• Acala Cotton Variety Trial, Safford Agricultural Center, 2001

      Clark, L. J.; Carpenter, E. W.; Norton, E. R. (College of Agriculture, University of Arizona (Tucson, AZ), 2002-06)
      Six New Mexico and California Acala cotton varieties were tested along with three upland varieties with good quality and excellent yield potential 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 DP 655BR with a yield of 1367 pounds of lint per acre. The next highest variety was Fiber Max 989. This latter variety, while not officially classified as an Acala, produced the longest fiber in the study. Yield and other agronomic data as well as fiber quality data are contained in this paper.
    • Effect of Buctril Rate on Weed Control in BXN® Cotton - 2001

      McCloskey, William B.; Department of Plant Sciences, University of Arizona, Tucson, AZ (College of Agriculture, University of Arizona (Tucson, AZ), 2002-06)
      Experiments were conducted at the University of Arizona Safford and Maricopa Agricultural Centers during the 2001 cotton season to compare the effectiveness of 0.5 and 1.0 lb a.i./A topical applications of Buctril (bromoxynil) on annual morningglory species. At Safford, the percent control of annual morningglory was statistically greater following 1.0 lb a.i./A Buctril applications at 97 percent control compared to 83 percent control resulting from 0.5 lb a.i./A Buctril applications. Both the 0.5 and 1.0 lb a.i./A Buctril rates, had similar initial effects on morningglory seedlings. Initial leaf symptoms included a dark-green “water soaked” appearance that progressed into leaf necrosis. At both rates, all morninglory leaf tissue was destroyed leaving green stems which sometimes remained viable and produced new leaves rather than turning chlorotic and dying. The number of escapes in the center two rows of four-row plots was significantly greater after 0.5 lb a.i./A Buctril applications at 12.4 escapes compared to 1.5 escapes following 1.0 lb a.i./A Buctril applications. An average of 12 escapes in an area 40 ft by two cotton rows is sufficient to cause substantial yield losses in the absence of other control methods. At Maricopa, there was no statistically significant difference in the phytotoxicity caused by 0.5 and 1.0 lb a.i./A Buctril rates when applied to 1, 2, or 3 true-leaf exposed morningglory seedlings (i.e., not partially covered or shaded by other plants) that were thoroughly contacted by the herbicide sprays. Both experiments found that morningglory control was significantly greater following two sequential 0.5 lb a.i./A Buctril applications compared to a single 1.0 lb a.i./A application due to continued emergence of seedlings. Growers with morningglory infested fields that make a 1.0 lb a.i./A application should be prepared to make an early season post-direct application using other herbicides to control later emerging morningglory plants.
    • Phosphorus Fertility Evaluation in Graham County

      Norton, E. R.; Silvertooth, J. C.; Clark, L. J. (College of Agriculture, University of Arizona (Tucson, AZ), 2002-06)
      A series of three phosphorus (P) fertility experiments were conducted in 2001 in Graham County. These studies follow similar experiments conducted over the past three seasons. Results from 2001 were consistent with previous results indicating a positive relationship between yield and P fertilizer applications in relation to soil test indices. Modest yield increases were observed from a minimum of 25 to 80 lbs. lint per acre with an application of approximately 70 lbs. of P as P₂O₅ per acre. Yield differences from previous years have been as great as 170 lbs. of lint per acre. With the increased use of UAN-32 as a primary fertilizer source and a reduction in the application of P fertilizers, which is typically associated with a rotation of small grains, a depletion of soil P is a potential result. A continuation of this research with varying rates of P fertilizer will take place in 2002 in an attempt to relate soil test P levels to yield increases observed in recent years. The results of this research demonstrate the possible need for a return to use of fertilizers with supplemental P for optimum yields that would be predictable based on soil test results.
    • Upland Cotton Variety Evaluation in Graham County

      Norton, E. R.; Clark, L. J. (College of Agriculture, University of Arizona (Tucson, AZ), 2002-06)
      A field trial was established during the 2001 growing season as part of the statewide Upland Cotton Variety Testing Program. This trial was located in Thatcher with Dennis Layton Farms as the cooperator. The location was one of eleven around the state. Seven Upland cotton varieties to be evaluated at this location were entered by various cooperating seed companies. A new variety from FiberMax produced the highest yield and also possessed the highest quality fiber making it the variety that would have produced the highest gross income to the producer.
    • Short Staple Variety Trial in Cochise County, 2001

      Clark, L. J.; Norton, E. R. (College of Agriculture, University of Arizona (Tucson, AZ), 2002-06)
      Twelve varieties were tested including three New Mexico Acalas and one Acala from Buttonwillow Research in California, six Roundup Ready varieties, five of which also contained the Bt gene, along with a couple of other varieties were planted including FiberMax 989, which has been the highest yielding variety in the trial for two of the past three years. The highest yielding variety in the trial was FiberMax 989R, the Roundup Ready version of FM 989, with a yield over 950 pounds of lint per acre. 1517-95 and SureGrow 521RR followed in yield. Yields were considerably lower than seen in the previous year’s study (1). Several Roundup Ready varieties were included in this study. Plant mapping data and HVI data are also included in this report.
    • Yield, Quality, and Economic Comparison of Single and Double Seed Line Per Bed Cotton Production

      Husman, S. H.; McCloskey, W. B.; Teegerstrom, T.; Clay, P.; Norton, R.; White, K.; University of Arizona Cooperative Extension (College of Agriculture, University of Arizona (Tucson, AZ), 2002-06)
      Three experiments were conducted in Maricopa, Marana, and Glendale, Arizona in 2001 to measure cotton growth, yield, micronaire, and production costs in single and double seed line per bed systems on 32 and 40 inch beds. Canopy development was faster and canopy closure was greater in the double seed line than in the single seed line systems and was greater in the 32 inch than in the 40 inch row systems. At Maricopa, the single line 32 inch system yield of 1571 lbs./A was significantly greater than the yields of the other seed line/row spacing systems. The yields of the single line 40 and the double line 32 inch systems were not significantly different at 1476 and 1411 lbs. of lint/A, respectively, and the yields of the double line 32 and the double line 40 inch systems also were not significantly different at 1411 and 1396 lbs. of lint/A, respectively. There were no significant lint yield differences at the Marana or Glendale location. At Marana, the lint yields were 1063 and 1066 lbs./A for the single and double seed line 40 inch row spacing systems, respectively. At Glendale, the single and double seed line 38 inch row spacing systems yielded 1474 and 1551 lbs. of lint/A, respectively. In all 2001 experiments, there was a trend for reduced micronaire in the double seed line per bed systems compared to the single seed line per bed systems. At Maricopa, the average micronaire was 5.0 and 4.7 for the single and double seed line per bed 32 inch row system, respectively, and 5.2 and 4.9 for the single and double seed line per bed 40 inch row systems, respectively. At Marana, the micronaire was 4.7 and 4.5 for the single and double seed line per bed 40 inch row systems, respectively. At Glendale, the micronaire was 5.1 and 4.6 for the single and double seed line per bed 38 inch row systems, respectively. Production costs were similar for the single and double seed line per bed systems. Additional research will be conducted in 2002 to determine the optimum plant populations and in-row plant spacings for double seed line per bed production systems.
    • Residual Soil Nitrogen Evaluations in Irrigated Desert Soils, 2001

      Silvertooth, J. C.; Galadima, A.; Norton, E. R. (College of Agriculture, University of Arizona (Tucson, AZ), 2002-03-18)
      Field experiments were conducted in Arizona in 2001 at three locations (Maricopa, Marana, and Safford). The Maricopa and Safford experiments have been conducted for14 consecutive seasons and the Marana site was initiated in 1994. The original purposes of the experiments were to test nitrogen (N) fertilization strategies and to validate and refine N fertilization recommendations for Upland (Gossypium hirsutum L.) and American Pima (G. barbadense L.) cotton. The experiments have 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. Generally, the more conservative, feedback approach to N management provided optimum yields at all locations. In 2001, a transition project evaluating the residual N effects associated with each treatment regime was initiated and no fertilizer N was applied. Therefore, all N taken-up by the crop was derived from residual soil N. In 2001 there were no significant differences among the original fertilizer N regimes in terms of residual soil NO₃⁻-N concentrations, crop growth, development, lint yield, or fiber properties. The lint yields were very uniform at each location and averaged 1500, 1100, and 850 lbs. lint/acre for Maricopa, Marana, and Safford, respectively.