34 research outputs found
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Do PIX® Application Guidelines Change for Bt Cotton?
Two PIX experiments were conducted on commercial cooperator sites in Waddell and Buckeye, Az in 1997 to evaluate the validity of the published University of Arizona (UA) PIX application guidelines for Bt cotton. Experimental treatments consisted of an untreated check, a calendar based application schedule (early bloom, peak bloom, cutout), and a feedback approach using plant growth measurements based on the UA PIX guidelines (height:node ratio, fruit retention). There were no significant yield differences at the Waddell site where height:node ratios and fruit retention values were above the optimum baseline season long, conditions not supportive of PIX applications. There was a significant yield decline at the Buckeye site between the untreated check and the calendar based treatment. Due to low plant vigor season long , there were no feedback based PIX applications. PIX applications under low vigor conditions can further compromise plant vigor and ultimately yield. The UA PIX application use guidelines are valid and should be used for both Bt and non -transgenic Upland cotton varieties
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Side-dress Temik® Effects on Lint Yields
Temik 15G was side-dressed at a rate of 7 lb./acre and 14 lb./acre and compared to an untreated check in 4 experiments in 1996 and 1997 in Buckeye, Az. Treatments were made just prior to early bloom. Lygus counts were taken using a sweep net on weekly intervals for four to six weeks post application. A net positive return on investment (ROI) ranging from 48.19/acre was realized in three of the four experiments with the seven lb./acre rate. One experiment resulted in a net economic loss of 23.31 to 28.28 to $93.27 using the fourteen lb./acre rate. It appears that lint yield increase responses are due in part to a plant response to Temik, not necessarily related to lygus density as evidenced in part by the lack of measured sweep count populations
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The Effects of Foliar Applies Potassium Thiosulfate on Upland Cotton Lint Yield and Fibert Quality
A replicated field study was conducted at the Maricopa Agricultural Center in 1992 investigating Upland cotton lint yield and fiber quality response to foliar applied potassium thiosulfate. Applications were applied at early, peak, and late bloom. There were no significant yield or lint quality response by treatment
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Growing Alfalfa for Seed in Arizona
Originally Published: 1999; Revised3 pp.Seed production for profitability is challenging. Cultural practices differ from those commonly used in forage production. This article outlines management recommendations that may help to accomplish profitable seed alfalfa yields
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Evaluation of Puma (Fenoxaprop) for Littleseed Canarygrass Control in Durum Wheat in Central Arizona (1998)
A field experiment was conducted in 1998 to determine the efficacy of Puma and Hoelon for littleseed canarygrass control in durum wheat. The herbicide treatments consisted of three rates of Puma, 0.83, 1.24, and 1.66 oz a.i./A, and one rate of Hoelon, 6.8 oz a.i./A, that were applied at two application timings. The early-postemergence (EPOST) applications when canarygrass had 2.2 leaves per plant did not result in commercially acceptable control due to water stress. Increasing rates of Puma applied mid-postemergence (MPOST) when canarygrass had 5 leaves per plant provided increasing canarygrass control (70 to 90 %) with the two higher rates of Puma providing commercially acceptable control. The two highest rates of Puma also resulted in better weed control than the commercial standard, Hoelon, which did not provide commercially acceptable weed control. No herbicide injury symptoms were observed on the wheat at any of the evaluation dates. Grain yield also increased as the rate of Puma applied MPOST increased and yields overall reflected the degree of weed control observed earlier in the season. These data indicate that the combination of Puma applications that killed or stunted emerged canarygrass combined with later season crop competition that suppressed stunted and later emerging canarygrass plants was sufficient to protect grain yields. The highest yielding Puma treatment was equivalent to 4150 lb/A compared to the Hoelon and control treatments which yielded the equivalent of 2753 and 1946 lb/A, respectively
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Nitrogen content of green crops
Application of chemical fertilizer is not permitted in production of crops certified as organic, but green manure crops may be used to supply the nutrient needs of these crops. An experiment was conducted on a commercial farm near Litchfield Park to determine the nitrogen content at plowdown of barley mixed with Austrian winter peas, Magnus peas, and/or Lana woolleypod vetch. The crop was planted on 21 October and sampled for plowdown nitrogen content on 1 March. The peas and vetch comprised less than 10% of the dry weight of the mixture since the barley grew more vigorously. The barley contained 66 lbs N/acre in the forage while the legumes in the mixture contained 16 lbs N/acre on average. The amount of N in the green manure, even if 100% was available, was not enough to supply the needs of a 2 bale/acre organic cotton crop. The planting date, plowdown date, or species composition in the green manure mixture needs to be altered for green manure to supply the N needs of organic cotton
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Irrigation practices and Solum test weight and yield, 2002
Solum is a barley adapted to one or two irrigations but the grain produced is often low in test weight. Studies were conducted on two commercial farms near Maricopa and Coolidge in an effort to verify data from previous studies suggesting that delaying the first post-emergence irrigation until boot increases test weight compared to earlier irrigation, but does not affect yield. The irrigation treatments consisted of 1) two irrigations – planting and boot, or 2) three irrigations – planting, 5- to 6-leaf stage, and heading (grower standard). The irrigation treatments had no effect on grain yield, test weight, kernel weight, or lodging at either location, but delaying the second irrigation until boot reduced plant height at Coolidge. Despite the lack of positive results from these studies, applying the second irrigation at boot may still be preferable to earlier applications because of reduced plant height and the risk of lodging. We have not been able to measure a benefit from a third irrigation for Solum barley in these or previous studies
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Durum response to soil water depletion levels at Stanfield, 2002
This research was conducted to test the effect of soil water depletion levels on durum productivity. An experiment was conducted at a commercial farm in Stanfield where irrigations were applied at 35, 50, or 65% depletion of plant available soil water. These soil water depletion levels were estimated from soil texture and weather data. The grain yields obtained with 35, 50, and 65% depletion were 6718, 6324, and 4752 lbs/acre, respectively. Grain protein decreased and HVAC increased by irrigating more frequently at lower depletion levels. Irrigating at 50% depletion was the most economical in this study considering irrigation costs and grain quality discounts
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Does a Preharvest Application of Roundup® Improve Cotton Defoliation?
Preharvest applications of Roundup improved defoliation and regrowth suppression when used in conjunction with an application of Dropp +Def on Upland cotton in experiments conducted in Buckeye, Maricopa, and Queen Creek, AZ. However, all treatments used provided commercially acceptable defoliation. Preharvest Roundup applications made about two weeks (or one irrigation interval) before the application of Dropp +Def did not reduce seed cotton yields, lint yields, or affect color-grade and fiber characteristics
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Growing Alfalfa for Seed in Arizona
Originally Published: 1999; Revised3 pp.Seed production for profitability is challenging. Cultural practices differ from those commonly used in forage production. This article outlines management recommendations that may help to accomplish profitable seed alfalfa yields