Dryland Sorghum-Cotton Rotation Trial at AG-CARES, Lamesa, TX, 2000
Calvin Trostle & Jim Barber, Sorghum PROFIT, TAEX-Lubbock; Danny Carmichael, TAES-Lubbock. firstname.lastname@example.org, (806) 746-6101
METHODS AND PROCEDURES (for sorghum planting):
Soil Type: Amarillo fine sandy loam
Planting: June 14, 2000 on 40” rows
Previous Crop: Sorghum
Seeding Rate: ~32,000 seeds/acre with vacuum planter (about 2.0 to 2.3 lbs./acre) and ~65,000 seeds/acre (about 4.0 to 4.5 lbs./acre)
Plot Set-up: Three blocks of 128 rows X 880’ long. Within each block there are four 32-row strips of which one is sorghum (seeding rate, residue, and N treatments) and three are cotton (two 32-row strips for Year 2001 and year 2002 rotation; one 32-row strip for continuous cotton)
Harvest Area: Drought loss on all treatments
Rainfall: See Lamesa area summary elsewhere in the AG-CARES report
Date Harvested: None
RESULTS AND DISCUSSION:
No harvestable yield was obtained for sorghum in 2000 due to drought.
A long-term 2:1 cotton-sorghum dryland rotation was established over 25 acres in three blocks (see table). At AGCARES Novartis KS 524 was seeded at two rates including 4 lbs./A, a high seeding rate that is too often used by growers in dryland sorghum. Sorghum residues in December 2000 were either cut with a stalk cutter or left standing. We believe the latter residue treatment may offer an advantage over cut stubble by reducing wind erosion or eliminating the need for sandfighting. Nitrogen treatments for sorghum were not applied due to the drought conditions.
For subsequent years the rotation program for sorghum and cotton is in place in spite of no yield data for 2000. Evaluation of sorghum rotation and sorghum residue effects on cotton will be compared to continuous cotton in addition to seeding rate and nitrogen work in sorghum.
Figure 1. AGCARES dryland arrangement of 1:2 sorghum-cotton rotation with continuous cotton comparison (26 acres).