Two common (Piper and Sweet Sudan), four hybrid sudangrass (NK Trudan 8, Cargill HS 35, and Germaine's G 555), and three sorghum-sudangrass hybrid (DK SX 17, TE Haygrazer II, and Pioneer 877F) varieties are currently being evaluated for hay yield and quality at four cuttings in large field plots located at Quail Mesa Farms in southwest La Paz County. Preliminary results from the first two hay cuttings are presented showing that of the nine sudangrass varieties examined in this study, Piper, Cargill HS 35, and NC+ 200 sudangrass varieties had superior hay tonnage and quality. However, we need to determine if this pattern of hay tonnage and quality can be maintained over at least four hay cuttings. The sorghum-sudangrass hybrids produced relatively poor quality hay, and had relatively high prussic acid levels at the second cutting.

Five yellow corn hybrids were compared for silage yield at the Lunt dairy in Greenlee county. Silage yields, several agronomic variables and nutritional variables are also reported. Funks G4673B was the highest yielding hybrid in the trial with a silage yield over 33 tons per acre and net energy of lactation value over 13,000 megacalories per acre.

Twenty alfalfa varieties grown in small plots on raised beds were evaluated for forage production beginning after planting in the fall of 1992. Data from eleven harvests were obtained in 1993 -1995, generally covering the summer months. No variety produced more forage than CUF 101 in each of the three years although Moapa had more tonnage than CUF 101 in two of the years. Moapa and Tillman (101.6% and 100.8% of CUF 101 respectively) had higher total production than CUF 101 during the study, although Tillman had the least production of varieties tested during the third year. The varieties Rio and WL 516 had least amounts of forage production over the three year period. Percentage bloom and plant height were very highly correlated from the July 1993 harvest. Total production from 1993-1994 were similar to the bloom and height of July 1993, as Tillman, Moapa and CUF 101 had the highest percentage bloom, while Rio and WL 516 had the least bloom. Cibola and CW 2981 had greater than 240, 000 crowns per acre following the 1994 season, followed by Tillman and Condor. WL 516, Madera, and ABI 9182 each had fewer than 180,000 crowns per acre. Tillman and Cibola had greater than 120,000 crowns /acre at the end of the third year; all other varieties had fewer. Hopperburn and associated yellows during the fall of 1995 was correlated with both crowns /acre and plant height, although crown numbers and height were not correlated.

Eight alfalfa varieties were evaluated for forage production during 1995 and the first half of 1996 following a Feb. 1995 planting. DK 189 has yielded the most tonnage thus far (104.8% of CUF 101), and all varieties have averaged over one ton of hay /acre/harvest.

Five alfalfa varieties (CUF 101, SW 14, SW8210, Pioneer 5888, and a grower selection primarily from CUF 101 and noted as Baldwin Select) were planted in October, 1994, into large plots (0.75 acres) to obtain actual field harvest data. Eight harvests were taken during 1995, and seven thus far in 1996. Varietal hay yields were very similar in 1995 until mid summer, when area soil temperatures reached above 100 °F at the four inch depth for a period of about 6 weeks. During the summer months of both years Baldwin Select significantly outyielded other varieties tested. Statistical differences in accumulated hay yields were noted beginning in August 1995 and have continued during 1996. Baldwin Select was the highest yielding variety during 1995 (103.3% of CUF 101), followed by CUF 101 and Pioneer 5888, both which averaged 1.16 tons /acre per harvest. SW 14 and SW 8210 yielded about 550 total lbs /acre less than CUF 101 during 1995. Baldwin Select has also been the highest yielding variety in 1996 thus far, yielding 113.6% of CUF 101. SW 8210 has been second (107.6% of CUF 101), followed by SW 14 (102.7% of CUF 101), with CUF 101 and Pioneer 5888 again being almost equal in yield at 1.14 tons /acre per harvest. For 1995- 1996 combined, Baldwin Select has yielded 108.2% of CUF 101, followed by SW8210 (101.9% of CUF 101). CUF 101, Pioneer 5888 and SW 14 are very similar in overall tonnage. Alfalfa varieties have been very similar in relative feed value when tested. Yellowing from Empoasca spp. leafhoppers was greatest during the 1995 -1996 winter on varieties with fall dormancy ratings of 9 or greater. Baldwin Select has yielded $121 /acre more hay than CUF 101, and SW8210 has yielded $44 /acre more hay than CUF 101 thus far in this trial.

Fourteen alfalfa varieties with fall dormancy ratings from 6 to 9 were tested in replicated small plot trials on the Kibler farm in Stewart District northwest of Willcox. The leading variety after one year of testing was DeKalb 189 with a yield over 8 tons per acre. Heat units with temperature thresholds of 77 °F and 40 °F are given for each cutting.

Summer weeds including established bermudagrass and nutsedge are of economic concern to alfalfa growers in western Arizona. Two replicated evaluations of norflurazon herbicide applications for summer weed control were conducted on established alfalfa fields in La Paz County. Zorial Rapid 80 WP and Evital 5G herbicides were tested for their effectiveness of bermudagrass and nutsedge control when applied following hay harvest but prior to irrigation in early spring. Zorial 80 WP was applied at 2.0 lb a. i. /acre. Evital 5G was applied at single application rates of 1.5, 2.0, and 3.0 lb a. i. /acre in spring and two split applications in spring and summer for a total of 2.0, 3.0, and 4.0 lb a. i. /acre. Norflurazon applications resulted in bleaching and shoot tip death of established bermudagrass 49 days after a single application (DAT), however by 78 DAT bermudagrass regrowth reinfested all plots resulting in zero control. Purple nutsedge control resulting from a single application of Evital 5G at 2.0 lb a.i./acre was 41, 82, and 35% at 35, 63, and 99 DAT, respectively. However, Zorial 80 WP applied at 2.0 lb a. i. /acre provided only 5, 23, and 0% purple nutsedge control at 35, 63, and 99 DAT, respectively. The limited effectiveness of the Zorial 80 WP spray solution for nutsedge control resulted from poor soil incorporation since the liquid was unable to penetrate the dense nutsedge foliage. The Evital 5G norflurazon formulation provided promising purple nutsedge control following one application to established alfalfa since the weight of the granules allowed the herbicide to reach the soil surface where irrigation could move the herbicide down through the soil profile to nutsedge roots. At 99 DAT a second split Evital treatment was applied to control nutsedge regrowth, and hopefully provide season long control. Nutsedge control results following this second split application are pending.

Twenty one alfalfa varieties with Fall Dormancy ratings of 8 or 10 were tested in a replicated small plot trial on the Safford Agricultural Center. The leading variety after four years of cuttings is Mesa (formerly known as 84D92, from MBS, Inc). Since this was the last year of the study, stand counts and stem counts were taken and reported in this report Heat units with thresholds of 77° F and 40° F are included for each cutting in the study.

No description available.

Plant growth regulators were aerially applied on April 26, 1996, to two alfalfa fields, one (Cibola) in its first year of production and the other field (CUF 101) in its third year. The first year field was approximately 50% through the cutting cycle and the third year field was approximately 30% through the cutting cycle when applications were made. No statistical differences were noted in hay tonnage the first cutting after application. Yield increases due to treatments were noted in the second cutting and maximum increases ranged from 277 -461 lbs of hay per acre. No yield or quality differences were noted the third cutting after application. The two fields differed in their response. The lowest rates of plant growth regulators produced higher yields in the first year field, but these treatment rates had greatly lowered hay quality the previous cutting. These effects were not noticed in the third year stand field. Increased hay tonnage was noted in the third year field from the 16 oz/acre rates, but was not evident in the first year field. Hay quality was usually highest in the check the first two cuttings after treatment. It is unknown if the differences noted between the two fields are due to different age of plants, variety and/or stage of growth when treatments were applied.