Recent research has shown that elevated soil nitrate levels may be a concern in the years following removal of turfgrass in landscape conversion plots. In order to better ascertain soil nitrogen levels in plots, soil samples (0-6 in. [0-15.24 cm.] depth) were collected from each plot on 10/19/21, with two cores removed from the center of each plot. Soil cores were divided into upper and lower depths and composited per plot for a single upper and lower sample.


Te soil sampling approach taken should provide us an ability to monitor the subsurface nitrogen status of each landscape. It seems that the top layer of SC, Xeriscape, and AT are stable three years after the installation, as the depth of sand and granite used for those landscapes have not noticeably changed over time. Te only plot onto which surface materials are annually topdressed are Mulch, which is reapplied at 1-in. (.454-kg.) depth annually due to mulch decomposition and vulnerability to water and wind erosion/runoff.


For soil nutrient dynamics, all soil samples have sent to the Texas A&M University soil testing lab for analysis. Requested testing parameters include NH4


-N, NO4 -N, and


organic matter, and samples are still being analyzed. Results will be available in our final report. We are also planning to take soil samples one more time in October 2022.


Sod Strength Characteristics of 24 Fine fescue Cultivars (2021-23, $20,351)


Editor’s Note: Tis project has been delayed a year due to a field trial failure. Below is a recap of the research activity to date, along with an overview of what is planned as the project moves forward.


Tere is a clear desire for lower-input sod species, such as fine fescue (Festuca spp.) from consumers (Hugie et al., 2012; Yue et al., 2012). In addition, increasing concerns over the environmental impacts of soil erosion from industrial and infrastructure development are also expected to be rapidly increasing sources of demand for sod. However, despite the fact that many different turfgrass species exist, most sites today in the northern U.S. are planted as sod with the same varieties of Kentucky bluegrass (Poa pratensis), regardless of site management.


Recent genetic improvements in low-input turfgrass species now provide sod farms other options when selecting what to plant (Braun et al., 2020). Since the selection of turfgrasses (either low- or high-input) by sod farms ultimately impacts the level of input required by those receiving sod installations (homeowners), decisions made by sod farmers and landscape contractors can have a tremendous impact on the environment and efforts to manage turf sustainably.


24


Preliminary 2019-2020 data from collaborative research at Purdue University and University of Minnesota investigating low-input sod production funded by USDA- AMS is showing some promising results with fine fescue sod production, especially with strong creeping red fescue (Festuca rubra ssp. rubra) because of its rhizome system. Results from this USDA funded sod research also show us that there is much variability in horizontal spread between genotypes of strong creeping red fescue. Tis indicates there may be potential differences among cultivars within a fine fescue species or subspecies.


In addition, preliminary results from a Te Lawn Institute- funded experiment in 2020 at Purdue University titled “Identification of Successful Nitrogen Fertilization Establishment Regimes for Fine Fescue Sod Production” is showing that strong creeping red fescue is producing the highest sod strength, slender creeping red fescue (F. rubra ssp. littoralis) is the next highest, and then Chewings fescue, and hard fescue (Festuca brevipila) is the lowest sod strength among fine fescues. Preliminary results from this experiment are also demonstrating that plant genetics and not nitrogen fertilization has the greatest impact on sod strength.


Overall, the preliminary results from these previous experiments consistently show there are differences in sod strength among the fine fescue taxa (i.e., species and subspecies). New release of fine fescue cultivars, as well as variable cultivar performance in differing environments (NTEP, 2014, 2018), necessitates further sod strength research to continue to provide more information and options for sod producers. Terefore, the objective of this experiment is to identify the best performing cultivars of fine fescues for sod production.


As originally scheduled, this field experiment was to be planted in early September 2021 and again in September 2022 with harvests to occur the following year. Te experiment will include 24 cultivar treatments arranged in a randomized, complete-block design with four blocks. All plots will receive the same rate of starter fertilizer at planting and the same annual Nitrogen (N) rate of 2.5 lb. N/1000 sq ft. (1.134 kg. N/92.903 sq. m.) per year. Te cultivars in the study include nine varieties of Strong creeping red fescue, six varieties of Slender creeping red fescue, five varieties of Chewings fescue, and four varieties of Hard fescue.


Sod harvests will occur at 9, 11, and 14 months after planting (MAP). Tese sod harvest timings were selected based on preliminary sod harvest data timings from low- input sod production experiments, which include various fine fescues and other cool-season turfgrass species at Purdue University at 11, 12, and 14 MAP funded by USDA-AMS. Data collection at each sod harvest timing will include measurements of sod tensile strength


TPI Turf News September/October 2022


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84