Crop, Forage and Turfgrass Management最新文献

The majority of soils in the Mississippi Delta are vertisols, whose shrink–swell behavior makes them prone to waterlogging when subjected to excessive infiltration amounts from conventional management of furrow irrigation. The goal of this investigation was to examine if corn (Zea mays L.) grain yield and quality (test weight, kernel composition, and kernel weight) can be improved in vertisols of this region by widening furrow irrigation spacing while increasing furrow inflow rate proportionally to reduce waterlogging. A research station study at the National Center for Alluvial Aquifer Research and an on-farm study near Glen Allan, Mississippi, were conducted from 2021 to 2023. Furrow irrigation spacing treatments in the research station study included 3.3 ft, 6.7 ft, 13.3 ft, and 26.7 ft. The on-farm study included 10 ft, 20 ft, and “tractor track” (alternating between 10 and 30 ft furrow irrigation spacing) treatments. The three years of the research station study showed that the 26.7-ft treatment yielded 8.5% higher than the narrower treatments at the top position of the field (50–100 ft from the topographically higher end of 500 ft furrows). Higher grain protein and kernel weight were observed halfway between two irrigated furrows of the 13.3-ft and 26.7-ft treatments than adjacent to irrigated furrows of any treatment. Corn grain yield in the on-farm study was not significantly different among furrow irrigation spacing treatments. This research demonstrates that furrow irrigation spacing can be widened to at least 26.7 ft in vertisols of the Mississippi Delta without decreasing corn grain yield and quality.

Bermudagrass (Cynodon spp. Rich) is a warm-season grass that is widely planted throughout tropical, sub-tropical, and even temperate climates, and it generally requires fewer inputs than most cool-season turfgrasses. In recent years, the area of adaptation for bermudagrass has progressively expanded to cooler climates due to the development of more cold-tolerant cultivars. The expanded area of adaptation as well as the reduced inputs required to maintain healthy turfgrass have made bermudagrass a popular choice in areas of marginal adaptation. In these areas, the greatest threat to bermudagrass health and survivability is winterkill. This management guide seeks to describe winterkill: what it looks like, what causes it, and where it occurs. Additionally, this management guide describes best management practices to both prevent winterkill and recover bermudagrass from winterkill damage.

Although yield responses of soybeans [Glycine max (L.) Merrill] to nitrogen (N) fertilizer are rare, occasional yield increases, especially in high-yielding soybeans, have encouraged some producers to apply N. We conducted nine field experiments between 2014 and 2017 over a range of soil types and environments to evaluate soybean yield response to N (as urea) applied at planting, R1, R3, R5, and at all four timings. Our results showed that a single N application at R1 did not increase soybean yield in any location, while applying N at R3 or R5 increased grain yield in only one of nine locations. At a location with irrigated loam soils, N at planting increased grain yield by 22.4 bu ac⁻¹ (35%) in 2015 and 19.7 bu ac⁻¹ (38%) in 2016 but did not affect yield in 2017. Applying N four times did not increase yield more than the application at planting at this location in 2015 and 2016, but it increased yield in 2017. Four applications of N increased yield in three of the other six locations by an average of 5.0 bu ac⁻¹ (6%). Applying N four times or at R5 increased soil inorganic N at R6 at five of nine locations but did not consistently increase yield. Grain yield was positively correlated to Normalized Difference Vegetation Index (NDVI) taken at stage R6 at seven of the nine locations. Except for the yield increases from planting-time N at two locations, yield responses were insufficient to cover the cost of fertilizer N. While in-season application of fertilizer N to soybeans in productive Corn Belt soils in the United States is unlikely to be consistently profitable, N at planting that stimulates early growth and N uptake, especially in lighter-textured soils, may sometimes increase yield substantially.

Winter injury can cause significant loss of hybrid bermudagrasses [Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt-Davy] in the transition zone. Current research has focused on high-value, low-acreage areas like putting greens, but those practices are impractical to implement on golf course fairways. To that end, multi-year research projects were conducted at three sites across Maryland and Virginia to investigate the influence of annual N fertility [2.0 lb N 1000 ft⁻² (early summer application) or 4.0 lb N 1000 ft⁻² (split applied early and late summer)] across multiple fall mowing heights (0.5 inches, 0.8 inches, or 1 inch) and to elucidate the effects of wetting agent (fall, fall + winter, or none) and irrigation (0.5 inches irrigation at <15% soil volumetric water content [VWC] or none) applications during dormancy on reducing winter injury of hybrid bermudagrass. Dry-down experiments were also conducted using plugs collected from field trials to impose an artificial freeze event and elucidate the effects of soil VWC on winter injury. Turfgrass quality and percent green cover were evaluated regularly as the turfgrass entered dormancy and throughout spring green-up each year. Late-season N applications helped retain fall green coverage without increasing winter injury and increasing fall mowing height did not impact winter injury. Temporary increase in soil VWC increased bermudagrass survival after a short-term freeze event and prevented root biomass loss. These studies demonstrate late-season N applications can help retain green color and increasing soil VWC prior to a short-term freezing event can greatly reduce winter injury.

This study aimed to quantify misses, overlaps, and oversprays on sports fields using different sprayer technologies across operator experience levels. Conducted from Winter 2022 to Summer 2023 at Veterans Park and Southwood Park in College Station, TX, identical studies were conducted on softball, baseball, and soccer fields. Employing a crossover design, six treatments were administered to three fields at each location, using manual, Global Navigation Satellite System (GNSS), and GNSS + autosteer sprayer technologies. Operators ranged from a highly experienced former sports field manager with nearly 20 years of experience to four inexperienced undergraduate students. Field boundaries were georeferenced for target area determination and treatment applications, using water and a spray volume of 65 gal per acre. ArcMap calculated percentage target area missed, overlapped, and oversprayed based on the actual versus intended volume sprayed. Data were subjected to analysis of variance, and means were separated using Fisher's protected LSD (α = 0.05). Applications by inexperienced operators using manual spray mode typically resulted in the highest rates of percentage target area missed and overlapped across locations and field types. The use of GNSS and autosteer technologithe percentagey reduced these errors and, consequently, percentage target area oversprayed. This enhancement in the consistency of applications led to a reduction of up to 4.6% in the total volume applied on the softball, baseball, and soccer fields. Therefore, the findings suggest that investing in GNSS-equipped sprayers with autosteer not only decreases the dependency on experienced operators but also minimizes errors and reduces total volume applied.

The primary objective of this paper is to quantitatively analyze the number of acres planted per suitable fieldwork day and the total number of fieldwork days available for the complete planting of soybeans (Glycine max L.) in Arkansas. Total days to plant soybeans in each spring from 1980 to 2023 averaged about 33 days, indicating that roughly 33 days are expected, on average, from the month of April to May based on USDA-NASS weekly crop progress and condition data. Furthermore, the average soybean planted acres is estimated at 106,736 acres per day within the study period. Recently, variations in this range appear more pronounced, likely due to the significant impact of extreme spring weather conditions. However, technological advancements have enabled soybean producers to plant crops as early as the first half of March or as late as June, contributing to the increased variability observed from year to year in recent times. Furthermore, Arkansas's optimal soybean planting window typically provides an average of 4.7 fieldwork days per week. These quantified estimates offer historical data on Arkansas's soybean planting performance and will prove highly valuable for informing future soybean planting strategies.

Throughout the mid-southern United States, indeterminate maturity group (MG) IV soybean (Glycine max L. Merr.) have largely taken the place of determinate MG V and VI soybean in order maximize yield. However, this shift towards earlier maturity groups results in more green plant material at physiological maturity. Consequently, harvest aids are of interest to producers who seek to defoliate and desiccate soybean in a timely and uniform manner. Field experiments were conducted from 2019 to 2020 to evaluate the impact of harvest aid, application volume, and spray droplet volume mean diameter (VMD) on soybean harvest aid efficacy in Mississippi. Applications of paraquat, saflufenacil, and sodium chlorate were made when soybean averaged 65% brown pods, with application volumes of 5 and 20 gal. acre⁻¹, and VMDs of 200, 500, and 800 µm. Defoliation, desiccation, and green stems were evaluated at 3, 7, 10, and 14 days after treatment (DAT). Soybean grain yield was obtained at harvest and adjusted to 13% moisture. Harvest aid efficacy did not vary due to application volume. Spray droplet spectra with a VMD of 200 µm maximized both defoliation and desiccation efficacy. At 14 DAT, applications of paraquat and sodium chlorate resulted in 95% defoliation but were similar to saflufenacil at 89%. Applications of paraquat resulted in desiccation of 16 more percentage points than saflufenacil, and 8 more percentage points than sodium chlorate. These data indicate soybean harvest aid applications should contain paraquat. Although efficacy was maximized with spray droplet spectra with a VMD of 200 µm, the total variance in efficacy due to VMD of spray droplets was minimal.

Plant growth regulators (PGRs) are regularly used on golf courses to reduce mowing requirements. PGR efficacy is commonly assessed via measurements of clipping weight; however, this process is time consuming and requires specialized equipment. Golf course superintendents have started to evaluate PGR efficacy via measurements of clipping volume. Field research was conducted in Knoxville, TN, during June 2022 and 2023 to evaluate the relationship between clipping weight and volume following trinexapac-ethyl applications to hybrid bermudagrass (C. dactylon × C. transvaalensis Burtt-Davy, cv. ‘Latitude 36’) and manilagrass (Zoysia matrella, cv. ‘Trinity’ and ‘Zorro’) golf course fairways. Four experimental formulations of trinexapac-ethyl [97 g ha⁻¹ (11.4 fl oz/A)] were applied to plots 16 ft² (1.5 m²) organized in a randomized complete block design with four replications. Clippings were collected twice weekly with volume assessed via a graduated cylinder; weight was quantified after drying clippings in a forced-air oven for 48 hours. For hybrid bermudagrass, clipping weight and volume measurements returned similar conclusions regarding trinexapac-ethyl efficacy for growth regulation. On dates where both metrics resulted in treatment differences, a linear relationship was present between clipping weight and volume data (R² = 0.84). Similar responses were observed on manilagrass; however, clipping weight and volume were less closely associated (R² = 0.78). This difference could be related to growth rate, as well as clipping size and mass differences between species. Overall, results indicate that either metric could be used to study efficacy of trinexapac-ethyl for regulating growth of these species maintained as golf course fairways.