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Turfgrass cover can be assessed qualitatively using visual ratings, but quantitative turfgrass cover measurements are desired for producing unbiased data. Digital image analysis and point intercept are two quantitative percent cover data collection methods used in turfgrass research. A potential weakness of digital image analysis is the difficulty in evaluating color variation. Considering this, a series of controlled environment and field experiments were conducted to evaluate the accuracy of the point intercept method compared to using a digital grid, digital image analysis, and visual ratings when utilized in turfgrass research. To explore this topic, four experiments were conducted in Corvallis, OR, and one in New Brunswick, NJ. Results from research conducted in Corvallis, OR, determined that the closest point intercept spacing (2.5 cm) resulted in a percent cover that was not statistically different from the known cover and the lowest variance, but the greatest amount of time required to collect the data. Digital image analysis was the most consistent method for measuring percent cover when a known percent cover was being quantified. The estimate of the percent dollar spot cover was reduced by a single pigment application regardless of the data collection method. In the absence of pigment applications, the point intercept frame, digital image analysis, and visual ratings were well‐correlated methods used to assess dollar spot cover. Digital image analysis was not correlated with the other data collection methods when used to evaluate percent anthracnose cover. The research conducted in New Brunswick, NJ, determined that the point intercept method and digital image analysis are well‐correlated methods for quantifying turfgrass establishment from seed. Core Ideas: The closest intercept spacing (2.54 cm) results in a percent cover that was not different from the known cover.Digital image analysis was the most consistent method for measuring a known percent cover.Digital image analysis and visual ratings were well‐correlated methods used to assess dollar spot cover.Well‐correlated methods for assessing anthracnose included the digital grid across the point intercept frame.Pigment application reduced dollar spot cover ratings regardless of the data collection method. [ABSTRACT FROM AUTHOR]

The western portion of the Pacific Northwest is known for being dry in the summer and cool and humid in the other months. Tall fescue is valued for its drought and heat tolerance, making it a desirable choice in regions where water is scarce and often restricted by legislation during periods of drought in the summer. However, cool and humid climates make it challenging to manage tall fescue in the winter because unacceptable quality is often observed due to low-temperature diseases and thinning in turf. A field trial was initiated in Autumn 2020 in Corvallis, OR, USA to assess the effects of mowing height as well as fertility timing and rate on tall fescue performance. Two mowing heights of 5.1 and 7.6 cm, four seasonal fertility timings, and three levels of annual N rates of 98, 196, and 294 kg⋅ha-1⋅yr-1 were evaluated using a 2 x 4 x 3 factorial experiment in a strip-plot design. Quantitative data of percent green cover and normalized difference vegetation index (NDVI) suggest that autumn fertilization is needed in cool, humid areas where tall fescue is actively growing in the winter months. The annual fertilization rate of 294 kg⋅ha-1⋅yr-1 N produced higher green turf cover and NDVI, compared with 98 or 196 kg⋅ha-1⋅yr-1 N. Furthermore, divergent effects of mowing heights were observed during winter compared with other months, suggesting that tall fescue could be mowed lower at 5.1 cm during cool, humid winter months and higher at 7.6 cm in other seasons for better overall turfgrass growth and less winter disease and thinning. Our research provides practical cultural practices for managing tall fescue turf in the Pacific Northwest or similar climates. [ABSTRACT FROM AUTHOR]