Establishing three warm-season turfgrasses with tailored water: I. Growth, cover, and nitrate leaching losses.

Although treated effluent is being increasingly used to irrigate mature turfgrass, information on its use to establish grass is limited. Greenhouse experiments were conducted in 2015 and 2017 to examine establishment and nitrate leaching from three warm-season grasses: buffalograss [Buchloe dactyloides (Natt.) Eng.] 'SWI 2000', inland saltgrass [Distichlis spicata (L.) Greene], and bermudagrass [Cynodon dactylon (L.) Pers.] 'Princess77'. All grasses were grown with tailored (tertiary treated effluent with 15 mg L-1 of NO3 -N) water. Grasses were established from seed in a loamy sand and irrigated with either tailored or potable water plus granular Ca(NO3 )2 fertilizer. Leachate collected at 10- and 30-cm depths was analyzed for NO3 -N and electrical conductivity. Overall, establishment was faster and coverage was greater in 2015 than in 2017, but neither differed between irrigation treatments when grasses were analyzed separately. At the end of both establishment periods, bermudagrass and buffalograss coverage was generally greater than that of inland saltgrass. In 2017, bermudagrass irrigated with tailored water resulted in greater coverage than buffalograss or inland saltgrass. In 2015, nitrate concentrations were greater in leachate collected from bermudagrass and inland saltgrass irrigated with tailored water than from grasses irrigated with potable water. Nitrate concentrations in leachate were generally lower in 2017, reaching a maximum value of 65.3 mg L-1 when averaged over all treatment combinations, and did not differ between treatments. Our data suggest that the three grasses studied can be successfully established from seed using tailored waters.

Establishing three warm-season turfgrasses with tailored water: II. Root development, nitrate accumulation in plant tissue and soil, and relationship with leaching.

Greenhouse experiments were conducted in 2015 and 2017 to assess the feasibility of establishing three warm-season grasses-buffalograss [Buchloe dactyloides (Natt.) Eng.] 'SWI 2000', inland saltgrass (Distichlis spicata L.), and bermudagrass (Cynodon dactylon L.) 'Princess77'-with tailored water (tertiary treated effluent with 15 mg L-1 of NO3 -N) and to examine the impact on nitrate accumulation in soils and plant tissue and on root development. Grasses were established from seed in a loamy sand and irrigated with either tailored or potable water plus granular Ca(NO3 )2 fertilizer. Leachate collected at 10- and 30-cm depths was analyzed for NO3 -N and electrical conductivity. Root samples were collected to measure root length density (RLD) and root surface area (RSA). Weekly clippings were collected to determine total clipping yield and measure N content. Generally, there was no difference in establishment, RLD, or RSA between the two irrigation treatments. Highest RLD values were reported for bermudagrass, followed by buffalograss and inland saltgrass. Correlation analyses suggest that nitrate levels in leachate were lower in faster-growing grasses and in grasses with more extensive root systems, compared with slower-growing grasses with less roots, regardless of fertilization treatment. Total N in clippings was highest in inland saltgrass and lower in buffalograss and bermudagrass, indicating that N was limiting for faster-growing grasses. More research is needed to determine optimal N rates for establishing grasses that both optimize growth and minimize nitrate leaching.

Plant uptake of depleted uranium from manure-amended and citrate treated soil.

Six plant species were tested for their ability to accumulate depleted uranium in their above-ground biomass from deployed munitions contaminated soil in New Mexico. In greenhouse experiments, Kochia (Kochia scoparia L. Schrad.) and pigweed (Amaranthus retroflexus L) were grown with steer manure added at rates of 22.4, 44.8, and 89.6 Mg ha(-1). Citric acid and glyphosate (N-(phosphonomethyl) glycine) applied at the end of the growing season increased DU concentrations from 2.5 to 17 times. Leaf and stem DU concentrations in kochia increased from 17.0 to 41.9 mg kg(-1) and from 3.5 to 18.0 mg kg(-1), respectively. In pigweed, leaf and stem DU concentrations increased from 1.0 to 17.3 and from 1.0 to 4.7 mg kg(-1), respectively. Manure generally decreased or had no effect on DU uptake. The effect of citric acid and ammonium citrate on DU uptake by kochia, sunflower (Helianthus annuus L), and sweet corn (Zea mays L) was also studied. Ammonium citrate was just as effective in enhancing DU uptake as citric acid. This implies that the citrate ion is more important in DU uptake and translocation than the solubilization of DU through acidification. In both experiments, leaves had higher DU concentrations than stems.