Sciarappa, W., County Agent II, Rutgers University
Bonos, S., Associate Professor, Rutgers University
Hulme, B., Agricultural Assistant, Rutgers Coopetative Extension
Meyer, W., Professor, Rutgers University
Mohr, M., Agricultural Technician, Rutgers University

ABSTRACT

Pasture grass trials conducted from 2007 to 2010 examined durability in order to select for improved forage potential in equine operations.  Forty cultivars of forage and turf grass species and mixtures were subjected to wear tolerance treatment with a horse hoof simulator in replicated trials.  Some cultivars and/or mixtures of orchardgrass (Dactylis glomerata), tall fescue (Festuca arundinacea), Kentucky bluegrass (Poa pratensis) and perennial ryegrass (Lolium perenne) held up well to the simulated horse hoof traffic while Timothy (Phleum pratense) and several other seed mixes did not.  Wear resistant selections could be promoted over consumer-preferred yet poor durability Timothy (Phleum pratense) and some commercial mixes in order to improve pasture quantity, increase sustainability and minimize erosion

INTRODUCTION

Several extension seminars in equine pasture management were held in Central New Jersey from 2004 to 2007.  Participants indicated that one of their main concerns was sustaining a permanent pasture in which grass species would improve durability of pastures subjected to hoof traffic from high stocking density (Zoller  2002).    Foot and hoof traffic on turfgrasses can result in major damage to turf sites, especially on high use recreational areas such as athletic fields (Carrow and Petrovic 1992, Evans, 1988) and equine pastures (Greene 2010).Traffic can result in four stresses; wear, soil compaction, divoting and soil displacement (Beard 1973). Wear injury affects aboveground plant parts and is defined as the immediate result of crushing, tearing, and shearing actions of foot, hoof and vehicular traffic (Beard et al. 1974; Shearman 1988).

Turfgrass species differ greatly in their ability to withstand the abrasion and compaction of traffic (Gaussoin, 1994,Younger 1961). Wear tolerance of turfgrass species and mixtures has been evaluated by a number of researchers (Meyer et al., 1997; Canaway, 1981; Fushtey et al., 1982; Taivalmaa et al. 1998). Evaluation of cultivars within a particular species has also been conducted (Bonos, et al. 2001; Minner, et al. 1993; Wood and Law 1972).

The combined impact of varietal durability, soil compaction, soil displacement, and divoting on pasture grasses can create important environmental issues as well as agricultural, economic and aesthetic problems.  Turfgrass traffic tolerance in pastures continues to be a concern in the small state of New Jersey with its dense horse population of over 50,000 and a large number of athletic fields and racetracks.  Horse hooves add a unique farm animal dimension in damage to turfgrass.  Bonos et al. 2001, developed an improved wear simulator that quickly and uniformly applies wear to a large number of turfgrass evaluation plots. This customized Rutgers model closely simulates severe horse hoof traffic in terms of abrasion, wear and durability.

OBJECTIVE

The main objective of our field trials was to assess various forage and turf grass cultivars and commercial mixtures to determine which ones might be more resistant to repeated horse hoof traffic over an extended period of time.  This study objective was a component within a larger study of the county watersheds where high densities of horse farms were surveyed in terms of pasture management, erosion and nutrient runoff.  Pasture grass health and wear resistance significantly relate to both farmsite and off-site transport of sediment, nitrogen, phosphorus, bacteria, salt and other non-point source pollutants. Selecting more durable cultivars is expected to increase pasture longevity and quantity of forage as well as limit soil erosion and reduce stormwater run-off.

MATERIALS AND METHODS

Simulator Methods - Horse hoof traffic simulation was performed with a mechanical mowing device in 2008 and 2009 to determine which cultivars were more durable and thus better suited in preventing soil erosion. Many traffic simulators have been developed (Bourgoin and Mansat 1982; Younger 1961). Most of the simulators developed mimic the effects of trampling, which imparts wear and compaction to soil  (Cockerham and Brinkman1989; Taivalmaa et. al. 1998).

Shearman and co-workers (1974) developed a wear simulator for small plot evaluations that resulted in wear injury without soil compaction. Although very effective, these wear/traffic simulators were not designed to travel across large numbers of turf plots in a relatively short period of time. We used the Rutgers model simulator (Bonos et al. 2001) because this unit can travel over a large area quickly.

Evaluation Site - Forage and turf grass cultivars, experimental selections and pasture mixtures were evaluated at the Rutgers Adelphia Turf Research Farm in Monmouth County, New Jersey.  Plots were arranged in a randomized design with three replications. Replicate plot size was 7’ x 5’ (width x length).  This trial was maintained at a 2½” mowing height and mowed weekly.  In June of 2008, a wear strip was applied to one-half of each plot using the 3’ wide Rutgers wear simulator.  During the period from June 19^th to September 16^th, a total of 20 passes once or twice a week depending upon seasonal grass growth were applied to each treatment side of each plot. Sub-samples of these randomized plots were first harvested with a 20-inch mower-bagger followed by an overall clipping with a small tractor and reel mower.   Plots were maintained in years 2009 and 2010 at a reduced wear treatment level.

Turfgrass Evaluation - Forty cultivars and varietal blends were obtained from major seed vendors and fall-seeded on September 20, 2007. Each plot was visually rated throughout the growing season for turf quality (i.e., overall appearance, turf color, uniformity, density, mowing quality, reduced rate of vertical growth, leaf texture, and damage due to insects and/or diseases). Establishment, spring green-up, and color were also rated as separate observations.  A scale of 1 to 9 was used for all ratings, with 9 representing the best turf characteristics. Plots were also rated for percent turfgrass cover (or fullness of turfgrass cover) immediately before the initiation of wear using a 0 to 100% scale, where 0 = absence of a turfgrass canopy and 100 = full cover. Fullness of cover was rated after 6, 12, and 18 passes of the wear simulator to assess wear tolerance. Fullness of cover was also rated at 15, 22, and 42 days after wear (DAW) to assess turfgrass recovery.  Grass blade bruising injury was assessed at 15, 22, and 42 DAW on a 1 to 9 scale, where 9 = no discoloration (bruising). Observers were not aware of the locations of the cultivars and mixtures to prevent observer bias. The main summary assessments were expressed as a composite rating of forage potential via observed color, growth and fullness of cover as well as by measuring biomass wet and dry weights from mowing.   All data was subjected to analysis of variance, and means were separated using the Fisher’s protected least significant difference (LSD) test.

RESULTS

PASTURE GRASSES     The grass group was characterized as 9 tall fescue types (TF), 6 Kentucky Bluegrass (KB), 6 Orchardgrass (OG), 3 Timothy (Tim), 2 Bentgrass (Bent), 1 Perennial Ryegrass (PR), 1 Festilolium (Fest), 1 Texas Crabgrass hybrid (Tx hyb) and 11 mixtures (Table 1).  Germination of these 40 cultivars or mixtures was generally rapid, especially Tiger 2 - Colonial Bentgrass  - rated at 8.7 compared to the nearest competitors ranked 7.3, 7.0 and 7.0.  Initial growth was expressed as height within 40 days of planting (Graph 1).

	CULTIVARS 1-20	SPECIES			CULTIVARS 21-40	SPECIES
1	PST-SYN-5GNAF	TF		21	102-1013	KB
2	Cowgirl (C8-03-5NF)	TF		22	Slezanka	KB
3	RAD-ERF48	TF		23	Aura	KB
4	Max Q	TF		24	Spring Green	Festilolium
5	Fawn (L141-5-F70	TF		25	Rose Agri-Seed Blend	TF/Fest/OG/KB/Bent/PR
6	Savory	TF		26	Showhorse Mix	OG/Duo Fest/KB/Tim
7	Martin 2E-	TF		27	Endurance/Savory	50% OG/50% TF
8	Martin 2 9901	TF		28	Slezanka/Tiger2	80% KB/20% Col
9	Martin 2 9902	TF		29	Calibra	4N PR
10	Edurance	OG		30	Calibra/Slezanka	70% PR/30% KB
11	Potomac	OG		31	Savory/Endurance/Slezanka	50% TF/30%OG/20%KB
12	Warrior II (MCF37)	OG		32	Becker Pasture Mix	Tim/4N AR/TF4N PR/RC
13	Shiloh II	OG		33	Horse Pasture Mix	KB4N PR/Tim/SM.Brome
14	8SS (C-8-07-8SS)	OG		34	Blue Ribbon # 5 Pasture Mix	PR/Tim/KB/m.red clover
15	Extend (B24-5-151)	OG		35	Pasture Mix	Multiple blend
16	ORAF (L2-6-48)	Bent		36	ProHorse Mix Pasture Seed	Multiple blend
17	Tiger 2	Col Bent		37	Winnetou	Timothy
18	Farenheit 90	Tx bl hyb		38	Crest (L# 6610)	Timothy
19	Thorough-blue	KB		39	Summit (L# 6613)	Timothy
20	RAD-5 (RAD-7-5)	KB		40	A99-712 Bjala	KB
Table 1. List of 40 cultivars tested and species composition

 

 A wide range of results contrasted the better and the poorer pasture grasses of 40 cultivars of pasture grass species and mixtures.  Biomass percentage yield remaining for all 40 cultivars before and after horse hoof simulation in the first year of establishment of 2008 ranged from 3% to 61%. Some turf cultivars and blends held up well to the to the horse hoof traffic simulation while others did not. The top five turf cultivars maintaining good biomass after horse hoof simulation in 2008 were Perennial Ryegrass Type Calibra, Bentgrass ORAF and Tall Fescue Types Savory, Martin 2-9901, and Fawn.  Tall fescue Savory was the best performer (Graph 2). In 2008, the three Timothy cultivars were ranked as the three lowest of the 40 selections, ranking with 3 of the 4 lowest biomass remaining values under 10%.   In 2009, five of the top seven cultivars ranked 6.0 or more on the wear quality scale were Kentucky Bluegrass despite a slow initial germination in 2007 and green-up in 2008.

Generalizing from large and combined data sets we noted:

• Significant differences in growth fall seeding measured as vertical leaf growth and plot cover.  These initial differences in pasture grass height were quickly leveled out with regular mowing at 2.5 inches.
• Spring green-up (SGU) differences in 2009 and 2010 were relatively minor in timing or appearances.
• Wear quality differences were visually apparent in terms of leaf blade shredding with minor to moderate discoloration among most cultivars.  Leaf color was generally a bit duller but typical as per cultivar, despite wear treatment.
• Percent cover comparisons side-by-side with untreated checks after 18 passes in year 2008 showed Timothy and Bentgrasses to quickly begin to decline in quantity, quality and coverage.
• Over the next 2 years, the survivorship and durability changed considerably, especially the highest ranking Tiger 2 Bentgrass in the first year fell into 36^th place by the third year.  Long-term, the Kentucky bluegrasses and combinations of Kentucky bluegrass, orchardgrass and tall fescue provided the highest level of wear tolerance.  Results for forage potential are tabulated and ranked in order in Table 2 with the first ten cultivars showing the best overall pasture grass performance.

			Forage Potential
		Species					SGU
	Cultivar Name	Composition					April
			2008-10	2008	2009	2010	2010
			Avg	Avg	Avg	Avg	Avg
1	Calibra/Slezanka	70% PR/30% KB	6.2	6.1	6.6	5.8	5.0
2	Savory/Endurance/Slezanka	50%TF/30%OG/20%KB	6.1	6.2	5.8	6.1	5.7
3	Slezanka	KB	5.9	5.7	5.8	6.1	4.0
4	Endurance/Savory	50% OG/50% TF	5.8	5.9	5.6	6.0	5.3
5	Extend	OG	5.7	5.3	5.5	6.3	6.3
6	Warrior II	OG	5.7	5.3	5.5	6.2	6.7
7	Aura	KB	5.6	5.5	6.4	5.1	5.7
8	Endurance	OG	5.6	5.6	5.1	6.2	5.7
9	Shiloh II	OG	5.6	5.2	5.4	6.2	6.3
10	Potomac	OG	5.6	5.5	5.2	6.0	6.3
11	PST-SYN-5GNAF	TF	5.5	5.9	5.4	5.3	4.0
12	Max Q	TF	5.5	5.7	5.6	5.3	5.7
13	Cowgirl	TF	5.5	5.7	5.3	5.4	4.3
14	ProHorse Mix Pasture Seed		5.5	5.6	5.3	5.5	6.0
15	A99-712 Bjala	KB	5.5	5.8	5.4	5.2	4.3
16	Savory	TF	5.5	5.6	5.1	5.7	3.7
17	Blue Ribbon # 5 Pasture Mix	PR/Tim/KB/m.red clover	5.4	5.5	5.5	5.3	5.7
18	RAD-5	KB	5.4	6.0	5.8	4.5	4.3
19	8SS	OG	5.4	5.3	4.7	6.2	6.0
20	Thourough-blue	KB	5.4	5.9	5.4	4.9	5.0
21	RAD-ERF48	TF	5.4	5.9	4.9	5.3	4.3
22	Slezanka/Tiger 2	80% KB/20% Col	5.4	6.4	5.7	4.0	4.7
23	Calibra	4N PR	5.3	5.6	5.9	4.5	5.7
24	Martin 2 E-	TF	5.3	5.7	5.0	5.2	5.0
25	Fawn	TF	5.2	5.4	5.3	4.8	4.7
26	Pasture Mix		5.2	5.1	5.3	5.1	5.3
27	Martin 2 9901	TF	5.1	5.4	5.2	4.7	5.0
28	Farenheit 90	Tx bl hyb	5.1	5.7	5.7	4.0	4.0
29	Martin 2 9902	TF	5.1	5.6	5.1	4.7	4.7
30	Rose Agri-Seed Blend	TF/Fest/OG/KB/Bent/PR	5.0	5.0	5.0	5.1	5.3
31	Showhorse Mix	OG/Duo Fest/PR/KB/Tim	5.0	4.9	4.7	5.4	5.7
32	Horse Pasture Mix	KB/4N PR/Tim/Sm.Brome	4.9	4.9	4.9	4.9	5.0
33	Becker Pasture Mix	Tim/4N AR/TF/4N PR/RC	4.8	4.5	5.0	5.0	4.0
34	102-1013	KB	4.6	4.1	5.2	4.6	4.7
35	Spring Green	Festilolium	4.6	4.8	4.8	4.2	6.7
36	Tiger 2	Col Bent	4.6	6.2	4.5	3.0	4.0
37	Summit	Timothy	4.2	4.6	4.3	3.6	5.7
38	Winnetou	Timothy	4.1	4.5	4.4	3.4	5.0
39	Crest	Timothy	4.0	4.3	3.9	3.7	5.0
40	ORAF	Bent	3.6	5.1	2.4	3.3	5.7
	LSD at 5% =		0.6	0.6	0.9	1.1	1.0
Table 2.  Cultivars, Species, Forage Potential & Spring Greenup SGU)

The tall fescues and tetraploid ryegrass (Lolium perenne) were intermediate for wear tolerance.  Colonial bentgrass (Agrostis capillaris) provided excellent wear tolerance and growth for the first two years and then abruptly declined.  The mixtures of forage grasses sold commercially and orchardgrass cultivars were below the mean for the wear evaluation while three Timothy (Phleum pratense) cultivars were the poorest for durability

In conclusion, these more resistant cultivars of tall fescue, Kentucky Bluegrass, perennial ryegrass, and perhaps bentgrass appear most promising for equine operations and could be promoted over consumer-preferred timothy cultivars and commercial mixtures.  Such forage grass selections may, improve pasturage quantity, foster vegetative cover, help prevent soil erosion and increase pasture sustainability.

REFERENCES

Beard, J.B. 1973. Turfgrass: Science and culture. Reagents - Prentice Hall, Englewood Cliffs, NJ.

Beard, J.B., J.P. Wilkinson, and R.C. Shearman. 1974.Turfgrass wear tolerance: The anatomical and physiological basis. Proceeding of the 44th Annual Michigan Turfgrass Conference, East Lansing. 15-16 Jan. 1974. Vol. 3(1-2) 145

Bonos., S.A., Watkins, E., Honig. A., Sosa, M., Molnar, T., Murphy. J.A., and Meyer, W. A. 2001.   Breeding Cool-Season Turfgrasses for Wear Tolerance Using a Wear Simulator. International Turfgrass Society Research Journal, Vol. 9, 2001, p.137-145.

Canaway, P.M. 1981. Wear tolerance of turf grass species. Journal Sports Turf Research Institute. Vol. 57, p.108-121.

Carrow, R.N. and  Petrovic, A.M., Waddington, R.N., Carrow and Shearman, R.C. 1992. Effects of traffic on turfgrass.  In Turfgrass (Eds.) p.285-330 .  Agronomy Monographs 32. ASA, CSSA, and SSSA, Madison, WI.

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Fushtey, S.G.,  Taylor, D.K. and Fairey, D. 1982. The effect of wear stress on survival of turfgrass in purestands and in mixtures. Canada Journal of Plant Science. Vol. 63, p.317-322.

Gaussion, RE. 1994. Choosing traffic-tolerant turf grass cultivars. Sports Turf.  Vol. 10:7, July 1994, p.25-26.

Greene, E. A., and Skelly, C.D. 2010.   An Extension Agent/Educator Guide to Consultations with Suburban/Urban Horse Owners.   Journal of the NACAA. ISSN 2158-9429. Vol. 3, Issue 1. July 2010.  

Minner, D.D, Dunn, H.D.,  Bughrara, S.S. and Fresenburg, B.S. 1993. Traffic tolerance among cultivars of Kentucky bluegrass, tall fescue, and perennial ryegrass. International Turfgrass Society Research Journal.  7. RN. Carrow, N.E. Christians, RC. Shearman (Eds.) Intertec Publishing Corp., Overland Park, Kansas.  Vol. 7, p. 687-694.

Meyer, W.A., Murphy, J.A., and Smith, D.A. 1997. Response of cool-season turf grasses to a novel traffic simulator. p. 125. In 1997 Agronomy abstracts. ASA, Madison, WI.

Shearman, R.C. 1988. Improving sports turf wear tolerance. Proc. of the 58th Ann. Michigan Turf. Conf. Vol. 17, p. 153-155.

Shearman, R.C., Beard, J.B., Hansen, C.M., and Apaclla, R. 1974.  Turfgrass wear simulator for small plot investigations. Agronomy Journal. Vol. 66, p. 332-334.

Taivalmaa, S.L., Talvitie,H., Jauhiainen, L. and Niemelainen, O.1998. Influence of wear-stress on turf grass species and cultivars in Finland. Journal Turfgrass Science. Vol. 74, p.52-62.

Wood, G.M. and Law, A.G. 1972. Evaluating Kentucky bluegrass cultivars for wear resistance. p. 65. In: Agronomy abstracts. ASA, Madison, WI.

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