|Baumhardt, Roland - Louis|
Submitted to: Agricultural Experiment Station Publication
Publication Type: Experiment station
Publication Acceptance Date: 11/1/2003
Publication Date: 12/15/2003
Citation: Baumhardt, R.L., Bean, B.W. 2004. Increasing returns of sorghum production systems with alternate summer crops and cattle grazing in rotations. Agricultural Experiment Station Publication. 4 p. Available: http://sorghum.tamu.edu/report_database/files/sub129/nnan.BAUM_PRFT-03rtn-rpt.pdf. Interpretive Summary:
Technical Abstract: Under dryland conditions, the wheat-sorghum-fallow (WSF) crop rotation consistently produces two crops in three years where 1/3rd of the land is cropped to wheat, 1/3rd is in sorghum, and the rest is fallowed. We investigated methods to increase cropping intensity by: 1) grazing cattle on wheat forage and sorghum stubble of the WSF rotation; and 2) annual summer cropping of continuous grain sorghum or sorghum grown in rotation with cotton, soybean, and sunflower. Rain during the 2000-2003 growing seasons was below normal and imposed drought on the sorghum, cotton, soybean, and sunflower crops. These crops struggled to establish seedlings and, subsequently, to reach physiological maturity and produce a yield. Fallow precipitation stored as soil water was crucial to crop growth during these droughts. Sunflower and cotton were better suited to annual rotation with sorghum than soybean, but annually cropped sorghum and the sorghum-cotton rotation produced the most consistent yields. Grazing cattle on dryland wheat and sorghum residues intensified dryland production of the WSF rotation. The winter growing conditions produced sufficient wheat forage to provide 32 days grazing with a mean 124.7 lbs/ac gain. Except for graze-out in 2001, wheat grain yields were unaffected by grazing. Without wheat residue (graze-out), however, the soil water storage during fallow was negligible and the subsequent sorghum crop failed. Timely removal of grazing cattle from wheat preserves residue accumulation, water conservation, and subsequent sorghum grain yield. With stubblemulch tillage residue management during fallow we observed no soil compaction with grazing. Our data suggest that grazing dryland wheat successfully increases the overall WSF cropping system productivity provided wheat residues are not consumed by graze-out.