Progress 06/02/14 to 09/30/18
Outputs
Target Audience:Golf Course Superintendents, Athletic Field Managers, Turfgrass Consultants, Turfgrass Faculty and Students. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Root zone response to amendments is generally influenced by texture, uniformity and the amounts of silt and clay of the amended sand. Thus, fine to medium textured sands exhibit a lesser response to added amendments whereas medium to coarse textured sand exhibit a greater response. This is also generally true when comparing less uniform sands with more uniform sand and sands containing greater silt and clay contents. The greater response, particularly with regard to water retention properties is observed with coarser, more uniform and cleaner sands. There is also, generally, an amendment rate effect observed with most sands where increasing amendment amounts lead to greater water and nutrient retention. But there is a subtle difference in how either water retention properties or nutrient retention properties increase at greater rates of incorporation. In the case of nutrient retention expressed as the CEC of the root zone, amendments that possess cation exchange capacity yield a linear increase in CEC with incrementally increasing rates of incorporation. Increasing water retention properties at successively greater incorporation rates, however, show diminishing returns. That is, smaller incorporation rates exhibit a greater water retention response than larger incorporation rates. Consequently, there is a practical upper limit in the ability of a particular amendment to increase the water retention of sand. These findings should allow golf course superintendents and athletic field managers greater flexibility in selecting root zone amendments. How have the results been disseminated to communities of interest?As was mentioned earlier, dissemination has been mostly to students and to turfgrass faculty through instructional modules I created and via personal communications. I have also been working with turfgrass industry professionals involved with marketing soil amendments to aid their understanding the role amendments play in sand-based root zones. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Objectives 1 and 2 Guidelines for Capillary Porosity (CP) limits measured at 30 cm water suction vary by authority. Thus the U.S. Golf Association specify that CP values must exceed 15% by volume, other researchers recommended CP values exceed 20% by volume, whereas still other researchers suggested that CP values equal about 25% by volume. These guidelines reflect that needed to achieve the minimum water retention for subsequent turfgrass uptake. Using sand particle size and CP data of 40 sand samples and 47 root zone mixes, a non-linear regression was formed relating the CP value to the sand mid-particle diameter (D50). Thus, uniformly fine sands having a D50 value of 0.18 generally met the 25% by volume CP guideline, uniformly medium sands having a D50 value of 0.38 generally met the 15% by volume CP guideline, and uniformly coarse sands having a D50 value of 0.75 could not meet any of the CP guidelines. Correspondingly, a root zone amendment added to fine sand has little effect on the Capillary Porosity value, but as the sand becomes coarser, the amendment contributes more, up to about a 5% by volume CP increase for the coarse sand. Yet, uniformly coarse sand containing an amendment still has A CP value less than the water retention criteria of 15% by volume Capillary Porosity. Finally, most USGA guideline sands have D50 values from 0.35 to 0.4 mm. So un-amended sand may just meet the minimum water retention criteria of 15% CP value and added amendment can bring this to approaching the 20% CP guideline. Objective 3 Using a validated simulation of water flow and turfgrass water uptake within a USGA putting green analyses were conducted for root zones containing either unamended sand, or sand amended with 15% vol. Profile. Physical property data for these root zone materials came from several independent testing labs all using the ASTM F 1815-97 standard method. Of particular use in the analysis were values of water retention and saturated hydraulic conductivity. The model simulation generates data of turfgrass response to water-related stress. The simulation was conducted by beginning with a fully charged capillary fringe, and using simulated ET rates of 5.1 mm day-1 and a 14 h daylight period for each successive day after rainfall. Expectedly, following this protocol, the root zones became progressively drier. This was reflected in the generally increasing values of turfgrass stress calculated by the simulation during daylight hours of days 4 through 7. This stress index also shows that starting on days 4 or 5 the unamended sand exhibited a drought stress responses with smaller values in the morning and larger values in the afternoon. This drought stress response was delayed in the 15% vol. Profile root zones as indicated by smaller stress index values on every day after day 4, particularly in the late afternoon. A stress index value of 12% was deemed to be a threshold indicating the need for irrigation. Thus the unamended sand green would likely be irrigated during the overnight hours at the end of either day 4 or 5 whereas the Profile amended root zone would likely be irrigated during the overnight hours at the end of either day 6 or day 7. Consequently one can conclude that the Profile amended root zone delayed the onset of turfgrass drought stress by about 2 to 3 days compared to unamended sand. The ET rates used in this simulation represent extreme drying conditions. For less extreme conditions, turfgrass stress would be delayed in all root zones. Yet, lower ET rates would also extend the differential between root zones, suggesting that the Profile root zone could delay drought onset by more than 2 days for less extreme drying conditions.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2014
Citation:
Cheng, Z., E.L. McCoy and P.S. Grewal. 2014. Water, sediment, and nutrient runoff from urban lawns established on disturbed subsoil or topsoil and managed with inorganic or organic fertilizers. Urban Ecosyst. 17:277-289.
- Type:
Journal Articles
Status:
Published
Year Published:
2016
Citation:
Freeland, R.S., B.J. Allred, L.R. Martinez, D.L. Gamble, B.R. Jones and E.L. McCoy. 2016. Performance of hybrid and single-frequency impulse GPR antennas on USGA sporting greens. J. Environ. & Engr. Geophysics 21(2):57-65.
- Type:
Journal Articles
Status:
Published
Year Published:
2016
Citation:
Allred, B., R. Freeland, K. Grote, E. McCoy, L. Martinez and D. Gamble. 2016. Ground-penetrating radar water content mapping of golf course green sand layer. J. Environ. & Engr. Geophysics 21(4):215-229.
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Progress 10/01/16 to 09/30/17
Outputs
Target Audience:Golf course superintendents, athletic field managers, turfgrass professionals. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Because the accomplishment is a tool for decision making I anticipate that just through itsuse some professional development will be gained. How have the results been disseminated to communities of interest?The simulation is presently under development but I anticipate that it will be described in trade journal articles and disseminated via email to interested parties. What do you plan to do during the next reporting period to accomplish the goals?The accomplishment requires further calibration to gain confidence in its applicability.
Impacts
What was accomplished under these goals?
Managing organic matter accumulation in golf course putting greens is a major agronomic challenge facing golf course superintendents. If organic matter levels become excessive, the putting surface will be soft, bumpy and prone to disease and scalping. Yet measures to control organic matter accumulation such as topdressing and core aeration are commonly disruptive and result in player dissatisfaction and reduced course revenues. We built a simulation of organic matter accumulation and dilution when applying control measures to provide superintendents a tool to better manage organic matter within their putting greens. The simulation runs on a monthly time step and spans the soil depth of 0 to 125 mm, separated into 25 mm increments. Organic matter accumulation is calculated by combining the recently developed Growth Potential Reference operating at a monthly time step with a negative logistic function to assign the accumulated organic matter to the discrete depth increments. Inputs into the Growth Potential Reference are mean monthly air temperatures for the given location under consideration and parameters specific to either cool season or warm season grasses. Inputs into the logistic function are the monthly surface organic matter accumulations from the Growth function as well as shape factors that have been calibrated from various literature sources. For a specified month when topdressing is applied as an organic matter control operation, the efficacy of this operation is calculated by a mixing model where a volume of sand added to the existing surface layer dilutes the organic matter. Additionally, the identical volume of the surface layer is combined with the second layer through use of a mixing model, and so forth, preserving the layer dimensions in the simulation. When core aeration is used as a control measure a quantity of soil is removed depending on the diameter, spacing and depth of the coring tool used. Subsequently a mixing model is employed where the volume of sand added to fill the aerifier hole serves to dilute the organic matter in the existing affected layers.
Publications
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Progress 10/01/15 to 09/30/16
Outputs
Target Audience:Atheltic field managers, golf course superintendents, turfgrass consulants and turfgrass scientists. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?The accomplishment of this report was focused on central Ohio rainfall and soil condtition. The techniques and methods of this study can be easily transfered to other regions of the world having problems of surface drainage of athletic fields. All that is needed is to customize simulation inputs for the climate of the region and general soil conditions. The simulations developed by this research can then be run for the region of interest; providing broad training and professional development of the target audience members. How have the results been disseminated to communities of interest?
Nothing Reported
What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Native soil athletic fields in humid climates and subjected play in the fall season frequently suffer from surface water ponding during the event. This often results in poor playing conditions and a rutted field following the sporting event. The situation could be greatly improved by installing surface interceptors within the field. However, there is little scientific guidance available for the design and installation of such interceptor drainage systems. Employing traditional surface interceptor drainage principles and a soil hydrologic simulation, several scenarios were examined with regard efficacy of intercepting overland flow and removal of surface water ponding. In all scenarios the simulated athletic field had a 1% slope, 50 mm turfgrass canopy and a clay loam soil with saturated conductivity of 1.3 mm h-1. To this field a 42 mm, moderately advancing rainstorm spanning 18 hours was applied. This corresponds to a 7 year return period storm for the months of September to November in Columbus, OH. The principal output from the model was a calculation of the percentage of the total surface area ponded with at least a 1 mm depth of water as a function of time from the beginning of the rainstorm. In the first scenario, sand backfilled interceptors were spaced at 6.1 m across the field and the simulation results indicated that the maximum ponded area approached 92% and that water covered at least 50% of the surface for a period of 15 hours. Approximately 57% of the rainfall was intercepted and ponding did not disappear for 35 hours after the beginning of the rain. Three more scenarios were examined with interceptor spacing of 3.7, 1.8 and 0.9 m. The progressively closer spacing resulted in a reduction of the maximum ponded area from 70% for the 3.7 m spacing to 20% for the 0.9 m spacing. Ponding disappeared after 25 hours for the 3.7 m spacing and after 15 hours for the 0.9 m spacing. Subsequently at the 0.9 m spacing 76% of the rainfall was intercepted. Also, at 0.9 m spacing only a narrow, 15 mm sand slit was required to effectively intercept the peak runoff flow. This analysis demonstrated the extreme challenge of surface draining native soil athletic fields and indicates that a sand -slit drainage system at close spacing is needed for adequate performance.
Publications
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Progress 10/01/14 to 09/30/15
Outputs
Target Audience:Golf course superintendents, athletic field managers, turfgrass consultants and turfgrass scientists. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?These findings revealed implications for turfgrass water use in USGA putting greens. Even though turfgrass rooting was concentrated very near the soil surface, a capillary fringe deep within the root zone was yet accessible by the plant. The mechanism for this was the sufficient rates of upward water flow to rehydrate the surface soil layers during the night. Thus, for the ET rates of this study, the capillary fringe within a USGA green appears to serve reasonably well as a water reservoir for subsequent turfgrass water use. Inclusion of 15% vol Profile aided in this water uptake. Consequently, these results stress the importance of water conserving irrigation practices that employ the capillary fringe reservoir and replenish it as needed. Yet it may be that for climates having greater atmospheric demand for water than Ohio or for turfgrass grown at a higher height of cut, the increased rate of water loss at the surface may exceed the capability of flow from deeper depths. In these cases, the capillary fringe may not as effectively serve the role of a water reservoir. Also, this endorsement of capillary fringe in UGSA greens must be tempered by acknowledging the effects of slope on lateral water flow. Localized loss of the capillary fringe within sloped regions of a green may exhaust the reservoir prior to appreciable water uptake by the turfgrass. How have the results been disseminated to communities of interest?
Nothing Reported
What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Using a validated simulation of water flow and turfgrass water uptake within a USGA putting green analyses were conducted for root zones containing either unamended sand, or sand amended with 15% vol. Profile. Physical property data for these root zone materials came from several independent testing labs all using the ASTM F 1815-97 standard method. Of particular use in the analysis were values of water retention and saturated hydraulic conductivity. The model simulation generates data of turfgrass response to water-related stress. The simulation was conducted by beginning with a fully charged capillary fringe, and using simulated ET rates of 5.1 mm day-1 and a 14 h daylight period for each successive day after rainfall. Expectedly, following this protocol, the root zones became progressively drier. This was reflected in the generally increasing values of turfgrass stress calculated by the simulation during daylight hours of days 4 through 7. This stress index also shows that starting on days 4 or 5 the unamended sand exhibited a drought stress responses with smaller values in the morning and larger values in the afternoon. This drought stress response was delayed in the 15% vol. Profile root zones as indicated by smaller stress index values on every day after day 4, particularly in the late afternoon. A stress index value of 12% was deemed to be a threshold indicating the need for irrigation. Thus the unamended sand green would likely be irrigated during the overnight hours at the end of either day 4 or 5 whereas the Profile amended root zone would likely be irrigated during the overnight hours at the end of either day 6 or day 7. Consequently one can conclude that the Profile amended root zone delayed the onset of turfgrass drought stress by about 2 to 3 days compared to unamended sand. The simulation model can also predict the distribution of air-filled pore space within the root zone at any location within the simulated putting green and at any time following rainfall or irrigation. Choosing a fully charged capillary fringe, such as would occur following a heavy rain or extended periods of rainy weather, calculations of air-filled pore space were conducted with depth in the root zone. In this condition, both root zones show greater air-filled porosities near the surface and declining with depth; leaving virtually no air-filled pores at the interface between the root zone and the gravel layer in a USGA green. The root zone aeration results also show that the 15% vol. Profile root zone maintains a larger air-filled pore space throughout most of the root zone depth. If one were to assume that 15% air-filled pore space represents a cut-off value between more or less favorable conditions for turfgrass rooting; then the results of this simulation suggests that favorable aeration conditions in Profile amended root zones extend approximately 2 to 3 cm deeper than the unamended sand root zone.
Publications
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Progress 06/02/14 to 09/30/14
Outputs
Target Audience: Golf course superintendents, athletic field managers, turfgrass consultants and turfgrass scientists. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided? Root zone response to amendments is generally influenced by texture, uniformity and the amounts of silt and clay of the amended sand. Thus, fine to medium textured sands exhibit a lesser response to added amendments whereas medium to coarse textured sand exhibit a greater response. This is also generally true when comparing less uniform sands with more uniform sand and sands containing greater silt and clay contents. The greater response, particularly with regard to water retention properties is observed with coarser, more uniform and cleaner sands. There is also, generally, an amendment rate effect observed with most sands where increasing amendment amounts lead to greater water and nutrient retention. But there is a subtle difference in how either water retention properties or nutrient retention properties increase at greater rates of incorporation. In the case of nutrient retention expressed as the CEC of the root zone, amendments that possess cation exchange capacity yield a linear increase in CEC with incrementally increasing rates of incorporation. Increasing water retention properties at successively greater incorporation rates, however, show diminishing returns. That is, smaller incorporation rates exhibit a greater water retention response than larger incorporation rates. Consequently, there is a practical upper limit in the ability of a particular amendment to increase the water retention of sand. These findings should allow golf course superintendents and athletic field managers greater flexibility in selecting root zone amendments. How have the results been disseminated to communities of interest?
Nothing Reported
What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Guidelines for Capillary Porosity (CP) limits measured at 30 cm water suction vary by authority. Thus the U.S. Golf Association specify that CP values must exceed 15% by volume, Murphy et al., 2001 recommended CP values exceed 20% by volume, and Murphy et al., 2005 suggested that CP values equal about 25% by volume. These guidelines reflect that needed to achieve the minimum water retention for subsequent turfgrass uptake. Using sand particle size and CP data of 40 sand samples and 47 root zone mixes, a non-linear regression was formed relating the CP value to the sand mid-particle diameter (D50). Thus, uniformly fine sands having a D50 value of 0.18 generally met the 25% by volume CP guideline, uniformly medium sands having a D50 value of 0.38 generally met the 15% by volume CP guideline, and uniformly coarse sands having a D50 value of 0.75 could not meet any of the CP guidelines. Correspondingly, a root zone amendment added to fine sand has little effect on the Capillary Porosity value, but as the sand becomes coarser, the amendment contributes more, up to about a 5% by volume CP increase for the coarse sand. Yet, uniformly coarse sand containing an amendment still has A CP value less than the water retention criteria of 15% by volume Capillary Porosity. Finally, most USGA guideline sands have D50 values from 0.35 to 0.4 mm. So un-amended sand may just meet the minimum water retention criteria of 15% CP value and added amendment can bring this to approaching the 20% CP guideline.
Publications
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