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May 13, 2019 by NYS BMP ·
The golfing season in northern climates includes managing cool-season turf playing surfaces through stressful summer months (e.g. high temperature, low moisture). To prepare for summer stress, use opportunities in the spring during dry periods to apply strategic moisture stress to your playing surfaces by purposefully withholding water from the plant. Allowing soils to dry and create stress in this way often results in increased rooting and improved drought stress tolerance that will pay off in the summer.
In addition, you should assess your irrigation system’s ability to produce uniform soil moisture before summer stresses occur. The application of supplemental irrigation water to maintain uniform soil moisture is critical for maximum playability and stress tolerance during dry periods. Increased accuracy in applying water through a well-designed in-ground irrigation system also allows for significant water conservation. These concepts are promoted in the following two BMP statements:
However, the application efficiency of an irrigation system, measured as Distribution Uniformity (DU), may not always be the most effective measurement of system application that results in uniform soil moisture. This is especially true for undulating surfaces, with higher elevations often too dry and lower elevations too wet.
Applied water sheds rapidly, internally and externally, in a progressive fashion from higher elevations, and along the surface, down to the lower elevations. Research investigating sloped greens conducted at Michigan State University suggests building variable soil profile depths to address the uniquely inconsistent water holding properties found on sloped terrain when constructing new putting surfaces. This will insure shallower depth of rootzone profiles in the higher elevations that will hold more water and deeper rootzone profiles in the low areas to expedite drainage.
The only option to address the disparity in soil moisture on existing undulating surfaces, when adding drainage is not an option, is to alter the DU. In fact, research from the University of Wisconsin-Madison has demonstrated that irrigating a putting surface with a one percent slope required a change in DU from 80 percent to 17 percent to apply the correct amount of water for uniform soil moisture as measured by a time-domain reflectometer (TDR) probe (Spectrum 300).
Therefore, the BEST irrigation practice includes measuring soil moisture to assess system uniformity—not traditional catch-can tests. This will insure that plants have the moisture they need to provide firm playing conditions.
May 7, 2019 by
Golf turf playability and performance lies at the heart of golf course Best Management Practices that protect and preserve water quality. Optimizing playability demands a well-drained, firm playing surface able to withstand traffic and demonstrate resiliency during normal play. The key to achieving these goals lies in the management of surface organic matter.
Turf is a perennial plant system that increases surface organic matter as a result of turf growth and management (Figure 1). Organic matter accumulates at the surface from the development and deposition of plant parts such as leaves, stems, and roots. Underground plant parts, such as stems (rhizomes) and roots, cycle as living, dead, and decomposing organic matter.
The accumulation of organic matter in the top 3 to 6 inches of a turf system increases over time and provides nutrients and water holding capacity, as well as Increasing the resiliency and traffic tolerance required of playing surfaces. However, when too much organic matter accumulates at the surface, it can restrict infiltration of water and when wet does not dry easily into a playable surface. This can reduce the effectiveness of fertilizer and pesticides and increase runoff volumes from the turf surface. The following NYS BMP statement is based on this premise:
Turfgrass species, fertilization, and soil properties influence turf growth and organic matter accumulation. Assuming proper growth is maintained, organic matter accumulation in grasses could be managed through less invasive cultivation and light applications of sand throughout the season. A light application (0.1 to 0.2 inches) of material applied and integrated into the surface of the turf dilutes the organic matter and creates a physical matrix that functions as a soil.
Topdressing is often performed in conjunction with some form of cultivation that simply makes a hole. Research at the University of Nebraska by Professor Roch Gaussoin shows clearly that topdressing frequency (even when compared to use with cultivation) had the greatest influence on organic matter accumulation. (Figure 2). Less invasive cultivation with solid tines provides minor disruption to create space for topdressing to serve the purpose of dilution and creation of a pseudo-soil matrix. Some research suggests the amount of topdressing sand that might be needed over a growing season increases. However, many opportunities to reduce organic matter accumulation exist via more precise N applications and more regular use of plant growth regulators. Ultimately, the goal of proper dilution is to ensure adequate infiltration while preserving sufficient retention of the turf system to prevent leaching.
So the good, better best practices for managing organic matter accumulation:
May 6, 2019 by
Drift when it comes to pesticide applications is something to be avoided, as it can potentially cause not only water quality impacts, but also damage to susceptible off target crops. In addition, a lower than intended rate of pesticide will be applied to the turfgrass, thus reducing its effectiveness. To avoid drift, the first step is to know the difference between There are two types of drift airborne (spray) drift and vapor drift and the contributing factors to each.
Spray Drift
The U.S. Environmental Protection Agency defines pesticide spray or dust draft as “the physical movement of pesticide droplets or particles through the air at the time of pesticide application or soon thereafter from the target site to any non- or off-target site”.
Spray drift is influenced by many inter-related factors including droplet size, nozzle type and size, sprayer design, weather conditions and the operator.
Droplet Size
Lower spray volumes can result in smaller droplets that enhance leaf coverage although there is a limit to droplet size due to drift. Droplets under 150 microns generally pose the greatest hazard; droplets less than 50 microns have insufficient momentum for impaction as they remain suspended in the air indefinitely or until they evaporate. The higher the operating pressure, the smaller the droplet. Conversely, low pressure produces large droplets that may bounce off the target. Certain spray surfactants can change the droplet spectrum, reducing the number of driftable droplets.
Nozzle Type and Size
Correct nozzle selection is one of the most important, yet inexpensive, aspects of pesticide application. A nozzle’s droplet size spectrum determines deposition and drift. Conventional flat fan nozzles fitted to a turfgrass sprayer produces droplets in the range of 10 – 450 microns. (Note: 25,000 microns = 1 inch.) Drift is a concern with droplets less than 100 microns. Increasing the Volume Median Diameter (VMD) reduces drift, but droplets that are too large bounce off the leaves to the ground.
Sprayer Design
Shields are better at targeting the spray into the grass, reducing drift and increasing deposition. They vary from the simple to the complex. Shielded sprayers allow managers to apply pesticides in variable weather conditions.
Weather Conditions
Wind speed and direction, relative humidity, temperature and atmospheric stability affects drift. =.
Calibration
Correct sprayer calibration ensures that all the nozzles are discharging the correct amount of liquid at the correct distance and angle to the target and at the correct forward speed.
Vapor Drift
Vapor drift is caused by pesticide volatilization – the chemical process whereby pesticide surface residues change from a solid or liquid to a gas or vapor after application. Once airborne, volatile pesticides may drift off site. Pesticide volatility varies, and not all pesticides volatilize.
The amount of vapor drift depends upon a pesticide’s volatility and atmospheric conditions such as humidity, temperature. Turfgrass pesticides with known volatility should be avoided. In some cases, the pesticide label may indicate low volatility. However, low volatility does not mean that a chemical will not volatilize under conducive conditions, such as high temperatures or low relative humidity.
Best Practices for Spraying
Before spraying:
3. Read and follow the pesticide label.
During spraying:
1. Stay alert: ensure the spray is not allowed to drift on to non-target areas and watch for changes in wind speed and direction.
2. Keep spray pressure as low as possible and ensure an accurate gauge is used.
3. Maintain a constant speed and pressure. If an automatic regulator is fitted, remember, small increases in speed result in large increases in pressure.
4. Avoid spraying near sensitive crops or watercourses; use a buffer zone.
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