No description available.

No description available.

The Arizona Meteorological Network provides weather-based estimates of reference evapotranspiration (ETo) for much of southern, central and western Arizona. A simple 3-step procedure to convert ETo data into reliable estimates of turfgrass water use is described The procedure requires that AZMET ETo values be multiplied by a correction factor known as a crop coefficient (Kc). The selection of the Kc depends on the type and height of the turfgrass as well as desired turf quality. The procedure is well adapted for use on computers.

No description available.

Bermudagrass germplasm was evaluated for turfgrass color, quality, chlorosis symptoms, leaf texture and percent plot ground cover, in order to assess turf adaptation under desert conditions. Both experimental materials and commercially available germplasm were different for these traits during 1988, which was the second year's evaluation of a 5-year-long national trial for turf-type bermudagrass.

Secondarily treated wastewater is used extensively in the southwestern United States for turfgrass irrigation, but deterioration in soil quality can occur from sodium (Na) delivered by this water. Application of gypsum (CaSO₄2H₂O) at 2 240 kg ha⁻¹ yr⁻¹ is often recommended to control the Na. Research to determine if this rate is effective on effluent -irrigated turfgrass sites is lacking. A 2-yr study was carried out on a golf course fairway (typic tomf7uvent soil) with a 10 yr history of effluent irrigation and elevated Na levels (800 mg kg⁻¹). Four rates of gypsum (0, 2 240, 4 480, and 8 960 kg ha⁻¹) were surface applied in November 1986 and 1987. Soil samples were collected every 3 months after treatment (MAT) and analyzed for Ca (total and water - soluble (WSCa)), Mg, K, Na, SO₄⁻²-S (S), pH, and electrical conductivity (EC). Results showed elevated WSCa and S levels 3 and 6 MAT in both years. The two highest rates resulted in elevated S levels 12 MAT. During both years, gypsum at the two higher rates decreased Na levels within 3 MAT. The lowest application rate did not reduce Na levels until 12 MAT in 1987 and its effects were not as great. Following the second annual application, the 2 240 kg ha⁻¹ rate was as effective as the higher rates in reducing Na levels 6 and 12 MAT. Total Ca levels were not affected by gypsum but Mg and K levels did decrease. In both years, a temporary increase in EC and decrease in pH occurred after gypsum treatment. It appears that gypsum at 2 240 kg ha⁻¹yr⁻¹ can be as effective as higher application rates in reducing Na in effluent-irrigated turf soil but only after two applications.

Repeat sequential applications (1 - 4) of imazaquin herbicide were applied to 100% pure stands of purple nutsedge during the summer of 198& Treatments were applied every two weeks. Maximum suppression for plots receiving only one application was reached 1 month after application (25% control). Two 14-day sequential applications achieved 60% control 2 weeks after the second treatment. Both 3 and 4 sequential applications resulted in 88% and 92% control after 2 and 4 weeks from the third and fourth applications, respectively. Resprouting eventually reoccurred on all plots. This data shows the enhanced effect of repeat applications of imazaquin for purple nutsedge suppression.

A field test was implemented at Paradise Valley Country Club to investigate the effect of two rates of imazaquin (Image) herbicide (0.38 and 0.50 lbs ai /a) in both the granular (G) and emulsifiable concentrate formulation on purple nutsedge and common bermudagrass in a mixed stand (85 ± 20% nutsedge).

An experiment was devised to evaluate application technique, and elucidate the plant response (herbicidal activity) of imazaquin herbicide on single plants of purple nutsedge. Herbicide treated plants showed increased filleting and stunting 31 days after treatment. Soil treatments tended to increase herbicidal response. Imazaquin activity was minimized when the herbicide was not irrigated into the soil. Soil applied-imazaquin postponed the emergence of shoots from viable nutlets, but did not prevent emergence altogether.

A one-time application of MON1S1S1 or 0.5 lb. ai /a on September 1, 1988, was evaluated for potential overseeding effects. Treated plots, which were overseeded with perennial ryegrass at 10, 20, or 30 lbs. per thousand square feet, were not significantly different compared to untreated plots for percent ryegrass stand and verdure. Only seed rate effects increased percent ryegrass and verdure weights slightly. These data show no detrimental effects of using MON15151 ("Dimension" trade name) six weeks before overseeding.