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The branched-chain amino acids (BCAA) leucine (L), isoleucine (IL), and valine (V) are synthesized in plants and are essential to growth in most organisms. These compounds can be absorbed by the plant when foliarly applied, but plant catabolism of BCAA is not completely understood. A recent study observed that BCAA applied in a 2:1:1 or 4:1:1 ratio (L:IL:V) increased creeping bentgrass (Agrostis stolonifera) shoot density compared with applications of equal urea nitrogen (N) at 3.03 lb/acre N. The present study investigated whether those increases could translate to a quicker establishment rate of creeping bentgrass grown from seed in standard greenhouse pots. The BCAA applications were compared with equal N applications using urea and a commercially available amino acid product. All N treatments were applied at 3.03 lb/acre N, per application and applied a total of four times on a 14-day interval starting 14 days after seeding. Measurements included final shoot density counts and root and shoot weights, as well as digital image analysis of percent green cover for each greenhouse pot every 7 days. No differences were observed after 70 days in shoot weight, or percent green cover between BCAA treatments and urea; however, BCAA 2:1:1 and 4:1:1 increased shoot density 21% and 30%, respectively, compared with urea, and were equal to the commercially available amino acid product. Applications of BCAA 4:1:1 also increased creeping bentgrass rooting weight by a factor of 7 compared with urea N.

Soil health and sustainable management practices have garnered much interest within the turfgrass industry. Among the many practices that enhance soil health and sustainability are applying soil additives to enhance soil biological activity and reducing nitrogen (N) inputs—complimentary practices. A two-year study was conducted to investigate if reduced N fertilizer rates applied with humic substances could provide comparable turfgrass quality as full N rates, and whether humic fertilizers would increase biological aspects of soil health (i.e., microbial biomass and activity). Treatments included synthetic fertilizer with black gypsum (SFBG), poly-coated humic-coated urea (PCHCU, two rates), urea + humic dispersing granules (HDG, two rates), urea, stabilized nitrogen, HDG, and a nontreated control. Reduced rates of N with humic substances maintained turfgrass quality and cover, and reduced clipping biomass compared to full N rates. There were no differences in soil physical and chemical properties besides soil sulfur (S) concentration. SFBG resulted in the highest soil S concentration. Fertilizer treatments had minimal effect on microbial biomass and other plant-available nutrients. However, PCHCU (full rate) increased potentially mineralizable carbon (PMC) and N (PMN) by 68% and 59%, respectively, compared to the nontreated control. Meanwhile SFBG and stabilized nitrogen also increased PMC and PMN by 77% and 50%, and 65% and 59%, respectively. Overall, applications of reduced N fertilizer rates with the addition of humic substances could be incorporated into a more sustainable and environmentally friendly turfgrass fertilizer program.

The center-of-origin of the grass and regions with similar climatic and edaphic conditions represent its optimum growth environments. Cool-season grasses, such as creeping bentgrass, and perennial ryegrass may be used in warmer climates, but the additional stress on the grass during high temperature periods results in the need for more frequent irrigation, and timely fungicide applications to prevent diseases than would be required to manage these species in their respective zones of adaptation. Kentucky bluegrass has excellent recuperative and reproductive capacity. Tall fescue (Festuca arundinacea Schreb.) is a cool-season bunch grass which is particularly well adapted to the transition zone of the US Creeping bentgrass is the principle cool-season grass used for high quality golf greens in temperate and sub-arctic climates. The turf-type buffalograsses were developed specifically for use as a low maintenance turf. Their aggressive vegetative growth habit makes them particularly well suited for use as an amenity turf for conservation and soil stabilization.

Athletic field playability and safety is a growing national concern, particularly at the high school sports level. Athletic field usage rates increase each year while field maintenance budgets are stagnant, if not reduced. Many municipal and high school athletic fields endure multiple practices and games per week, despite weather-related conditions detrimental to field integrity. For example, Friday night high school games cannot be rescheduled due to a past or pending rain event. Research is needed to improve current cultural practices and to maximize playability and safety of natural grass athletic fields, especially in reference to prolonging field surface integrity throughout the high school football season. The objective of this trial is to investigate the use of wetting agent products and application timings as part of a sand-capped natural grass athletic field management plan in preparation for a game event coinciding with a large rain event. Six products and three timings will be investigated to improve rootzone water content management

Athletic field playability and safety is a growing national concern, particularly at the high school sports level. Athletic field usage rates increase each year while field maintenance budgets are stagnant, if not reduced. Many municipal and high school athletic fields endure multiple practices and games per week, despite weather-related conditions detrimental to field integrity. For example, Friday night high school games cannot be rescheduled due to a past or pending rain event. Research is needed to improve current cultural practices and to maximize playability and safety of natural grass athletic fields, especially in reference to prolonging field surface integrity throughout the high school football season. The objective of this trial is to investigate the use of wetting agent products and application timings as part of a native soil natural grass athletic field management plan in preparation for a game event coinciding with a large rain event. Six products and three timings will be investigated to improve rootzone water content management.

Athletic field playability and safety is a growing national concern, particularly at the high school sports level. Athletic field usage rates increase each year while field maintenance budgets are stagnant, if not reduced. Research is needed on improving cultural practices to maximize playability and safety of natural grass athletic fields, especially in reference to prolonging field surface integrity throughout the extended high school football season. Many athletic fields endure multiple practices and games per week. Despite weather-related conditions detrimental to field integrity, Friday night games cannot be rescheduled and practice field availability is often lacking. The objective of this trial is to investigate the use of wetting agent products and application timings as part of a native soil natural grass athletic field management plan to improve rootzone water content management. Multiple types of wetting agents and two application timings/rates were tested to determine product methodology and efficacy.

Sand-based turfgrass root zones have limited nutrient retention and water-holding capacity. Peat moss often is used to offset these deficiencies, but peat moss decomposes. Biochar is a co-product of several biofuel production processes used to produce bio-oil. Biochar is stable and could have similar water and nutrient retention impacts as peat moss when mixed in sand-based turfgrass root zones. The objective of this research was to evaluate the efficacy ofbiochar as a sand-based root zone amendment. Water retention, water infiltration, creeping bentgrass (Agrostis stolonifera L.) rooting depth, and nutrient evaluation experiments were conducted on six sand and biochar root zone mixtures. At field capacity, sand-based media containing 25% (v/v) biochar retained 260 and 370% more water compared to media containing 5% biochar and a pure sand control, respectively. Saturated hydraulic conductivity (K sat ) of the root zones decreased as biochar concentrations increased. The rooting depth of bentgrass was reduced up to 46% at biochar concentrations >10%. Extracted pore water electrical conductivity and dissolved total organic carbon increased as biochar concentrations increased. Nitrogen leachingwas reduced as biochar concentrations increased. According to the results, biochar may improve water storage, reduce overall water use, and decrease N fertilizer applications in sand-based turfgrass ecosystems.

Research was conducted to evaluate the installation of an activated carbon (AC) layer to reduce pesticide leaching from sand-base constructed root zones. Soil profile columns included unamended pure sand (PS), sand amended with 10% vlv peat moss (PM), sand overlying a 3-cm layer ofAC (Ch-1), and sand overlying a 13-cm layer of sand mixed with the same amount of AC as that in the 3-cm layer (Ch-2). Soil profiles treatments included tebuconazole at 0.125 mg a.i. m -2 , ethoprophos at 300 mg a.i. m-2 and ethoprophos at 1500 mg a.i. m -2 . Total detected leachate from the PS was 52 and 80% of applied tebuconazole and ethoprophos, respectively. Both materials were detected at

Reduced-growth, glyphosate-resistant Kentucky bluegrass (Poa pratensis L.) has recently been developed. There has been no comparative analysis of the newly developed transgenic Kentucky bluegrass lines to conventional cultivars or tissue culture-derived lines to determine vegetative and flower characteristic differences and similarities. This study measured the vegetative and reproductive characteristics of the transgenic lines, tissue culture-derived control lines, and reference cultivars during 2004 and 2005, in Ames, IA. The study was conducted in a noncompetitive, nonmown, spaced plant setting. Data collection of vegetative characteristics included rhizome spread and total plant area. Data collection for flower characteristics included flower phenology and morphological characteristic measurements, including panicle length, number of spikelets per panicle, and flag leaf characteristics. Transgenic lines as a group exhibited 29 and 32% less rhizome spread than the reference cultivars and tissue culture-derived control lines, respectively, in 2004 and 37 and 40% less rhizome spread than reference cultivars and tissue culture-derived control lines, respectively, in 2005. Flower emergence times for all transgenic lines were comparable to their respective tissue culture-derived control lines and reference cultivars.

The stability of sand-based athletic fields is critical to maximizing playability and safety. The objective of this study was to assess the contributions of sand and plant factors to the surface stability of sports fields. In September 2000, Hallet mason sand (subround), Hallet concrete sand (subround, wide size range), Sidley Pro/Angle sand (angular), Bunker White sand (round), and a mixture of 85% Hallet mason sand + 15% soil (v/v) were filled into pre-excavated field plots. The plots were compacted using a plate compactor and consolidated naturally. Half of each plot was planted with washed sod and half seeded, both with 'Unique' Kentucky bluegrass (Poa pratensis L.). Angular sand in the root zones provided 10 to 47% higher cone penetration resistance than Hallet mason sand during the turf establishment. The cone resistances of Sidley Pro/Angle sand in established turf were 873.3 kPa for seeded and 976.8 kPa for sodded. Peak deceleration was positively correlated with organic matter content in the thatch/mat layer and soil moisture content. Traction could be used as a complement to the cone penetration method because both root biomass and organic matter content in the mat layer were positively correlated to the shear strength (R 2 = 0.55-0.72). The higher stability due to angular sand was still evident 4 yr after turfgrass establishment. Subround sand with particle-size distribution within the specified ranges of USGA specification should be avoided for construction or topdressing. Hallet concrete sand, with a high coefficient of uniformity, did not result in higher surface stability.

A field experiment was conducted to determine the optimal method for turfgrass revegetation at the new Incheon International Airport, Republic of Korea. The existing soil base was reclaimed sea sand dredged from the Yellow Sea. Ten different soil media main plots were created by treating the sand with combinations of mountain soil, chemical fertilizer [15–11–14 nitrogen–phosphorus–potassium (N–P–K)], peat moss, a wetting agent, pig manure, and composted pine bark. Subplots were established with five turfgrass treatments that included Zoysia japonica (ZJ), Z. sinica (ZS), Z. koreanna (ZK), cool‐season grass combination I (CSG I: Festuca arundinacea 30%, Poa pratensis 40%, and Lolium perenne 30%), and cool‐season grass combination II (CSG II: Festuca arundinacea 40%, L. perenne 20%, F. rubra 20%, and Puccinellia distans 20%). The highest percentage cover rate for all grass treatments occurred in sea sand treated with 5 cm of mountain soil plus 114 g m−2 of chemical fertilizer. Zoysia japonica had t...

Regrowth of leaf tissue after mowing is necessary to form photosynthetic leaf area required for CO2 assimilation and plant growth and development. Leaf tissue regrowth often is dependent on levels of reserve carbohydrates stored in leaf sheaths and leaf bases. The objective of this study was to quantify mowing injury by measuring levels of fructan, sucrose, glucose, and fructose and efficiency of photosystem II (PSII) in not-cut, rolled, single-cut, and double-cut creeping bentgrass (Agrostis stolonifera L.) grown in a greenhouse. Efficiency of PSII was reduced in double-cut grasses by as much as 9% compared with not-cut grasses. Fructan levels were reduced in single- and double-cut grasses compared with not-cut grasses by 52% and 45%, respectively, 36 h after mowing. Glucose levels were 31% lower in double-cut grasses compared with not-cut grasses. No differences were observed in sucrose and fructose levels among not-cut, rolled, single-cut, and double-cut grasses. Mowing transiently reduced fructan and glucose levels in mowed grasses. Duration of reduction of fructan levels, magnitude of reduction in glucose levels, and efficiency of PSII were greatest in double-cut grasses, suggesting that multiple cuttings may be more damaging to plant vigor than single cutting.

Scouting to determine soil water status throughout a golf course or large athletic field complex is quite time consuming and requires numerous observations to characterize variability across the site. The objective of this research was to evaluate the use of a ground-based remote sensing system to predict soil water content through partial least squares regression analysis of canopy reflectance data collected from perennial ryegrass [Lolium perenne L.) maintained at 12.7 mm and creeping bentgrass (Agrostis stolonifera L.) maintained at 6.3 mm during 2002 and 2003 on a Coland silty clay loam. Volumetric soil water at a 5 cm depth was measured by time domain reflectometry and was collected in conjunction with spectral radiance measurements obtained using a fiber optic spectrometer. Volumetric soil water content was best predicted with partial least squares regression analysis of of creeping bentgrass canopy reflectance data with a maximum r 2 of 0.64 (P < 0.001) 1 d before development of drought stress symptoms. Similar results were observed for canopy reflectance data collected from perennial ryegrass plots, indicating that this technology and method of data analysis may be useful in the development of automated turfgrass irrigation management systems.

Creeping bentgrass creates a dense, high-quality playing surface on golf courses, but it often encroaches adjacent areas of Kentucky bluegrass. Mesotrione can control creeping bentgrass in Kentucky bluegrass, but more information is needed regarding the effect of herbicide rate and number of applications on creeping bentgrass control and the impact to Kentucky bluegrass. Field experiments were conducted to determine the effect of application rate and number of applications on creeping bentgrass control. One application of mesotrione controlled 7 to 43% of creeping bentgrass in Kentucky bluegrass, and two applications of mesotrione controlled 39 to 88% as rates increased from 70 to 1,120 g ai/ha. Gaps present in the canopy after the creeping bentgrass died reduced overall turfgrass quality 2 to 6 wk after treatment (WAT) before recovering. These data indicate the capability of mesotrione to selectively control creeping bentgrass while providing excellent safety to Kentucky bluegrass. Nomenclature: Mesotrio...

Development of a remote sensing system that can reliably identify nutrient deficiencies may reduce time spent sampling turfgrass areas and allow for site-specific applications of fertilizers. The objectives of this research were to evaluate the use of a ground-based remote sensing system and partial least-squares (PLS) regression to predict the N concentration, biomass production, chlorophyll content, and visual quality of creeping bentgrass (Agrostis stolonifera L. 'Penncross') growing under varying N rates, and to compare PLS regression to other vegetative indices. The study consisted of three N treatments (0.0,12.2, and 24.4 kg ha -1 15 d -1 ) arranged in a randomized complete block design. Spectral radiance measurements were obtained from plots using a fiber-optic spectrometer to calculate vegetative indices. The PLS regression analysis yielded a strong relationship between actual and predicted N concentration of creeping bentgrass plant tissue during 2002 and 2003 (r 2 = 0.95 and 0.71 respectively). However, PLS regression failed to produce a prediction for the chlorophyll concentration. Regressing the normalized vegetation index (NDVI), Stress1 (R 706 /R 760 ), and Stress2 (R 706 /R 813 ) ratios against N concentration yielded better results in 2003 when there were distinct differences in N concentration between the N rates. These results indicate that the traditional vegetation indices like NDVI might be better suited for determining the relative N status of turfgrass plants when compared against a well-fertilized control. More research will be required to determine if the PLS regression analysis produces prediction models that are able to specifically identify a particular nutrient deficiency or plant stress, and how the results will vary between grass species.

Colonial bentgrass (Agrostis capillaris L.) is a cool-season grass, native to temperate Asia and Europe. It has good tolerance to low temperatures and partial shade and is well suited to golf course fairways and tees. Little information is available regarding levels and patterns of genetic variation among populations of colonial bentgrass, which would be useful for breeding programs. To study the genetic relationships among 27 colonial bentgrass accessions obtained from the US National Plant Germplasm System (NPGS), randomly amplified polymorphic DNA (RAPD) markers were scored and analyzed. Out of 80 primers screened, 16 were selected for further analysis, which yielded a total of 120 polymorphic bands used to differentiate the accessions. Dice's similarity coefficients for pair-wise comparisons ranged from 0.23 to 0.84 based on the RAPD data. Since there was no similarity coefficient value close to 1 between any two accessions, there was no apparent duplication among the sampled accessions. A dendrogram constructed on the basis of the Unweighted Pair Group Method with Arithmetic average (UPGMA) clustering algorithm clearly separated 26 of the accessions into three clusters with one accession distinct from the rest. The least similar pair of accessions was PI 204397 from Turkey and PI 628720 from Bulgaria, and the most similar pair was PI 509437 from Romania and PI 491264 from Finland. Clustering patterns based on principal components analysis (PCA) corresponded well with the dendrogram. A high cophenetic correlation (r = 0.82) was found between the RAPD data matrix and cophenetic matrix. The accession PI 628720, from Bulgaria, did not cluster with any other accessions.

Information on genetic variation in rough bluegrass (Poa trivialis L.), a cool-season grass that is grown for sports fields and lawns, is needed. The objective of this study was to assess genetic variation in 27 accessions of rough bluegrass obtained from the National Plant Germplasm System (NPGS) by random amplified polymorphic DNA (RAPD) markers. Fifteen of the 80 primers screened generated 64 highly repeatable polymorphic bands. A dendrogram constructed on the basis of the Unweighted Pair Group Method with Arithmetic Average (UPGMA) clustering algorithm revealed that 26 of 27 accessions formed two distinct clusters. Genetic similarity coefficients calculated from the RAPD data ranged from 0.07 to 0.74 with the lowest value of 0.07 measured between PI 254908, PI 594396, PI 250982, and PI 229782 from Iraq, the USA, Yugoslavia, and Iran, respectively. The highest value of 0.74 was measured between PI 225826, PI 289643, and PI 592521 from Denmark, Spain, and the USA, respectively. The cophenetic correlation coefficient (r) was 0.90, indicative of a very good fit between the data matrix and the resulting cluster analysis. Principal coordinate analysis (PCO) clearly grouped 26 accessions on the two axes, with a single accession that did not cluster with the others. The PCO clustering pattern corresponded well with the dendrogram. PI 254908 from Iraq did not cluster with any other accessions, either in the dendrogram or on the basis of the PCO.

Sand-based athletic fields and golf course greens may contain large amounts of CaCO 3 . Calcium is frequently applied to these areas based on the belief that the Ca within the CaCO 3 is not readily available for plant use. Our objectives were to determine if Ca applied to creeping bentgrass grown on calcareous sand increases Ca uptake, affects the clipping yield or quality of the grass plant, or affects the availability of other nutrients. A 2-yr field trial was initiated on a calcareous sand-based green established with 'Crenshaw' creeping bentgrass {Agrostis palustris Huds. [= Agrostis stolonifera var. palustris (Hods.) Farw.]}. Treatments included gypsum (CaSO 4 ), CaCO 3 , Ca nitrate j[a(NO 3 ) 2 -4H 2 O], and liquid Ca chelate applied across five months at 4.5 g Ca m -2 per month and an untreated control. Urea was added to balance the N found in the Ca(NO 3 ) 2 and Ca chelate treatments. Throughout the experiment, there were no differences in tissue Ca content, visual quality, or clipping yield in response to the Ca treatments. With the exception of the CaSO 4 treatment in 1999, application of Ca did not significantly affect the leaf concentrations of the other nutrients. During the first year, creeping bentgrass grown in plots receiving CaSO 4 contained 11% less tissue Mg than the creeping bentgrass in the control plots. Supplemental Ca applications to creeping bentgrass established on calcareous sand had no beneficial effects.

The number of herbicides available for use in strawberry (Fragaria×ananassa Duch.) production is limited. Corn gluten hydrolysate (CGH) is a water-soluble extract of corn gluten meal (CGM), a by-product of corn wet-milling. Both CGH and CGM have been shown to inhibit root development of seedlings and can provide nitrogen (N). Four weed control and/or N- containing products were studied: CGH, CGM, urea (46N-0P-0K), and urea applied with DCPA at 8.4 kg·ha-1 a.i. Treatments were applied at N rates of 0, 9.8, 19.5, and 29.3 g·m-2. The 0 g·m-2 of N treatment served as the control. During the 1995 establishment season, all treatments were applied in June, July, and August. Treatments were applied in July and August during the 1996, 1997, and 1998 growing seasons. Dicot and monocot weed number and weed shoot dry weights were determined ≈30 days after both July and August treatments. Strawberry yield data were collected in June. Leaf N data were collected during the first week of July, before renovation. When CGH was applied in July, dicot weed number in August decreased in one of four years, but CGH never affected the number of monocot weeds. CGM application in July, reduced the number of dicot weeds found in plots in Aug. 1995 and 1998. Urea had no effect on dicot weed number from 1995 to 1997. However, in 1998, dicot weed number was reduced by as much as 79% as the rate of urea increased. In all study years, dicot weed number was reduced between 86% and 97%, for the high rate of DCPA + urea, compared with control plots. With few exceptions, rate of N had no effect on leaf N or yield. CGH exhibited limited potential as a natural weed control product; it reduced dicot weed number in one year, but did not affect the number of monocot weeds in any year. Strawberry yield in plots receiving CGH showed a linear increase in one year (1998), but did not show an increase in the other 2 years. Chemical name used: dimethyl tetrachloroterephthalate (DCPA)

Annual grassy weeds often inhibit establishment of spring-seeded creeping bentgrass (Agrostis palustris Huds.) on golf courses. The objective of this experiment was to evaluate the safety of the annual grass herbicide quinclorac in spring-seeded creeping bentgrass in varying climatic regions of the United States. Experiments were initiated in Indiana, Iowa, and North Carolina in Spring 2000. Treatments included siduron at 6.72 kg·ha -1 a.i. applied immediately prior to planting (PRE), and quinclorac at 0.84 kg·ha -1 a.i. applied 7 days before seeding (DBS), PRE, and 14 or 28 days after emergence (DAE). Herbicides were applied to three creeping bentgrass cultivars at each location. Siduron reduced establishment of 'Providence', 'L93', and 'Putter' creeping bentgrass in Indiana. Quinclorac applied PRE, 14 DAE, and 28 DAE caused short-term phytotoxicity, primarily in 'Providence' in Indiana. Quinclorac applications did not significantly affect cover of 'Providence', 'L93', or 'Putter' in Indiana or 'L93', 'Pennlinks', or 'Penncross' in Iowa. All applications of quinclorac reduced cover of 'L93', 'Pennlinks', and 'Penncross' in North Carolina. Though quinclorac applications resulted in no long-term damage when applied to creeping bentgrass seedlings in Indiana or Iowa, results from North Carolina indicate that caution should be exercised when using quinclorac on seedlings of creeping bentgrass. Chemical names used: 3,7-dichloro-8-quinolinecarboxylic acid (quinclorac); 1-(2-methylcyclohexyl)-3-phenylurea (siduron). Creeping bentgrass is often seeded on golf courses during spring and early summer in new construction projects or after winter dam- age of existing turf. However, crabgrass (Digitaria spp.) often outcompetes creeping bentgrass seeded at this time of year. Siduron is labeled for use in creeping bentgrass and can be applied at time of seeding to effectively control crabgrass with little risk of damage to seedlings (Moshier et al., 1976). However, siduron has short residual activity and repeat applications are often needed for season-long crabgrass control. Other preemergence or postemergence herbicides labeled for use in cool-season turf have restrictions limiting use in seedling turf, on creeping bentgrass, or both. Quinclorac was labeled in 1998 for turfgrass use and has both preemergence and postemergence activity on large crabgrass (Digitaria sanguinalis L.) (Enache and Ilnicki, 1991) and provides control of a variety of broadleaf weeds including white clover (Trifolium reptans L.) (Neal, 1990). Label recommendations allow application of

The past few years have been difficult for rose growers in the Midwest region due to an increase in Japanese beetle (Popillia japonica) populations. Japanese beetles can cause damage to many different areas on the rose plant. Their first target is normally the rose bud, feeding on pollen. Damage appears as a small, round hole going through the side of the flower bud. Buds that are able to fully open are normally the next target. The damage to the flowers is a small hole in the flower petals. As beetle populations increase, and after the first bloom of the rose is finished, they begin to attack the foliage. Typical damage to the foliage ranges from small holes in the leaf to complete destruction, resulting in unattractive plants in the landscape. In recent years, because of the Japanese beetle problem, homeowners are eliminating roses from the landscape. An efficient way of getting rid of these pests is needed.

Inorganic soil amendments have been suggested for use in turf to alleviate soil compaction, increase water retention and hydraulic conductivity, and improve many other soil physical properties. The objectives of this study were to determine the effects of ceramic, porous ceramic clay (PCC), calcined diatomaceous earth (CDE), and polymer coated clay (PC) on the physical characteristics of sand-based media and to determine the effects of these amendments on bulk density following freeze-thaw treatments. Inorganic materials were added to a sand-based golf green at 10% on a volumetric basis during construction in 1996. Data collected from the field included saturated hydraulic conductivity (K sat ), water retention, water release curves, bulk density and total porosity on compacted samples collected at construction, and undisturbed samples collected from the treated plots 1 and 2 yr after establishment. The PCC treatment had an 8 and 7% higher cation-exchange capacity (CEC) than the control in 1997 and 1998, respectively. The PCC increased the K sat by 26 and 20% in the compacted and undisturbed samples, respectively, in 1998. The CDE increased water retention by 13% in both compacted and undisturbed samples. Saturated hydraulic conductivity of the sand-inorganic mixtures decreased in the 2 yr, although some increases in K sat were observed each spring. The K sat of plots receiving all inorganic amendments was reduced by 75% in November of 1998. The K sat values in the spring of 1999 increased from the low levels of 1998 by 19% (PC), 44% (control), 59% (ceramic), 72% (PCC), and 82% (CDE). The changes of K sat over the winter may have been induced by freezing and thawing. These changes may not necessarily be caused by total porosity increases; instead they may be caused by increases in macropores. This hypothesis was further tested in the laboratory in a freeze-thaw study conducted in 1999. The PC, control, CDE, and PCC decreased bulk density by 10.7, 7.2, 2.5, and 2.2%, respectively, following a freeze-thaw cycle.

Our objective was to investigate the movement of the dimethylamine salt of (2,4-dichlorophenoxy) acetic acid (2,4-D), dicamba, and 2-(2-methyl-4-chlorophenoxy) propionic acid (MCPP), when applied to Kentucky bluegrass turf under both infrequent and frequent irrigation regimes. The turfgrass was established on 50-cm length and 20-cm diameter undisturbed soil columns of Nicollet (fine-loamy, mixed, mesic-Aquic Hapludolls) with intact macropores. The infrequent irrigation regime consisted of four 2.54-cm applications, and the frequent regime consisted of 16 0.64-cm applications. On average, the amounts of 2,4-D, dicamba, and MCPP recovered from the soil columns, and in the leachate, under the infrequent irrigation regime were 3.0, 22.4, and 1.1%, respectively. The average amounts of 2,4-D, dicamba, and MCPP recovered from soil columns, and in the leachate, under the frequent irrigation regime were 3.2, 6.3, and 2.3%, respectively. Average values of 1.9, 21.8, and 0.7% of the applied 2,4-D, dicamba, and MCPP, respectively, were measured in the leachate from the soil columns under infrequent irrigation, in contrast to 0.1, 3.4, and 0.2%, respectively, from the soil columns under frequent irrigation. We concluded that the frequency of irrigation can have an impact on the movement of these herbicides through soil profiles.

Zoysiagrass is known for its slow rate of growth and for its ability to form a low growing turf with infrequent mowing. The objective of this study was to investigate the effects of mowing height on the regrowth potential, turf density, and morphology of Zoysia japonica £wild type'. Treatments included an unmowed control, and biweekly mowing at 5.1, 3.8, 2.5, and 1.3 cm. Shoot regrowth after mowing was greater for grass in plots mowed at 2.5 cm and higher than for grass mowed at 1.3 cm through the growing season. Lower mowing heights changed the morphology of the grass by reducing the leaf size, sheath length and also reduced the SiCb content of tissue. Turf density was improved by increased growth of rhizomes and stolons at the 5.1, 3.8, and 2.5 cm height. Shoot and root weight were increased by the 5,1 and 3.8 cm height as compared to the lower mowing heights and the unmowed plot. This research indicates thai Zoysia japonica ‘wild type’ should be mowed at 3.8 cm or higher for best performance u...