• Mepiquat Chloride Effects on Irrigated Cotton in Arizona

      Norton, E. J.; Silvertooh, J. C.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 2000)
      A series of experiments have been conducted from 1988 to 1999 at various locations across the cotton producing regions of Arizona to evaluate mepiquat chloride (MC) applications in terms of plant growth and yield. These experiments were designed to evaluate MC under three application regimes. These regimes included low rate multiple applications, late season applications, and a feedback vs. scheduled management of MC and nitrogen (N) applications. The objective of this summary (including a total of 31 site-years) is to determine which of these three application regimes offer the greatest opportunity for a positive lint yield response to MC. Stability analysis was conducted by regressing the treatment mean lint yield against the environmental mean for each application regime. Results from the stability analyses revealed that the most viable method of application is a feedback approach for both MC and fertilizer N. The most reliable technique associated with plant assessment in a feedback approach was the height to node ratio (HNR) to indicate vegetative tendencies for determining the appropriate rate and timing of MC applications.
    • The New U. S. - China Trade Agreement and Arizona Cotton

      Ayer, Harry; Frizvold, George; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 2000)
      Gaining greater access to export markets, particularly Asian markets, is important to Arizona cotton producers. Over 80 percent of Arizona’s cotton shipments are exports, roughly double the U.S. average. Asian countries typically account for half of world cotton imports. Relative to the rest of the United States, Arizona (along with California) has a location advantage supplying these markets. In November 1999 the United States and China signed a trade agreement to reduce China’s trade barriers and win U.S. support for China’s entry into the World Trade Organization (WTO). According to recent USDA projections, the agreement would increase China’s net cotton imports by $359 million when fully implemented in 2005 and by $328 million per year between 2000-09. Political uncertainty surrounds the timing of China’s accession to the WTO, however, and China’s return to cotton net-importer status could be delayed by Chinese policies to draw down their large accumulation of cotton stocks.
    • Johnsongrass Control in Cotton with BAS 620

      Clay, P. A.; Isom, L. D.; Silvertooth, Jeff; University of Arizona Cooperative Extension (College of Agriculture, University of Arizona (Tucson, AZ), 2000)
      Johnsongrass control with BAS 620 was 60% and 67% for the 0.124 and 0.248 lb ai/A rates respectively, 14 d after initial application. Control was comparable to Select at the corresponding rates. Control 28 d after the second application of graminicides ranged from 60% to 88%. Both rates of BAS 620 and Select as well as Fusilade DX provided the most effective control. Seed cotton yields ranged from 1347 to 3134 lbs/A and all herbicide treatments yielded significantly greater than the nontreated check.
    • Upland Cotton Regional Variety Trial

      Moser, H.; Hart, G.; Clark, L.; Silvertooth, Jeff; University of Arizona Cooperative Extension (College of Agriculture, University of Arizona (Tucson, AZ), 2000)
      Each year the University of Arizona conducts upland cotton variety tests to evaluate the performance of a diverse set of experimental lines and commercial varieties in Arizona. One such program is the Regional Variety Test (RVT). In 1999, we evaluated a total of 59 varieties at one or more locations in Arizona. These varieties were submitted to us for testing by 16 private seed companies and two public breeding programs. This report presents the results of the trials conducted at Maricopa, Marana, and Safford.
    • Influence of Ironite and Phosphorus on Long and Short Cotton on the Safford Agricultural Center, 1999

      Clark, L. J.; Carpenter, E. W.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 2000)
      Ironite and phosphorus were applied to plots planted to long and short staple cotton to find their effect on crop development and lint yield. The soil analysis indicated sufficient iron and phosphorous in the soil for cotton production and that yield increases from additions of these elements were unlikely. No statistically significant increases in lint yield were seen with the addition of Ironite nor phosphorous fertilizer. However, an interesting yield trend with ironite was seen in long staple cotton.
    • Evaluation of an Arid Soil Conditioner in an Irrigated Cotton Production System

      Norton, E. R.; Silvertooth, J. C.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 2000)
      A single field study was conducted on a sodium-affected soil at the University of Arizona’s Maricopa Agricultural Center (MAC) in 1999. Deltapine DP33B was dry planted and watered-up on 13 April 1999. Two treatments were evaluated; treatment 1 received no acid and treatment 2 received water-run acid applications. The acid used in this evaluation was sulfuric acid (H2SO4) and was applied at approximately 11 gallons acid/acre at each scheduled irrigation throughout the entire growing season. All other agronomic inputs and decisions were uniformly applied to both treatments. Lint yields were not significantly different.
    • Agronomic and Economic Evaluation of Ultra Narrow Row Cotton Production in Arizona in 1999

      Husman, S. H.; McCloskey, W. B.; Teegerstrom, T.; Clay, P. A.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 2000)
      An experiment was conducted at the University of Arizona Maricopa Agricultural Center, Maricopa, Arizona in 1999 to compare and evaluate agronomic and economic differences between Ultra Narrow Row (UNR) and conventional cotton row spacing systems with respect to yield, fiber quality, earliness potential, plant growth and development, and production costs. Row spacing was 10 and 40 inches for the UNR and conventional systems, respectively. Two varieties were evaluated within each row spacing, Sure Grow 747 (SG 747) and Delta Pine 429RR (DP 429RR). Lygus populations were extremely high in the Maricopa, Arizona region in 1999 which resulted in poor fruit retention from early through mid-season. As a result of poor boll load through mid-season, the UNR plots were irrigated and grown later into the season than desired along with the conventional cotton in order to set and develop a later season boll load. The mean lint yield averaged across row spacing was significantly greater (P=0.05) in the UNR row spacing at 1334 lb/A than for the conventional row spacing at 1213 lb/A. SG 747 produced 1426 and 1337lb/A of lint in the UNR and conventional systems, respectively. DP 429RR produced 1242 and 1089 lb/A of lint in the UNR and conventional systems respectively. Fiber grades were all 21 or 31 in both UNR and conventional systems. Micronaire was 4.9 or less in both varieties within the UNR system. Micronaire was high at 5.3 in the conventionally produced SG 747 resulting in discount but was acceptable at 4.7 in the conventionally produced DP 429RR. Length and strength measurements met base standards in all cotton variety and row spacing combinations. Neither the conventional or the UNR cotton production systems were profitable due primarily to high chemical insect control costs and early season boll loss. However, UNR production costs were lower by $0.09 per pound than in the conventional system on a cash cost basis and $0.14 per pound lower when considering total costs including variable and ownership costs.
    • Evaluation of a Feedback Approach to Nitrogen and Pix Applications, 1998 and 1999

      Norton, E. J.; Silvertooth, J. C.; Norton, E. R.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 2000)
      A single field experiment was conducted at Marana, AZ in 1988 and 1999 to evaluate a scheduled (based upon stage of growth) versus a feedback approach (based upon growth parameters and crop conditions) to nitrogen (N) and mepiquat chloride (PixTM) applications on Upland cotton (Gossypium hirsutum L.). The parameters used in the feedback applications for both N and Pix included fruit retention (FR) levels and height to node ratios (HNRs) with respect to established baselines for irrigated cotton grown in the desert Southwest. Treatments consisted of all combinations of feedback and scheduled applications of both N and Pix. In 1998, the highest lint yields occurred in the treatment consisting of Pix feedback and N feedback (treatment two) management. However, there were no significant differences (P≤0.05) among any of the treatments with respect to yield. In 1999, significant light yield increases (P<0.05) were found in the treatments consisting of Pix feedback and N feedback (treatment two), Pix scheduled and N scheduled (treatment three), and Pix scheduled and N scheduled (treatment five) management approaches.
    • Pima Cotton Regional Variety Trial, Safford Agricultural Center, 1999

      Clark, L. J.; Carpenter, E. W.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 2000)
      Thirty long staple varieties were tested in a replicated small plot trial on the Safford Agricultural Center in Graham county at an elevation of 2950 feet. The highest yielding variety in this study was Hazera 83-208 with a yield of 1272 pounds of lint per acre. This interspecific hybrid from Israel yielded nearly 300 pounds per acre more lint than the next closest variety. The average yield in the trial was lower than in the previous year’s study. Yield and other agronomic data as well as fiber quality data are contained in this paper.
    • Reduced Whitefly Infestations in Cotton Using a Melon Trap Crop

      Castle, S. J.; Silvertooth, Jeff; USDA, ARS, Western Cotton Research Lab (College of Agriculture, University of Arizona (Tucson, AZ), 2000)
      A second year of field experiments was completed in 1999 at MAC that explored the potential of using a melon trap crop to reduce whitefly infestations in cotton. The experimental design was altered from 1998 to gain isolation among treatment blocks by using 4 separate fields that helped to avoid the influence of one treatment upon the other. A consistent response of significantly fewer whiteflies in cotton planted within a surrounding melon trap crop, relative to the same area of cotton without the trap crop, was observed throughout the July- September sampling period. Better chemical management of whiteflies in the melons during the second season helped to reduce the large differential in whitefly densities between melons and cotton observed the previous year, but preferentially contributed to a greater differential observed between melonprotected cotton and unprotected cotton. Although the infestation buildup was delayed and the season-long densities of whiteflies in the melon-protected cotton were reduced, the action thresholds for treatment with IGRs were ultimately attained and exceeded. In the present management environment of perhaps only 1 IGR treatment per season, it is unlikely that the melon trap crop approach would provide acceptable control unless a grower was willing to tolerate lateseason whitefly densities higher than the current IPM recommendations.
    • How to Obtain Cotton Advisories from the Internet

      Brown, P.; Russell, B.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 2000)
      Weekly production advisories and weather updates are now available from the Internet. Nineteen location-specific advisories are developed each Monday morning and then transferred to the Main AZMET Internet Web Page located at URL address http://ag.arizona.edu/azmet. To retrieve advisories or updates from the Internet users must 1) log on to the Internet using the procedures required by your Internet service provider; 2) enter the URL for the Main AZMET Web Page; 3) move to the Cotton Advisory sub-page; and 4) select the advisory or update of interest. Advisories for the most recent week, this year to date, and all of 1999 are available at this Internet address.
    • Arizona Upland Cotton Variety Testing Program, 1999

      Moser, H.; Clark, L.; Husman, S.; Clay, P.; Silvertooth, J.; Silvertooth, Jeff; University of Arizona Cooperative Extension (College of Agriculture, University of Arizona (Tucson, AZ), 2000)
      Each year the University of Arizona conducts on-farm variety trials across the state to evaluate the performance of upland cotton varieties. These tests provide many segments of the industry with unbiased, independent data on the performance of varieties from several seed companies when tested side-by-side under typical production practices. Ten trials were planted in the cotton producing areas of the state, ranging from Wellton in Yuma county to Kansas Settlement in Cochise county. Seed companies entered a maximum of two varieties per location resulting in eight to thirteen commercially available varieties per test. The results show that many varieties performed well at several locations, indicating good adaptation to Arizona conditions.
    • The 2000 Arizona Cotton Advisory Program

      Brown, P.; Russell, B.; Silvertooth, J.; Ellsworth, P.; Olsen, M.; Husman, S.; Clark, L.; Schneider, M.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 2000)
      Arizona Cooperative Extension generates and distributes weather-based Planting Date and Cotton Development Advisories for 19 cotton production areas (Aguila, Buckeye, Cochise Co., Coolidge, Eloy, Greenlee Co., Harquahala, Laveen, Litchfield Pk., Marana, Maricopa, Mohave Valley, Paloma, Parker, Pinal Co., Queen Creek, Roll, Safford and Yuma Valley). Planting Date Advisories are distributed from legal first planting date until the end of April and provide updates on heat-unit-based planting windows, recent and forecasted weather conditions, heat unit accumulations, variety selection, soil temperatures, recommended plant population, and early insect management and control. Cotton Development Advisories are distributed from early May through early September and provide updates on crop development, insects, weather and agronomy. The Cotton Advisory Program will continue in 2000, and growers may obtain from the AZMET Internet Web Page (http://ag.arizona.edu/azmet) or by mail/fax from local extension offices.
    • Evaluation of Commerical Ultra Narrow Cotton Production in Arizona

      Clay, P. A.; Isom, L. D.; McCloskey, W. B.; Husman, S. H.; Silvertooth, Jeff; University of Arizona Cooperative Extension (College of Agriculture, University of Arizona (Tucson, AZ), 2000)
      Seven commercial ultra narrow row (UNR) cotton fields were monitored on a weekly basis in Maricopa County, AZ in 1999. Varieties of Delta Pine and Sure Grow were planted from April 15 to June 1 and reached cut-out after accumulating 1913 to 2327 heat units after planting. Average yield for UNR cotton was 2.1 bales per acre which was 0.4 bales per acre lower than the five year average for cotton planted on conventional row spacings. Fiber quality from gin records for 801 bales had average micronaire readings of 4.54 and grades of 11 and 21 for 74% of bales. Discounts for extraneous matter (bark, grass, and cracked seed) was 5.4% and average strength (34.8) and staple lengths (27.12) were in acceptable ranges. Total cash costs ranged from $450 to $705.
    • Nitrogen Management Experiments for Upland and Pima Cotton, 1999

      Silvertooth, J. C.; Norton, E. R.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 2000)
      Two field experiments were conducted in Arizona in 1999 at two locations (Maricopa and Marana). The Maricopa experiment has been conducted for nine consecutive seasons, the Marana site was initiated in 1994. The purposes of the experiments were to validate and refine nitrogen (N) fertilization recommendations for Upland cotton. The experiments each utilized N management tools such as pre-season soil tests for NO₃⁻-N, in-season plant tissue testing (petioles) for N fertility status, and crop monitoring to ascertain crop fruiting patterns and crop N needs. At each location, treatments varied from a conservative to a more aggressive approach of N management. Results at each location revealed a strong relationship between the crop fruit retention levels and N needs for the crop. This pattern was further reflected in final yield analysis as a response to the N fertilization regimes used. The higher, more aggressive, N application regimes did not benefit yields at any location. In 1999, fruit retention levels were low and crop vigor was high at the Maricopa site. As a result, even slight increases in N fertilization and crop vigor translated into lower yield.
    • Date of Planting by Long Staple and Short Staple Variety Trial, Stafford Agricultural Center, 1999

      Clark, L. J.; Carpenter, E. W.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 2000)
      Four varieties each of Long Staple and Short Staple cotton were tested over five and four dates of planting, respectively, in this study. The first date of planting for the Long Staple cotton was the 18th of March and for Short Staple cotton the 1st of April. The latest planting was May 13th. Cultivars of differing maturities were tested for both long and short staple cotton to determine their optimal planting time. Many agronomic parameters were evaluated to determine the effect of different planting dates
    • Planting Date Effects on Soil Temperature, Crop Growth, and Yield of Upland Cotton, 1999

      Silvertooth, J. C.; Norton, E. R.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 2000)
      A field study was conducted in 1999 at the University of Arizona Marana Agricultural Center (1,974 ft. elevation) to evaluate the effects of three planting dates on yield and crop development for eight Upland varieties. Soil temperature effects associated with date of planting and method of planting (dry or wet planting) were also evaluated in relation to soil temperature at the depth of seed placement. Planting dates ranged from 28 April to 20 May and 821-1157 heat units accumulated since Jan 1 (HU/Jan 1, 86/55o F thresholds). Lint yields generally declined with later dates of planting for all varieties. Soil temperatures associated with the dry planting method, which requires a water-up irrigation, experienced much wider diurnal variations, had slightly lower mean temperatures, and were more strongly coupled to ambient air conditions. Thus, dry planting methods impose more potential risk in terms of seedling stress. Overall, crop growth and development patterns or yield results were not significantly different between the planting methods. Either method can provide satisfactory results if managed appropriately.
    • Preliminary Investigations in Ultra-narrow Row Cotton, Safford Agricultural Center, 1999

      Clark, L. J.; Carpenter, E. W.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 2000)
      A preliminary investigation was made in Ultra-narrow row cotton production on the Safford Agricultural Center to see if there was any promise in that technology for cotton producers in the high deserts of Arizona. Increases in plant populations to near 100,000 plants per acre in single lines, double lines and quadruple lines per bed were the goals of the study. In-season plant mapping to evaluate differences in plant growth characteristics were done along with yield measurements to evaluate differences. Yield increases were not seen with increases in plant populations in single row plantings nor in multiple row plantings.
    • Pesticide Use in Arizona Cotton: Long-Term Trends and 1999 Data

      Agnew, G. E.; Baker, P. B.; Silvertooth, Jeff; Pesticide Information and Training Office (College of Agriculture, University of Arizona (Tucson, AZ), 2000)
      Arizona pesticide use, as reported on the Department of Agriculture's form 1080, can be summarized to provide a rich picture of pest management in Arizona cotton. Limitations in the pesticide use reporting system complicate the process but do not undermine results. Overall pesticide use decreased over the period 1991 to 1998 despite a peak during the whitefly infestation of 1995. Decreases in insecticide use are responsible for most of the reduction in pesticide use. Recently released 1999 data indicates that reductions continued. Comparison of the composition of pesticide applications between 1995 and 1998 reflect the changes in pest control efforts. A new "target pest" category on the 1080 provides an even richer picture of pest management practices in Arizona cotton.
    • Cotton Defoliation Evaluations, 1999

      Silvertooth, J. C.; Norton, E. R.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 2000)
      Two field experiments were conducted near Marana and Coolidge, AZ in 1999 to evaluate the effectiveness of a number of defoliation treatments on Upland (var. DP 33b and AP 6101) cotton. All treatments consisted of materials commercially available in Arizona. Results reinforce general recommendations regarding the use of low rates (relative to the label ranges) under warm weather conditions and increasing rates as temperatures cool. Defoliation treatments of Ginstar alone did a satisfactory job of defoliation and regrowth/topgrowth contol and were very similar to treatments including Prep or Integrate. Adding Prep or Integrate to Ginstar in this experiment did not improve defoliation or topgrowth control.