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Particulate organic matter (OM) and surface area-limited sands are associated with soil water repellency (SWR) in turfgrass systems. The increasing ubiquity of amended sand rootzones warrants investigation of factors contributing to SWR. Our objective was to identify how amendment type and/or inclusion rate affect rootzone SWR over a range of irrigation regimes. A U.S. Golf Association-specified sand was amended with dried turfgrass roots and either sphagnum peat moss (SPM), reed sedge peat (RSP), biosolid compost (BSC), or calcined clay (CC) at 0, 0.1, or 0.2 [m.sup.3] [m.sup.-3]. Mixes were saturated, gravitationally drained, incubated under isothermal ventilation having mean vapor pressures of 1.78, 2.19, or 2.45 kPa, and reirrigated when matric tension exceeded 300 kPa. After 138 d, rootzone subsamples were eluted of particulate OM before measuring mineral-adsorbed hydrocarbon content (MAHC) by infrared spectroscopy. The repellency index was used to quantify SWR of intact ([R.sub.intact]) and eluted ([R.sub.eluted]) samples. Amendment rate (0.2 > 0.1 > 0 [m.sup.3] [m.sup.-3]) and type (BSC > RSP = SPM > CC) significantly affected [R.sub.intact]. Only CC-amended rootzones were more wettable than the control. Severely elevated [R.sub.eluted] and MAHC were observed in all sands amended by BSC. Inclusion of SPM or RSP at 0.1 [m.sup.3] [m.sup.-3] resulted in [R.sub.eluted] and MAHC values statistically equivalent to the control rootzone. At 0.2 [m.sup.3] [m.sup.-3] inclusion, all organic amendments significantly increased [R.sub.eluted] and MAHC relative to the control (BSC > RSP = SPM).

Seed germination and vegetative growth studies were conducted to determine relative salinity tolerance of greens-type Poa annua L. compared with other cool-season turfgrass species. Effects of increasing salinity stress on final germination percentage (FGP), germination rate (GR), clipping yield dry weight (CYD), verdure dry weight (VD), root dry weight (RD), and the longest root length (LRL) were evaluated for nine experimental lines of greens-type P. annua, two cultivars of Kentucky bluegrass (P. pratensis L.), three cultivars of creeping bentgrass (Agrostis stolonifera L.), and one cultivar of perennial ryegrass (Lolium perenne L.). Generally, FGP, GR, CYD, VD, and RD declined with increasing salinity; LRL increased at lower salinity levels but decreased at higher levels. Perennial ryegrass 'Charger II' and creeping bentgrass 'Mariner' exhibited the most salinity tolerance while Kentucky bluegrass cultivars exhibited the least. Salinity tolerance of greens-type P. annua was intermediate; however, some experimental lines exhibited nearly equal salinity tolerance to that of Mariner. Our data suggest greens-type P. annua possesses moderate to good salinity tolerance during seed germination and vegetative growth relative to other cool-season turfgrass species and has potential to be used on golf courses with moderate salt problems affecting turf establishment and maintenance.

Current literature suggests Poa annua L. (annual bluegrass) is intolerant to salinity stress. Response of greens-type Poa annua to chronic salinity stress (12 wk at 8.0 dS [m.sup.-1]) was evaluated over two greenhouse experiments. Vegetative samples of 33 greens-type P. annua experimental lines were maintained at a 6.4-mm mowing height and irrigated daily with modified Hoagland's solutions possessing salinity levels of 0.7 dS [m.sup.-1] (nonsaline control) or 8.0 dS [m.sup.-1] (NaCI treatment, approaching 0.25 strength sea water, approx. 13.5 dS [m.sup.-1]). Clipping yield dry weight (CYD) and leaf water content (LWC) were measured weekly. Digital images were collected at the end of weeks 1, 4, 8, and 12 to determine percentage cover (PC) and dark green color index (DGCI). Across all lines, all sample dates, and both experiments, salinity stress significantly reduced PC (30.8%), DGCI (9.3%), CYD (33.9%), and LWC (3.3%) compared with nonsaline controls ([alpha] = 0.05), suggesting chronic salinity stress is detrimental to greens-type P. annua quality. However, significant differences in relative PC and relative CYD were observed among lines, indicating that substantial variation in salinity tolerance exists in greens-type P. annua. Numerous greens-types P. annua experimental lines, such as PSU 99-9-21, PSU 01-1-46, and PSU 05-1-14, possess moderate-to-good salinity tolerance and are potentially suitable for use on golf courses with moderate salt problems.

Seed germination and vegetative growth studies were conducted to determine relative salinity tolerance of greens-type Poa annua L. compared with other cool-season turfgrass species. Effects of increasing salinity stress on final germination percentage (FGP), germination rate (GR), clipping yield dry weight (CYD), verdure dry weight (VD), root dry weight (RD), and the longest root length (LRL) were evaluated for nine experimental lines of greens-type P. annua, two cultivars of Kentucky bluegrass (P. pratensis L.), three cultivars of creeping bentgrass (Agrostis stolonifera L.), and one cultivar of perennial ryegrass (Lolium perenne L.). Generally, FGP, GR, CYD, VD, and RD declined with increasing salinity; LRL increased at lower salinity levels but decreased at higher levels. Perennial ryegrass 'Charger II' and creeping bentgrass 'Mariner' exhibited the most salinity tolerance while Kentucky bluegrass cultivars exhibited the least. Salinity tolerance of greens-type P. annua was intermediate; however, some experimental lines exhibited nearly equal salinity tolerance to that of Mariner. Our data suggest greens-type P. annua possesses moderate to good salinity tolerance during seed germination and vegetative growth relative to other cool-season turfgrass species and has potential to be used on golf courses with moderate salt problems affecting turf establishment and maintenance. [ABSTRACT FROM AUTHOR]