Crop, Forage and Turfgrass Management最新文献

Cover crops are an effective way to reduce soil erosion and promote soil health. However, in North Dakota and other northern climates where corn (Zea mays L.) is an important commodity crop, killing frosts generally occur before harvest, leaving little opportunity for cover crop planting. By interseeding cover crops into corn during the growing season, the cover crops are given a longer period to establish. The purpose of this study was to identify the impact cover crops interseeded into wide-row (60-inch) corn have on soil water content and corn productivity. Two experimental sites were established in 2020 near Leonard and Rutland, ND. Both sites were organized into randomized complete block designs, with three cover crop treatments in Leonard (n = 9) and four cover crop treatments in Rutland (n = 16). Cover crops were no-till drilled into the corn at the V4 growth stage. The cover crop treatments were diverse mixes developed to either provide pollinator habitat, overwinter, or winter-kill. Throughout the growing season, soil gravimetric water content and cover crop biomass was monitored. At the end of the growing season, dry cover crop biomass ranged from 189 to 1445 lb ac⁻¹. The presence and type of interseeded cover crops did not have a statistically significant effect on soil water content or corn yield. It is suspected the above average precipitation during the month of July led to adequate amounts of soil water for the entirety of the cover crop growing season, limiting the difference between treatments.

Improved management strategies are needed to increase corn (Zea mays L.) production. This study aimed to determine suitable cultural practices for improved corn production in Mississippi. Two experiments were setup side-by-side (addition/deletion) at Verona and Stoneville, MS, from 2020 to 2022. A randomized complete block design was implemented that included two row configurations (single- and twin-row), two plant populations (32,000 and 40,000 plants acre⁻¹), and six combinations of nutrients with or without a fungicide. Nutrients including nitrogen (N) 210 and 280 lb acre⁻¹, phosphorus (P) 40 lb acre⁻¹, potassium (K) 100 lb acre⁻¹, elemental sulfur (S) 20 lb acre⁻¹, zinc (Zn) 10 lb acre⁻¹, and fungicide at 3.72 oz acre⁻¹ were applied. In the addition trial, nutrients plus fungicide were added incrementally, whereas in the deletion trial these were withheld in a stepwise manner. Among the tested factors, row configuration impacts were the most consistent among all site-years; specifically, twin-rows resulted in higher yield compared to single-row. Additionally, higher plant population under irrigated conditions (Stoneville) resulted in greater yield compared to rainfed conditions (Verona). Higher rate of N and fungicide application affected grain yield positively, but these agronomic benefits were not economically feasible. This study determined that application of different nutrients can enhance the yield to a limited extent, and farmers should consider the economic investment of fertilizer and fungicides. Moreover, producers should balance yield and profit by taking soil testing and fertilizer prices into consideration.

Global demand for corn (Zea mays L.) is increasing, and it remains one of the most consumed crops by both humans and animals due to its high calorie content. However, corn grain quality research is sparse and often focused only on a few selected influencing factors. Therefore, two side-by-side studies (Addition and Deletion) were conducted in 2020 and 2021 in Mississippi to assess the grain composition including protein, starch, oil, and moisture of corn under several management practices. A randomized complete block design was implemented in both experiments involving a complete factorial of three factors including two plant populations (32,000 and 40,000 seed acre⁻¹), two-row configurations (single and twin), and six combinations of nutrients plus fungicide application (NF). The trials differed based on the manner of NF applications. In the trial termed Addition, all NF treatments were added incrementally, whereas in the Deletion trial they were withheld in a stepwise manner. Conditional inference tree analysis was conducted to examine interaction effects among the three factors over 3 site-years. Corn protein content ranged between 8.2% and 9.8% across all years and locations. All three factors and certain interactions significantly influenced both protein and starch content. Specifically, single row planting, 40,000 seeds acre⁻¹, and higher rates of N resulted in higher protein content. Contrarily, the starch content was positively influenced by twin row, 32,000 seeds acre⁻¹ and only N application. Single row configuration resulted in higher oil than twin rows. This study determined that different management factors have the potential to positively influence protein, starch, and oil. These management strategies could extend farmers profitability and provide superior products for industrial purposes with additional implications for livestock feed supplements.

In Florida, multiple counties restrict the application of N to turfgrass and landscapes during the summer rainy season. These summer fertilizer blackout periods could impact turfgrass quality and the functionality of warm-season turfgrass species. A 2-year study was conducted at the University of Florida's Fort Lauderdale Research and Education Center (FLREC) and West Florida Research and Education Center (WFREC) to assess turfgrass performance of ‘Floratam’ and ‘Classic’ St. Augustinegrass [Stenotaphrum secundatum (Walter) Kuntze] as well as ‘Empire’ and ‘Palisades’ zoysiagrass (Zoysia japonica Steud.), respectively, receiving no N fertilization during summer blackout period using eight fertilization programs compared to an unfertilized control. Visual quality, normalized difference vegetation index, percentage green cover, and dark green color index were assessed biweekly. Roots were collected before and after the fertilizer blackout period to determine root dry weight. While no differences were detected in St. Augustinegrass at the FLREC and zoysiagrass at the WFREC, all fertilized treatments except urea reached and maintained an acceptable turfgrass quality (≥6) throughout the blackout period, suggesting that urea by itself was not sufficient to support an optimal turfgrass performance during a fertilizer blackout period. The addition of P to nutrition programs did not influence turfgrass quality. Results indicate that N source is the most important factor to sustain turfgrass quality year-round in Florida.

Foliar fungicides are available to suppress Diplodia ear rot (DER), caused by Stenocarpella maydis (Berk.) Sutton and Stenocarpella macrospora (Earle) Sutton) in corn (Zea mays L.), but previous research has indicated these fungicides have limited efficacy against the disease using traditional over-canopy application methods. In an effort to improve coverage within the canopy and potentially improve disease control of DER, experiments were conducted in 2020, 2021, and 2022 to examine the effect of ground-driven, in-canopy fungicide nozzle technology on DER severity and spray coverage on the ear leaf and ear of corn plants. Application methods included over-canopy nozzles, over-canopy + drop nozzles, and over-canopy + 360 Undercover nozzles. Within each application method, treatments consisted of a non-inoculated control, or were inoculated with a conidial suspension of S. maydis. The fungicides benzovindiflupyr + azoxystrobin + propiconazole and pydiflumetofen + azoxystrobin + propiconazole were applied within each application method to measure efficacy against DER. In all years, neither fungicide product nor application method reduced DER severity. No fungicide applications increased yield compared to the non-treated control. The addition of drop nozzles or 360 Undercover nozzles to traditional over-canopy nozzles increased spray coverage on the ear (P < 0.0001) compared to over-canopy nozzles alone.

Take-all root rot (TARR) is a detrimental disease of ultradwarf bermudagrass (Cynodon dactylon × Cynodon transvaalensis; UDB) putting greens frequently diagnosed where warm-season grasses are grown. Since this disease is largely aggregated and variable under field conditions, field research is difficult and often yields inconsistent results. Multiple pathogens have only recently been associated with this disease, so practical management solutions such as fungicide efficacy and fungicide application timing have not been thoroughly investigated. Therefore, the objectives of this research were to determine the influence of fungicide selection and fungicide application timing on take-all root rot management under field and greenhouse conditions. In general, fungicides from the quinone outside inhibitor and/or demethylation inhibitor chemical classes provided the greatest reduction in take-all root rot severity. Fungicide applications that were made when soil temperatures were between 77–86°F provided the greatest disease suppression. The in vivo greenhouse method developed in this research proved to be an efficient and consistent method to evaluate management practices such as fungicide efficacy on take-all root rot. This research improves our understanding of fungicide efficacy and fungicide application timing for take-all root rot management on ultradwarf bermudagrass.

Proper N fertilization and higher mowing heights are recommended to enhance rooting for greater turfgrass summer drought stress. To examine the effects of these primary cultural practices on centipedegrass [Eremochloa ophiuroides (Munro) Hack.] drought response in the mid-Southern United States, a study was conducted to evaluate four mowing heights (1, 2, 3 and 4 inches) and N fertilization versus no fertilization. During the study, roots were periodically harvested at upper (0–3 inches) and lower (3–6 inches) soil depths, and roots were analyzed for architecture which included root length (RL) and surface area (SA), and root weight (RW). In July, plant-soil cores were subjected to 36-day drought simulation under greenhouse conditions. All turfgrass exhibited a pattern of decreasing leaf quality as drought progressed with unfertilized treatments maintaining acceptable leaf color (≥5) for 19 days at 5.9 compared to 4.8 for fertilized centipedegrass regardless of mowing height. In the field, root architecture and biomass across all mowing heights, fertilities, and soil depths peaked at 883.9 inches, 35.6 in², and 5.8 grains for RL, SA, and RW, respectively, six weeks prior to drought simulation (WDPS) before declining to 740.5 inches, 29.6 in², and 4.9 grains at the initiation of the drought simulation. The inability of N fertility and mowing height to enhance root growth particularly from spring into summer indicates soil temperatures may be a factor in centipedegrass root growth and thus drought stress avoidance.

Sorghum [Sorghum bicolor (L.) Moench] is a resilient forage crop due to its drought tolerance and adaptation to low-N environments. Sorghum produces a cyanogenic glucoside called dhurrin. The breakdown of dhurrin leads to the release of hydrogen cyanide (HCN), which can cause cyanide toxicity in livestock. Dhurrin-free sorghum lines have been developed through chemical mutagenesis by mutagenizing the gene for the first enzyme, CYP79A1, in the biosynthetic pathway. The CYP79A1 mutation was bred into sorghum lines to create a dhurrin-free experimental hybrid. Grazing preference of ewes was assessed when allocated to the dhurrin-free hybrid and three commercial hybrids. Near isogenic lines (NIL), contrasting in dhurrin production, were also compared for grazing preference. Forage mass was measured before and after grazing to determine the amount of forage mass grazed by the ewes. An unmanned aerial vehicle (UAV) was flown to quantify changes in normalized difference vegetation index (NDVI) over time for each hybrid. The nutritive values of the hybrids were also evaluated. The dhurrin-free hybrid was grazed 19% and 13% more (p-value ≤ 0.05) in comparison to the commercial hybrids for the second and third grazing cycles in 2019 and 2020. The NIL Tx623 bmr6 CYP79A1, was grazed 20% more than Tx623 bmr6 in two grazing cycles in 2020. Remote sensing data showed a similar pattern with the dhurrin-free hybrid having the largest decline in NDVI for three grazing cycles in 2019. Nutritive value of the dhurrin-free hybrid was similar to the two hybrids with the brown midrib (bmr) trait.