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Historically, white clover (Trifolium repens) seed was included in turfgrass seed mixtures to provide biodiversity and nitrogen (N) to lawns. White clover dicultures have been studied recently for inclusion in both warm- and cool-season turfgrasses, with the goals of reducing fertilizer applications and providing pollinator forage in lawns; however, other clovers have not been as widely researched in turfgrass. The objectives of this study were to evaluate 1) if white, strawberry (T. fragiferum), crimson (T. incarnatum), and rose (T. hirtum) clovers can persist in dicultures with Kentucky bluegrass (Poa pratensis); 2) if clover inclusion in dicultures impacts broadleaf weed cover; and 3) if low levels of N fertilization impact clover persistence or quality of clover–bluegrass dicultures. Kentucky bluegrass was grown as a monoculture or as a diculture with each of the four clover species. Each mono- or diculture was then treated with a low rate of N fertilizer (48.8 kg⋅ha–1 N) or no N fertilizer to determine quality and percentage of grass, clover, or weed and bare-soil cover. Dicultures contained similar or less weed and bare-soil cover, and maintained similar or greater quality compared with bluegrass monocultures, indicating clover and Kentucky bluegrass dicultures are suitable alternatives to Kentucky bluegrass monoculture lawns, and can potentially lead to reduced fertilizer and pesticide requirements. Fertilizer generally had no effect on cover, likely because of the low rates of N applied.
Fruit quality, storage potential, and consumer acceptance were evaluated for `Elegant Lady' peach fruit from non-conventional and conventional fertilizer management systems. Conventional treatments were fertilized with synthetic sources of nitrogen (ammonium nitrate), while the non-conventional plots received organic sources of nitrogen such as vetch cover, biosolids compost, grass compost, chicken manure, or steer manure. Fertilization treatments were applied at high (300 N unit per acre) and low rates (100 N unit/acre) 2 years before the first postharvest evaluation. Evaluations were carried out for three seasons. There were no significant differences in fruit firmness (N) measured at different fruit positions, soluble solids concentration (%), pH, titratable acidity (% malic acid), water loss susceptibility (%), rate of softening, red color (%), or inking incidence. The incidence of flesh browning, mealiness, and flesh bleeding was only related to storage time and not to the fertilizer source. Therefore, the storage potential was not affected by the nitrogen fertilizer source. In our in-store consumer preference test during the 1995 season, 950 consumers did not perceive any taste differences between fruit from the different nitrogen fertilizer sources. Despite this, consumers still would prefer to buy fruit produced using an organic source of nitrogen rather than synthetic sources.
Broad concerns over water shortages and drought where irrigated urban landscapes are common in high desert regions have focused attention on drought tolerance of turfgrass species. We investigated the physiological responses of kentucky bluegrass (KBG) and tall fescue (TF) under a prolonged drought under high desert conditions. The experimental design was a split plot with three replicates. Two irrigation treatments as a whole plot—well-watered and no water—were applied to subplots of ‘Midnight’ KBG and ‘Gazelle’ TF. Stomatal conductance (g S), canopy temperature, and predawn leaf water potential were measured over two seasons. KBG g S and leaf water potential decreased faster and to a greater extent than TF in response to soil drying, and KBG was in complete dormancy and brown within 5 weeks after cessation of irrigation. By contrast, TF maintained a green canopy throughout the drought periods. In the no-water plots, TF appeared to consume water from the deepest measured soil profiles (80- to 100-cm depth), whereas KBG used most of the water in the 50- to 60-cm depths. When watered for recovery in late summer, KBG plots were mostly green within 3 weeks after rewatering. The surface temperature of the well-watered plots was 6–13 °C cooler than the no-water plots and TF showed 5–7 °C lower temperature than KBG in no-water plots. TF is suitable for deep soil, exploiting a larger volume of water to avoid drought, whereas KBG's rapid drought avoidance would likely perform better in shallow landscape soils under drought.
The ongoing drought in the Intermountain West has brought a great deal of attention to water conservation over the past several years. During that time, turfgrass irrigation has been targeted as a source for large potential water savings. Some communities promote downsizing turfgrass areas as the best water conservation measure. In reality, turfgrass controls erosion, reduces evaporation from a site, and provides a safe surface for human activities. One alternative to elimination would be wider use of low water-use-grasses appropriate to the area. However, many questions arise regarding the choice of such grasses and their management. Our research addresses these questions. Plots have been established at Montana State University, Bozeman; Utah State University, Logan; and USDA-NRCS Plant Materials Center, Bridger, Mo. The grasses considered include 12 single species and 12 mixed species stands of `Cody' buffalograss, `Foothills' Canada bluegrass, `Bad River' blue grama, sheep fescue, sandberg bluegrass, muttongrass, and wheatgrasses `Sodar' streambank, `Road Crest' crested, `Rosana' western, and `Critana' thickspike with Kentucky bluegrass and tall fescue as controls. Line source irrigation allowed the plots to be evaluated at a number of levels of irrigation. Experimental measurements on the plots included growth response as determined by clipping yield and quality ratings, and species composition. Fescues and wheatgrasses retained their color, texture, and density throughout the growing season, regardless of moisture level. Warm-season grasses performed well in June, July, and August only, and worked poorly in mixtures as the green cool-season grasses could not mask the brown dormant leaves in cooler weather.
Abstract
Three auxins (4-amino-3,5,6-trichloropyridine-2-carboxylic acid; 3,5,6-trichloropyridine-2-oxyacetic acid; and 4-chlorophenoxyacetic acid) and 2 inhibitors of ethylene biosynthesis (i.e., aminoethoxyvinylglycine and aminoxyacetic acid) have been shown to inhibit abscission of stem parts (buttons) from fruit of lemon (Citrus limon Burm. f.) stored in controlled ethylene (about 5 ppm) atmosheres. Freshly picked lemons were treated by dipping them in aqueous solutions containing 500 ppm Triton X-100 plus-or-minus additions and then were stored at a packing house for 13 days; the fruit then were color-stored and analyzed for evidence of button abscission. When the abscission inhibitors were tested in concentrations equal to or greater than commercial concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D) (2|0 ppm) and its isopropyl ester (250 ppm), only 4-amino-3,5,6-trichloropyridine-2-carboxylic acid (picloram) was found to be as effective in inhibiting button abscission. As little as 50 ppm picloram gave inhibition of abscission comparable to 250 ppm isopropyl ester of 2,4-D. All of the auxin inhibitors of button abscission including the free acid and isopropyl ester of 2,4-D delayed the degreening of fruit in the packing house. Triclopyr (3,5,6-trichloropyridine-2-oxyacetic acid) had the severest effect, picloram had a moderate effect, and the free base and isopropyl ester of 2,4-D had mild delaying effects on degreening. Aminoethoxyvinylglycine (200 ppm) and aminoxyacetic acid (1840 ppm) did not inhibit degreening.
Fruits from five mayhaw selections were harvested and frozen at –2 °C. Juice was extracted with a steamer and kept in storage at 5 °C until processing. Percent soluble solids, percent malic acid, initial pH, and color were then determined for postharvest characteristics. 550 mL juice was placed in a 2000-mL beaker and heated until boiling. Dry pectin mixed with a portion of the total sugar equivalent to 5–10 times the weight of the pectin was sprinkled into the boiling juice. Once pectin was in solution, the amount of sugar to obtain a ratio of ≈45 parts fruit: 55 parts sugar was added to the mixture. The mixture was cooked until the soluble solid reading reached 65% and then poured into jars to cool to room temperature. The five mayhaw jellies alone with one commercial apple and one commercial mayhaw were evaluated using a panel preference test. Evaluation was based on a scale from dislike extremely to like extremely. Preference scores indicated that mayhaw jellies were preferred to a commercially available apple jelly. There was a definite preference to deep red colored jellies. The specific varietal jellies were preferred to a commercially available mayhaw jelly.
With the exception of the undesirable characteristic of summer dormancy and the accompanying low aesthetic value, crested wheatgrass has many desirable characteristics in semiarid environments, making it a promising candidate for lower water use turf. Using a population of 27 half-sib families, this study characterized the underlying genetics of turf quality (based on a 1–9 rating scale) of crested wheatgrass and compared the performance of crested wheatgrass turf with traditional control cultivars (‘Cody’ buffalograss, ‘Gazelle’ tall fescue, ‘Manhattan 3’ perennial ryegrass, and ‘Midnight’ Kentucky bluegrass) over 2 years under space-planted conditions. Heritability estimates were generally high (h2 = 0.44 to 0.84) and suggested a strong additive genetic component for crested wheatgrass turf quality throughout the summer months. Genotypic correlations among the monthly turf quality scores were very high (greater than 0.90) indicating a strong commonality for the genetics underlying turf quality during any point in the growing season. Thus, a breeding program aimed at improving turf quality in this population of crested wheatgrass would stand a good chance for success. However, primarily as a result of summer dormancy, the crested wheatgrass turf performed poorly compared with the control cultivars during late spring and early summer. Turf quality scores in early July were ≈3 for the crested wheatgrass half-sib families compared with scores between 5 and 6 for the traditional turf species. Thus, crested wheatgrass, for the near future, will likely be a viable turf candidate only in situations in which turf aesthetics are secondary to a desire for low-input requiring species.
Although transplanted trees typically establish and grow without incident in frequently irrigated turfgrass, their performance in precisely irrigated turfgrass in an arid climate is not known. We investigated the effect of precision irrigation scheduling on growth and water relations of balled-and-burlapped littleleaf linden (Tilia cordata Mill. `Greenspire') planted in buffalograss (Buchloë dactyloides [Nutt.] Engelm. `Tatanka') and kentucky bluegrass (Poa pratensis L.). Over 2 years, trees in turfgrass were irrigated either by frequent replacement based on local reference evapotranspiration, or precision irrigated by estimating depletion of soil water to the point of incipient water stress for each turfgrass species. Predawn leaf water potential and stomatal conductance of trees were measured during first-year establishment, and predawn leaf water potential was measured during a mid-season water-deficit period during the second year. Trunk diameter growth and total tree leaf area were measured at the end of each year. Values of predawn leaf water potential and stomatal conductance of trees in precision-irrigated buffalograss were lower (–0.65 MPa, 25.3 mmol·m–2·s–1) than those of trees in the other treatments near the end of the first growing season. The longer interval between precision irrigations resulted in mild water stress, but was not manifested in growth differences among trees across treatments during the first season. During the water-deficit period of the second year, there was no evidence of stress among the trees regardless of treatment. At the end of the second season, total leaf area of trees grown in precision-irrigated kentucky bluegrass (1.10 ± 0.34 m2) was 46% of that of trees grown in buffalograss (2.39 ± 0.82 m2) that were irrigated frequently. Trunk diameter growth of trees in frequently irrigated kentucky bluegrass (1.91 ± 2.65 mm) was 29% of that of the trees grown in buffalograss (6.68 ± 1.68 mm), regardless of irrigation treatment, suggesting a competition effect from kentucky bluegrass. We conclude that frequent irrigation of balled-and-burlapped trees in turfgrass, particularly buffalograss, is more conducive to tree health during establishment than is maximizing the interval between turfgrass irrigation. Regardless of irrigation schedule, kentucky bluegrass appears to impact tree growth severely during establishment in an arid climate.
Management of agricultural irrigation water is extremely important as fresh water resources are being depleted on a global scale. In anticipation of regulatory restrictions, several greenhouse and nursery operations in New Jersey have implemented systems that disinfect and recycle their irrigation water. This study compared the disinfection methods at two greenhouses and three container nurseries, focusing on the qualitative and quantitative benefits of using chlorine gas, ultraviolet light, ozone, and copper for water disinfection. The data were collected during on-site visits where the growers were interviewed on camera. A cost analysis was performed, but the most efficient disinfection technique could not be determined due to the variability between businesses and various unquantifiable benefits of proactive water management recycling, such as improved plant health, decreased fungicide and fertilizer use, a cleaner operation, reduced runoff, reduced pressure on aquifers, and increased customer satisfaction. The investment and maintenance costs per hectare and 1000 L were calculated, which can be useful reference tools for growers. The net present value (NPV) of each disinfection system was calculated to analyze the profitability of the investments. All three container nurseries had positive NPV values and profitable investments, which improved with cost sharing from the National Resource Conservation Service. This information will be useful in the future as growers throughout the state, and country, may be required to deal with the stricter regulation of their irrigation runoff.