Crop, Forage and Turfgrass Management最新文献

North Carolina soybean [Glycine max (L.) Merr.] growers use a diverse range of row spacings, commonly between 7.5 and 38 inches. Research findings regarding the effect of row spacing on soybean yield have been inconsistent and influenced by factors such as planting date and environmental conditions. Although small-plot data from North Carolina often indicates that narrower row spacings lead to higher yields, growers have raised concerns about the potential benefits of wide rows when ripping is employed in environments exhibiting symptoms of subsurface compaction. Research was conducted over 2 years (2021–2022) in the Coastal Plain region to evaluate the effects of wide row ripped spacing (36 or 38 inches) compared to un-ripped narrower spacing (15 inches) on plant population, canopy cover, soil compaction, and yield across four environments. One of the environments included an additional treatment with an un-ripped drilled row spacing of 7.5 inches. Although seeding rates were calibrated similarly, the ripped wide-row spacing treatments led to lower achieved plant population, predominantly due to adverse seed bed conditions resulting in lower germination caused by the inline ripper. The un-ripped narrow row spacings (7.5 and 15 inches) consistently demonstrated 7–25% greater canopy cover than ripped wider spacings (36 and 38 inches) by the flowering stage (R1). Soil penetration resistance varied by row spacing in only two environments, with differences generally lacking agronomic significance (i.e., penetration resistance <2 MPa). Yield results indicated no significant effect of row spacing in three out of four environments; in the fourth environment, the un-ripped 15-inch row spacing yielded significantly more than both the un-ripped drilled and ripped wide-row soybeans. In the environments in this study, wide-row ripped treatments offered no agronomical advantage over narrow row un-ripped treatments.

Buckwheat (Fagopyrum esculentum) is a fast-growing plant that quickly produces a dense groundcover. The utilization of buckwheat as a cover crop in vegetable production could be beneficial to Georgia producers, however for successful adoption, weed control in the cover crop coupled with control of buckwheat volunteers must be achievable. A preemergence (PRE) and a postemergence (POST) experiment were each conducted three times in Ty Ty, GA (2020–2021) addressing these objectives. In the PRE study, acetochlor at 0.56 lb ai acre⁻¹ injured buckwheat up to 16% without negatively influencing growth, suggesting potential for use in buckwheat for weed control. Flumioxazin, fomesafen, halosulfuron, ethalfluralin and S-metolachlor lacked adequate buckwheat safety. However, flumioxazin at 0.05 lb ai acre⁻¹, fomesafen at 0.19 lb ai acre⁻¹, and halosulfuron at 0.02 lb ai acre⁻¹ were identified as effective options to manage volunteer plants, as control exceeded 80%. In the POST experiment, buckwheat injury from 2,4-D, clethodim, dicamba, glufosinate, glyphosate, halosulfuron, linuron, paraquat, and prometryn was evaluated, and when considering all evaluation parameters, paraquat (0.50 lb ai acre⁻¹) was the most effective option for the control of buckwheat. This was followed by glufosinate (0.59 and 1.17 lb ai acre⁻¹) and glyphosate (1.20 and 2.40 lb ai acre⁻¹). For potential applications over buckwheat for weed management, clethodim (0.12 lb ai acre⁻¹) was the only POST herbicide that provided adequate crop safety.

Though costly, pasture restoration is necessary when forage stands decline. Interseeding legumes (e.g., alfalfa, Medicago sativa L.), along with crabgrass (CG; Digitaria sanguinalis L.) as a warm-season forage with high nutritive value, can play a key role in supporting pasture restoration. Our objective was to quantify changes in forage mass (FM) and nutritive value and the associated cost of pasture restoration using different strategies. The experiment was carried out in Spring Hill, TN, for 2 years in established swards of tall fescue [TF; Schedonorus arundinaceus (Schreb.) Dumort] or orchardgrass (OG; Dactylis glomerata L.), with the addition of alfalfa with or without CG. The treatments were: 1) control (C-TF or C-OG), 2) synthetic N fertilization (TF+N or OG+N), 3) fall seeding of alfalfa (FA), 4) spring seeding of alfalfa (SA), 5) fall seeding of alfalfa + summer seeding of CG (FA+CG), and 6) spring seeding of alfalfa + summer seeding of CG (SA+CG), with four replications. The FM was greatest when N fertilizer was applied to TF and OG. In both grass types, N fertilization also resulted in greater nutritive value than the control. The addition of alfalfa and CG did not result in an increase in nutritive value, and this response probably may be pronounced in the medium to long term when overseeded species are well established. Thus, synthetic N still incorporates greater outcomes, showing the need for long-term researchers to provide deeper information into overseeding cool- and warm-season grasses, thereby contributing to the restoration of ecosystems.

Relative maturity (RM) selection is important for corn (Zea mays L.) farmers because it has significant effects on yield and profit. Selecting the appropriate RM is particularly important for corn farmers in the northern Corn Belt where growing season length is often a limiting factor. However, there is limited information on optimal RM for maximizing yield and partial returns in Michigan and other northern states. The objective of this study was to examine optimal RM across Michigan over the last two decades to identify RM that maximizes yield and partial returns. Data from irrigated and dryland corn hybrid trials conducted in Michigan between 2006 and 2022 were analyzed. Partial returns were estimated at a single grain price ($4.38 bu⁻¹) and two drying costs ($0.045 and $0.06 bu⁻¹ point⁻¹). Our results showed that optimal RMs remained similar for most years (14 out of 17) and decreased significantly in 2009, 2014, and 2019. Averaged across years, optimal RMs for maximum yield were lowest (ranged from 84 to 95) in northern locations (latitude >44°N) and highest (ranged from 104 to 109) in the south (latitude 42°N). The optimal RM for maximum partial returns was up to 3 units lower than that maximized yield for central and southern locations but showed variability in northern locations. Overall, our results provide useful regional recommendations for Michigan corn farmers to optimize RM selection.

Early in the growing season, abiotic (freezing temperatures, hail, flooding, etc.) and biotic (slugs, deer, disease, insects, etc.) factors often reduce soybean [Glycine max (L.) Merr.] plant populations. Although seeing a soybean field with poor seedling vigor, slow plant growth, and low plant population density often triggers an urge to replant, such fields do not always need to be replanted. The objectives of this management guide are to (a) address the necessary considerations prior to replanting a soybean field; (b) provide images depicting common early season stressors affecting soybean; and (c) explain the potential yield limitations from early season soybean injuries. US soybean agronomists representing a diversity of growing regions collated replant guidelines to generate applicable recommendations and pictures showing effects of early-season stressors that reduce soybean plant population. The minimum soybean stand required to produce near-maximal yields has been as low as 50,000 plants per acre, but more plants than that may be required in the case of adverse growing conditions, in northern regions, or with early-maturing varieties. When the plant population is low, repair planting—adding seeds without destroying established plants—portions of the field instead of destroying the existing stand and starting over is recommended. Management in reaction to stand loss should consider the cause and type of damage and should focus on maximizing profitability.

Silage corn (Zea mays L.) in Michigan and the Great Lakes region is prone to an emerging foliar disease called tar spot (caused by Phyllachora maydis). When corn is infected with Phyllochora maydis, stromata develop on the leaves resulting in early senescence and drying. Therefore, to understand the effect of tar spot on forage yield, nutritive value, and predicted milk yield, field trials were conducted at multiple Michigan locations from 2021–2023. Field trials were arranged in randomized complete block design with four replications. Treatments included hybrid resistance (one susceptible and one partially resistant hybrid) and three fungicide treatments using Delaro 325 SC at 8 oz acre⁻¹ (non-treated, one application at silking [R1], and two applications [one at R1 and second at dough stage]). Results showed that tar spot severity increased over time in silage corn. Fungicide application in susceptible hybrid had the lowest tar spot severity across all hybrids and fungicide treatments. Hybrid disease resistance resulted in 50% reduction of tar spot severity and contributed to a lower yield penalty. Reduction of tar spot severity due to hybrid disease resistance also minimized decline in neutral detergent fiber digestibility and predicted milk yield. Fungicide application reduced tar spot severity but did not affect dry yield and forage nutritive value. Overall, our study shows that tar spot reduces forage yield and nutritive value and requires an integrated approach to disease management.

Managing winter wheat (Triticum aestivum L.) for both grain and straw production is a common practice, especially where cropping and animal systems are integrated, with wheat straw being used for animal bedding. Trinexapac-ethyl (TE) is a common plant growth regulator used in winter wheat and has been studied for its potential to mitigate lodging risk and improve grain yield but its influence on straw yield and quality still needs to be elucidated. Here, we evaluated the effect of TE (control, single, and split application) in combination with three spring nitrogen (N) fertilizer rates for a total of nine treatments over two growing seasons in Pennsylvania. Compared to the control, the application of TE reduced plant height without increasing basal internode diameter, which led to an 8% decrease in straw yield when TE was split applied and a 5% decrease (although not significant at p = 0.05) in straw yield when TE was applied in a single dose. TE did not affect straw water holding capacity, thus preserving its value for animal bedding. No lodging was observed across both growing seasons, and grain yield was not affected by treatments, similar to other studies where TE did not provide a grain yield benefit in the absence of lodging. Grain protein concentration increased with increasing N fertilizer rates, which were achieved through late spring N applications. When considering the use of TE, winter wheat producers must weigh the potential tradeoff between grain and straw yield, although grain and straw quality are maintained.

Soybean [Glycine max (L.) Merr.] is a crucial crop for global food, feed, and biofuel industries, with its yield influenced by agronomic practices such as row spacing and seeding rate. This study aimed to evaluate the effects of these practices on soybean yield across 7 years (2016–2023) in Iowa. Using a split-split-plot design, we examined three row spacings (15, 20, and 30 inches) and varying seeding rates at two experimental sites. The research was conducted under typical Iowa conditions with different soybean cultivars and soil types. Grain yield data were standardized to 13% moisture and analyzed using ANOVA to assess the interactions between row spacing, seeding rate, and cultivar. Results indicated the effects of row spacing and seeding rate on yield were inconsistent across years and locations. Narrower row spacings (15 and 20 inches) tended to improve yield in high-productivity environments, while wider spacing (30 inches) performed better in some low-yielding environments. The seeding rate response varied, with no clear pattern across site-years, suggesting that soybean plants can compensate for lower planting densities by adjusting branching and pod set. These findings highlight the adaptability of soybean to different planting practices, offering farmers flexibility in optimizing seeding rates and row spacings without significant yield loss. This research provides valuable insights into potentially reducing input costs while maintaining productivity in soybean production.

Cool-season annual grasses complement bermudagrass [Cynodon dactylon (L.) Pers.] pastureland production in the southern United States. These species can be planted in the fall or in late winter to provide supplemental forage strategically in the growing season. Late winter plantings can also provide emergency forage where perennial stands have been affected by drought. The optimum late winter planting date is not well established for these annual forages. This experiment sought to compare the forage production from three late-winter planting dates of four annual grasses. This experiment was conducted at the Arkansas State University farm in Jonesboro, AR, from 2021–2024. Winter wheat (Triticum aestivum L.), spring and winter oats (Avena sativa L.), and annual ryegrass (Lolium multiflorum Lam.) were no-till planted into a glyphosate-suppressed bermudagrass sod on one of three planting dates. Early planting dates were in late February, Mid planting dates were in mid-March, and Late planting dates were in late Match. Plots were harvested once in early May of each year. Winter wheat was the least productive forage across planting dates in all years. Spring oat was the most productive forage (approximately 4200 lbs acre⁻¹). The early and mid-planting dates produced similar amounts of forage at time of harvest. Late plantings were less productive (approximately 3000 lbs acre⁻¹). These results were consistent despite the variability in weather conditions across multiple seasons and establishment attempts. This experiment suggested that the optimal planting period for late winter-planted annual forages is between late February and mid-March in the southern United States.

Effective disease and pest management in peanut (Arachis hypogea L.) requires adequate spray penetration within the canopy during pesticide applications. Field studies were conducted to assess spray deposition within the peanut canopy at three carrier volumes of 10, 15 and 20 gallons per acre (GPA), with each volume applied using three different nozzle types (extended range [XRC], air induction extended range [AIXR], and Turbo TeeJet Induction [TTI]). Spray deposition was assessed using water at various application timings (45, 60, 90, and 120 DAP) by placing water-sensitive paper at upper, middle, and lower positions within the peanut canopy. Fungicide applications using different carrier volume and nozzle treatments were made at regular intervals throughout the season, and disease ratings along with peanut yield were recorded at harvest. The carrier volume of 20 GPA consistently provided the greatest deposition in the upper and middle canopy, followed by 15 and 10 GPA. The XRC nozzle exhibited the greatest deposition in the upper canopy, followed by the AIXR and TTI nozzles. Within the lower canopy, the effect of carrier volume and nozzle type on spray deposition varied among the application timings. For disease control, the lower carrier volume of 10 GPA and XRC nozzle showed an increased incidence of late leaf spot (Nothopassalora personata) and southern stem rot (Sclerotium rolfsii Sacc.) in one of the study years. Carrier volume and nozzle type did not affect peanut yield during both years. Overall, the findings suggest that spray deposition within the peanut canopy is influenced by carrier volume and nozzle type; however, it does not necessarily lead to reduced peanut yield, especially in most fields with low to moderate disease pressure.