Crop, Forage and Turfgrass Management最新文献

‘KSUZ 0802’ zoysiagrass (Innovation zoysiagrass, Zoysia matrella × Z. japonica) is a new cultivar that provides a high-quality playing surface on golf course fairways and tees. However, seedheads produced in late spring disrupt the playing surface. The plant growth regulator (PGR) ethephon has produced variable results in prior studies in suppressing zoysiagrass seedheads, and information for KSUZ 0802 is lacking. A two-year field experiment was conducted from 2019–2021 in Manhattan, KS, to assess the performance of ethephon (Proxy) on seedhead suppression of KSUZ 0802 zoysiagrass. Treatments included ethephon applied in a single application at 5 fl. oz. 1000 ft⁻² on multiple dates between August and November. Seedhead suppression was determined by counting seedheads in late spring. Ethephon applied in September provided >60% seedhead suppression; however, when applied during other months, variations were large between the two study years. Applying ethephon when accumulated cooling degree days (68°F base) were <37 resulted in >70% seedhead suppression, except for application on September 25, 2019. Late August ethephon applications, despite achieving good seedhead suppression (ranging from 54 to 80%), caused transient yet commercially unacceptable injury to KSUZ 0802 in both years. Application timing affected turf quality in late spring as KSUZ 0802 with fewer seedheads had better quality post-mowing, but no effect on spring greenup was observed. Ethephon can be an effective PGR for seedhead suppression in KSUZ 0802 zoysiagrass. However, careful consideration of application timing is essential as applying ethephon in late summer or late autumn can produce undesirable results.

Warmer than normal late fall temperatures may change standard fall harvest management of alfalfa (Medicago sativa L.) in western Canada. The objective of this study was to evaluate the forage yield and nutritive value of three types of alfalfa cultivars under different harvest managements. A field experiment was conducted from 2013 to 2017 using rhizomatous type (RR), cv. AC Yellowhead (M. sativa subsp. falcata), tap root type (TR), cv. Equinox (ssp. sativa) and creeping root type (CR), cv. Spredor 4 alfalfa (ssp. sativa), at Melfort, SK, Canada. The five harvest treatments were two 1-cut systems (early July or late July) and three 2-cut systems (early July + early or late September, late July + late September). Total forage yield was greater in TR and CR alfalfa than RR alfalfa; however, RR alfalfa had higher total forage yield under dry growing conditions versus CR alfalfa. The three alfalfa cultivars had a similar response to 2-cut harvest managements. The first cut yield was affected by the timing of the second cut of the previous year with the early September harvest reducing yield more than the late September. Three alfalfa cultivars had similar crude protein (CP), total digestible nutrient (TDN), and acid detergent fiber (ADF) concentrations. There was a significant nutrient yield benefit of TR and CR alfalfa under a 2-cut system over the RR alfalfa. Although the prairie climate is warming, the findings suggest that a fall rest period until late September is recommended regardless of alfalfa types to maintain high hay yield over multiple years.

High deoxynivalenol (DON) levels in corn (Zea mays L.) is a grain quality issue for many growers in the US Great Lakes region. High DON levels can be attributed to the interaction of environment, pathogen (Fusarium spp. causing ear rot), and hybrid susceptibility. However, ear-feeding insects can provide easy access for fungal infection and increase DON accumulation, hence the evaluation of insect protection strategies such as hybrid insecticidal proteins is crucial. Field trials were conducted at four locations in Michigan to study the impact of hybrids insect protection trait on ear injury, ear rot infection, and DON levels. Fungicide application (prothioconazole at silking stage) was conducted at two locations and included non-treated control. Insect feeding incidence (IFI) and ear rot incidence (ERI) were correlated at three locations but were stronger at locations with environments not conducive to fungal growth soon after silking. Correlation between IFI and DON was observed only at locations with highest insect pressure. Hybrid with Vip3A protein reduced IFI by >70% at all locations but lowered DON concentration at one out of three tested locations compared to non-Vip3A hybrids. Fungicide application reduced ear rot severity at one of two locations but did not impact ERI or DON levels. Overall, results showed that ear-feeding by insects can lead to an increase in ear rot and DON levels, and use of hybrids with Vip3A protein can reduce DON levels especially under high insect pressure.

Overseeding of bermudagrass (Cynodon dactylon L.) with perennial ryegrass (Lolium perenne L.) is often performed to provide green cover of dormant warm-season turfgrass in the winter. Fraise mowing is a cultural practice that can be used to disrupt the soil surface and hasten establishment of overseeded perennial ryegrass. Research was conducted to determine the most effective timing of overseeding for perennial ryegrass establishment in Northeast Mississippi, and to compare fraise mowing with other common cultural practices performed to enhance overseeding establishment. Treatments included fraise mowing at two depths (0.3 or 0.6 inches), scalping to a height of 1 inch, or vertical mowing to a depth of 1 inch at three timings (mid-September, mid-October, and end-October) prior to seeding perennial ryegrass at 435 lb pure live seed acre⁻¹. Plots were evaluated weekly for turfgrass quality, visual perennial ryegrass cover, and total green cover with digital image analysis. Fraise mowing to a depth of 0.6 inches and scalping resulted in quicker perennial ryegrass establishment. Fraise mowing to a depth of 0.3 inches resulted in quicker perennial ryegrass establishment than both the untreated control and vertically mowed treatments. End-October fraise mowing resulted in the slowest establishment, as growing conditions were not favorable for perennial ryegrass growth. Although the mid-September and mid-October treatments provided the most rapid perennial ryegrass establishment, almost all seeding timings were visually similar by March 15th of the following year. Though fraise mowing temporarily causes an undesirable playing surface, more rapid perennial ryegrass establishment is afforded by restricting bermudagrass competition.

Stockpiled tall fescue [Lolium arundinaceum (Schreb.) Darbysh.] is an alternative to extend the grazing season and reduce feeding costs during the winter. In addition, adequate fertility management with N, P, and K nutrients can improve forage production. Our objective was to evaluate the impact of N, P, and K fertilization (from 0 to 120 lb/a, 0 and 50 lb/a, and 0 and 30 lb/a, respectively) on forage accumulation (FA) and nutritive value in stockpiled tall fescue in claypan soils. The study was carried out in Columbus, KS, on established ‘Kentucky 31’ tall fescue pastures in the fall of 2019 and 2021 (two years). The treatments were one unfertilized control and fertilization with six combinations of nitrogen (0, 40, 60, 80, and 120 lb/a), phosphorus (0 and 50 lb/a), and potassium (0 and 30 lb/a) rates. Forage accumulation was greater in the treatments with at least 60 lb N/a compared with the unfertilized control (1,235 vs. 570 lb DM/a). However, the greatest crude protein content (CP; 13%) and crude protein accumulation (CPA; 163 lb CP/a) were produced when 120 lb N/a was applied. Nitrogen fertilization also resulted in greater total digestible nutrients, net energy gain, net energy maintenance, and lower acid detergent fiber. Phosphorus and potassium had little effect on the measured responses. Nitrogen fertilization can be an alternative to increase stockpiled tall fescue FA and nutritive value, reducing the need for energy and protein supplementation of livestock during the winter.

Rice (Oryza sativa L.)–wheat (Triticum aestivum L. emend. Fiori et Paol.) is the main crop rotation in subtropical conditions of northwestern Indo-Gangetic plains. To meet fodder demand, corn (Zea mays L.) is grown in spring (February–June) for silage making after short duration oilseed crop (Brassica rapa ssp. oleifera) in rice-based crop rotation. To fulfill the increasing silage demands, production potential of winter cereals for silage making under rice-based crop rotations was explored. Rice–wheat (for silage)–spring corn (for silage) (R-W-SpM) and rice–barley (for silage) (Hordeum vulgare L.)–spring corn (for silage) (R-B-SpM) crop rotations were evaluated for silage production in randomized complete block design with four replications during 2020–2021 and 2021–2022. Rice–wheat (for grains) (R-W) crop rotation was also evaluated for economic comparison of silage production in rice-based crop rotations. The silage yield of barley was 15.21% higher as compared with wheat, while silage yield of spring corn grown after barley and wheat was statistically similar. The quality of barley silage was better than wheat. The system silage yield (winter cereal + spring corn) was 9.61% higher in R-B-SpM than R-W-SpM crop rotation. Rice equivalent yield and gross margin of R-B-SpM crop rotation (based on silage yield) were 6.54% and 11.02%, respectively higher than R-W-SpM. Silage-based R-W-SpM and R-B-SpM crop rotations resulted in 79.19% and 98.93%, respectively higher gross margin than R-W crop rotation.

Recommendations for timing insecticides against billbugs have historically been based on adult activity and a corresponding degree-day (DD) model that is optimized for the eastern United States. A DD model was recently developed for billbugs in Utah and Idaho that refines predictions of adult activity based on the phenology of species that inhabit the Intermountain West (IMW) region. However, timings still follow eastern US recommendations and have not been verified with field applications in the IMW. We evaluated the synthetic insecticides Merit 75 WP and Acelepryn 1.67 SC and the bioinsecticides Grandevo and Venerate for controlling larvae when using the eastern recommended treatment thresholds of 30% and 50% adult activity (adults collected in pitfall traps) based on the Utah–Idaho model for two years. Applications of insecticides at these adult emergence thresholds provided >75% control of billbug larvae preventively and curatively in Utah, confirming these are appropriate action thresholds to use in the Utah–Idaho model to time insecticides. Insecticides applied at various calendar dates around these recommended timings, but typical for a professional applicator in Utah based on site history and weather, were assigned model-calculated DD for testing in the Utah–Idaho model. Instances where a professional applicator treated within model-predicted timings resulted in larval reductions, further validating that the model parameters are good recommendations for the region and should be adopted. Additionally, several calendar-based applications made earlier or later than optimal timings based on model predictions were effective, suggesting that applicators have flexibility for timing applications when targeting larvae.

The critical soil test value (CSTV) of phosphorus (P) is the threshold where it is possible to obtain 95–100% of the maximum crop yield. Although the P buildup in the topsoil of conservation tillage may affect this threshold, the effect of soil sampling depth on CSTV value has not been determined for conservation tillage in the southern United States. The objective of this study was to evaluate CSTV of P using different soil layers from two long-term experiments managed under varying P rates, planted to corn (Zea mays L.)/soybean [Glycine max (L.) Merr.] rotation under minimum tillage (Tidewater) or no-tillage (Piedmont) in North Carolina. Soil samples were taken from depths of 0–2, 2–4, 4–8, and 8–12 inches. The CSTV for different soil layers was calculated using a quadratic-plateau model with Mehlich-3 P and relative yield of soybean and corn (2021–2022). The CSTV decreased as the soil sampling depth increased. The CSTV of P at the Tidewater site was 128, 111, 86, and 74 lb ac⁻¹, and at the Piedmont site was 28, 20, 16, and 15 lb ac⁻¹ for the 0–2, 0–4, 0–8, and 0–12 inches soil layers, respectively. Using multiple sampling layers or deeper layers did not improve the quality of CSTV measurement. The current sampling depths used in North Carolina are appropriate for minimum tillage (0–8 inches) and no tillage (0–4 inches), as similar quality models were obtained using either soil layers in both sites. However, it is important to be cautious when changing the sampling depth, as this affects the CSTV value.

Seeded bermudagrass (Cynodon dactylon L.) cultivars are a popular choice for many athletic fields and golf course areas throughout the transition zone and southern United States, but the nitrogen (N) needs to optimize turf coverage are not well defined, and N is likely often applied in excess of actual plant needs. A field study was conducted to compare a controlled release versus readily soluble N-source, total N-rate, and application frequency for seeded bermudagrass establishment on a native soil in the northern transition zone. ‘Rio’ bermudagrass was seeded in June 2020 and 2021 to evaluate eight granular N-fertilizer programs using either ammonium sulfate or polymer-coated urea (PCU). Total N ranged from 0.0 to 6.0 lb N 1,000 ft⁻² among three application frequencies, including applications only at planting (PCU only), or applications at planting with repeat applications every 7 or 14 days following bermudagrass germination. Time to 50% green coverage ranged from 20 to 24 and 23 to 30 days in Year 1 and 2, respectively, and varied by N-program. Applying PCU at planting, 2 lb N 1,000 ft⁻², resulted in similar number of days to 90% green coverage compared with other fertilization programs in both study years but with less overall N and fewer applications. These results indicate that applying more than 3 lb N 1,000 ft⁻² over the first 60 days of establishment provided no measurable benefit in terms of time to maximum turf coverage.

Black oat (Avena strigosa Schreb.) is a cool-season annual grass with Mediterranean origin. In contrast to other cool-season grasses, black oat is more heat tolerant and disease resistant, making it an attractive option for the US upper Midwest, since it can be utilized during summer, when there is decreased productivity of cool-season forages due to photorespiration. Black oat is recommended for USDA Plant Hardiness Zones 8b–10a, far away from the upper Midwest (zones 2a-5b). The objective was to evaluate 10 black oat breeding lines (referred to as ‘UF1’ through ‘UF10’) for herbage accumulation, crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), and in vitro digestible organic matter (IVDOM) concentrations. The experiment was carried out on May–July 2021 and 2022 in Stratford, WI. Triticale (x Triticosecale Wittmack cv. ‘TriCal 342′) and ‘Legend 567′ oat (Avena sativa L.) were included as controls, as well as ‘Ogle’ oat as a regionally recommended cultivar. Herbage accumulation differed by treatment (P = 0.002) and averaged 5900 lb acre⁻¹ among black oat lines, with ‘UF3’ and ‘UF10’ having greater herbage accumulation than oat checks Ogle and Legend 567, and Trical 342 triticale. Crude protein concentration of UF7 and UF3 was 8.5 to 9.5%, respectively. The IVDOM concentrations were above 58% for all black oat. Results indicate certain black oat have the potential to provide forage resources during the early summer in the upper Midwest, but further studies are warranted to evaluate how to best manage this species into cropping or pasture systems in the region.