A field study was conducted to determine the relationship between pungency, soluble solids content, and susceptibility to neck rot in onions. `Golden Cascade', `Sweet Amber', `Valdez', and `Vega' onions were planted in a field with low soil S content. Sulfur, as coarse-ground calcium sulfate, was applied as a band before planting. After harvest, yield was determined and a sample of jumbo onions was taken from each plot to determine pungency, dry matter content, and soluble solids content. Healthy bulbs were returned to storage and evaluated for neck rot after 4 months. Yield, grade, and neck rot incidence after storage were not affected by S treatments. However, there was a trend toward lower neck rot incidence at the highest S application rate (160 lb/acre). Pungency of jumbo onions increased after the application of S as gypsum. `Sweet Amber' and `Valdez' were less pungent than `Golden Cascade' or `Vega'. Neck rot susceptibility was evaluated with an inoculation test of detached bulb scales. Growth and sporulation of the neck rot pathogen Botrytis allii were reduced by S application. Pungency and neck rot susceptibility were negatively correlated.
Michael Thornton, James Torell, and Daryl Richardson
Paige E. Boyle, Michelle M. Wisdom, and Michael D. Richardson
Most pollinating insects require a season-long succession of floral resources to fulfill life-cycle requirements. Incorporating forbs into turfgrass sites may create a season-long sequence of flowers to support foraging pollinators. However, persistence of forbs in warm-season turfgrasses such as bermudagrass (Cynodon spp.) may be affected by the competitive nature of the turfgrass and routine management practices such as mowing. A 2-year study was conducted to evaluate seven forbs (Bellis perennis L., Lotus corniculatus L., Prunella vulgaris L., Trifolium fragiferum L. ‘Fresa’, Trifolium repens L. ‘Durana’ and ‘Resolute’, Trifolium subterraneum L.) for persistence and ability to produce floral resources for pollinating insects in a low maintenance bermudagrass lawn. Plugs of each species were incorporated into ‘Riviera’ bermudagrass in Apr. 2016. Vegetative cover, flower production, flowering period and pollinator foraging were assessed. Prunella vulgaris bloomed July through August and achieved 100% cover (0% bermudagrass) by 2017. Trifolium repens achieved a more balanced competitive density with the bermudagrass and produced flowers from June through August in both years. Trifolium fragiferum persisted over two growing seasons but only bloomed in 2017. Bellis perennis, Lotus corniculatus and Trifolium subterraneum did not persist. Pollinators were observed foraging on all persistent, flowering forbs, including Trifolium repens, Prunella vulgaris, and Trifolium fragiferum. Trifolium repens and Prunella vulgaris produced the most flowers and attracted the most pollinators.
Ying Liu, Huawei Song, Juming Zhang, and Michael D. Richardson
Bahiagrass (Paspalum notatum) is widely used for slope protection and water and soil conservation in southern China. The plants develop an extensive root system that plays a crucial role in the protection of both soil and water. However, little is currently known about the factors that influence early root growth in bahiagrass. Here, the effects of boron (B), calcium (Ca), iron (Fe), lanthanum (La), cerium (Ce), salicylic acid (SA), and melatonin (MLT) on root growth characteristics were examined. Bahiagrass seedlings were grown in 1/25 strength modified Hoagland nutrient solution supplemented with boric acid, calcium chloride, ferric ethylenediaminetetraacetic acid (Fe-EDTA), lanthanum chloride, cerium chloride, SA, or MLT. Root lengths, root surface areas, and the number of root tips were analyzed using a root scanning system after 2, 4, and 6 days of treatment. We found significant effects on root growth after some treatments. Thus, 0.270 or 0.360 mm B for 2 days enhanced root tip number, whereas 0.15 mm Fe for 6 days increased root surface area. Although 3 or 5 mm Ca caused an increase in root tip numbers, the root length was reduced. The addition of La to the nutrient solution significantly increased root length and surface area, and addition of Ce increased root surface area and root tip numbers. Root growth characteristics were optimal after 0.3 μm La for 6 days or 1.0 μm La for 4 days. For Ce treatment, optimal root characteristics were observed at 0.5 μm Ce for 6 days. Root tip numbers increased after 0.1 or 1.0 μm MLT for 6 days, whereas SA treatment reduced the root length, surface area, and root tip numbers. Overall, the analyses indicate that treatment with B, Fe, La, Ce, and MLT benefited root growth in bahiagrass seedlings.
Aaron J. Patton, Jon M. Trappe, and Michael D. Richardson
Covers, mulches, and erosion-control blankets are often used to establish turf. There are reports of various effects of seed cover technology on the germination and establishment of warm-season grasses. The objective of this study was to determine how diverse cover technologies influence the establishment of bermudagrass (Cynodon dactylon), buffalograss (Buchloe dactyloides), centipedegrass (Eremochloa ophiuroides), seashore paspalum (Paspalum vaginatum), and zoysiagrass (Zoysia japonica) from seed. Plots were seeded in June 2007 or July 2008 with the various turfgrass species and covered with cover technologies, including Curlex, Deluxe, and Futerra products, jute, Poly Jute, polypropylene, straw, straw blanket, Thermal blanket, and the control. Establishment was reduced in straw- and polyethylene-covered plots due to decreased photosythentically active radiation penetration or excessive temperature build-up, respectively. Overall, Deluxe and Futerra products, jute, and Poly Jute allowed for the highest establishment of these seeded warm-season grasses.
Michael D. Richardson, John McCalla, Tina Buxton, and Filippo Lulli
Many early spring bulb species are naturally found in grassy areas such as meadows or lawns. However, few studies have been conducted to define this concept in maintained lawns, especially warm-season lawns such as zoysiagrass (Zoysia japonica) or bermudagrass (Cynodon dactylon). Four early spring bulb species, including two crocus species (Crocus tommasinianus ‘Ruby Giant’ and Crocus chrysanthus ‘Goldilocks’), reticulated iris (Iris reticulata ‘Cantab’), and snowdrop (Galanthus elwesii) were established in a zoysiagrass lawn site in Fall 2010. In Spring 2011 and 2012, five common preemergence herbicides used on lawns were applied across the plots to determine phytotoxicity. In addition, mowing treatments were started on plots at two timings (15 Mar. and 15 Apr.) to determine how mowing might affect survival and performance of the bulb species. Early performance was good for all bulb species and greater than 50% flower production was observed in the first spring (2011) after planting. However, in the subsequent 3 years (2012–14), the only species that persisted and continued to flower adequately each spring was ‘Ruby Giant’ crocus. Herbicides and mowing did not affect bulb survival or performance in the trial, suggesting that typical lawn management practices will not be deleterious to the bulbs. These results demonstrate that early spring bulbs may be incorporated into dormant, warm-season lawns, but species and cultivar selection will be crucial for long-term performance.
Francesco Rossini, Roberto Ruggeri, Tiziano Celli, Francesco Maria Rogai, Ljiljana Kuzmanović, and Michael D. Richardson
In the transition zone, warm-season grasses are often overseeded with diploid perennial ryegrass (Lolium perenne L., 2n = 2x = 14) to provide a temporary green surface for winter sporting activities. Because improved cultivars of perennial ryegrass will often persist into summer in overseeded turf, alternative cool-season grasses have been developed to facilitate more rapid transition back to the warm-season species. Limited information is available on these alternative species, especially with regard to their germination characteristics under shade and performance under limiting factors, such as low temperature and restricted photoperiod. Greenhouse and growth chamber studies were designed to test four alternative overseeding grasses in comparison with diploid perennial ryegrass, to verify their potential use in the artificial environment of modern stadiums. Meadow fescue (Festuca pratensis Huds.), tetraploid perennial ryegrass (Lolium perenne L., 2n = 4x = 28), annual ryegrass (Lolium multiflorum Lam.), and spreading diploid perennial ryegrass [Lolium perenne L. subsp. stoloniferum (C. Lawson) Wipff.] were tested. Six different shade treatments were used in the greenhouse study, including 30%, 50%, 70%, 90%, and 100% shade and a nonshaded control (0% shade). Germination was monitored daily over a 21-day period by counting and removing emerged seedlings. The experimental design for this study was a randomized complete block design, with four replications of each species and shade level for a total of 120 experimental units. In the growth chamber study, the same plant material was tested simulating optimal, suboptimal, and critical environmental conditions that can be potentially found within a modern sport facility. In the greenhouse study, the highest final germination was observed with annual ryegrass at 90% shade (98.7%), whereas the lowest for tetraploid perennial ryegrass at 30% shade (58.8%). Annual ryegrass was the fastest emerging species, whereas meadow fescue the slowest. In the growth chamber study, in comparison with perennial ryegrass, the following results may be summarized: 1) meadow fescue and tetraploid ryegrass showed coarser leaf texture, similar growth rates and Normalized Difference Vegetation Index (NDVI) value; 2) annual ryegrass had similar leaf texture, accelerated growth characteristics, and lower NDVI value; and 3) spreading perennial ryegrass displayed finer leaf texture, lower vertical growth, and similar NDVI value.
Michelle M. Wisdom, Michael D. Richardson, Douglas E. Karcher, Donald C. Steinkraus, and Garry V. McDonald
Early-spring flowering bulbs can increase biodiversity while adding color to lawns and other grassy areas. However, few studies have investigated whether bulbs can flower and persist in warm-season lawns or provide feeding habitat for pollinating insects. Thirty early-spring flowering bulbs, including species of Anemone, Chionodoxa, Crocus, Eranthis, Hyacinthus, Ipheion, Iris, Leucojum, Muscari, and Narcissus, were established in bermudagrass (Cynodon dactylon L. Pers) and buffalograss [Buchloe dactyloides (Nutt.) J.T. Columbus] lawns in late autumn 2015 in Fayetteville AR. Bulbs were assessed over three growing seasons for flowering characteristics, persistence, and their ability to attract pollinating insects. A growing degree day model was also developed to predict peak flowering times in our region. Numerous bulb entries produced abundant flowers in bermudagrass and buffalograss lawns in the first year after planting, but persistence and flower production were reduced in both the second and third years of the trial. Five bulbs persisted for multiple years in both turfgrass species and continued to produce flowers, including Crocus flavus Weston ‘Golden Yellow’ (crocus), Leucojum aestivum L. (spring snowflake), Narcissus (daffodil) ‘Baby Moon’, Narcissus ‘Rip Van Winkle’, and Narcissus ‘Tete-a-Tete’. Several bulbs, primarily crocuses and Muscari spp. (grape hyacinth), were also observed to attract pollinating insects, principally honey bees (Apis mellifera). These results demonstrate that some early-spring bulbs can persist in competitive warm-season turfgrasses, while providing pollinator forage, but species and cultivar selection is critical for long-term success.
Juming Zhang, Michael Richardson, Douglas Karcher, John McCalla, Jingwen Mai, and Hanfu Luo
Many bermudagrass (Cynodon sp.) and zoysiagrass (Zoysia sp.) cultivars are not available as seed and are commonly planted vegetatively using sprigs, especially for sod production or in sand-based systems. Sprig planting is typically done in late spring or early summer, but this can result in an extended grow-in period and delay the use of the turf in the first growing season. The objective of this study was to determine if sprigs of bermudagrass and zoysiagrass could be planted earlier in the year, during the dormancy phase, to hasten establishment. A field study was carried out in Fayetteville, AR, in 2014 and 2016 using ‘Tifway’ hybrid bermudagrass (Cynodon dactylon × Cynodon transvaalensis) and ‘Meyer’ zoysiagrass (Zoysia japonica), and in Guangzhou, China, in 2015, using ‘Tifway’ hybrid bermudagrass and ‘Lanyin III’ zoysiagrass (Z. japonica). Sprigs were planted in March (dormant), May (spring) and July (summer) in Fayetteville, and in January (dormant), March (spring) and May (summer) in Guangzhou. Sprigging rates of 30, 60, and 90 m3·ha−1 were tested at both locations and across all planting dates. Bermudagrass was less affected by planting date, with dormant, spring or summer plantings effectively establishing full cover in the first growing season. Zoysiagrass that was sprigged in the dormant season was successfully established by the end of the first growing season while a full zoysiagrass cover was not achieved with either spring or summer plantings in Arkansas. Dormant sprigging reached full coverage as fast or faster than traditional spring or summer planting dates at both locations, indicating that bermudagrass and zoysiagrass establishment can be achieved earlier in the growing season using dormant sprigging methods.