• Economic Impacts of Bt Cotton Adoption: A National and Regional Assessment

      Frizvold, George; Tronstad, Russell; Mortensen, Jorgen; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 2000)
      This study uses a quadratic programming model to estimate impacts of Bt cotton adoption on consumer benefits, cotton program outlays, and producer returns, by state and by grower adoption status. Three scenarios were considered simulating low, moderate, and high impacts of Bt cotton adoption. For the moderate impact scenario, U.S. benefits from Bt cotton adoption grew from $44 million in 1996 to $66 million in 1998. Annual U.S. consumer benefits ranged from $46– $55 million. Benefits to Bt adopters grew from $57 million in 1996 to $97 million in 1998. Losses to non-adopters fell from -$59 million in 1996 to -$8 million in 1998 as rising commodity program payments countered the impact of lower prices. In 1998, gains to Arizona Bt cotton adopters (net of adoption costs) were about $9 million, averaging over $15,000 per adopting farm.
    • Lygus Control Decision Aids for Arizona Cotton

      Ellsworth, Peter C.; Silvertooth, Jeff; The University of Arizona, Department of Entomology & Maricopa Agricultural Center (College of Agriculture, University of Arizona (Tucson, AZ), 2000)
      Changes in insecticide use, available pest control technologies, and local crop ecology together with severely depressed cotton prices place a renewed premium on Lygus control decision aids for Arizona cotton. As part of an on-going program to develop research-based Lygus management recommendations, we investigated the impact of various timings of chemical controls on Lygus population dynamics, number of sprays, costs of control, and net revenue as well as cotton heights, trash, lint turnouts, and yields. Once there were at least 15 total Lygus per 100 sweeps, sprays were made according to the number of nymphs in the sample (0, 1, 4, 8 or 16 per 100 sweeps). Up to 7 sprays were required (15/0 regime) to meet the needs of the target threshold. Lygus adult densities were largely unresponsive to the treatment regimes or individual sprays made. Three generations of nymphs, however, were affected by the treatments with the ‘15/4’ regime harboring the fewest nymphs through July. This ‘moderate’ regime required 4 sprays and had the shortest plants, cleanest harvest, and highest lint turnouts. In addition, this regime out-yielded all other treatment regimes including the 6- (15/ 1) and 7- (15/0) spray regimes. Regression analyses of the data suggest that adult Lygus are less related to yield loss than nymphs and that large nymphs are best correlated with yield loss. Thus, spraying based on adults only would appear illadvised. Returns were highest ($747/A) for the 15/4 regime with over $100 more than the more protective regimes. Thus, there is no economic advantage in advancing chemical control when nymph levels are low. Maximum economic gain was achieved by waiting for the 4 nymphs per 100 level (with 15 total Lygus/100; 15/4) before spraying. However, waiting too long (beyond the 8 nymphs / 100 level; 15/8) resulted in significant reductions in yield and revenue. Our recommendations, therefore, are to apply insecticides against Lygus when there are at least 15 total Lygus, including at least 4 nymphs, per 100 sweeps. These recommendations are stable over a wide variety of economic conditions (market prices & insecticide costs). Continued work is necessary to verify these findings over a wider range of cotton developmental stages, varieties, and other environmental conditions.
    • Soil Test Calibration Evaluations for Phosphorus on Upland and Pima Cotton

      Thelander, A. S.; Silvertooth, J. C.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 2000)
      Numerous field experiments were conducted at a wide range of sites in Arizona from 1988 through 1999 involving phosphate (P) fertilization of cotton (Gossypium spp.). A total of 21 site-years were used to study the effects of P on both Upland (G. hirsutum L.) and Pima (G. barbadense L.) varieties. The purpose of these experiments was to evaluate University of Arizona (UA) soil fertility guidelines with respect to soil test results (NaHCO3 extractable P) and to possibly fine-tune or calibrate these guidelines in relation to soil test P, applied P, and yield for common Arizona soils used in cotton production. Results from these experiments, based on soil test information, plant measurements, and lint yield showed no significant difference (P 0.05) due to treatments for all the studies with the exception of one P study conducted in Graham County in 1998 and another P study conducted in Pinal County in 1999. The 1998 Graham County site had a preseason soil test value of 7.6 ppm NaHCO₃ extractable P. The 1999 Pinal County site had a preseason soil test value of 3.0 ppm NaHCO3 extractable P. Analysis of yield results vs. soil P show that soil test P levels greater than 5 ppm are consistently sufficient for both Upland and Pima cotton. Yield results vs. applied P (lbs. P₂O₅/acre) for both Upland and Pima did not indicate a positive response over the rates of fertilization tested (20-160 lbs. P₂O₅/acre). Based on the results from these studies, the current UA soil fertility guidelines for P fertilization of cotton appear to be valid. Furthermore, the data indicates that the UA soil fertility guidelines may be further refined to provide the following categories: < 5 ppm = high probability of response to an added P fertilization; 6-10 ppm = medium probability of response to an added P fertilization; and > 10 ppm = low probability of response to an added P fertilization.
    • Cotton Fertility Study, Safford Agricultural Center, 1999

      Clark, L. J.; Carpenter, E. W.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 2000)
      Three different nitrogen fertilizer regimes were practiced in this study along with an unfertilized check. The same amount of nitrogen fertilizer was sidedressed in the plots in one, two or three applications. No statistically significant differences were seen between lint yields in this study nor in the previous study, but the yield trends were very similar. Applying the fertilizer nitrogen in two equal portions at the onset of rapid vegetative growth and just before peak bloom appeared to produce the best lint yield.
    • Agronomic Evaluation of Transgenic Cotton Varieties

      Moser, H. S.; McCloskey, W. B.; Silvertooth, J. C.; Silvertooth, Jeff; Department of Plant Sciences, University of Arizona (College of Agriculture, University of Arizona (Tucson, AZ), 2000)
      Four field tests were conducted at three Arizona locations in 1999 to evaluate the performance of transgenic cotton varieties in Arizona. We included a total of 34 varieties in one or more of these tests. Across locations and varieties, Bollgard (BG) and stacked BG and Roundup Ready (BGRR) varieties produced about 7 to 8% greater lint yields than the conventional varieties from which they were derived. Across all varieties and all tests, the average lint yield of the Roundup Ultra sprayed RR or BGRR treatments was 1569 lb./A, while the average yield of the unsprayed RR or BGRR treatments was 1580 lb./A. Roundup Ready (RR) varieties produced lint yields similar to the conventional varieties with a couple of exceptions. Roundup Ready varieties tended to be taller and more vigorous than the conventional parent. Transgenic varieties were often different from the conventional parent in one or more traits, such as fiber quality, lint percent, boll weight, or maturity, but the variation was not associated with a particular transgene.
    • Effects of High Frequency Irrigation on Irrigation Uniformity II

      Martin, E. C.; Wegge, R.; Sheedy, M.; Silvertooth, Jeff; University of Arizona, Cooperative Extension (College of Agriculture, University of Arizona (Tucson, AZ), 2000)
      Another year of data was collected to determine the effects of high frequency irrigation on irrigation uniformity in cotton production. A field located at the Marana Agricultural Center was split into two treatments. Treatment one was irrigated at approximately 35% depletion of available water in the plant rootzone. Treatment two was irrigated at approximately 65% depletion in the crop rootzone. Increased frequency of irrigation has shown improved yields in many cotton studies. However, these more frequent and lighter irrigation applications may cause problems with irrigation uniformity. Frequent rains during critical time periods made it difficult to ascertain the impact of the irrigation schedule on uniformity. However, the less frequent, heavier application rate did result in a more uniform irrigation.
    • 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.
    • 1999 Integrated Cotton Management Demonstration

      Martin, Edward C.; Dittmar, Stefan H.; Ellsworth, Peter C.; Silvertooth, Jeffrey C.; McCloskey, William B.; Olsen, Mary W.; Roth, Robert L.; Tronstad, Russell E.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 2000)
      An Integrated Cotton Management (ICM) Demonstration project was conducted on the Demonstration Farm at the Maricopa Agricultural Center in 1999 for the second year. In this project, all current guidelines and recommendations disseminated by the University of Arizona were integrated in a systems approach for cotton production. The Extension Specialists in agronomy, entomology, irrigation management, weed sciences, and plant pathology following the University recommendations made the management decisions. On a 52.7 acre field, 78% Bt and 22% non-Bt cotton was planted into moisture on April 9, 1999. Because of problems with cool temperatures and deep seeding, a stand of only 25,000 plants/acre was established. Weed control was achieved with one preplant application and two cultivations. The field was sprayed three times for lygus and two times for whitefly control. Approximately 38.6 acre-inches of irrigation water was applied. An average of 3005 lb/acre of seed cotton were harvested. After harvesting, a field budget was established. The variable costs per acre were $594.96 and the total cost was $957.96/acre. Average micronaire was 4.45, strength was 28.41 gm/Tex, length was 1.10 (1/100 in.) and grade color was 21. The price received for the cotton was 74.82¢/lb, including LPD and hail damage payments, just over 3¢/lb below the break-even price. An additional $139/acre in PFC payments was received but not calculated into the budget. This project demonstrates the utility and compatibility of current recommendations and the potential for integration of all disciplinary guidelines in one system.
    • 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.
    • Short Staple Variety Trials, Graham County, 1999

      Clark. L. J.; Carpenter, E. W.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 2000)
      Two replicated on-farm short staple variety trials were planted in 1999. Twenty-two varieties were evaluated on the Claridge farm in Solomon and fifteen varieties on the Colvin farm near Ft. Thomas. Several new varieties were planted in these studies, including 2 transgenic varieties: DP 5690RR, BXN 16; 4 Israeli inter-specific hybrids and six other varieties seen for the first time. DP 35B was the highest yielding variety in the Claridge trial with BXN 47 a close second. Both varieties yielded over 1300 pounds of lint per acre. PM 1440 was the highest yielding variety in the Colvin trial with SG 747 and DP 5690RR following closely behind. These varieties yielded between 700 and 800 pounds of lint per acre. Other agronomic data from the varieties and HVI values from the lint are also included in this report.
    • 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.
    • Weed Control in Arizona Ultra Narrow Row Cotton: 1999 Preliminary Results

      McCloskey, William B.; Clay, Patrick A.; Husman, Stephen H.; Silvertooth, Jeff; Department of Plant Sciences, University of Arizona, Tucson, AZ; Maricopa County Cooperative Extension, University of Arizona, Phoenix, AZ; Pinal and Pima County Cooperative Extension, University of Arizona, Tucson, AZ (College of Agriculture, University of Arizona (Tucson, AZ), 2000)
      In two 1999 Arizona studies, a preplant incorporated (PPI) application of Prowl (2.4 pt/A) or Treflan (0.75 lb a.i./A) followed by a topical Roundup Ultra (1 qt/A) application at the 3 to 4 true leaf cotton growth stage provided good weed control. At the University of Arizona Maricopa Agricultural Center field that had low density weed populations, a postemergence topical Staple (1.8 oz/A) application also provided good weed control was more expensive. At the Buckeye, Arizona study site, a PPI application of Prowl at a reduced rate (1.2 pt/A) was as effective as the full rate (2.4 pt/A) but a preemergence application of Prowl (2.4 pt/A) was not as effective as either of the PPI Prowl rates or PPI Treflan (0.75 lb a.i./A). A postemergence topical Staple application (1.8 oz/A) following the Roundup Ultra application did not significantly improve weed control. After one field season of experimentation and observation in Arizona UNR cotton, experience suggests that in fields with low to moderate weed populations, a PPI Prowl or Treflan application followed by a postemergence topical Roundup Ultra application will provide acceptable weed control in most fields. However, the presence of nutsedge or other difficult to control weeds may require two postemergence topical Roundup Ultra application prior to the four leaf growth stage of cotton. More research is needed to further explore weed control options in Arizona UNR cotton production systems.
    • 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.
    • Comparison of Obsolete and Modern Cotton Cultivars for Irrigated Production in Arizona

      Holifield, C. D.; Silvertooth, J. C.; Moser, H.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 2000)
      A study was conducted at the University of Arizona Maricopa Agricultural Center (MAC) to compare growth and development characteristics and determine differences in fruiting pattern and retention among two obsolete (Deltapine 16 and Acala 442) and three modern (Deltapine Acala 90, Deltapine 5415, and NuCotn 33b) Upland (G. hirsutum L.) cotton cultivars grown in an irrigated production system in Arizona. Results indicated that the majority of yield was produced at fruiting branches 10 through 18 at position one. Lint yield results indicated no significant differences among all cultivars tested, except for Acala 442, which was significantly lower than all others. Obsolete cultivars produced significantly higher amounts of lint on vegetative branches than modern varieties. Deltapine 16, followed by NuCotn 33b, had the highest harvest index and was the most efficient cultivar grown with respect to dry matter partitioning.
    • Development of a Yield Projection Technique for Arizona Cotton

      Norton, E. R.; Silvertooth, J. C.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 2000)
      A series of boll measurements were taken at numerous locations in cotton producing areas across Arizona in 1999 in an attempt to continue to develop a yield prediction model with a project that began in 1993. Results from 1995 showed the strongest relationship between final open boll counts and yield compared to a number of other measurements. Based on these results, data collection on boll counts began in 1996 and has continued in 1997, 1998, and 1999. Boll counts were taken as the number of harvestable bolls per meter. All boll count measurements were made within one week of harvest. Number of bolls per unit area were then correlated to lint yield and an estimate for the number of bolls per area needed to produce a bale of lint was calculated. Estimates using all four years of data combined indicate that approximately 38 bolls per meter are needed to produce one bale of lint per acre.
    • 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 a Calcium-Based Soil Conditioner in Irrigated Cotton

      Silvertooth, J. C.; Norton, E. R.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 2000)
      A two site evaluation of a calcium (Ca²⁺)-based soil conditioner was conducted during the 1999 cotton season. The two locations included one at the Maricopa Agricultural Center (MAC) in Maricopa, AZ and the other was on a growercooperator field in Tacna, AZ. Both studies involved the use of CN-9, a Ca – nitrate solution with 9% nitrogen and 11% Ca. At MAC theCN-9 solution was sprayed over the seedbed post planting but prior to the first water-up irrigation. At the Tacna site CN-9 was applied in a sidedress application at planting. Routine plant measurements were taken throughout the duration of both studies and lint yield estimates were made at each location at the end of the season. No significant differences due to the application of CN-9 were detected in any data collected.
    • 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.
    • 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.
    • Short Staple Variety Trial in Cochise County, 1999

      Clark, L. J.; Silvertooth, Jeff (College of Agriculture, University of Arizona (Tucson, AZ), 2000)
      The Acala and Upland Variety trials typically grown in Cochise County were combined into one study in 1999 and were planted on the Glenn Schmidt farm, in Kansas Settlement. Twelve varieties were tested including three New Mexico Acalas and one Interspecific Hybrid from Israel. The highest yielding variety in the trial was FM 989 with a yield near 1200 pounds of lint. It was also the highest yielding variety in the Cochise County trial in 1998. PM 1560 BG came in a close second with the Israeli varity (Hazera 151-208) and the two New Mexico varieties (1517-95 and 1517-99) yielding over 1100 pounds of lint.