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Corn gluten meal (CGM), a by-product of corn wet-milling, has weed control properties and is a N source. The weed control properties of CGM have been identified in previous studies. The hydrolysate is a water soluble, concentrated extract of CGM that contains between 10% to 14% N. Our objective was to investigate corn gluten hydrolysate as a weed control product and N source in `Jewel' strawberry production. The field experiment was a randomized complete block with a factorial arrangement of treatments with four replications. Treatments included application of granular CGM, CGM hydrolysate, urea, urea and DCPA (Dacthal), and a control (no application). Granular CGM and urea were incorporated into the soil at a depth of 2.5 cm with N at 0, 29, 59, and 88 g/plot. Plot size was 1 × 3 m. Percent weed cover data on 12 Aug. showed plots receiving the 29 g N from CGM hydrolysate had 48% less weed cover than the control (0 g). Plant growth variables showed similar numbers of runners and runner plants among all nitrogen sources.

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Amino acids have been reported to improve turfgrass growth compared with mineral nutrition; however, amino acid catabolism in plants has not been well studied. A number of turfgrass fertilizers contain amino acids; however, some amino acids may be more effective additives in fertilizers than others. Three amino acids that could be effective nitrogen sources for plant growth are the branched-chain amino acids (BCAAs). The BCAA leucine (L), isoleucine (IL), and valine (V) could be effective additives because they are nonpolar and hydrophobic, which can promote plant uptake of these compounds. Although the effect of exogenously applied BCAA on plant growth is not well known, BCAAs have been reported to increase protein synthesis in humans, and that rate of increase is related to the intake ratio of L to IL and V. The objective of this study was to evaluate the use of L, IL, and V as a nitrogen sources on creeping bentgrass (Agrostis stolonifera) and to investigate the effect of BCAAs on plant growth when all three are applied as a combination. Using specially made rooting tubes, L, IL, and V were applied in a complete factorial and compared with equal urea nitrogen at four rates, as well as an untreated control. Where all three BCAAs were applied in combination, the application ratios of 2:1:1 and 4:1:1 (L:IL:V) were tested. At 63 days after seeding, there were no differences in root length, root weight, or shoot weight; however, BCAA 2:1:1 and 4:1:1 increased creeping bentgrass shoot density by 24% and 32%, respectively, compared with equal urea nitrogen. Where shoot density was increased, nitrogen application rate had no effect. On the basis of these results, BCAAs applied in a complete combination using ratios of 2:1:1 or 4:1:1 (3.03 lb/acre N) will provide a greater creeping bentgrass shoot density compared with equal urea nitrogen.

Open Access

The number of herbicides available for use in strawberry (Fragaria×ananassa Duch.) production is limited. Corn gluten hydrolysate (CGH) is a water-soluble extract of corn gluten meal (CGM), a by-product of corn wet-milling. Both CGH and CGM have been shown to inhibit root development of seedlings and can provide nitrogen (N). Four weed control and/or N- containing products were studied: CGH, CGM, urea (46N-0P-0K), and urea applied with DCPA at 8.4 kg·ha-1 a.i. Treatments were applied at N rates of 0, 9.8, 19.5, and 29.3 g·m-2. The 0 g·m-2 of N treatment served as the control. During the 1995 establishment season, all treatments were applied in June, July, and August. Treatments were applied in July and August during the 1996, 1997, and 1998 growing seasons. Dicot and monocot weed number and weed shoot dry weights were determined ≈30 days after both July and August treatments. Strawberry yield data were collected in June. Leaf N data were collected during the first week of July, before renovation. When CGH was applied in July, dicot weed number in August decreased in one of four years, but CGH never affected the number of monocot weeds. CGM application in July, reduced the number of dicot weeds found in plots in Aug. 1995 and 1998. Urea had no effect on dicot weed number from 1995 to 1997. However, in 1998, dicot weed number was reduced by as much as 79% as the rate of urea increased. In all study years, dicot weed number was reduced between 86% and 97%, for the high rate of DCPA + urea, compared with control plots. With few exceptions, rate of N had no effect on leaf N or yield. CGH exhibited limited potential as a natural weed control product; it reduced dicot weed number in one year, but did not affect the number of monocot weeds in any year. Strawberry yield in plots receiving CGH showed a linear increase in one year (1998), but did not show an increase in the other 2 years. Chemical name used: dimethyl tetrachloroterephthalate (DCPA)

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The branched-chain amino acids (BCAA) leucine (L), isoleucine (IL), and valine (V) are synthesized in plants and are essential to growth in most organisms. These compounds can be absorbed by the plant when foliarly applied, but plant catabolism of BCAA is not completely understood. A recent study observed that BCAA applied in a 2:1:1 or 4:1:1 ratio (L:IL:V) increased creeping bentgrass (Agrostis stolonifera) shoot density compared with applications of equal urea nitrogen (N) at 3.03 lb/acre N. The present study investigated whether those increases could translate to a quicker establishment rate of creeping bentgrass grown from seed in standard greenhouse pots. The BCAA applications were compared with equal N applications using urea and a commercially available amino acid product. All N treatments were applied at 3.03 lb/acre N, per application and applied a total of four times on a 14-day interval starting 14 days after seeding. Measurements included final shoot density counts and root and shoot weights, as well as digital image analysis of percent green cover for each greenhouse pot every 7 days. No differences were observed after 70 days in shoot weight, or percent green cover between BCAA treatments and urea; however, BCAA 2:1:1 and 4:1:1 increased shoot density 21% and 30%, respectively, compared with urea, and were equal to the commercially available amino acid product. Applications of BCAA 4:1:1 also increased creeping bentgrass rooting weight by a factor of 7 compared with urea N.

Open Access

Creeping bentgrass (Agrostis stolonifera L.) is well adapted to golf course greens, tees, and fairways but may become a weed in Kentucky bluegrass (Poa pratensis L.) roughs and lawns. The objectives of this study were to determine effects of sulfosulfuron rate and application date on control of creeping bentgrass and safety on Kentucky bluegrass. Field experiments were initiated in 2003 and 2004 in Ames, IA, and West Lafayette, IN. Single applications of sulfosulfuron at 0.011 or 0.022 kg·ha−1 were applied over a 9-week period during the fall of each year. Phytotoxicity on Kentucky bluegrass was recorded weekly and control of creeping bentgrass was determined in the spring after fall treatments. No treatment provided greater than 31% control, and there were few differences in control between the two rates of sulfosulfuron. In West Lafayette, late fall applications were the most effective providing up to 31% control of creeping bentgrass. Sulfosulfuron provided less than 18% control in Ames in either year. Kentucky bluegrass was tolerant of all sulfosulfuron applications. Late fall applications of sulfosulfuron may be useful in partially removing creeping bentgrass from a heavily contaminated sward of Kentucky bluegrass.

Chemical names used: 1-(4,6-dimethoxypyrimidin-2-yl)-3-(2-ethylsulfonylimidazo[1,2-a]pyridin-3-ylsulfonyl)urea (sulfosulfuron)

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Field plots of four production systems of `Tristar' dayneutral and `Earliglow' Junebearing strawberry (Fragaria xananassa Duch.) were established in 1993. Productions systems included conventional practices (CONV), best-management practices including integrated crop management (ICM), organic practices using corn gluten meal, a natural weed control product, (ORG-CGM), and organic practices using a natural turkey manure product (ORG-TM). `Earliglow' plants grown with ORG-CGM showed the highest number of runners and total vegetative biomass. Plots with CONV and ICM systems using standard herbicide treatments had lower total weed numbers (11 and 18, respectively) than ORG-CGM (63) and ORG-TM (58). `Tristar' plant growth, yield and berry number were reduced when plants were grown under straw mulch in ORG-CGM and ORG-TM compared to CONV and ICM plots with polyethylene mulch.

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Tall fescue (Schedonorus arundinaceus) offers an alternative to kentucky bluegrass (Poa pratensis) for use on athletic fields. Tall fescue has the ability to withstand athletic field traffic, but little is known about the best management practices such as optimal height of cut (HOC). A 2-year study was conducted on established ‘Snap Back’ tall fescue grown over a native soil root zone to determine optimal HOC under simulated athletic field traffic. Plots were maintained at various HOC treatments (1.5, 2, or 3 inches) for the duration of the growing season. Twenty-five simulated traffic events were applied each fall with a modified Baldree traffic simulator. The percentage of green cover (GC) loss per traffic event by HOC varied between years. In 2017, the 1.5-inch HOC improved traffic tolerance (–1.7% GC per event) compared with the other HOC treatments (–2.6% GC per event) in terms of percentage of GC. In 2018, the HOC did not have an impact on traffic tolerance. Differences in traffic tolerance between years could be a result of differences in precipitation (78 mm in 2017, 6 mm in 2018) during the period when traffic occurred, which suggest that the lower HOC performs better under wet conditions compared with the greater HOC. There were no differences among treatments for the safety variables measured (surface hardness, rotational resistance, and soil moisture).

Open Access

Aeration and sand topdressing are important cultural practices for organic matter management on golf course putting greens. Many golf courses lack the budget for applications of new sand topdressing material. A 2-year study was conducted to investigate the effect of recycling sand from hollow-tine aerification cores on a sand-based creeping bentgrass (Agrostis stolonifera) putting green soil properties and playability. Treatments included traditional [T (cores removed and sand topdressed)], verticut [V (cores broken up with verticutter)], and recycle [R (cores recycled using a core recycler)]. There were no differences in root zone organic matter, bulk density, soil porosity, infiltration rates, percent sand recovered during mowing, surface firmness, and ball roll distance between treatments during the study. Immediately after aerification treatments, T had the highest percent green cover (PGC) (38.3%) compared with V (26.9%) and R (26.8%), indicating that T offered the least sand present on the surface. Seven days after treatments, there was no difference in PGC (85.3% to 90.1%), indicating all treatments recovered similarly. Alternative aerification treatments V and R could be useful techniques to minimize or reduce the amount of sand used for backfilling core aeration holes without compromising the putting green soil properties and playability.

Open Access

A major limiting factor in producing container-grown herbaceous perennials is low-temperature injury to cold sensitive roots and crowns during above ground winter storage. Growers and retailers of these plants understand the need for protection systems, yet specific recommendations are unavailable. The ability of several structureless systems to moderate temperature and protect 16 species of container-grown herbaceous perennials from low-temperature injury was investigated. Two light-excluding treatments consisting of 30 cm of straw between 2 layers of 4 mil white copolymer, and 18 cm deep in-ground beds protected with 1 layer of 4 mil white copolymer and 30 cm of woodchips provided the greatest moderation of winter low and early spring high temperatures but resulted in severe etiolation among test plants, A bonded white copolymer-microform overwintering blanket with translucent properties provided comparable plant survival, and prevented etiolated growth allowing plants to grow rapidly after uncovering, despite dramatic temperature extremes observed beneath this cover.

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Annual grassy weeds often inhibit establishment of spring-seeded creeping bentgrass (Agrostis palustris Huds.) on golf courses. The objective of this experiment was to evaluate the safety of the annual grass herbicide quinclorac in spring-seeded creeping bentgrass in varying climatic regions of the United States. Experiments were initiated in Indiana, Iowa, and North Carolina in Spring 2000. Treatments included siduron at 6.72 kg·ha-1 a.i. applied immediately prior to planting (PRE), and quinclorac at 0.84 kg·ha-1 a.i. applied 7 days before seeding (DBS), PRE, and 14 or 28 days after emergence (DAE). Herbicides were applied to three creeping bentgrass cultivars at each location. Siduron reduced establishment of `Providence', `L93', and `Putter' creeping bentgrass in Indiana. Quinclorac applied PRE, 14 DAE, and 28 DAE caused short-term phytotoxicity, primarily in `Providence' in Indiana. Quinclorac applications did not significantly affect cover of `Providence', `L93', or `Putter' in Indiana or `L93', `Pennlinks', or `Penncross' in Iowa. All applications of quinclorac reduced cover of `L93', `Pennlinks', and `Penncross' in North Carolina. Though quinclorac applications resulted in no long-term damage when applied to creeping bentgrass seedlings in Indiana or Iowa, results from North Carolina indicate that caution should be exercised when using quinclorac on seedlings of creeping bentgrass. Chemical names used: 3,7-dichloro-8-quinolinecarboxylic acid (quinclorac); 1-(2-methylcyclohexyl)-3-phenylurea (siduron).

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