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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]

Anthracnose (caused by Colletotrichum cereale Manns sensu lato Crouch, Clarke & Hillman) of annual bluegrass [ABG, Poa annua L. f. reptans (Hausskn.) T. Koyama] turf is a destructive fungal disease that has been shown to be more severe under nitrogen (N) deficiencies. Little is known about the effect of soluble N source on this disease. A 3-yr field study was initiated in 2010 to evaluate the effect of soluble N source on anthracnose severity and to determine if N source alters the effect of N frequency on this disease during midseason on an ABG turf maintained at 3.2 mm. Nitrogen treatments were applied at 4.9 kg N ha-1 every 7 or 14 d (frequency factor) as solutions of ammonium sulfate, ammonium nitrate, urea, calcium nitrate, or potassium nitrate. Both N frequency and N source affected disease severity throughout 2010, 2011, and 2012. In general, soluble N applied at 4.9 kg N ha-1 every 7 d reduced disease compared with N applied at the same rate every 14 d. Of the N sources, potassium nitrate provided the greatest reduction in disease severity over the 3-yr study, whereas ammonium sulfate treatments resulted in the greatest disease severity. Soil pH was also influenced by N source, with ammonium sulfate treatments resulting in the lowest soil pH (most acidic), and potassium nitrate consistently producing the highest soil pH (most basic) throughout the study. Potassium nitrate also greatly increased soil K. This study has shown that anthracnose severity on ABG putting green turf is influenced by N source, and that low-rate applications of potassium nitrate every 7 d were most effective at reducing disease severity under moderately acidic soil conditions and moderate to low soil K levels. [ABSTRACT FROM AUTHOR]

Increased N fertilization, mowing height, and sand topdressing are management practices that can suppress anthracnose disease of annual bluegrass [Poa annua L. f. reptans (Hausskn) T. Koyama; ABG] caused by Colletotrichum cereale Manns. A 3-yr field study evaluated the relative importance and interactions of these factors on anthracnose severity, turfgrass quality, and ball roll distance (BRD) on ABG turf in North Brunswick, NJ. A factorial combination of mowing height (2.3 and 3.2 mm), N fertilization (100 and 200 kg ha-1 yr-1), and sand topdressing (46 and 98 Mg ha-1 yr-1 in 2012; 37 and 81 Mg ha-1 yr-1 during 2013 and 2014) was arranged in a split-split-plot design with four replications. The practice of applying greater N fertilization (200 kg ha-1) provided the greatest reduction in disease severity and improvement in quality than the practices of higher mowing (3.2 mm) or greater sand topdressing (98 or 81 Mg ha-1). Combining greater N with higher mowing and greater sand topdressing provided acceptable disease suppression without the use of fungicides during moderate but not severe anthracnose epidemics. Higher mowing often produced unacceptable BRD (<2.9 m) especially when combined with greater N fertilization; whereas, under lower mowing, BRD was acceptable on most observation dates (91-96%) and less influenced by greater N fertilization. Thus, when adjustments in best practices for anthracnose management are needed to enhance BRD; lowering the mowing height will provide that enhancement while not greatly increasing the risk for anthracnose especially when greater N and increased topdressing practices are also employed. [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]

The article presents an update from the Acoustical Society of America, including the names of the candidates for the election of the society set to take place on May 23, 2013 and the schedule of meetings and congresses of interest to members of the society.

An obituary for internationally famed acoustician Manfred Robert Schroeder is presented.

There is increasing interest in understanding plant-associated microbial communities and their impact on plant health. However, research has been limited to major agronomic systems and little is known about the resident microorganisms in economically important specialty crops, such as turfgrass. In this study, we generated a community-wide inventory of the archaea and bacteria that inhabit the soil of Poa annua L. putting green turf at five time points over a 1-yr period. Next-generation sequencing of the nuclear ribosomal DNA 16S revealed 1.5 ' 105 unique operational taxonomic units from 25 pooled soil samples. Seventeen archaeal taxa were identified at the species level, 53% of which were members of the Crenarchaeota. Proteobacteria was the most abundant bacterial phylum, comprising 36% of the 442 taxa present. Distance analysis and analysis of similarities revealed that the archaeal and bacterial communities clustered according to sample date, with samples collected during warm months grouping separately from those collected during cool months. Clustering was less distinct when plotted using detrended correspondence analysis. These data indicate that microbial community structure varied throughout the growing season, possibly due to seasonal changes in temperature and/or other environmental factors. This research also shows that P. annua putting green turf supports a diverse microbial community despite management practices that include frequent pesticide applications. [ABSTRACT FROM AUTHOR]

The article discusses the volatile and semivolatile organic compounds (VOCs) emissions pattern in old books. It cites the method material degradomics, which was developed by Matija Strlič and colleagues that links a book's physical state to its VOC emissions pattern in which they used documents from 19th an 20th century. The documents are made with rosin, bleached pulp groundweed, and rag fiber. Moreover, it states that the most problematic contents in paper are lignin and rosin.

The article announces the members of the Nominating Committee for the 2008 Election of the Acoustical Society of America.