The use of sandy rooting media with rapid infiltration rates in the construction of golf greens provides the potential for N pollution of nearby water supplies. This study was designed to measure the effects of different N sources on NO−3 and NH+4 concentrations in leachate and runoff from golf greens constructed with various rooting media. Individual golf greens with USGA‐type profiles were constructed in the field with upper 30 cm layers consisting of sand‐peat, sandsoil‐peat and sandy loam soil mixtures. All profiles were equipped with subsurface tile drains over a plastic sheet and were treated sequentially with the following N fertilizers: NH4NO4, ureaformaldehyde, 12‐12‐12, Milorganite, and IBDU. Leachate and runoff were collected and analyzed for NO−3 and NH+4. Nitrate concentrations in leachate from sand, mixed, and soil greens fertilized with quick release materials ranged from 45 to 326, 8 to 314 and 8 to 170 mg liter−1, respectively and remained in this range for a 3‐week period. Runoff concentrations from the greens constructed of sandy loam soil exceeded 30 mg liter−1. No runoff was collected from sand or mixed greens. Nitrate N losses from various sources were in the order of NH4NO3 > 12‐12‐12 > Milorganite > Isobutylenediurea (IBDU) > Ureaformaldehyde. lsobutylenediurea provided a very uniform release rate. Milorganite had a 25 to 30 day delay before NO−3 appeared in the leachate. Soluble sources, NH4NO3, and 12‐12‐12 exhibited leaching within 5 days after application. It appears that regular moderate applications of slow release N sources would provide minimum NO−3 loss while supplying a continuous N supply. Ammonium losses ranked from greatest to smallest were NH4NO3 > Ureaformaldehyde > Milorganite > 12‐12‐12 > IBDU. Ammonium losses contributed very little to the total N losses from golf greens. Highest total N loss was 23% of the applied N.

Because golf greens are constructed of very sandy soil mixtures over a gravel and tile drainage system and subjected to heavy irrigation schedules, there is a high potential for loss of applied N through leaching. This study was undertaken to determine the influence of management practices during different seasons on the fate of N applied to golf greens. Small isolated golf greens (3 m on a side) were constructed according to USGA specifications and equipped with drainage and runoff collection systems. Mixtures of sand and Houston black clay soil (Udic Pellusterts) were used in some plots while others were made of a Tabor sandy loam soil (Udertic Paleustales). All plots were planted with Tifdwarf Bermudagrass (Cynodon dactylon L). N sources were applied at various rates during different seasons. The golf greens were irrigated at three different rates. Leachate and runoff samples were analyzed for NO3 to evaluate the influence of management practices on N losses from the golf greens. The results show that N losses and concentrations of NO3 in the leachate immediately after application of soluble sources were a function of the rate of N and water applied. When the irrigation rate was kept at or near the evapotranspiration rate, the loss of NO3 from inorganic soluble sources was minimized. The irrigation rate did not affect the NO3 losses from organic sources. Seasonal studies indicated that losses and concentrations of NO3 were highest in winter. This appeared to be associated with the large volume of water which leached from the plots during the season. It was concluded that N losses and NO3 concentrations could be lowered by: using organic sources of N; reducing irrigation rates to equal the evapotranspiration rate; and decreasing fertilizer rates during periods of slow growth.

Chemical and in vitro characteristics of six perennial summer grasses {common, ‘Coastal’ and ‘Coastcross‐1’ bermudagrasses [Cynodon dactylon (L.) Pers.]; ‘Pensacola’ bahiagrass [Paspalum notatum Flugge]; common weeping lovegrass [Eragrostis curvula (Schrad.) Nees.]; and ‘Kleingrass 75’ [Panicum coloratum L.]} were determined to identify factors limiting the performance of grazing animals. In vitro dry‐matter digestibility (IVDMD), cell wall content (CWC), acid‐detergent fiber (ADF), acid‐detergent lignin (ADL), silica, and in vitro cell‐wall digestibility (IVCWD) were determined for samples of available forage taken at 14‐day intervals. Animal performance was obtained from yearling heifers grazing established stands of each grass. Available forage was estimated from strips harvested from each pasture at 2‐ to 4‐week intervals. Animal performance was significantly correlated (r = 0.85**) with available forage when dry‐matter digestibility was relatively uniform. As IVDMD of available forage decreased, more available forage was required to reach maximum average daily gain (ADG). Also, as IVDMD decreased, maximum ADG decreased. The CWC of the grasses ranged from 45 to 82% with cell wall digestibility ranging from 82 to 36%, respectively. CWC and IVDMD were significantly correlated with animal performance (r = —0.80**, and 0.78**, respectively). Cell wall digestibility calculated from Van Soest's “summative equation” significantly over‐estimated IVCWD. Lignification was one factor limiting cell wall digestibility (r = —0.76**) and in Coastcross‐1 bermudagrass and Pensacola bahiagrass silica was as important as lignin. CWC and IVCWD could be used to accurately predict IVDMD in Kleingrass 75 (r = —0.96** and 0.95** respectively). High lignin and/or silica content of available forage was associated with poor animal perfortnance on all grasses.

Large amounts of money are invested each year in the preparation of mixtures for the construction of golf greens and athletic fields. Few efforts have been made to completely characterize the physical properties of the resulting greens. Therefore, a greenhouse experiment was conducted to determine the physical characteristics of a range of sand and soil mixtures for golf green construction. Treatment variables included the amount and texture of soil used in the mixture and the presence or absence of a sand layer between the mixture and the gravel drainage layer. The mixtures were placed in 30 cm diam. containers. They were compacted and grass was established. Infiltration rates decreased after the grass was established and decreased again after the soil mixture was compacted. Mixtures with greater than 3% clay had infiltration rates too small to assure a playable surface after heavy water applications. The depth of available water held by mixtures with 5% soil averaged 6.6 cm for a 35 cm layer. Pure sands held about half this amount of water. Measured water retention agreed well with that calculated from the unsaturated conductivity of the gravel layer and the water retention characteristics of the mixture. Provided the gravel used as the drainage layer has a particle distribution such that less than half the particles are greater than 0.64 cm, little evidence of particle migration was found even without a layer of sand between the mixture and the gravel. Optimum physical characteristics were achieved with mixture containing 5% soil, 85% sand, and 10% peat moss by volume.

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