Comparison of six zero-till seed drill openers for establishment and persistence of sod-seeded alfalfa (Medicago sativa L.) in a cool-season perennial grass pasture

Zero-till seed drills are readily available for crop seeding in the prairie region of western Canada but have not been evaluated for sod-seeding in perennial forage. Sod-seeding a legume, such as alfalfa (Medicago sativa L.), into the existing perennial grass vegetation improves forage yield and quality for ruminant livestock grazing and production. Suppression of the existing vegetation with herbicide has been reported to increase alfalfa seedling establishment. We evaluated six commercially available zero-till seed drill openers by sod-seeding alfalfa into a crested wheatgrass [Agropyron cristatum (L.) Gaertn.] pasture with or without glyphosate suppression of the existing vegetation in Lanigan Saskatchewan. Alfalfa seedling establishment (52.2 vs. 21.9 seedlings m−1 ± 6.8), alfalfa composition (42.5% vs. 0.2% ± 8.6), and alfalfa yield (1105 kg·ha−1 vs. 12 kg·ha−1 ± 206) in 2011 were increased by the application of herbicide. Seed drill openers performed similarly for all three variables. Nine years later, in June 2020, there was greater alfalfa composition (13.3% vs. 0% ± 2.3) and forage yield (1325 vs. 957 kg·ha−1 ± 127) in the sod-seeded plots than in the unseeded controls but the alfalfa plant cover, alfalfa composition, alfalfa yield and forage yield were similar among seed drill openers. There was also no difference in these variables due to herbicide application nine years prior. Livestock producers can utilize currently available zero-till seeding equipment for sod-seeding alfalfa to rejuvenate grass pastures in the thin Black soil zone of western Canada with the expectation of persistence of alfalfa for nine years.

Biology and Management of Torpedograss (Panicum repens) in Ornamental Landscape Planting Beds

Torpedograss is one of the most invasive perennial grass species in Florida landscapes. This new 5-page publication of the UF/IFAS Environmental Horticulture Department was written for green industry professionals and others to aid in the identification and management of torpedograss in landscape planting beds. Written by Yuvraj Khamare, Candice Prince, and Chris Marble.https://edis.ifas.ufl.edu/ep615

Dimethoate insecticide application seldom reduces silvertop incidence in grass seed fields on the Canadian Prairies

Many arthropods have been reported (but none confirmed) as causal agents of sterile seed heads in perennial grass seed fields, known as silvertop or white head. Field studies to identify the arthropods that cause silvertop were conducted in five perennial grass species at seven sites in Saskatchewan, Canada over several years. The effect timing of insecticide application in spring – early, mid or late – and of post-harvest residue management – mowing, close mowing with straw removed (scalping), and burning – on subsequent arthropod populations, silvertop incidence and seed yield were assessed. Samples of grass tillers and sweep net collections were taken regularly, and the arthropods collected were identified to family level and counted. Arthropod populations from sweep samples varied among sites and dates in number and taxon composition, but no arthropod assemblage was consistently associated with silvertop in any grass species. Thrips were the most numerous arthropods on tillers at all sites. Insecticide application often temporarily reduced arthropod populations, but reduced silvertop incidence at only 1 of 15 site-years, and increased seed yield at only 1 of 17 site-years. Scalping or burning did not reduce silvertop incidence but often increased healthy seed head numbers and seed yield relative to mowing, the standard treatment. The majority of Kentucky bluegrass fields had extremely low seed yields unrelated to silvertop or arthropod levels. This extensive study, across a range of grass species and management regimes, provides strong support for the conclusion based on previous work that arthropod pests are not the sole cause of silvertop.

UROCHLOA GRASS GROWTH AS A FUNCTION OF NITROGEN AND PHOSPHORUS FERTILIZATION

The urochloa grass (Urochloa mosambicensis) is a perennial grass, C4 plant, with a high photosynthetic rate and CO2 fixation, persistent to water deficit, adapted to a wide diversity of soils and hot climate regions. Thus, the objective was to evaluate the urochloa grass growth and define the best models to estimate plant height as a function of nitrogen and phosphate fertilization. The experimental design was completely randomized, in the 2 x 2 factorial design (presence and absence of nitrogen presence and absence of phosphorus), with four replications. Was used a dose of nitrogen and phosphorus equivalent to 100 kg.ha-1 of N and 150 kg.ha-1 of P2O5, respectively. The following models were used: linear, power, gamma andlogistic to estimate plant height as a function of the following explanatory variables: days after planting, nitrogen and phosphorus doses. The criteria used to determine the best model(s) were as follows: higher adjusted coefficient of determination, lower Akaike information criterion, lower sum of square of residuals and high Willmott index. The plant height in the absence of nitrogen and phosphorus and when applied 100 kg.ha-1 of N and 150 kg.ha-1 of P2O5 was estimated more accurately by the Gamma model with high power of explanation. The adoption of the Gamma model allows to estimate the U. mosambicensis plant height, in a non-destructive manner, with high precision, speed and low cost, depending of age plant and nitrogen and phosphate fertilization.

Evaluation of Perennial Grass-legume Cropping Systems for Year-round Supply of Fodder for Dairy Farms

Background: Long-term and stable livestock productivity could be possible only through a year-round supply of quality green fodder and it is essential for the sustainability of dairy farms. The year-round supply of quality green fodder is challenging to livestock farmers; however, it is possible by adopting perennial grass-legume intercropping systems. Methods: A field experiment with eight treatments consisting of two perennial grasses (Napier- bajra hybrid grass and guinea grass) alone or in combination with three fodder legumes (Lucerne, Hedge Lucerne and Sesbania) was conducted for 3 years (2016-17, 2017-18 and 2018-19) in a sandy loam soil at the Agricultural Research Institute, Professor Jayashankar Telangana State Agricultural University, Hyderabad. The treatments were replicated thrice in a randomized block design. Perennial grasses were raised in paired row method (row to row 120cm and plant to plant 60 cm. The legume intercrops were grown with their respective spacing within 120 cm row. Sesbania inter crop was allowed to grow for 6 months and later trimmed to a height of 1 meter in the establishment year. Growth parameters were measured only for grasses at each harvesting and green fodder, dry matter and crude protein yields were recorded for both grasses and legumes at each cut and accumulated annually (total 6 cuts/year) for statistical analyses. Result: The results indicated that among the grasses, Napier-bajra hybrid recorded significantly higher green fodder, dry matter and crude protein yields; in case of leguminous inter crops, Sesbania recorded highest green fodder, dry matter and crude protein yields followed by Hedge Lucerne. About total productivity of the system, Napier-bajra hybrid + Sesbania (2:1) cropping system recorded highest green fodder, dry matter and crude protein yields. Highest net returns and B:C ratio was also noted with Napier bajra hybrid +Sesbania (2:1) cropping system and proved to be the best perennial fodder system for year-round supply fodder to the livestock.

Seeding Rate Effects on Forage Mass and Vegetation Dynamics of Cool-Season Grass Sod Interseeded with Sorghum-Sudangrass

Interseeding annual warm-season grasses into perennial cool-season grasses has the potential to increase summer forage mass and nutritive value. Knowledge of how seeding rate affects annual warm-season grass establishment, forage mass, and vegetation dynamics remains limited. From 2016–2017, we conducted a field experiment evaluating the effects of seeding rates on sorghum-sudangrass (Sorghum bicolor × S. bicolor var. sudanense) density and forage mass and on the frequency of occurrence of plant species in cool-season grass sod in Lincoln, NE. The experiment had a completely randomized design consisting of six replicates of four seeding rates [0, 14, 28, and 35 kg pure live seed (PLS) ha−1] in sod mowed at a 2.5-cm height and one unseeded, non-mowed control treatment. Sorghum-sudangrass establishment increased with seeding rate from an average of 20 to 45 plants m−2 as the seeding rate increased from 14 to 35 kg PLS ha−1. Forage mass depended on a seeding rate × harvest interaction, showing positive linear and cubic responses to seeding rate in consecutive harvests at 45 and 90 d after interseeding. To increase forage mass in perennial cool-season grass sod, producers should interseed sorghum-sudangrass with at least 28 kg PLS ha−1. One-time seedings into cool-season, perennial grass sod have no residual effects on subsequent forage mass and vegetation dynamics.