Cattle Impacts On Cotton Production On a Piedmont Landscape.

Grazing of winter annual cover crops may offset costs and increase farm revenue in conservation tillage systems. However, cattle may create management problems due to soil compaction and removal of surface residues which may cause potential loss of yield. We report on a four year study to evaluate grazing effects on conservation tillage cotton (Gossypium hirsutum L.) grown on Cecil soil (fine, kaolinitic, thermic, Typic Kanhapludult) at the USDA-ARS Research Center, Watkinsville, GA. In 2006 and 2007 cereal rye (Secale cereale L.) provided 4.0 to 4.5 Mg ha^-1 of forage, enough for 3.5 Angus heifers (Bos Taurus) ha^-1 between February 1st and April 15th. Rye consumed in 2008 was about ½ this amount due to dry weather.  The four year average forage consumption was 2.6 Mg ha^-1 (dry matter basis).  At $20 to $40 for a 365 kg round bale the forage value would equal $144 to $290 ha^-1. Because grazed rye quality is greater than baled forage and grazed forage also reduces labor, feeding losses and storage costs the adjusted equivalents to feeding hay is estimated closer to 3.1 Mg ha^-1 and value likely ranges from $170 to $350 ha^-1. Cotton lint yields averaged 1.3 Mg ha^-1 in 2006, 0.45 Mg ha^-1, and 0.89 Mg ha^-1 in 2008 with no differences due to grazing. In 2009, wet weather during the grazing period resulted in compaction on the grazed fields. Ungrazed fields produced significantly more cotton than the grazed treatment (0.64 Mg ha^-1 vs. 0.42 Mg ha^-1).  Returns from grazing rye can be profitable for cotton producers in the Southeast as long as cattle are managed to avoid excessive soil compaction and to leave sufficient residues for conservation practices.