Crop, Forage and Turfgrass Management最新文献

High-quality forages can benefit from being harvested as baleage when the environmental conditions are not favorable for dry hay production. Currently, it is recommended that baleage should be fed within 9-months post-harvest; however, mild winters can reduce the demand for these stored forages. Data are limited on the changes in nutritive value of baleage stored beyond the recommended timepoint. Therefore, the objective was to determine the effect of storage length on nutritive value of forage harvested and stored as baleage. This study evaluated baleage harvested from 2016 to 2018 in Tifton, GA, consisting of either bermudagrass (Cynodon dactylon L. Pers.), or a mixture of bermudagrass and alfalfa (Medicago sativa L.). Baleage was sampled for nutritive value analysis at 6-weeks and 9- and 12-months post-harvest, with a subset of bales sampled at 24 months. Regardless of forage, crude protein, total digestible nutrients, and in-vitro dry matter digestibility at 48 h were not impacted in bales sampled up to 12-months post-harvest (p > 0.07). However, acid detergent fiber increased when baleage was stored beyond 6 weeks but did not change from 9 to 12 months (p < 0.01). In the subset of bales stored up to 24-months post-harvest, all nutritive value parameters evaluated were negatively impacted (p < 0.01). The prolonged storage period may negatively affect the baleage plastic integrity, resulting in a decline in nutritive value if anaerobic conditions are not maintained. Future research is warranted to evaluate the changes in the fermentation profile of baleage under extended storage conditions.

Preemergence herbicides (PRE) have become integral for weed control in cotton (Gossypium hirsutum L.), especially with the prevalence of glyphosate-resistant Palmer amaranth (Amaranthus palmeri S. Wats.). However, PRE herbicides have the potential to injure cotton seedlings. Previous research has shown that a larger seed size can compensate for early season stresses which could mitigate potential PRE herbicide injury. In this study, we evaluated growth and yield of two cotton varieties with different seed sizes (large and small) in response to three PRE herbicides alone and in combination. Percent visual injury, biomass, plant heights, stand counts, lint yield, and fiber quality were obtained to make comparisons between seed sizes and PRE treatments. In both years, the large-seeded variety had a higher biomass at 3-leaf stage. However, both varieties had “grown out” of the herbicide injury at 42 days after planting and the early season vigor of the larger seed did not result in higher lint yield. The small-seeded variety had greater yield in both years of the study. This may be due to the genetics or yield potential of the small-seeded variety, or bolls containing smaller seeds typically have a greater number of seeds with more opportunity for lint production. Cotton treated with diuron had the most visual injury and decreased biomass. The results from this study will allow growers to make more informed decisions with regards to seed size, vigor, and PRE herbicide choices. If crop injury is likely, a larger seeded cotton variety may mitigate potential early season injury; however, seed size did not have an impact on final lint yield.

Canola (Brassica napus) and pennycress (Thlaspi arvense L.) are winter oilseed crops that can be used to create sustainable aviation fuel. They have been grown successfully in the Upper Midwest and Great Plains and are garnering interest in the Mid-South. A field study was conducted in Tennessee to determine management practices and average yields expected for the region. From this study, a budget and breakeven analysis was conducted. Budgets were created for tilled and no-till canola and pennycress systems. Based on average yields obtained and projected oilseeds prices, canola systems are potentially profitable, while pennycress systems are not. However, breakeven prices were highly variable between years, locations, oilseed species, and tillage type. Canola has been relatively established in the region and can be promoted to growers as a profitable crop. Presently, the adoption of pennycress in the Mid-South is not recommended without further research on best management practices, breeding efforts for higher yielding varieties, and the creation of a viable market for sale.

Poultry litter (litter) is a nutrient dense fertilizer that increases nutritive value and yield in pastures in the mid-southern US. Nutrient losses due to runoff and nitrogen volatilization are common when broadcasting litter. As such, incorporating litter below the soil surface (subsurface) was evaluated in comparison to broadcasting in 2021 and 2022 by quantifying yield and nutritive value of annual forages. The study was a randomized complete block design with three forage treatments—sorghum-sudangrass only (Sorghum bicolor L.), cowpea only (Vigna unguiculata L.), and their mixture, and three litter application methods (broadcast, subsurface, and a no litter control). Litter was applied in 2021 only as biennial application is common to save on application cost. Nutritive analyses included neutral detergent fiber and crude protein (CP). Partial budgeting led to relative profitability estimates by accounting for yield and cost differences across treatments. In comparison to the second-highest yielding forage mixture, sorghum-sudangrass yielded 4.5%–18.4% more regardless of litter application method. The forage mixture did not improve forage nutritive value, as cowpea were vastly outcompeted and did not average more than 5% of the total forage harvested in mixtures. Cowpea yields did not benefit from litter application. Subsurface application resulted in 8%–10% greater CP content compared to no litter and broadcast litter, respectively, across all forage species. Sorghum-sudangrass with subsurface applied litter earned nearly $70/acre more than sorghum-sudangrass with broadcast litter, the next highest treatment combination, and, with lesser nutrient loss.

Annual bluegrass (Poa annua L.) is the most troublesome weed on golf courses in the US. Many agronomic practices intended to promote high-quality playing surfaces favor the growth and development of annual bluegrass, resulting in high weed pressure. One commonly used herbicide for annual bluegrass control on golf courses is ethofumesate, which is a very long chain fatty acid inhibitor. Annual bluegrass resistance to this herbicide is documented and confirmed in grass seed production systems, but potential resistance on golf courses was previously unknown. The objective of this study was to determine the frequency and magnitude of potential ethofumesate resistance from a sample of US golf courses. A dose-response experiment was initiated at Purdue University using 30 annual bluegrass populations collected from Alabama, California, Indiana, and Oregon golf courses. Ten ethofumesate doses included 0, 0.5, 1.0, 2.5, 5.0, 7.5, 10.0, 15.0, 20.0, and 40.0 lb a.i. acre⁻¹, with 1.0 to 2.0 a.i. acre⁻¹ as the standard label application rate for perennial ryegrass turf. A low level of resistance (R/S < 3) was found in several populations collected in each state. The mean effective dose necessary to kill 50% of the populations (ED₅₀) was 5.1, 9.2, 3.5, and 3.4 lb a.i. acre⁻¹ for populations from Alabama, California, Indiana, and Oregon, respectively. The most resistant population originated from California, with an ED₅₀ of 13.2 lb a.i. acre⁻¹. To reduce selection pressure from ethofumesate populations, golf course superintendents are encouraged to develop site-specific weed control programs that rotate herbicide sites of action, as well as utilize diverse control tactics.

Lentil (Lens culinaris Medik.) production has increased exponentially in Montana in the last two decades. However, there are important gaps in knowledge on best management practices for lentil. Agronomic recommendations are based on performance of old cultivars outside of the area for seeding rate, and on anecdotal evidence for proper roll timing, particularly since the widespread adoption of no-till farming. Replicated field experiments were conducted at three sites during the 2019, 2020, and 2021 growing seasons in Montana to determine the impacts of roll timing and seeding rate on lentil yield and identify best practices. Overall, rolling at emergence and at the 10-leaf stage decreased yields by 5% and 8%, respectively, but rolling just after planting or at the early vegetative stage (two- to four-leaf stage) did not decrease yields. Higher yields were achieved at higher seeding rates, with yields increasing between 6 and 52 lb ac⁻¹ for each additional plant established per square foot, but emergence rates were variable and relatively low, so a higher seeding rate may be necessary to achieve plant densities above 12 plants ft⁻² in this region. In five out of nine site years, the largest partial economic returns were achieved with 22.5 or 30 live seeds ft⁻² seeding rate, corresponding to achieved plant densities of 12 to 16 plants ft⁻². It was generally economical to increase seeding rate from 15 to 22.5 live seeds ft⁻², thus increasing average achieved plant density from 8 to 13 plants ft⁻², except when seed costs were high (>$0.45 lb⁻¹) combined with low market prices (< $0.20 lb⁻¹).

Western ragweed (Ambrosia psilostachya DC) is one of the most common perennial, native forbs of western US rangelands. Cattle consume small quantities of western ragweed in their diets when present in the forage sward, and forage nutritive value tends to be greater than the associated grass component in those swards. Yet, many producers view western ragweed as an undesirable forb in rangelands. We conducted a study over two years to compare vegetative and stocker animal productivity in pastures that were either sprayed with dicamba at 6 oz/acre (0.19 lb a.i./acre) for western ragweed control or were left unsprayed. Pastures started the study with high western ragweed densities (>9 western ragweed plants/ft²) before pasture treatment, and spraying with dicamba significantly reduced western ragweed density and yield compared to unsprayed pastures (0.2 vs. 3.5 ragweed plants/ft², and 0 vs. 206 lb/acre, respectively). Grass production and total vegetation production were similar between treatments. Crude protein and total digestible nutrients of western ragweed was greater than grass at all mid-season and end of season sampling dates both years. Stocker animal gain was not different between pastures sprayed for ragweed control and pastures left unsprayed in either year, nor when averaged over the two years (189 vs. 188 lb/head, sprayed vs. unsprayed, respectively). Beef production per acre was also similar. The spray treatment was an added expense that did not result in greater total forage, grass, or animal production. With natural fluctuations in western ragweed population densities due to weather patterns, producers will likely experience little benefit from spraying for western ragweed alone in pasture.

Farmers are making decisions every year under weather variability, input cost fluctuations, and commodity price uncertainty. Traditional replicated field trials cannot recommend actionable knowledge at the field level accounting for all sources of variability and uncertainty. Decision support tools aim to fill the gap that traditional agricultural research cannot. Agroptimizer (www.agroptimizer.com), a machine learning cloud-based decision support tool (DST) has a user-friendly interface that users can easily input field and management information and was designed to identify optimum corn and soybean cropping systems, for maximum yield and profit, across the United States. The recommended management practices of the DST were compared against cropping systems that were generated by University of Wisconsin researchers (called typical hereafter) across Wisconsin between 2021 and 2023. Agroptimizer recommendations for corn resulted in similar yield and profit compared to typical. For soybean, Agroptimizer recommendations resulted in increased yield and similar profit compared to typical. There was no downside yield and profit risk difference between Agroptimizer-based and typical cropping systems for both crops. Overall results showed that Agroptimizer successfully identified cropping systems that resulted in high yield and profit for both crops suggesting that in the absence of available expert recommendation, it can provide management practices with high yield and profit potential. Agroptimizer is being constantly updated and will be evaluated in additional locations across the United States in subsequent years.

Recent research has demonstrated the ability of a fenclorim seed treatment to reduce rice (Oryza sativa L.) injury to acetochlor. However, all studies were conducted on silt loam soils and have not evaluated rice tolerance or weed control on clay soils. Experiments were initiated in 2021 and 2022 at the Northeast Research and Extension Center near Keiser, AR, to determine rice response and the effectiveness of delayed-preemergence (DPRE)-applied microencapsulated (ME) acetochlor (1.1, 1.7, and 2.3 lb ai acre⁻¹) when applied to a clay soil with and without a fenclorim seed treatment at 0 or 2.5 lb ai 1000-lb⁻¹ of seed. Averaged over the fenclorim seed treatment, acetochlor at 1.1 and 1.7 lb ai acre⁻¹ caused similar injury levels to rice; however, barnyardgrass [Echinochloa crus-galli (L.) P. Beauv.] control increased at 1.7 lb ai acre⁻¹, eliciting 19% injury to rice and 82% barnyardgrass control at 28 days after emergence (DAE). Palmer amaranth (Amaranthus palmeri S. Watson) control ranged from 82% to 93%. Additionally, fenclorim did not influence barnyardgrass or Palmer amaranth control, but it did reduce rice injury and increase shoot density, plant height, and rough rice grain yield. At 14 and 28 DAE, fenclorim at 2.5 lb ai 1000-lb⁻¹ of seed (averaged over acetochlor rates) reduced visible rice injury from 61% to 13% and 40% to 8%, respectively. Results from this study indicate ME acetochlor could be successfully applied to rice grown on a clay soil when a fenclorim seed treatment is used, providing producers a new site of action for use in U.S. rice production.