EPTC IO percent granules, Trifluralin 10 percent granules and Poast were evaluated for southern sandbur (cenchrus echinatus) control. Trifluralin resulted in variable control ranging from 90 percent down to 55 percent. EPTC produced good but sometimes varied control when applied in February, prior to the germination of the weeds, and repeated in April, June and July. Poast was effective postemergence only when applied to small seedlings. It was ineffective when applied to established sandbur.

Alfalfa irrigation is often withheld as a water conservation measure in Arizona. The objective of this research was to test the hypothesis that alfalfa yield and stand can be permanently damaged by withholding irrigation water. Irrigation was terminated during the summer (July through October) or winter (November through February) on a Superstition sand in Yuma. Summer irrigation termination reduced plant density from 4 to 1.5 plants per square foot and reduced hay yield from 0.76 to 0.27 tons per acre per cutting after irrigation was resumed. Winter irrigation termination had no residual effect on yield or plant density. Termination of alfalfa irrigation can permanently damage stands and reduce yield on sandy soil.

Alfalfa irrigation is often withheld as a water conservation measure in Arizona. The objective of this research was to test the hypothesis that alfalfa can be permanently damaged by withholding irrigation water. Irrigation was terminated during the summer (July or August through September) or summer through winter (July or August through mid -March) on a Casa Grande sandy loam at Maricopa. Irrigation termination at Maricopa was not detrimental to stand although hay yields were depressed from 1.47 to 1.28 tons per acre following the second cycle of summer irrigation termination and from 1.57 to 1.23 tons per acre per cutting following summer through winter irrigation termination. Alfalfa water use was reduced by irrigation termination even after irrigation was resumed. Total nonstructural carbohydrates in the roots were never less than the control during irrigation termination but decreased relative to normally irrigated alfalfa when irrigation resumed.

Twenty alfalfa varieties with Fall Dormancy ratings of 8 or 9 were tested in a replicated small plot trial on the Safford Agricultural Center. The leading variety after two years of cuttings is Mesa (formerly known as 84D92, an experimental from MBS, Inc). Two other varieties with FD ratings of 6 and 10 were included in the study for comparison. Heat units with thresholds of 77° F and 40° F are included for each cutting in the study.

No description available.

Twenty alfalfa varieties with Fall Dormancy ratings of 8 or 9 were tested in a replicated small plot trial on the Safford Agricultural Center to aid alfalfa growers in southeastern Arizona with their planting decisions. This multi -year study gives yield data by cutting in the current year and yearly averages throughout the study. The leading variety after three years of cuttings is Mena (formerly known as 84D92, an experimental from MBS, Inc). Two other varieties with FD ratings of 6 and 10 were included in the study for comparison. Heat units with thresholds of 77°F and 40°F are included for each cutting in the study.

Five Alfalfa varieties were planted in the fall of 1994. Each plot consisted of a 3 acre border and each variety was replicated 3 times. The plots have been under the current management regime of the cooperating grower. Samples have been collected and yield and quality parameters recorded. The experiment is planned to continue for at least one more season.

Alfalfa is the second largest production crop grown in Arizona with an estimated 150,000 acres of production in 1993. Water requirements for alfalfa have been estimated at 6 acre-feet per year. These two facts together make it imperative that data be gathered to help growers apply their irrigation water efficiently while maintaining their yields. In 1994, a study was initiated in the Parker Valley region of La Paz County, Arizona, to measure daily water use in alfalfa. Two sites were chosen for measurement: one site was a surface irrigated field located at the Quail Mesa Farm; the second site was a surface irrigated field located on the Colorado River Farm. The two sites were chosen to give a contrasting schedule of irrigation and allow for data collection at differing times throughout the year. Nine neutron probes were installed in each field, three 113 in from the head, three in the center, and three 113 in from the tail on one field at each location. Neutron probe readings were taken at 18", 30", 42", and 54" depths below the soil surface to measure soil moisture from 1' -2', 2' -3', 3'-4', 4' -5'. The soil moisture for the top foot was determined by gravimetric sampling. The data gathered by this study was used to compare with data used in AZSCHED, a computerized irrigation scheduling program. With this data, determination of alfalfa water used based on heat units after cutting was made to help growers better use their irrigation water.

No description available.

Twenty alfalfa varieties grown in small plots on raised beds were evaluated for forage production beginning in 1993 after planting in the fall of 1992. Data from four harvests, generally covering the summer months, were obtained annually. No variety produced more forage than CUF 101 in both 1993 and 1994, but the varieties Tillman and Moapa had higher total production during the two year period The varieties Rio and WL 516 had least amounts of forage production over the two year period, primarily due to low production in 1993. Percentage bloom and plant height were very highly correlated from the July 1993 harvest. Total forage production from 1993 -1994 may be correlated to the bloom and height measurements taken in 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 AB19182 each had fewer than 180, 000 crowns per acre.