TITLE:

             Guar Varieties and Dryland Guar-Cotton Rotation Trial at AG-CARES, Lamesa, TX, 2001

             (Call for to request report of final results)

AUTHOR:

Calvin Trostle, Texas Cooperative Extension--Lubbock; Danny Carmichael, TAES-Lubbock,

c-trostle@tamu.edu, (806) 746-6101

METHODS AND PROCEDURES (for guar planting):

Soil Type:                Amarillo fine sandy loam

Planting:                  Guar, June 29, 2001 on 40” rows; cotton, May 18, 2001

Previous Crop:        Cotton

             Seeding Rate:          80,000 seeds/acre with vacuum planter (~6.5 lbs./A)

Plot Set-up:             Four replicated strips, test area per variety 4 rows X 75’

Harvest Area:          2 rows X 26’2”

Fertilizer:                 Treatments included 30 lbs. P2O5/A or 30 lbs. actual N/A vs. unfertilized

Herbicide:               1.0 pt Treflan

Insecticide:              None

Rainfall:                  See summary in AG-CARES report, 2.32” from June 29-Oct. 31

Date Harvested:       December 12

RESULTS AND DISCUSSION:

No economically harvestable yield was obtained for cotton in 2001 due to drought. Guar threshing results are not yet available. Please call for a complete report.

A long-term 2:1 cotton-guar dryland rotation was established in 2000 at AG-CARES as well as continuous cotton strips to gauge guar production among four varieties (Esser, Kinman, Lewis, and Santa Cruz), nitrogen and phosphorus applications, and different Bradyrhizobium treatments. No treatments were applied to the cotton. Continuous cotton is maintained to compare the rotational benefit of guar to cotton.

Guar was seeded on June 29 into minimal moisture at 1.5” deep. A stand was achieved among Kinman, Lewis, Esser, and Santa Cruz varieties at approximately 45,000 plants/A. Cotton was damaged by hail then in early June zeroed by insurance. The remaining cotton plants, however, were maintained so as to not lose the rotation for 2002 if any later rain might occur to generate a minimum of cotton growth.

Bradyrhizobium treatments for guar inoculation. Planter box seed inoculant treatments prior to 2001 for guar have given little if any nodule development when applied at about 1 pouch per 100 lbs. of seed. These products include Liphatech’s seedbox inoculant, which to apply properly requires wetting of the guar seed to adhere the inoculant, and Urbana Lab’s RhizoStick (seedbox treatment which contains a sticker). Because some peanut Bradyrhizobium strains cross inoculate guar in the laboratory, we tested 1 gallon of Liphatech liquid Lift diluted to 5 gallons then poured on four 10-foot lengths of row at planting. No differences were observed in any treatment vs. the control (no inoculant), and average plant nodule number was less than one. Seedbox inoculants in West Texas often fail. Lower biological numbers in seedbox inoculants, high soil pH, and hot soil temperatures are the most likely reasons.

For more information about guar check with your local ag. agent, Calvin Trostle, or the Texas A&M—Lubbock website at http://lubbock.tamu.edu