‘Meyer’ zoysiagrass (Zoysia japonica Steudel) is commonly planted on home lawns and golf courses in the transition zone; however, poor shade tolerance limits its widespread use. This study was conducted to determine changes and differences in growth among selected Zoysia cultivars and progeny under a natural shade environment over a 3-year period in the transition zone. The study was initiated in June 2010 at the Rocky Ford Turfgrass Research Center in Manhattan, KS. Soil type was a Chase silt loam (fine, montmorillonitic, mesic, Aquic, Argiudoll). Zoysia genotypes were sodded in 0.37-m2 plots and arranged in a randomized complete block with five replications under silver maple (Acer saccharinum L.) shade that resulted in a 91% reduction in photosynthetically active radiation (PAR). Genotypes included ‘Zorro’ [Z. matrella (L.) Merrill], ‘Emerald’ [Z. japonica × Z. pacifica (Goudswaard) Hotta & Kuroki], ‘Meyer’, Chinese Common (Z. japonica), and experimental progeny Exp1 (Z. matrella × Z. japonica), and Exp2 and Exp3 [(Z. japonica × Z. pacifica) × Z. japonica]. ‘Zorro’ and ‘Emerald’ experienced winter injury, which negatively affected their performance. Tiller numbers decreased 47% in ‘Meyer’ from June 2010 to June 2012, but declines in [(Z. japonica × Z. pacifica) × Z. japonica] progeny were only 1% for Exp2 and 27% for Exp3, and both Exp2 and Exp3 maintained high percent green cover throughout the study. In general, by the third year of evaluation, progeny of [(Z. japonica × Z. pacifica) × Z. japonica] had higher quality ratings and higher tiller numbers than ‘Meyer’ and may provide more shade-tolerant cultivar choices for transition zone turf managers.

Core Ideas Evapotranspiration from ASCEDM, ASCEDC was equivalent to lysimeters. Net radiation from global irradiance is sufficient in daily‐step model in absence of measured net radiation. ASCEDC improves irrigation scheduling in turfgrass when measured net radiation is not available. Evapotranspiration (ET) from turfgrass can be measured directly using lysimeters (LYS), estimated from weather data using models, or approximated using atmometers. Evapotranspiration measurements from LYS were compared with ET estimates from the American Society of Civel Engineers standardized ET equation using hourly steps from measured net radiation (Rn) (ASCEHM) and Rn calculated from global irradiance (ASCEHC), and daily steps from measured net radiation (ASCEDM) and Rn calculated from global irradiance (ASCEDC), the Priestley–Taylor (PT) model, and atmometers, all collocated in a sward of tall fescue (Festuca arundinacea Schreb.) turfgrass near Manhattan, KS. Data were collected on precipitation free days during the growing seasons 2010 through 2012 and analyzed by periods with high ET, low ET, and pooled across all days. Overall mean ET (May–October) ranged from 5.58 (LYS) to 4.47 mm d−1 (ASCEHC). During days with high evaporative demand ET from daily‐step models (ASCEDM, ASCEDC) were equivalent to LYS, based on paired t tests. Similarity in ET among LYS, ASCEDM, and ASCEDC indicate using Rn calculated from global irradiance is sufficient in the daily‐step model in the absence of measured Rn. At high ET rates ET from ASCEHM and PT was 5 to 9% lower than LYS, but accuracy was significantly reduced (by 22%) with ASCEHC. Atmometer ET averaged 17% lower than LYS, but performance was better at low than high ET. Results indicate the ASCEDC could improve irrigation scheduling in turfgrass by providing accurate ET estimates from standard weather station data where measured Rn is not available.

Infrared thermometry provides accurate measurements of plant canopy temperature, which, along with basic weather variables, allows estimation of canopy stomatal conductance to water vapor flux (gc) and transpiration. Our objectives were (i) to compare single‐ versus two‐source energy balance approaches for sensible and latent heat flux calculations; (ii) to use gc calculated with the method of Blonquist et al. (2009) to estimate transpiration from a dense, well‐watered sward of tall fescue (Festuca arundinacea Schreb.) turfgrass; and (iii) to compare calculated canopy transpiration with measured lysimeter evapotranspiration (LYSET). The study was conducted from June to October 2012 near Manhattan, KS. Three microlysimeters containing ambient cores of turfgrass were used to measure LYSET. Four infrared radiometers, used to measure canopy temperature, were positioned on a weather station that recorded all data necessary for calculating gc. Transpiration calculated from modeled gc averaged 1.71 mm d−1 (29.6%) less than mean LYSET, suggesting 29.6% of LYSET was from soil water evaporation. Nighttime LYSET may have inadvertently contributed to the soil water evaporation component using this method (our conductance model assumed zero nighttime transpiration). Differences were negligible between the single‐ and two‐source energy balance approaches for sensible and latent heat flux calculations. Results indicate transpiration may be reliably estimated via calculation of gc in turfgrass.

2359ReseaRch T urfgrasses in the United States are estimated to cover 16 to 20 million hectares, an area three times larger than any irrigated crop (Morris, 2003;Milesi et al., 2005). The total turfgrass area in the United States is likely to increase greatly as urbanization continues to expand (Alig et al., 2004). Irrigation of turfgrasses in urban areas is a common practice, creating an increasing demand for water in expanding urban areas. However, many homeowners do not understand how to manage the irrigation for their lawn (Bremer et al., 2012(Bremer et al., , 2013(Bremer et al., , 2015. A better understanding of turfgrass irrigation requirements (i.e., ET) would help homeowners manage irrigation more efficiently, reducing the demand for water.Turfgrass irrigation requirements are often determined by ET estimates. Typically ET estimates are obtained from either on-site or off-site weather stations that collect weather data to calculate ET using an empirical model. However, a weather station can be expensive to set up and maintain. Siting of the weather station can also create a bias resulting in inaccurate ET estimation (Ley et al., 1996). This is problematic for practitioners who utilize ET-based irrigation scheduling.ABSTRACT An atmometer is an inexpensive tool used to measure evapotranspiration (ET) in situ. The effects of microclimates associated with urban lawns on the performance of atmometers are not well documented. our objective was to compare ET estimates between atmometers and the FAo-56 penman-Monteith equation (pM ET , FAo56-pM), including within urban lawns. The study was conducted in six lawns in 2010 and one in 2011 in Manhattan, KS, and four lawns in Wichita, KS, in 2011. A weather station and atmometer were positioned in an open sward of turfgrass near each city during each measurement period in Manhattan and Wichita. A commercially available Bellani plate atmometer, using a green canvas cover for grass reference ET (AT ET ), was placed next to a portable weather station in two contrasting microclimates within each lawn. Weather stations recorded temperature, net radiation, relative humidity, and wind speed data used to calculate pM ET . open sward AT ET (4.73 mm d -1 ) averaged 14% less than pM ET (5.48 mm d -1 ). Within microclimates, AT ET (3.94mm d -1 ) averaged 22% greater than pM ET (3.23 mm d -1 ). The differences in ET estimates between measurement techniques varied with wind speed, net radiation, and vapor pressure deficit. The best relationships between AT ET and pM ET , at the open sward and within microclimates, occurred when wind speed was >1 m s -1 , vapor pressure deficit was >2 kpa, and net radiation was >5 MJ m -2 d -1 . overall, atmometers can provide reliable estimates of pM ET and could benefit practitioners with irrigation management within microclimates. Dep. of Horticulture, Forestry and Recreation Resources, Kansas State Univ., 2021 Throckmorton Plant Sciences Center, Manhattan, KS 66506. Contribution no. 15-152-J from the Kansas Agric. Exp. Station.

Determination of total nonstructural carbohydrate levels in turf‐type buffalograss [Buchloë dactyloides (Nutt.) Engelm.] genotypes as influenced by mowing height has not been previously investigated. The objectives of this study were to determine the influence of buffalograss genotype and mowing height on total nonstructural sugar and starch content during the growing season. The study was conducted at the John Seaton Anderson Turfgrass Research Facility located near Mead, NE. Cultivars Legacy and Prestige along with selections NE‐2979 and NE‐2964 from the buffalograss breeding program at the University of Nebraska were studied. The genotypes were mowed at 1.6 and 5.0 cm. Sugar and starch content trends were similar, but differences in carbohydrate concentration among genotypes were observed. NE‐2964 exhibited the greatest sugar content, 6.37% at 5‐cm mowing height, and NE‐2979 the lowest sugar content, 1.75% at 5‐cm mowing height. Legacy exhibited the greatest starch content, 12.6% at 5‐cm mowing height, and NE‐2979 the lowest starch content, 1.3% at 5‐cm mowing height. Surprisingly, mowing height had little effect on sugar or starch levels of buffalograss. Genotype was the greatest source of variation for sugar and starch content, indicating that different genotypes partition or allocate carbohydrates differently. These results show the seasonal carbohydrate content variations among buffalograss genotypes and provide some insight as to why those changes occur.