1. The area was cultipacked after seeding to improve seed-to-soil contact. About 150 kg N ha^–1 as 19–19–19 fertilizer was applied to each plot in a split application with 75 kg of N at planting and 75kg of N after the first clipping of a particular strip.

Clipping began 74 d after planting (DAP) in 2003 and 65 DAP in 2004. A new strip was cut from standing herbage at 14-d intervals throughout autumn each year. Each yield strip was harvested with a collection-bag-equipped, rotary mower adjusted to allow a 100-mm residue height. Sampled areas (yield strips) were assigned at random within a plot at the first harvest. Herbage was dried at 60°C in a forced-air oven, weighed for dry matter (DM) estimation, and ground in a cyclone mill. The botanical composition of each strip scheduled for harvest was determined before clipping. Botanical composition was determined visually using a point–intercept method (Warren-Wilson, 1959).

Nitrogen was determined by combustion of dry plant tissue (Carlo Erba EA 1108 CHNSO analyzer, Fisons Instruments, Beverly, MA) and expressed as crude protein (CP; g N kg^–1 x 6.25). Total nonstructural carbohydrates (TNC) were determined by an autoanalyzer (Alpkem RFA 300, Astoria-Pacific, Int., Clackamas, OR) procedure. Computations for estimates of nutritive value, presented as total digestible nutrients (TDN), included TNC and CP (Belesky et al., 2005) where:

[1]

Calculations
Relative yields (RY) for prairiegrass and brassica hybrid were computed according to Fowler (1982) and relative yield mixture (RYM) computed according to Wilson (1988). The RY of each target species, either prairiegrass or brassica hybrid, was computed as:

[2]

[3]

where Y_P and Y_B are yields of prairiegrass and brassica hybrid, respectively, for stands of each at each harvest date; P_P and P_B are the relative proportions of prairiegrass and brassica hybrid, respectively, in mixtures at each harvest date; and Y_PB represents yield of prairiegrass in presence of brassica hybrid, and Y_BP is yield of brassica hybrid in presence of prairiegrass.

Relative yield mixture was computed as:

[4]

Relative nutrient yield (RNY) and relative nutrient yield mixture (RNYM) for prairiegrass and brassica hybrid were calculated in the same manner as relative yield. The RNY was computed as:

[5]

Cumulative yield data were fit to the Gompertz equation tocompute inflection points representing the instantaneous growth rate (Draper and Smith, 1981):

[6]

where = herbage mass (kg DM ha^–1), t = day of year, and (asymptotic yield), ß (time function), and k (dimensionless) are calculated regression parameters.

The experiment was established as a split plot with plant stand and planting methods as main plots and harvest dates within each as the split plot. Data for cumulative DM yield (seeded species), components of botanical composition, CP, and TNC were analyzed as a randomized complete block design using PROC MIXED procedures in SAS (Littell et al., 1996). Data for the third clip (92 DAP) of 2004 are not included in the analysis. Seeded species, planting method, and harvest dates were considered fixed effects and replication random in the model. Years were analyzed separately within the mixed model because ² test indicated heterogeneity of variance.

	RESULTS AND DISCUSSION

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS NOTES RESULTS AND DISCUSSION REFERENCES

 
Growing Conditions
Maximum and minimum temperatures were somewhat below the 30-yr mean in 2003 and at or above the means in 2004 (Fig. 1 ). Precipitation varied from month to month in each year, at times exceeding and falling below the 30-yr mean for a given month (Fig. 1). The greatest disparity in precipitation between years occurred immediately after planting in July. The relatively small amount of precipitation in July of 2003 and ample amount in July 2004 probably influenced stand establishment and consequently sward composition and total herbage productivity in the respective growing seasons. Gerrish and Sanderson (2000) reported similar fluctuation in total productivity with varying precipitation for swards differing in floristic complexity. Total precipitation (610 mm in 2003 and 630 mm in 2004) might be less of a concern than when events occurred and the amount occurring at each event.

View larger version (19K): [in this window] [in a new window]   Fig. 1. Monthly and 30-yr mean maximum and minimum air temperatures and precipitation for 2003 and 2004, at Beckley, WV.

View larger version (46K): [in this window] [in a new window]   Fig. 2. Botanical composition of prairiegrass, brassica hybrid, and a prairiegrass–brassica hybrid mixture during 2003 and 2004. Values representing the number of contacts (as a percentage) are the mean of three replicates.

Herbage Productivity
In our experiment, species density varied as a function of site-specific conditions and the growth habit and patterns of resource acquisition and allocation of each component of the stand over time. Dry matter productivity varied substantially between years (P < 0.001). The variation may be attributable in part to fluctuating weather and stand damage caused by selective grazing by white-tail deer (Odocoileus virginianus) that occurred each year, but especially in 2003 (Fig. 3 ). Declining brassica hybrid herbage DM production could arise from shifts in photosynthate allocation from aerial herbage to tubers. Precipitation was scarce in July of 2003 and is reflected in relatively greater prairiegrass yields and stand composition compared with brassica hybrid. Ample precipitation after planting occurred in July 2004 and is reflected in relatively greater brassica hybrid presence and productivity. Planting method influenced DM yield of seeded species with a slight increase in productivity for broadcast compared with no-till sown stands (P < 0.05).

View larger version (31K): [in this window] [in a new window]   Fig. 3. Seeded species dry matter (DM) yield of prairiegrass, brassica hybrid, and prairiegrass–brassica hybrid mixtures in 2003 and 2004 as a function of planting method. Vertical bars are standard error of the mean.

View larger version (26K): [in this window] [in a new window]   Fig. 4. Mean values for (A) relative yield and (B) relative yield of mixture for prairiegrass–brassica hybrid stands in 2003 and 2004.

The apparent advantage of prairiegrass–brassica hybrid mixtures in terms of yield distribution could be attributable, in part, to different resource acquisition and use patterns (Wilson, 1988). Superior-yielding mixtures are more likely to occur in natural than controlled environment or artificially structured associations because differing morphological and physiological characteristics provide plants with the ability to access resource patches in different parts of the sward.

Nutritive Value
Forage-based livestock production requires synchronized management of herbage mass and nutritive value to sustain forage production and persistence over time while meeting the nutritional needs of grazers. Stands containing brassica hybrids show good potential for meeting the herbage dry matter intake needs of several grazing livestock species although there is some concern that fiber might be limiting and restrict nutrient use efficiency by growing lambs (Ovis spp.) (Guillard et al., 1988). Brassica species grow vigorously and retain nutritive value in autumn; however, the high soluble nutrient content should be balanced with fiber and energy to optimize rumen microbial function and nutrient use by the grazer (Wikse and Gates, 1987; Guillard et al., 1988; Cassida et al., 1994).

Crude protein concentrations varied significantly during the growth interval each year (Table 2). The CP concentrations of prairiegrass declined from about 110 to 75 g CP kg^–1 in 2003 and from 150 to 80 g CP kg^–1 during the 2004 growing season (Fig. 5A ). Concentrations probably declined because of slower growth and nutrient uptake associated with decreasing light and temperature during the autumn stockpiling interval. The CP concentrations of brassica hybrid and the prairiegrass–brassica hybrid mixture were somewhat similar throughout the growth interval, ranging from a low of about 50 g CP kg^–1 in 2003 to a high of 170 g CP kg^–1 in 2004 for brassica hybrid (Fig. 5A). Concentrations less than 100 g kg^–1 would be considered CP limiting from a rumen function and animal requirement standpoint.

View larger version (39K): [in this window] [in a new window]   Fig. 5. Mean values for (A) crude protein (CP), (B) total nonstructural carbohydrate (TNC), and (C) total digestible nutrient (TDN) concentrations of prairiegrass, brassica hybrid, and prairiegrass–brassica hybrid mixtures during 2003 and 2004. Vertical bars are standard error of the mean.

Brassica hybrid TDN declined from about 70 to 35 g TDN 100 g^–1 in 2003 and from 90 to 60 g TDN 100 g^–1 in 2004, and prairiegrass declined from a season high of about 85 g 100 g^–1 to about 50 g 100 g^–1 in 2003 and 2004 (Fig. 5C). Mixtures generally were equivalent to or superior in TDN when compared with monospecific stands of either brassica hybrid or prairiegrass and reflect TDN concentrations of individual components of the sward. The TDN values for brassica hybrid reflect the effects of seasonal weather conditions on herbage nutritive value (Wiedenhoeft and Barton, 1994), with relatively low TDN early in the 2003 growing season when precipitation was limited and improving as temperatures moderated and precipitation occurred in autumn (Fig. 5C). Changes in CP, TNC, and TDN reflect influences of season and sward composition.

Energy requirements of rumen microorganisms might not be met, nor those of the grazer, when large amounts of herbage N are present relative to carbohydrate (Wallace and Cotta, 1988). Conversely, fiber energy (which depends on microbial activity for release) is not available when N is deficient. An imbalance in energy relative to crude protein could lead to inefficient protein utilization and N loss.

The TDN:CP quotient provides an indication of energy and N balance (Belesky et al., 2006). Based on microbial and animal requirements, TDN:CP occurring in the range of 5 to 7 indicates neither excess nor inadequate N relative to a given amount of available energy. It does not, however, provide any insight into actual levels or whether requirements are met. For example, forage with TDN of 30 and CP of 5 would have an "ideal" TDN:CP of 6 but essentially would be useless to the animal. A forage with TDN of 80 and CP of 30 (TDN:CP of 2.7) would support high levels of production in many classes of livestock based on energy estimates. The imbalance of N relative to energy would lead to inefficient N utilization and negative energy balance. Expressing nutritive value as TDN:CP (Fig. 6 ) showed values generally occurring within the 5 to 7 range and could be considered satisfactory for rumen microbe activity and grazing animal response. The TDN:CP values tended to exceed 7 in early harvests when TNC concentrations were relatively high (Fig. 5B).

View larger version (11K): [in this window] [in a new window]   Fig. 6. Mean values for total digestible nutrient (TDN):crude protein (CP) quotients of stockpiled herbage of prairiegrass, brassica hybrid, and a prairiegrass–brassica hybrid in 2003 and 2004. Vertical bars are standard error of the mean.

We applied the relative yield model to TDN data to determine how individual components sown in mixture contributed to available herbage nutritive value and how nutritive value was related to herbage mass (expressed as relative nutrient yield in Fig. 7A ). Values greater than RNY_P = RNY_B suggest that prairiegrass was the dominant source of nutritive value, and lesser values indicate brassica hybrid as the primary nutrient contributor. Brassica hybrid was the dominant nutrient source in 2003, whereas prairiegrass was in 2004 (Fig. 7A). When brassica hybrid dominated production, the relative nutrient yield was stable, reflecting in vitro dry matter disappearance patterns reported by Jung et al. (1986) for autumn-grown brassica forage. Relative nutrient yield of mixtures (Fig.7B) suggest that prairiegrass–brassica hybrid mixtures provided superior herbage nutritive value in both years, with clear benefit attributable to the mixture throughout 2003 and a slight benefit early in the 2004 growth interval.

View larger version (23K): [in this window] [in a new window]   Fig. 7. Mean values for (A) relative nutrient yield and (B) relative nutrient yield of mixture for prairiegrass–brassica hybrid stands in 2003 and 2004.

	ACKNOWLEDGMENTS

 
The authors thank M. Huffman, E. Mathias, and C. Ellison for technical assistance with plot maintenance and sampling and Dr. E. Felton and Mr. E. Nestor, West Virginia University, for nutritive value estimates.

	NOTES

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS NOTES RESULTS AND DISCUSSION REFERENCES

 
¹ Trade names are used for reader convenience and do not imply endorsement by USDA over comparable products or services.

	REFERENCES

TOP ABSTRACT INTRODUCTION MATERIALS AND METHODS NOTES RESULTS AND DISCUSSION REFERENCES

 

• Baker, M.J., E.C. Prigge, and W.B. Bryan. 1988. Herbage production from hay fields grazed by cattle in spring and fall. J. Prod. Agric. 1:275–279.
• Belesky, D.P., and K.A. Cassida. 2004. Prairiegrass–brassica hybrid swards for autumn dry matter production in the Appalachian highlands. Proc. Am. Forage Grassl. Conf. 13:371–375.
• Belesky, D.P., N.J. Chatterton, and J.P.S. Neel. 2006. Dactylis glomerata growing along a light gradient: III. Nonstructural carbohydrate concentrations and nutritive value of plants establishing in spring or late-summer. Agrofor. Syst. 67:51–61.
• Belesky, D.P., J.P.S. Neel, and J.M. Ruckle. 2005. Can total nonstructural carbohydrate-crude protein be used to predict total digestible nutrient–crude protein relationships of cool-temperate pasture herbage? Proc. Am. Forage Grassl. Conf. 14:174–178.
• Belesky, D.P., and J.M. Ruckle. 2005. Prairiegrass (Bromus catharticus Vahl.) for late season production in the highlands of central Appalachia. Proc. Am. Forage Grassl. Conf. 14:179–183.
• Belesky, D.P., and W.L. Stout. 1994. Growth of prairiegrass (Bromus willdenowii) and tall fescue x perennial ryegrass (Festuca arundinacea x Lolium perenne) on the Appalachian Plateau of southern West Virginia, USA. Grass Forage Sci. 49:21–24.
• Burns, J.C., D.S. Fisher, and H.F. Mayland. 2001. Preference by sheep and goats among hay of eight tall fescue cultivars. J. Anim. Sci. 79:213–224.[Abstract/Free Full Text]
• Cassida, K.A., B.A. Barton, R.L. Hough, M.H. Wiedenhoeft, and K.Guillard. 1994. Feed intake and apparent digestibility of hay-supplemented brassica diets for lambs. J. Anim. Sci. 72:1623–1629.[Abstract]
• Cassida, K.A., B.A. Barton, R.L. Hough, M.H. Wiedenhoeft, and K. Guillard. 1995. Productivity and health of gestating ewes grazing Tyfon pastures containing weeds. J. Sustainable Agric. 6:81–95.
• Draper, N.R., and H. Smith. 1981. Applied regression analysis. 2nd ed. John Wiley & Sons, New York.
• Forbes, J.M. 1986. The voluntary intake of farm animals. Butterworths, London.
• Fowler, N. 1982. Competition and coexistence in a North Carolina grassland. J. Ecol. 70:77–92.[CrossRef]
• Gerrish, J., and M.A. Sanderson. 2000. Productivity of diverse pastures in a wet versus dry year [Online]. Available at http://aes.missouri. edu/fsrc/research/paspro.stm. (verified 5 Apr. 2006). Missouri Agric. Exp. Stn. Forage Syst. Res. Cent., Linneus.
• Guillard, K., D.W. Allinson, and R.L. Hough. 1988. Performance of sheep grazing fall-grown Tyfon. Appl. Agric. Res. 3:86–93.
• Hitz, A.C., and J.R. Russell. 1998. Potential of stockpiled perennial forages in winter grazing systems for pregnant beef cows. J. Anim. Sci. 76:404–415.[Abstract/Free Full Text]
• Jung, G.A., R.A. Byers, M.T. Panciera, and J.A. Shaffer. 1986. Forage dry matter accumulation and quality of turnip, swede, rape, Chinese cabbage hybrids, and kale in the eastern USA. Agron. J. 78: 245–253.[Abstract/Free Full Text]
• Littell, R.C., G.A. Milliken, W.W. Stroup, and R.D. Wolfinger. 1996. SAS systems for mixed models. SAS Inst. Inc., Cary, NC.
• Matches, A.G., and J.C. Burns. 1995. Systems of grazing management. p. 179–192. In R.F Barnes et al. (ed.). Forages: Volume II. The science of grassland agriculture. Iowa State Univ. Press, Ames.
• Rumball, W., and J.E. Miller. 2003a. ‘Grasslands Dixon’ prairie grass (Bromus catharticus Vahl.). N. Z. J. Agric. Res. 46:65–66.
• Rumball, W., and J.E. Miller. 2003b. ‘Grasslands Lakota’ prairie grass (Bromus catharticus Vahl.). N. Z. J. Agric. Res. 46:61–63.
• Silvertown, J.W., and D.J. Lovett-Doust. 1993. Introduction to plant population biology. 2nd ed. Blackwell Sci. Publ., Oxford, UK.
• Tilman, D.A. 1999. The ecological consequences of changes in biodiversity: A search for general principles. Ecology 80:1455–1474.[CrossRef][ISI]
• Trenbath, B.R. 1974. Biomass productivity of mixtures. Adv. Agron. 26:177–210.
• Wallace, R.J., and M.A. Cotta. 1988. Metabolism of N-containing compounds. p. 217–249. In P. Hobson (ed.) The rumen microbial ecosystem. Elsevier, New York.
• Warren-Wilson, J. 1959. Analysis of spatial distribution of foliage by two-dimensional point quadrat. New Phytol. 58:92–101.
• Wiedenhoeft, M.H., and B.A. Barton. 1994. Management and environment effects on Brassica forage quality. Agron. J. 86:227–232.[Abstract/Free Full Text]
• Wikse, S., and N. Gates. 1987. Preventative health management of livestock that graze turnips. Bull. EB 1453. Washington State Univ. Coop. Ext. Serv., Pullman.
• Williams, C.A., and B.C. McCarthy. 2001. A new index of interspecific competition for replacement and additive designs. Ecol. Res. 16:29–40.
• Wilson, J.B. 1988. Shoot competition and root competition. J. Appl. Ecol. 25:279–296.[CrossRef]

This Article Abstract Figures Only Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via ISI Web of Science (1) Citing Articles via Google Scholar Google Scholar Articles by Belesky, D. P. Articles by Ruckle, J. M. Search for Related Content PubMed Articles by Belesky, D. P. Articles by Ruckle, J. M. Agricola Articles by Belesky, D. P. Articles by Ruckle, J. M. Related Collections Forage Management