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.

Irrigation has been proposed as a possible disposal method for large quantities of water having high concentrations of Mo (5-100 mg -1) resulting from mining and reclamation activities. To assess this possibility, laboratory and greenhouse experiments were conducted to evaluate the influence of competing ions in the soil solution on the relationship between the sorption of Mo by soils and Mo uptake by grass. Laboratory experiments assessed Mo sorption by Edroy clay (Vertic Haplaquoll), Olmos loamy sand (Petrocaicic Calciustoll), and Randado sandy loam (Ustoilic Paleargid). Soil treatments included 1, 5, 10, 20, 50, and 100 mg Mo L -1 added as ammonium molybdate in solutions of 0, 167, 333, and 500 mg L -1 concentrations of CI-and 0, 226, 451, and 677 mg L -t concentrations of SOl" salts. Sorption data fit the Freundlich isotherm. The Olmos soil had the highest CaCO3 content and sorbed the most Mo. The Edroy soil had the lowest pH and sorbed the least Mo. The presence of Ci-in solution increased Mo sorption, while SOl-reduced Mo sorption in all three soils. In the greenhouse study, soils were treated with 0, 6.5, 13.0, and 26.0 mg Mo kg -t soil; 167, 334, and 501 mg CI kg -~ soil; and cropped with bermudagrass, Cynodon dactyion (L.) Pets. No toxic symptoms or yield decreases were noted as a result of Mo or salt additions. Plants grown in soil containing 26.0 mg Mo kg -~ accumulated up to 600 mg Mo kg -~ dry matter and would be toxic to ruminants. The Mo concentrations in grass grown on the three soils were ranked from highest to lowest as Edroy > Randado > Olmos. Chloride addition to the soil had no significant (P <0.05) effect bermudagrass Mo content. Both the concentration of Mo in the vegetation and the amount of Mo taken up by the vegetative cover were well correlated (r~ = 0.73 and 0.83, respectively) with the equilibrium solution Mo in the soil as calculated from the sorption isotherms. Thus, the results indicate that there is a strong relationship between the laboratory sorption data and the equilibrium solution Mo in the soil and that grass grown on soil irrigated with waters high in Mo may reach levels that are expected to be toxic to animals. Additional index words: Freundilch isotherm, Chloride, Sulfate, Bermudagrass, Cynodon dactylon (L.) Pets.

Present industrial uses of Co result in elevated metal concentrations in soils around industrial activities and land treatment facilities. Laboratory and greenhouse studies were conducted to determine Co uptake by tall fescue (Festuca arundinaceaSchreb.) as affected by soils, Co levels, lime additions, Mn additions, and soil layering. In a laboratory sorption study using solutions containing 5 to 1000 mg Co L−1, the Marietta (Aquentic Dystrochrepts) and Norwood (Typic Udifluvent) soils had sorption maxima of 1440 and 3787 mg Co kg−1, respectively. The higher sorption of the Norwood soil was presumably due to the formation of complexes or precipitates between the CaCO3and Co. Addition of up to 6.7 Mg lime ha−1resulted in decreased concentrations of Co in tall fescue grown in soils containing 400 mg Co kg−1. Addition of 50 to 2000 mg MnO2kg−1soil had no effect on Co accumulation by tall fescue. Layering of uncontaminated soil over Co‐amended soil increased plant uptake of Co over that taken up by plants grown in Co‐amended soil alone. Apparently, the healthy roots in the upper layers of soil removed Co from the lower layers of soil; whereas, elevated Co in the total soil volume retarded root development sufficiently to prevent Co uptake. Total Co determinations were as good as or better than any of the three extractants (2.5% acetic acid, 0.01 MEDTA [ethylenediamine tetracetic acid] and DTPA‐TEA [diethylenetriamine pentacetic acidtriethanolamine]) in predicting plant accumulation of Co. Of the tested extractants, acetic acid had the lowest correlation coefficient when compared with plant Co accumulation.

Background: Increasing nitrogen (N) plant uptake efficiency may result in better plant quality and growth, less N susceptible to leaching and potential contamination to surrounding environments. Soil surfactants have been documented to increase water infiltration and enhance water uniformity throughout the soil profile. Thus, applying a surfactant may increase N uptake and use efficiency. Methods: To investigate this theory, four treatments were applied to bermudagrass grown in leaching columns filled with one of three soils (sand, sandy loam, and sandy clay loam): (1) 10% alkoxylated polyols and 7% of glucoethers surfactant with 15N labeled urea, (2) 10% oleic acid esters of block copolymer surfactant with 15N labeled urea, (3) water with 15N labeled urea, and (4) water without 15N labeled urea. Ambient 15N was determined by the no surfactant and no urea treatment. Each treatment combination was replicated five times and the greenhouse experiment was repeated. Bermudagrass quality and density, leachate volume, and volumetric water content were determined over a 28d period following application. Determination of 15N recovery in plant, soil, and leachate occurred at experiment termination. Results: Applying either surfactant with urea resulted in significantly higher soil volumetric water content (in sandy loam and sandy clay loam soils) and higher bermudagrass clipping yield (in all soils) than urea. Surfactants applied with urea decreased percent 15N recovery in leachate from sand by 37–46%, increased percent 15N recovery in the sandy loam by 37%, and increased percent utilization of 15N by bermudagrass grown in the sandy clay loam by 61–67% compared to urea applied alone. Conclusion: Applying surfactants with urea can increase bermudagrass N uptake efficiency and reduce potential N leaching.

Fresh mine spoil is virtually devoid of organic matter (OM) and N. The needed N is commonly added as inorganic fertilizer; however, sewage sludge additions could supply both OM and N. This study was conducted to compare the mineralizable N resulting from inorganic fertilizer and sludge applications to overburden. Nitrogen mineralization potentials were determined from laboratory data on a pre‐mined native soil (Elmina fine sandy loam) and 4‐yr old reclaimed mixed overburden that received 180 kg N ha−1 yr−1 as NH4NO3 using the Stanford and Smith model (1972). In addition, the effect of anaerobically digested sewage sludge (sludge) on N‐mineralization potential of overburden was evaluated on samples collected from field plots. Treatments were as follows: 0 kg N ha−1, 212 kg N ha−1 as NH4NO3, 106 kg N ha−1 as NH4NO3 plus 106 kg N ha−1 as sludge, and 212 kg N ha−1 as sludge applied to 13.8 m2 plots of overburden. Soil and spoil samples (0–15 cm deep) were collected from these plots 2 weeks, 26 weeks, and 52 weeks after amendment. Mineralization rates were determined using columns containing 0.2 kg of soil or treated overburden plus 0.1 kg of sand which were incubated for 18 weeks at 35°C. These columns were leached with saturated CaSO4 and a N‐free nutrient solution at 0, 2, 6, 10, 14, and 18 weeks and were extracted to a tension of −0.066 MPa after each leaching. The leachate was analyzed for NH+4 and NO‐3 by colorimetric methods. Application of 56 Mg sludge ha−1 significantly (α = 0.05) increased the total N 26 and 52 weeks after application to levels present in the 4‐yr old mineral fertilized reclaimed spoil. Sludge application also resulted in a sustained release of plant available N for 52 weeks after application. Mineralization potentials 2 weeks after the plots were treated were ranked as unamended overburden = NH4NO3 treated overburden < native spoil = 4‐year old reclaimed overburden < NH4NO3 plus sludge treated overburden < sludge treated overburden.