performance of turfgrass under supplemental irrigation and rain-fed conditions in the central great...

ORIGINAL ARTICLE

Performance of turfgrass under supplemental irrigationand rain-fed conditions in the Central Great Plains of USAM. Anowarul Islam, Augustine K. Obour, James M. Krall, Jack T. Cecil and Jerry J. Nachtman

Department of Plant Sciences, University of Wyoming, Laramie, Wyoming, USA

Keywords

Drought tolerant; rain-fed condition;

supplemental irrigation; turf quality; turfgrass

cultivars.

Correspondence

M. Anowarul Islam, Department of Plant

Sciences, University of Wyoming, Laramie,

WY 82071, USA.

Email: [email protected]

Received 10 December 2012;

accepted 3 March 2013.

doi: 10.1111/grs.12018

Abstract

Identifying drought tolerant turfgrass for semiarid Central Great Plains (CGP)

of Wyoming is imperative because of limited water availability for irrigation.

This study evaluated the performance and quality of different turfgrass species/

cultivars under irrigated and rain-fed conditions in southeastern Wyoming.

The species/cultivars evaluated in the study included Kentucky bluegrass

(Poa pratensis L. ‘Bandera’, ‘Common 85/80’ and ‘Midnight’), tall fescue

(Schedonorus arundinaceus [Schreb.] Dumort., formerly Festuca arundinacea

Schreb.; ‘Blackwatch’, ‘Tar Heel II’ and ‘Watchdog’), buffalograss (Bouteloua

dactyloides [Nutt.] J.T. Columbus; ‘Bison’, ‘Bowie’ and ‘Cody’), and blue grama

(Bouteloua gracilis [Willd. ex Kunth] Lag. ex Griffiths; ‘Alma’, ‘Bad River’ and

‘Hachita’). The study was planted in a randomized complete block with four

replicates in a factorial design. Coverage of turfgrasses used in the study was

similar in both irrigated and rain-fed conditions. In general, better performance

and turf quality in terms of vigor and color were obtained in irrigated condi-

tions compared to rain-fed. Plant vigor and color rankings were in the order

of tall fescue > Kentucky bluegrass > buffalograss > blue grama under irrigated

conditions. However, plant vigor and color were superior for the warm-season

turfgrass species (buffalograss and blue grama) under rain-fed conditions.

Overall performance of the turfgrass species tested in the study was tall fes-

cue � Kentucky bluegrass > blue grama � buffalograss. Tall fescue cultivars

‘Tar Heel II’ and ‘Watchdog’, blue grama cultivar ‘Bad River’, and buffalograss

cultivar ‘Cody’ were among the most promising drought tolerant cultivars.

Introduction

Most traditional turfgrass species require large amounts

of irrigation water to produce good quality turf. In the

semiarid Central Great Plains (CGP) of Wyoming where

average annual precipitation is low (~350 mm), water

availability for turfgrass irrigation is limited. Identifying

drought tolerant and low maintenance turfgrass is of

prime interest to both land owners and turf managers.

Kentucky bluegrass and tall fescue are the most widely

planted cool-season turfgrass species used for both high

and low-maintenance turf systems. Recent studies

reported that several cultivars of Kentucky bluegrass and

tall fescue provided high visual quality under reduced

inputs (e.g. irrigation and fertilization) (Meyer and Funk

1989; Karcher et al. 2008; Richardson et al. 2009, 2012).

Although tall fescue has been reported to produce high

quality turf under low maintenance conditions across sev-

eral regions in the Midwestern United States (Diesburg

et al. 1997), information on the performance of recently

released cool-season turfgrasses under drought conditions

is limited in the semiarid CGP. Selecting grasses that have

the ability to maintain green cover for long periods with-

out supplemental irrigation could have a significant

impact on seasonal water use.

Blue grama and buffalograss are native grass species

found in the North American Great Plains (Beetle 1950).

These warm-season grasses are tolerant to drought,

adapted to semiarid regions, and are currently being used

as low-maintenance turfgrass species across the US Great

© 2013 Japanese Society of Grassland Science, Grassland Science, 59, 111–119 111

Japanese Society of Grassland Science ISSN1744-6961

Japanese Society of Grassland Science

Plains (Phillips 1999; Mintenko et al. 2002). Efforts have

been made to breed native grass species, particularly buf-

falograss for their suitability as turfgrass in the CGP.

‘Bowie’ and ‘Cody’ are turf-type buffalograss cultivars

released recently by the University of Nebraska with supe-

rior turf quality and drought tolerance (Severmutlu et al.

2005a,b). Elsewhere in Manitoba (Canada), blue grama

cultivar ‘Bad River’ has been reported to produce good

quality turf with excellent drought tolerance with great

potential as a low maintenance turf (Mintenko et al.

2002). These newly released cultivars are reported to have

wider geographic adaptability but their performance in

the CGP has not been widely evaluated. The objectives of

this study were to identify turfgrasses adapted to the

semiarid conditions of Wyoming and compare the perfor-

mance and quality of different turfgrass species/cultivars

under irrigated and rain-fed conditions.

Materials and methods

Study site

The study was conducted at the University of Wyoming

James C. Hageman Sustainable Agriculture Research and

Extension Center (SAREC), Lingle, WY (42°14′N, 104°30′W; 1272 m elevation) during 2009–2011. The CGP region

is characterized by cool temperatures and short growing

seasons (Curtis and Grimes 2004). Average frost-free per-

iod at SAREC is 125 days with average annual precipita-

tion of 350 mm. Precipitation amounts during the 3-year

study period (2009–2011) of the study were greater than

or near the 30-year average (Table 1). In general, more

than 70% of annual precipitation in the experimental site

occurred in March through August, with May and June

being the months with the highest rainfall. The year 2011

was relatively dry compared to 2009 and 2010. Except for

the fall of 2009, monthly average temperatures were simi-

lar to the 30-year average (Table 1). The soils are gener-

ally loams and sandy loams with organic matter content

of 1–2%. The soil at the experimental site was a Haverson

loam soil (fine-loamy, mixed, superactive, calcareous,

mesic Aridic Ustifluvent) with 1.2% organic matter, pH

8.0, phosphorus (P) 20 mg kg�1 and potassium (K)

344 mg kg�1.

Experiment set up and treatments

Two treatments were imposed: cultivars/species and irri-

gation management. Three cultivars of Kentucky blue-

grass (‘Bandera’, ‘Common 85/80’ and ‘Midnight’), tall

fescue (‘Blackwatch’, ‘Tar Heel II’ and ‘Watchdog’), buf-

falograss (‘Bison’, ‘Bowie’ and ‘Cody’), and blue grama

(‘Alma’, ‘Bad River’ and ‘Hachita’) were included in the

study (Table 2). Cultivar selection for each species was

based on reported drought tolerance (Mintenko et al.

2002; Severmutlu et al. 2005a,b; Richardson et al. 2009).

Irrigation management included irrigated versus rain-fed.

Treatments were arranged in a randomized complete

block with four replicates in a factorial design. The indi-

vidual plot size of the study was 1.5 m by 6.1 m. The

study was planted on 11 May 2009. Seeds were broadcast

onto a clean, firm and smooth seed bed then softly

raked-in, and finally rolled into soil. Sowing rates (pure

live seed) were 196, 489, 98 and 147 kg ha�1 for Ken-

tucky bluegrass, tall fescue, buffalograss and blue grama,

respectively.

During the establishment year of 2009, rain-fed plots

received irrigation water as needed to ensure good emer-

gence. Good precipitation conditions following sowing in

2009 aided rapid plant establishment. Plot establishment

in the autumn of 2009 was identical among all treat-

ments. This was critical for drought tolerance assessment

in 2010 and 2011, which was accomplished by comparing

grasses in one-half of the study which received continu-

ous irrigation to the other one-half, which did not receive

any supplemental irrigation. The irrigated and rain-fed

plots were separated by an 8-m grass alleyway to ensure

that supplemental irrigation water from the irrigated plots

does not get into the rain-fed plots. The supplemental

amounts of water added to the irrigated turfgrass plots

through center pivot sprinkler irrigation were 229, 245

and 267 mm in 2009, 2010 and 2011, respectively. On

average, the irrigated treatment received 67% more water

than the rain-fed treatment (Table 1). Starting in July

2009, all plots were mowed bi-weekly to control weeds

and stimulate growth. Plots were fertilized (based on soil

test results) with 56 kg ha�1 of N (as urea) and P (as

mono-ammonium phosphate), and 22 kg ha�1 of sulfur

(as elemental sulfur) in mid-September in the second and

third year of the study.

Data collection and statistical analysis

Data on seedling emergence and turfgrass visual ratings

during the establishment year were collected on 1 July

(51 days after seeding) and 29 July, respectively in 2009.

In subsequent years, data collection for early summer was

done on 1 and 6 June in 2010 and 2011, respectively. Late

summer visual ratings were done on 5 August in 2010

and 26 July in 2011. Visual rating data included coverage,

plant vigor, color, dormancy, steminess, density and weed

infestation. All visual ratings (based on National Turfgrass

Evaluation Program (NTEP, http://ntep.org/contents2.

shtml); available at www.ntep.org/reports/ratings.htm)

except for coverage, dormancy and weed infestation were

based on a scale of 1–9; where 1 was poor and 9 was the

© 2013 Japanese Society of Grassland Science, Grassland Science, 59, 111–119112

Performance of turfgrass M. A. Islam et al.

best. For steminess, 9 was no stem and 1 was the maxi-

mum stem (i.e. the higher the number the better). Turf-

grass density was recorded as living plants or tillers per

unit area (excluding dead patches) with a visual rating of

1–9 with 9 equaling maximum density. Coverage, dor-

mancy and weed infestation were rated from 0 to 100%,

with 0 being least and 100 being the highest. For instance,

100% coverage meant the entire plot area was covered by

the turfgrass species while 0% meant no plant cover. Sim-

ilarly, 100% dormancy represented limited growth with

turfgrass turning brown in color, whereas 0% dormancy

meant plants were actively growing with green leaves.

Also, 100% weed infestation meant the entire plot was

covered by undesirable plant species and 0% weed infes-

tation represented a weed free plot.

Statistical analyses for analysis of variance (ANOVA)

for all visual responses were done using the PROC MIXED

procedure of SAS (SAS Institute 2010). Turfgrass species/

Table 1 Monthly precipitation and irrigation over the study period and average temperature at the University of Wyoming James C. Hageman

Sustainable Agriculture Research and Extension Center (SAREC)

Month

Precipitation (mm) Irrigation (mm) Temperature (°C)

2009 2010 2011 30-yr average† 2009 2010 2011 2009 2010 2011 30-yr average

January 12 0 5 8 – – – �2.8 �3.6 �3.7 �3.9

February 4 23 14 10 – – – 0.2 �4.7 �4.6 �1.1

March 17 26 25 18 – – – 2.3 3.6 3.9 3.1

April 64 85 59 42 – – – 6.1 7.8 6.9 7.8

May 23 66 114 64 78 82 90 13.5 11.2 10.0 13.4

June 82 108 53 52 75 82 90 16.8 18.2 17.3 19.1

July 22 25 24 45 76 81 87 20.3 20.9 22.7 22.4

August 86 21 28 30 – – – 19.3 21.2 22.0 21.2

September 16 0 3 32 – – – 13.4 15.4 15.3 15.4

October 41 24 3 24 – – – 3.9 10.2 8.7 8.7

November 3 14 11 14 – – – 3.1 �0.1 1.7 1.1

December 9 11 6 9 – – – �7.7 �2.3 �4.8 �3.2

Average 31 34 29 29 76 82 89 7.8 7.3 8.0 8.7

Total 379 403 345 348 229 245 267 – – – –

†From 1972 to 2001 (Curtis and Grimes 2004).

Table 2 Seed sources and characteristics of turfgrass entries used in the study

Species Cultivar Seed sources Characteristics

Blue grama ‘Alma’ Pawnee Buttes Seed Inc.,

Greeley, CO, USA

Bunch-type grass that spread by tillers, adapted to US Great Plains,

deep roots and drought tolerant

‘Bad River’ Pawnee Buttes Seed Inc.,

Greeley, CO, USA

Bunch-type grass that spread by tillers, quality turf, adapted to US

Great Plains, deep roots and drought tolerant, selection from

South Dakota

‘Hachita’ Pawnee Buttes Seed Inc.,

Greeley, CO, USA

Bunch-type grass that spread by tillers, quality turf, adapted to US

Great Plains, drought tolerant

Buffalograss ‘Bison’ Pawnee Buttes Seed Inc.,

Greeley, CO, USA

Stoloniferous and sod forming, native to US Great Plains, easily seeded,

low maintenance, cold tolerant

‘Bowie’ Pawnee Buttes Seed Inc.,

Greeley, CO, USA

Stoloniferous and sod forming, native to US Great Plains with wide

adaptation range, easily seeded, low maintenance, cold tolerance.

‘Cody’ Pawnee Buttes Seed Inc.,

Greeley, CO, USA

Stoloniferous and sod forming, native to US Great Plains, easily seeded,

low maintenance, early fall dormancy

Kentucky bluegrass ‘Bandera’ Pawnee Buttes Seed Inc.,

Greeley, CO, USA

Semi-upright growth, spread by rhizomes, goes dormant in extreme drought

‘Common 85/80’ Pawnee Buttes Seed Inc.,

Greeley, CO, USA

Rhizomatous, fine textured, some drought tolerance

‘Midnight’ Pawnee Buttes Seed, Inc.,

Greeley, CO, USA

High quality turf but needs maintenance, adapted to Central Great Plains

Tall fescue ‘Blackwatch’ Pawnee Buttes Seed Inc.,

Greeley, CO, USA

Perennial bunch-type, deep rooted, some drought tolerance, requires

maintenance

‘Tar Heel II’ Pawnee Buttes Seed Inc.,

Greeley, CO, USA


maintenance

‘Watchdog’ Pawnee Buttes Seed Inc.,

Greeley, CO, USA


maintenance


M. A. Islam et al. Performance of turfgrass

cultivars, irrigation management and year were considered

as fixed effects and replicate and their interactions were

considered as random effects. Since year interaction with

treatments was significant (P < 0.001), data were analyzed

separately for each year and irrigation management. Turf-

grass cultivar mean separation was done by Fisher’s Least

Significant Difference (LSD) test at P � 0.05. Interactions

and treatment effects were considered significant when F

test P-values were � 0.05.

Results and discussion

Turfgrass performance in establishment year

Turfgrass establishment was successful and plant perfor-

mance was similar among irrigated and rain-fed treat-

ments (Table 3). Average plant emergence recorded on 1

July 2009 was 72 and 75% for irrigated and rain-fed

plots, respectively. Emergence counts were highest among

tall fescue cultivars (93–95%) and least for buffalograss

(47–59%). Similarly, coverage, vigor, color and density of

buffalograss cultivars in the summer of the establishment

year (29 July 2009) were least among the turfgrass culti-

vars tested. Tall fescue cultivars had the best visual rat-

ings. The performance of blue grama and Kentucky

bluegrass were intermediate between tall fescue and buffa-

lograss under both irrigated and rain-fed conditions. Ste-

miness was similar among all cultivars except cultivars of

buffalograss.

Buffalograss performed poorly in terms of coverage,

vigor, color and density but it had the least dormancy

(2–4%) among the cultivars tested (Table 3). The poor

performance of buffalograss is probably due to the poor

germination and emergence, consistent with previous

studies that reported the difficulty and slow establishment

of buffalograss from seed (Fry et al. 1997; Frank et al.

1998). As a warm-season grass, early planting (May)

might have contributed to the poor performance as well;

however, there was variation between cultivars. ‘Cody’

which provided the highest emergence (56–59%) had the

highest coverage, vigor and color ratings among the buf-

falograss cultivars evaluated thus supporting the above

Table 3 Turfgrass performance under irrigated and rain-fed conditions at SAREC, Lingle in the establishment year (emergence recorded on 1 July

2009 [51 days after seeding]; other parameters recorded on 29 July 2009)

Species Cultivar Emergence (%) Coverage (%) Vigor† Color† Dormancy (%) Density†

Irrigated

Blue grama ‘Alma’ 72.5 81.3 6.0 5.3 13.8 7.5

‘Bad River’ 78.8 88.8 6.5 6.5 13.8 8.3

‘Hachita’ 55.0 40.0 5.5 5.8 3.8 2.3

Buffalograss ‘Bison’ 55.0 45.0 5.5 5.3 4.0 1.8

‘Bowie’ 46.5 60.0 5.5 5.5 4.0 5.0

‘Cody’ 58.8 68.8 6.8 6.3 1.8 4.0

Kentucky bluegrass ‘Bandera’ 68.8 72.5 6.8 7.3 15.0 7.0

‘Common 85/80’ 73.8 77.5 7.3 6.8 9.0 7.3

‘Midnight’ 72.5 77.5 7.5 9.0 29.0 6.0

Tall fescue ‘Blackwatch’ 93.8 97.3 8.8 9.0 6.3 8.5

‘Tar Heel II’ 95.0 93.8 8.5 8.3 42.5 8.8

‘Watchdog’ 92.5 95.0 8.3 8.5 38.8 8.5

Mean 71.9 74.8 6.9 7.0 15.2 6.3

SE 5.3 7.4 0.7 0.6 8.3 0.5

Rain-fed

Blue grama ‘Alma’ 71.3 90.0 6.8 5.8 13.8 8.5

‘Bad River’ 72.5 90.0 6.3 5.8 14.0 8.3

‘Hachita’ 61.3 51.3 5.3 5.0 10.5 4.3


‘Bowie’ 58.8 60.0 5.5 5.5 4.0 5.0

‘Cody’ 56.3 68.8 6.8 6.3 1.8 4.0


‘Common 85/80’ 83.8 96.3 7.8 7.0 4.0 8.8

‘Midnight’ 78.8 95.0 7.5 8.5 4.0 8.8


‘Tar Heel II’ 92.5 96.3 8.0 8.0 29.0 8.8

‘Watchdog’ 92.5 93.8 8.0 8.5 25.0 8.3

Mean 75.1 80.4 6.9 6.8 10.8 7.0

SE 5.3 7.4 0.7 0.6 8.3 0.5

†Visual ratings are based on 1–9 rating scale where 1 = poorest or lowest and 9 = best or highest. SAREC,Sustainable Agriculture Research and

Extension Center; SE, standard error for mean comparison.



statement of relationship of establishment with emer-

gence.

Early summer (early June) performance ofturfgrass

Visual ratings differed significantly (P < 0.001) among

turfgrass cultivars under both irrigated and rain-fed con-

ditions in 2010 (Table 4). Plant coverage under irrigated

conditions ranged from 60% for ‘Hachita’ (blue grama)

to 100% (Kentucky bluegrass cultivar ‘Common 85/80’;

tall fescue cultivars ‘Blackwatch’ and ‘Tar Heel II’). In

rain-fed conditions, coverage ranged from 70% for

‘Hachita’ (blue grama) to 100% for ‘Tar Heel II’ (tall fes-

cue). In general, plant coverage for tall fescue culti-

vars > Kentucky bluegrass > blue grama > buffalograss

under both irrigated and rain-fed conditions (Table 4).

Among the tall fescue cultivars, performance of ‘Tar Heel

II’ was similar in both irrigated and rain-fed conditions.

The performance of blue grama and buffalograss cultivars

were similar in both irrigated and rain-fed conditions.

However, performance of the cool-season grasses (Ken-

tucky bluegrass and tall fescue) were superior under irri-

gated conditions compared to the water limiting

conditions.

In the third year of the study (2011), plant coverage

was not different among turfgrass cultivars under irri-

gated conditions (Table 5). However, plant coverage

under irrigation (99.8%) was superior to rain-fed (81.4%)

conditions. In rain-fed conditions, plant coverage ranged

from 53% for ‘Blackwatch’ (tall fescue) to 100% for

‘Cody’ (buffalograss). Plant vigor and color for tall fescue

cultivars were > Kentucky bluegrass > blue grama > buf-

falograss in both irrigated and rain-fed plots. Dormancy

rankings were buffalograss > blue grama > Kentucky

bluegrass > tall fescue (Table 5). This observation is con-

sistent with growth pattern of warm- and cool-season

grasses. Most warm-season grasses show complete green-

up by early June while cool-season grasses show complete

green-up in early May (Mintenko et al. 2002). Turf

density was similar among cultivars under irrigation but

significantly different (P = 0.001) under rain-fed condi-

Table 4 Turfgrass performance under irrigated and rain-fed conditions at SAREC, Lingle in early summer (data [visual ratings] recorded on 1 June

2010)

Species Cultivar Coverage (%) Vigor† Color† Dormancy (%) Steminess† Density†

Irrigated

Blue grama ‘Alma’ 92.5 5.5 6.3 4.8 7.8 8.3

‘Bad River’ 97.5 7.8 7.0 8.5 8.0 9.0

‘Hachita’ 60.0 6.0 6.8 6.0 6.8 6.0


‘Bowie’ 82.5 7.0 7.0 6.8 7.8 8.8

‘Cody’ 82.5 5.3 5.3 4.5 7.8 7.8


‘Common 85/80’ 100.0 6.8 6.8 7.0 6.5 8.8

‘Midnight’ 87.5 7.8 8.0 8.3 8.0 8.5


‘Tar Heel II’ 100.0 8.0 7.3 8.0 8.0 9.0

‘Watchdog’ 95.0 7.5 7.0 7.8 8.0 8.3

Mean 88.5 7.0 7.0 7.0 7.7 8.2

SE 5.0 0.5 0.3 3.7 0.5 0.4

Rain-fed

Blue grama ‘Alma’ 82.5 4.8 6.8 5.5 6.8 8.3

‘Bad River’ 92.5 7.8 7.3 8.0 8.0 9.0

‘Hachita’ 70.0 7.0 6.3 6.3 7.5 6.5


‘Bowie’ 72.5 7.8 7.5 7.3 7.8 7.5

‘Cody’ 85.0 7.5 7.3 7.3 7.8 8.5


‘Common 85/80’ 95.0 7.5 7.5 7.5 8.0 8.8

‘Midnight’ 92.5 8.0 7.8 7.5 7.8 8.8


‘Tar Heel II’ 100.0 8.0 7.3 8.0 8.0 9.0

‘Watchdog’ 85.0 7.5 7.0 7.5 7.8 8.8

Mean 85.4 7.4 7.2 7.2 7.7 8.3

SE 14.6 0.9 0.5 1.2 0.8 1.4

†Visual ratings are based on 1–9 rating scale where 1 = poorest or lowest and 9 = best or highest; for steminess, 1 = highest stem or seed head

and 9 = no stem or seed head. SAREC, Sustainable Agriculture Research and Extension Center; SE, standard error for mean comparison.



tions. Turf density under rain-fed conditions were least

for ‘Hachita’ (blue grama; 2.5) and ‘Bowie’ (buffalograss;

3.0) and highest (9.0) for tall fescue cultivar ‘Watchdog’

(Table 5). Steminess ratings were least among buffalograss

cultivars, followed by blue grama. However, Kentucky

bluegrass and tall fescue cultivars had similar steminess

ratings.

Late summer (late July to early August)performance of turfgrass

Plant coverage ratings were similar under both irrigated

and rain-fed conditions in the late summer of 2010 with

average coverage of 96% (Table 6). Coverage for all turf-

grass cultivars except ‘Hachita’ (blue grama; 77.5%)

was � 91% under irrigated conditions. In rain-fed con-

ditions, only buffalograss cultivar ‘Bison’ had coverage

below 90% (Table 6). After 3 years of the study in 2011,

ratings of turfgrass cultivar coverage under irrigated

conditions in the late summer were buffalograss > tall

fescue > blue grama > Kentucky bluegrass (Table 7).

Under rain-fed conditions, coverage rankings were in

the order of buffalograss (72.6%) > blue grama

(63.1%) > Kentucky blue grass (60.9%) > tall fescue

(49.9%). There was little to no weed infestation in tall

fescue plots in both irrigated and rain-fed plots compared

to the other turfgrass species (Tables 6 and 7). Weed

infestation rankings during the study period were tall fes-

cue < Kentucky bluegrass < buffalograss < blue grama.

Among the warm-season grasses, ‘Bad River’ (blue grama)

and ‘Cody’ (buffalograss) showed better weed competi-

tion. Although both ‘Cody’ and ‘Bowie’ are acclaimed as

highly tolerant to drought and well adapted to the CGP

region (Severmutlu et al. 2005a), the performance of

‘Cody’ was the best among the buffalograss cultivars eval-

uated in the present study. This observation can partly be

explained by the ability of ‘Cody’ to outcompete with

weeds. Species/cultivars selected for low-maintenance

turfgrass should have the capability to withstand environ-

mental stresses such as extreme temperature, low mois-

ture availability, low fertility levels and weed competition

due to limited pesticide use (Diesburg et al. 1997). The

greater competitive ability of tall fescue against weed

invasion makes it a suitable candidate for low-mainte-

Table 5 Turfgrass performance under irrigated and rain-fed conditions at SAREC, Lingle in early summer (data [visual ratings] recorded on 6 June

2011)

Species Cultivar Coverage (%) Vigor† Color† Dormancy (%) Steminess† Density†

Irrigated

Blue grama ‘Alma’ 100.0 2.3 1.3 94.2 3.3 9.0

‘Bad River’ 100.0 3.5 3.0 75.0 5.8 9.0

‘Hachita’ 98.8 2.0 1.3 97.0 2.8 9.0


‘Bowie’ 100.0 2.0 1.0 95.0 3.0 9.0

‘Cody’ 100.0 1.5 1.0 97.0 3.3 9.0


‘Common 85/80’ 100.0 5.8 4.5 21.0 5.3 8.8

‘Midnight’ 99.2 5.8 5.8 16.3 6.0 9.0


‘Tar Heel II’ 100.0 6.8 6.5 7.3 5.0 9.0

‘Watchdog’ 99.5 6.3 6.0 8.3 5.0 9.0

Mean 99.8 4.2 3.6 53.2 4.4 9.0

SE 5.0 0.5 0.3 3.7 0.5 0.4

Rain-fed

Blue grama ‘Alma’ 74.5 4.5 4.8 32.5 5.0 7.0

‘Bad River’ 92.0 3.3 3.0 53.3 5.3 5.8

‘Hachita’ 78.5 2.0 2.0 81.3 3.5 2.5


‘Bowie’ 94.5 1.5 1.3 96.5 3.0 3.0

‘Cody’ 100.0 1.5 1.5 91.3 3.3 7.5


‘Common 85/80’ 77.5 4.5 4.5 29.3 5.0 5.8

‘Midnight’ 81.3 6.3 7.0 3.5 5.8 7.5


‘Tar Heel II’ 74.5 4.5 4.8 32.5 5.0 7.0

‘Watchdog’ 67.5 5.8 6.0 8.0 4.8 9.0

Mean 81.4 4.0 4.1 44.7 4.5 6.2

SE 14.6 0.9 0.5 1.2 0.8 1.4





nance turfgrass species where inputs such as pesticide and

water application are often reduced (Diesburg et al.

1997).

Plant vigor ratings were 7.5 and 3.7 for irrigated and

rain-fed plots, respectively in the late summer of 2010

(Table 6). Vigor ratings of blue grama cultivar ‘Bad River’

(7.8), Kentucky bluegrass cultivar ‘Midnight’ (8.8) and tall

fescue cultivar ‘Watchdog’ (8.3) were above the mean

plant vigor under irrigated conditions (Table 6). Vigor

ratings in rain-fed plots ranged from 2.3 for ‘Bad River’

(blue grama) to 5.5 for ‘Bandera’ (Kentucky bluegrass).

Similarly, plant color ratings in late summer of 2010 were

significantly different among irrigated and rain-fed plots.

Average plant color was 6.9 for irrigated plots and 3.4 for

rain-fed plots. Under irrigated conditions, color ratings of

Kentucky bluegrass and tall fescue were similar and greater

than ratings for blue grama and buffalograss. However, in

rain-fed conditions, color ratings for turfgrass cultivars

were 2.3–4.3 for blue grama, 3.3–4.3 for buffalograss, 1.5–4.5 for Kentucky bluegrass, and 2.5–5.5 for tall fescue.

At the end of the study, plant vigor and color ratings

were superior for irrigated plots compared to rain-fed

plots (Table 7). In irrigated plots, vigor ratings for tall

fescue cultivars (6.8–7.3) and Kentucky bluegrass

(6.5–7.0) were greater than buffalograss (6.0–6.5) and

blue grama (6.3). Similarly, color rankings were tall fes-

cue > Kentucky bluegrass > buffalograss > blue grama

under irrigated conditions. Under rain-fed conditions,

plant vigor and color were superior for the warm-season

turfgrass species (blue grama and buffalograss) compared

to cool-season grasses (tall fescue and Kentucky blue-

grass) (Table 7). This performance of warm-season turf-

grass in terms of vigor and color during the hot summer

periods is expected because of C4 physiology. C4 (warm-

season) grasses are well adapted to high temperature and

low moisture conditions and have high water use effi-

ciency compared to C3 (cool-season) grasses (Biran et al.

1981; MacAdam and Nelson 2003). Due to their drought

tolerance and better adaption to semiarid environments,

warm-season grasses have been recommended to use as

Table 6 Turfgrass performance under irrigated and rain-fed conditions at SAREC, Lingle in late summer (data [visual ratings] recorded on 5

August 2010)

Species Cultivar Coverage (%) Vigor† Color† Dormancy (%) Steminess† Density† Weeds (%)

Irrigated

Blue grama ‘Alma’ 95.0 7.0 6.3 17.5 7.5 8.5 20.0

‘Bad River’ 100.0 7.8 6.8 13.8 7.3 9.0 15.0

‘Hachita’ 77.5 7.0 6.8 17.5 7.5 7.8 48.8

Buffalograss ‘Bison’ 91.3 7.3 6.8 13.8 7.3 8.5 23.8

‘Bowie’ 97.5 7.3 6.0 10.0 7.3 9.0 11.3

‘Cody’ 100.0 7.3 5.8 22.5 8.0 9.0 11.3

Kentucky bluegrass ‘Bandera’ 98.8 7.5 7.8 20.0 7.5 9.0 2.5

‘Common’ 85/80’ 96.3 7.3 6.3 52.5 7.3 8.5 2.8

‘Midnight’ 97.5 8.8 8.8 10.5 7.5 9.0 5.0

Tall fescue ‘Blackwatch’ 100.0 7.0 6.0 50.0 6.8 9.0 0.0

‘Tar Heel II’ 97.5 7.5 7.5 42.5 6.0 8.0 0.0

‘Watchdog’ 95.0 8.3 8.0 38.8 6.5 8.3 2.5

Mean 95.5 7.5 6.9 25.8 7.2 8.6 11.9

SE 6.9 0.4 0.3 10.0 0.4 0.7 7.0

Rain-fed

Blue grama ‘Alma’ 97.5 4.8 4.3 53.8 5.3 8.0 27.5

‘Bad River’ 100.0 2.3 2.3 71.0 3.8 9.0 17.5

‘Hachita’ 93.8 3.5 2.8 71.3 3.3 8.5 40.0


‘Bowie’ 95.0 4.5 4.3 50.0 4.3 8.8 52.5

‘Cody’ 98.8 3.3 3.3 62.5 4.3 9.0 37.5


‘Common 85/80’ 100.0 2.5 1.5 73.8 2.3 9.0 40.0

‘Midnight’ 93.8 1.8 1.8 93.8 1.3 8.5 45.0


‘Tar Heel II’ 96.3 5.0 5.5 52.5 4.8 8.3 0.0

‘Watchdog’ 91.3 4.0 4.0 68.8 3.3 9.0 0.0

Mean 95.5 3.7 3.4 65.7 3.8 8.6 30.7

SE 13.4 1.5 1.2 22.0 1.0 1.2 5.3





low-maintenance turfgrass species in semiarid regions of

the US Great Plains (Phillips 1999; Mintenko et al. 2002).

The value of warm-season grasses, particularly buffalo-

grass as turfgrass species, which withstand extreme

environmental stresses including cold, heat and drought,

has long been recognized in the CGP (Beetle 1950).

Hence, buffalograss has been extensively studied and sev-

eral cultivars have been developed for potential use as

low-maintenance turfgrass (Riordan et al. 1993; Johnson

et al. 2000). The ability of buffalograss to thrive in

extreme conditions is primarily due to its profuse stolon-

iferous morphology and structure, prostrate growth habit,

and ability to enter dormancy under stress conditions

(Beetle 1950; Riordan et al. 1993).

Dormancy rating under irrigation in late summer of

2010 was least in the warm-season grasses (buffalograss,

10.0–22.5%; blue grama, 13.8–17.5%) compared to cool-

season grasses (Kentucky bluegrass, 10.5–52.5%; tall

fescue, 38.8–50%) (Table 6). Dormancy of all turfgrass

cultivars were significantly greater in rain-fed plots, with

dormancy ranging from 49.5 for ‘Bandera’ (Kentucky

bluegrass) to 93.8 in ‘Midnight’ (Kentucky bluegrass). In

both irrigated and rain-fed conditions, plant dormancy

was least in warm-season grasses over the 3-year study

period. Turfgrass with more green color during the sum-

mer months will provide more desirable aesthetic values

than dormant lawns to home owners or turf managers.

Therefore, buffalograss and blue grama will be more

suitable in this regard. Notwithstanding, the performance

of tall fescue cultivars ‘Tar Heel II’ and ‘Watchdog’ were

similar to blue grama and buffalograss cultivars under

rain-fed conditions indicating their superior performance

under limited water supply. Water availability had either

no or minimal effect on turfgrass density; however, ste-

miness rating was greater under irrigation (mean 7.2)

compared to rain-fed turfgrass plots (mean 3.8)

(Table 6). Steminess ratings for all turfgrass cultivars

were above 5.5 under irrigation. Steminess ratings ranged

from 1.3 for Kentucky bluegrass cultivar ‘Midnight’ to

5.3 (blue grama cultivar ‘Alma’) under rain-fed

conditions (Table 6). Density was greatest in buffalo-

grass, followed by blue grama and least for Kentucky

bluegrass cultivars under rain-fed conditions (Table 7).

Superior performance of warm-season turfgrass (e.g. buf-

Table 7 Turfgrass performance under irrigated and rain-fed conditions at SAREC, Lingle in late summer (data [visual ratings] recorded on 26 July

2011)

Species Cultivar Coverage (%) Vigor† Color† Dormancy (%) Steminess† Density† Weeds (%)

Irrigated

Blue grama ‘Alma’ 69.5 6.3 6.0 23.0 6.0 5.8 23.3

‘Bad River’ 82.0 6.3 6.0 17.0 6.0 7.0 11.7

‘Hachita’ 56.2 6.3 5.8 17.5 6.0 4.0 43.3


‘Bowie’ 87.5 6.5 6.3 10.3 6.0 6.5 15.0

‘Cody’ 83.7 6.0 5.3 17.0 6.5 6.8 13.3


‘Common 85/80’ 74.3 6.5 6.3 10.5 7.5 5.8 0.0

‘Midnight’ 55.0 7.0 7.0 34.5 8.0 5.3 5.0


‘Tar Heel II’ 73.8 7.3 7.3 20.0 7.5 6.3 0.0

‘Watchdog’ 74.0 6.8 7.0 22.0 6.3 8.0 0.0

Mean 71.8 6.6 6.4 18.3 6.8 6.0 11.1

SE 6.9 0.4 0.3 10.0 0.4 0.7 7.0

Rain-fed

Blue grama ‘Alma’ 66.5 5.0 5.0 30.0 4.8 3.3 33.3

‘Bad River’ 66.3 3.3 3.5 49.3 3.5 5.8 23.3

‘Hachita’ 56.5 3.8 4.0 47.5 5.3 4.3 43.3


‘Bowie’ 76.5 3.3 3.5 73.4 6.0 5.0 26.7

‘Cody’ 78.8 4.0 4.2 46.3 5.5 6.3 13.3


‘Common 85/80’ 42.3 1.5 1.5 94.5 1.0 2.8 16.7

‘Midnight’ 60.0 1.8 1.8 96.5 1.5 3.5 30.0


‘Tar Heel II’ 65.0 3.8 4.0 61.3 4.8 5.0 0.0

‘Watchdog’ 38.8 4.0 4.5 55.0 4.5 4.0 0.0

Mean 61.6 3.3 3.5 64.3 4.0 4.1 18.9

SE 13.4 1.5 1.2 22.0 1.0 1.2 5.3





falograss, blue grama) under water stress conditions is in

agreement with other published reports (Beetle 1950;

Phillips 1999; Mintenko et al. 2002; Severmutlu et al.

2005a,b).

Conclusions

Coverage of turfgrasses used in the study was similar in

both irrigated and rain-fed conditions. In general, better

performance and turf quality in terms of vigor and color

were obtained in irrigated plots. Plant vigor and color

rankings were tall fescue > Kentucky bluegrass > buffalo-

grass > blue grama under irrigated conditions. However,

under limited water supply, plant vigor and color were

superior for the warm-season turfgrass species (buffalo-

grass and blue grama). Notwithstanding, tall fescue culti-

vars ‘Tar Heel II’ and ‘Watchdog’ performed very well

under rain-fed conditions showing their superior drought

tolerance and low water requirements comparable to

‘Cody’ (buffalograss) and ‘Bad river’ (blue grama). There

was little to no weed invasion in tall fescue turfgrass plots

over the 3-year study period indicating its superior com-

petitiveness to weed infestation compared to other turf-

grass species tested. Based on 3-year results from the

study, tall fescue cultivars ‘Tar Heel II’ and ‘Watchdog’,

blue grama cultivar ‘Bad River’, and buffalograss cultivar

‘Cody’ are the most promising drought tolerant cultivars

and have potential for use in the CGP of Wyoming, and

perhaps beyond, under limited irrigation.

Acknowledgments

The authors thank Dr Justin Moss with Oklahoma State

University for providing cultivar information, Emi

Kimura for assistance in visual scoring, and Wyoming

Department of Agriculture for funding.

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