Reducing salinity with cultivation practices and products on golf course fairways
Bermudagrass is a warm season turf species that is widely used on golf course fairways in the Southwestern US because of its adaptions. In semiarid and arid regions, turfgrasses rely on irrigation water to maintain performance. The high evapotranspiration caused by high temperature and wind conditions results in a higher water demand for turfgrass growing in these regions. However, the salts accumulated in soil due to the poor quality of irrigation water from the Ogallala aquifer may have potentially negative effects on soil and turf. Cleaner water may not always is available for leaching. The objective of this research was to determine if application of products and cultivation practices can provide benefits for salts remediation and turf quality improvement with normal levels of irrigation water. Rawls Golf Course and Meadowbrook Golf Club with different soil and turf characteristics in Lubbock, TX were selected to conduct this research. Cultivation practices, core aerification, slicing, and non-cultivated control were applied in middle June 2015 and 2016. The rate and timing of 10 product (surfactants and gypsum based products) applications were based on the product label. Soil samples of each experimental plot were collected three times each year and analyzed for electrical conductivity and pH measurement. Large molecular weight chemical elements were measured with the portable x-ray fluorescence instrument. Data including visual turf quality, digital image analysis, normalized difference vegetation index, ratio vegetation index, and volumetric water content were measured at the frequency of every other week from June to October in 2015 and 2016. Precipitation was the main factor to regulate soil EC. The high amounts of rainfall received prior to this research in 2015 likely reduced the accumulated salts in the soil from extended drought. Gypsum and Verde-Cal G significantly reduced soil pH after two years of applications. Granular products generally increased soil EC compared to control, especially at Meadowbrook, with normal irrigation levels. Cultivation practices were the main factor that caused significant differences on above ground turf parameters. Core aerified treatments were slower to heal at the Rawls Golf Course, which resulted in poorer cover and color throughout the summers in 2015 and 2016. The ratio vegetation index and turf quality were significantly improved by cultivation practices on the common bermudagrass fairway at Meadowbrook Golf Club. The lower volumetric water content by core aerification compared to non-cultivated or sliced treatments at Meadowbrook may demonstrate a higher infiltration rate associated with core aerified practice. Few consistent significant differences on turf parameters were observed based on product applications. Soil with 5% more clay content at Rawls may have higher buffering capacity to limit soil EC changes in this short study period. The high clay content 19.7% and potential poor soil structure at Rawls may have limited turf recovery from core aerified treatments. Overall, the salt remediation ability was limited by applications of products and cultivation practices without leaching fraction. The soil salinity never reached a level that significantly impacted the relatively salt tolerant bermudagrass, which may have limited the potential benefits that could have been provided by products.