• Arizona Upland Cotton Variety Testing Program, 2001

      Husman, S.; Norton, R.; Norton, E.; Clay, P.; Clark, L.; Zerkoune, M.; White, K.; University of Arizona Cooperative Extension (College of Agriculture, University of Arizona (Tucson, AZ), 2002-06)
      Each year the University of Arizona conducts variety trials across the state to evaluate the performance of upland cotton varieties. These tests provide unbiased data on the performance of varieties when tested side-by-side under typical production practices. In 2001, we planted a total of 12 trials, one in the Yuma region (Yuma county), two in the western region (La Paz and Mohave counties), five in the central region (Maricopa and Pinal counties), one in the southern region (Pima county), and three in the eastern region (Graham, Greenlee, and Cochise counties). We tested seven to twelve commercially available varieties at each test site. The purpose of this report is to present the results of the 2001 tests conducted in the Yuma, western, central, southern, and eastern regions of Arizona.
    • Defoliation of Pima and Upland Cotton at the Safford Agricultural Center, 2001

      Clark, L. J.; Coleman, R. D.; Carpenter, E. W.; Norton, E. R. (College of Agriculture, University of Arizona (Tucson, AZ), 2002-06)
      Nine defoliation treatments based on standard and reduced rates of Ginstar and Chlorate plus two additives (compounds F and S) were applied to Pima and Upland cotton to compare the treatment effects on percent leaf drop and yields. All of the treatments were beneficial to leaf drop compared to the untreated check with the Ginstar treatments generally performing better than the Chlorate. Both of the additives enhanced the early defoliation effectiveness for the reduced rates of Chlorate and Ginstar over all other treatments, including the full rates of the Chlorate and Ginstar. Generally, this same enhanced effectiveness was seen of the additives plus reduced rates over the full rates of Chlorate and Ginstar throughout the defoliation process. This is the second year of the study.
    • Evaluation of Crop Management Effects on Fiber Micronaire, 2000-2001

      Silvertooth, J. C.; Galadima, A.; Tronstad, R. (College of Agriculture, University of Arizona (Tucson, AZ), 2002-06)
      Arizona has experienced a trend toward increasing fiber micronaire values in recent years resulting in substantial discounts on fiber value. There is some evidence to suggest management can influence fiber micronaire. Approximately 400 cases were identified in cotton production areas in Arizona ranging from the lower Colorado River Valley to near 2,000 ft. elevation with grower cooperators in the 2000 and 2001 seasons. Field records were developed for each field by use of the University of Arizona Cotton Monitoring System (UA-CMS) for points such as variety, planting date, fertility management, irrigation schedules, irrigation termination, defoliation, etc. Routine plant measurements were conducted to monitor crop growth and development and to identify fruiting patterns and retention through the season. As the crop approached cutout and the lower bolls began to open, open boll samples were then collected from the lowest four, first position bolls (theoretically the bolls with the highest micronaire potential on the plant) from 10 plants, ginned, and the fiber analyzed for micronaire (low 4). From that point forward, total boll counts per unit area and percent open boll measurements are being made on 14-day intervals until the crop is defoliated. Following defoliation, final plant maps were performed. Relationships among low 4 sample micronaire, irrigation termination (IT), defoliation, and final crop micronaire were analyzed. Results indicate strong relationships with final fiber micronaire for factors such as total heat units (HU) accumulated by the crop from planting to IT, variety, region of production (environment), and green boll load at cutout. Results showed that as total HU accumulated from planting to IT exceeded approximately 2950 HU, micronaire levels significantly increased.
    • Evaluation of Irrigation Termination Effects on Fiber Micronaire and Yield of Upland Cotton, 2001-2002

      Silvertooth, J. C.; Galadima, J. (College of Agriculture, University of Arizona (Tucson, AZ), 2002-06)
      Arizona has experienced a trend toward increasing fiber micronaire values in recent years resulting in substantial discounts on fiber value. There is some evidence to suggest that irrigation termination management can impact fiber micronaire. Field studies were conducted in 2000 and 2001 at the University of Arizona Maricopa Agricultural Center (MAC; 1,175 ft. elevation) and the Yuma Valley Agricultural Center (YVAC; 150 ft. elevation) to evaluate the effects of three dates of irrigation termination on the yield of several Upland cotton varieties. Three dates of irrigation termination (IT1, IT2, and IT3) were imposed based upon crop development. The earliest irrigation termination date, IT1 was made slightly ahead of an optimum date to provide sufficient soil-water such that bolls set at the end of the first fruiting cycle would not be water stressed and could be fully matured. Thus, the IT1 date was imposed to try to reduce overall micronaire. The second termination (IT2) date provided one additional irrigation over an optimal point for the first cycle fruit set and two irrigations beyond IT1. The final (IT3) date (later September) was staged so that soil moisture would be sufficient for the development of a full top-crop potential. Lint yield and micronaire results have consistently revealed significant differences among the IT treatments. The micronaire values were consistently less than 5.0 for the IT1 treatments. Micronaire and lint yield values increased with later IT dates.
    • Planting Method and Seeding Rate Evaluation in Graham County

      Norton, E. R.; Clark, L. J.; Carpenter, E. W. (College of Agriculture, University of Arizona (Tucson, AZ), 2002-06)
      A single field experiment was established in 2001 at the Safford Agricultural Center to evaluate the effects planting method and seeding rate have on plant population and yield of an Upland cotton cultivar Deltapine DP655BR. Two planting methods; planting into moisture (pre-irrigate) and dry plant/water-up, were main effects with three seeding rates of 10, 20, and 30 lbs./acre as sub-effects. These effects were evaluated with respect to stand establishment and yield. Analysis of variance showed no significant differences with respect to planting method for either plant population or yield, so data was combined across main effects. Significant differences were observed in plant population and yield as a function of seeding rate. A linear increase in yield with plant population was observed. These results are not consistent with previous research performed examining plant population effects on yield. This experiment will be conducted again in 2002 in an effort to validate results observed in 2001.
    • Planting Date by Variety Evaluation in Graham County

      Norton, E. R.; Clark, L. J.; Carpenter, E. W. (College of Agriculture, University of Arizona (Tucson, AZ), 2002-06)
      A single field study was established in 2001 at the Safford Agricultural Center to evaluate the effects of planting date and variety on crop growth and yield. Ten varieties were selected and planted on three separate planting dates in a split-plot randomized complete block design with four replications. Results from this experiment indicated significant differences due to planting date and variety. The interaction between planting date and variety was not significant. Yield trends were increasing with later planting dates which is thought to be a function of the inclement weather conditions surrounding particularly planting date one but also two. This experiment provides some interesting results with respect to seedling vigor, survivability, and ultimately yield for the different varieties tested.
    • Review of the 2001 Arizona Cotton Season

      Silvertooth, Jeffrey C. (College of Agriculture, University of Arizona (Tucson, AZ), 2002-06)