The salinity tolerance of golden barrel cactus (Echinocactus grusonii), ocotillo (Fouquieria splendens), saguaro cactus (Carnegiea gigantea), and Gentry’s agave (Agave parryi truncata) was tested. Plants were irrigated with a solution of EC 0.6, 5.0, 10.0, and 15.0 dS/m. Duration of treatments were 18 weeks for saguaro and 26 weeks for the other three species. In general, fresh weight, dry weight, and moisture content decreased with increasing salinity levels, with the exception of saguaro dry weight which was not affected by the treatments, and ocotillo moisture content which increased with increasing salinity. Runoff was collected three times during the experiment and indicated that ion uptake was higher for barrel cactus than the other three species. EC of runoff averaged for all dates and species showed an increase of 17%, 54%, 46%, and 64% over the salinity treatment solutions of 0.6, 5.0, 10.0, and 15.0 dS/m, respectively.

The long-term use of reclaimed water for landscape maintenance and the effects on soil chemistry and soil structure were investigated. Irrigation with reclaimed versus potable water for five years or more affects chemical properties of soil. Soils irrigated with reclaimed versus potable water had higher EC. Monsoon precipitation had less of a leaching effect than anticipated and significantly reduced EC only on two out of 13 sites. Soils irrigated with reclaimed water had higher SAR values than those irrigated with potable water and can potentially develop infiltration problems in the future. Contour maps of the EC for three depths of one site as measured by soil samples and EC as predicted by EM38 measurements for pre- and post-monsoon sampling times were developed.

Severe freezing temperatures during January 2007 caused temporary and permanent damage in several species of ornamental landscape plants. The damage was exacerbated by three consecutive nights of frost and freezing temperatures lasting between 7and 14 hours each day. Observations of frost damage and recovery in Phoenix and Tucson were recorded.

This study was conducted in a greenhouse, using hydroponics system, to compare growth responses of three cool-season turfgrass species, Creeping bentgrass (Agrostis stolonifera), Rough bluegrass (Poa trivialis), and Perennial ryegrass (Lolium sperenne) in terms of shoot and root lengths and dry matter (DM), and percent canopy green cover (%CGC) under salinity and drought stresses. Grasses were grown in Hoagland solution for 90 days prior to initiation of salinity or drought stresses. Then, 24 meq NaCl/L culture solution/day were added for each -0.1 MPa OP of salinity stress, or 75 and 119 g of PEG/L were added for -0.2 and -0.4 MPa OP of drought stress treatments, respectively. The treatments included control, -0.2 and -0.4 MPa OP salinity, -0.2 and -0.4 MPa OP drought stress. Four replications of each treatment were used in a RCB design experiment. During the stress period, grass shoots were clipped weekly for DM production, shoot and root lengths were measured, and %CGC was evaluated. The weekly clippings and the roots at the last harvest were oven dried at 60° C and DM weights were recorded. All 3 grass species were more severely affected by drought than salinity. Bluegrass was the most and bentgrass the least severely affected by either drought or salinity stress.

Various saltgrass (Distichlis spicata) clones were studied in a greenhouse to evaluate their growth responses in terms of shoot and root lengths and shoot and root dry matter (DM) weights under salt stress. Plants were grown hydroponically using Hoagland solution No. 1. Treatments included control plants and plants grown with salt (NaCl) at EC of 20 dSm⁻¹. Twelve different clones were grown with four replications of each variety. Plants were grown in a randomized complete block (RCB) design. Plant shoots (clippings) were harvested weekly, oven-dried at 60° C and DM weights were recorded. At the last harvest, plant roots were also harvested, oven-dried at 60°C and DM weights were determined and recorded. The results show increased shoot length in control plants, increased root length in most of the plants grown in saline conditions, greater shoot dry weight in control plants and greater root dry weight in saline plants. All results for shoots are based on a weekly average for six weeks and for roots are based on an average of the four replicated clones at the end of the study.

Seashore Paspalum (Paspalum vaginatum) is a warm-season halophyte with excellent salt tolerance after establishment. In areas which require overseeding, there is a need for a cool-season counterpart suitable for over-seeding. The goal of this field research is to evaluate a year-round turfgrass system for saline conditions using perennial ryegrass (Lolium perenne), alkaligrass (Puccinellia distans), and a combination of perennial ryegrass and Puccinellia as the cool-season grasses. In the summer months, paspalum quality and density were reduced when overseeded with ryegrass or with a combination of puccinellia and ryegrass. Ryegrass quality and density decreased slightly as irrigation water salinity was increased from 0 to 3000 to 6000 mg/L. In addition, the percentage of cover by overseeded ryegrass decreased significantly when 6000 mg/L irrigation water was applied. Puccinellia was much more sensitive to salinity than ryegrass and overall quality, turf density, and percent cover by puccinellia were greatly reduced by addition of salt. However, in the absence of added salt, puccinellia quality, percent cover, density, and color were generally greater than that of ryegrass. The puccinellia/ryegrass overseed mixture generally performed intermediate relative to either grass alone.

Application of Certainty*, Manor*, Monument*, Revolver*, TranXit, Kerb*, and flazasulfuron in early June eliminated most ryegrass in one month with the onset of high summer temperatures. Certainty at 0.06 lb a.i./A, Manor at 0.012 lb a.i./A, Monument at 0.0047 lb a.i./A, Revolver at 0.008 lb a.i./A, TranXit at 0.0078 lb a.i./A, and flazasulfuron at 0.0039 lb a.i./A performed equivalent to higher rates to effectively remove ryegrass when applied in June. The herbicides at the lower rate range were not as effective in early May when ryegrass tended to regrow in cooler temperatures. Spring transition was achieved by applying higher rates of TranXit* at 0.031 lb a.i./A and flazasulfuron at 0.0156 lb a.i./A in early May to completely remove perennial ryegrass. Kerb at 1.0 lb a.i./A was effective in removing 80% of the ryegrass with a May application and 90% in June.

Thirteen herbicide treatments were applied on May 8, 2006, on a golf course fairway to assess transition and turf quality effects. Initial injury to perennial ryegrass was most extreme for Tranxit GTA when applied at 1.0 oz/prod/acre and Katana applied at 2.0 oz/prod/acre. Katana resulted in the total elimination of ryegrass and resulted in a fully necrotic canopy (straw cover) within two weeks after application to July 19, 2006 (72 Days after treatment). The development and persistence of necrotic leaf tissue of perennial ryegrass (straw) had the greatest impact on decreasing overall turfgrass quality ratings. No treatment went through the summer without some loss of quality at some point, including the untreated control. Certainty had little or no effect on transition when applied once at the rate of 1.25 oz/prod/acre. Surflan was not effective in ryegrass transition. The tank mix of Transit and nicosulfuron applied at the rate of 0.25 oz/prod./A each, produced an enhanced transition with nominal quality. In similar fashion, Monument applied at 0.35 oz./A produced an enhanced transition with nominal quality. A rates used in this test, other treatments had either too slow of a transition or had poor and extended low quality turf scores from rapid development of dead ryegrass (straw) and subsequent slow bermudagrass re-establishment. The UTC turf maintained a high percentage of living green ryegrass into the summer and 20% live ryegrass on August 8, 2006 which is roughly six weeks before the next overseeding.

Ethofumesate as an emulsifiable concentrate (EC) formulation (Prograss*) demonstrated slightly more activity against Poa annua, though not statistically significant, than the suspension concentrate (SC) herbicide (PoaConstrictor*). Following two applications, P. annua control was equivalent for Prograss at 0.75 lb a.i./A and PoaConstrictor at 1.0 lb a.i./A at approximately one month later. Late season evaluations showed that Prograss at one-half the rate of PoaConstrictor gave acceptable P. annua control. Both products needed to be applied two times at 2.0 lb a.i./A to achieve better than acceptable P. annua control as spring transition occurred.

Velocity* at 20 g a.i./A provided P. annua control better than at 10 g a.i./A. Velocity at 20 or 30 g a.i./A offered similar P. annua control with a single application. Velocity at 20 g a.i./A with the addition of non-ionic surfactant Latron CS-7* or Primo*, P. annua control was almost similar to that of Prograss* at 80%. Velocity at 10 g a.i./A combinations or at 20 g a.i./A without additives gave less than 75% control.