|Siri-Prieto, G - UNIV DE LA REP URUGUAY|
|Gamble, B - AUBURN UNIVERSITY|
Submitted to: Southern Conservation Tillage Systems Conference
Publication Type: Proceedings
Publication Acceptance Date: April 15, 2005
Publication Date: June 27, 2005
Citation: Siri-Prieto, G., Reeves, D.W., Raper, R.L., Gamble, B.E. 2005. Forage and tillage systems for integrating winter-grazed stocker cattle in cotton production. In: Proceedings of the 27th Southern Conservation Tillage Systems Conference, Florence, SC, June 27-29, 2005. p. 160-161. Interpretive Summary: Southeastern cotton producers can generate greater income if they could double-crop cattle and cotton, i.e., graze cotton in winter and follow with cotton planted in spring. But grazing can result in excessive soil compaction by cattle trampling, which can severely limit cotton yields. ARS scientists at the J. Phil Campbell Sr. Natural Resource Conservation Center, Watkinsville, GA and the Soil Dynamics Research Unit in Auburn, AL, cooperated with scientists from Auburn University and the University of the Republic of Uruguay to conduct a 3-year field study to develop a conservation tillage system for integrating cotton with winter-annual cattle grazing. They grazed oat and ryegrass during winter with stocker cattle and tested eight tillage systems for cotton planted after the cattle were removed in April each year. Tillage systems included: moldboard and chisel plowing; and combinations of non-inversion deep tillage (none, in-row subsoil or paratill) with and without disking. Net returns over variable costs from winter-annual grazing were between $75 to $81/acre/year. Oat increased cotton stands an average of 25% and seed-cotton yield by 7% compared to ryegrass. Non-inversion deep tillage in no-till, especially with a paratill, following grazed oat provided the greatest cotton yields(3535 lb seed-cotton/acre). This information can be used by extension specialists, USDA-NRCS, crop consultants, and producers to increase farm profits and promote the use of environmentally and economically sustainable conservation practices on the 4 million acres of cotton grown in the Southeast.
Technical Abstract: Winter grazing cattle followed by cotton (Gossypium hirsutum L.) offers profits for producers, but could result in soil water depletion and soil compaction. We conducted a 3-yr field study on a Dothan loamy sand (fine-loamy, kaolinitic, thermic Plinthic Kandiudults) to develop a conservation tillage system for integrating cotton with winter-annual grazing of stocker cattle. Winter annual forages and tillage systems were evaluated in a strip-plot design where winter forages were oat (Avena sativa L.) and annual ryegrass (Lolium mutiflorum L.). Tillage systems included: moldboard and chisel plowing; and combinations of non-inversion deep tillage (none, in-row subsoil or paratill) with/without disking. We evaluated forage dry matter, N concentration, average daily gain, net returns from grazing, soil water content, and cotton leaf stomatal conductance, plant populations and yield. Net returns from winter-annual grazing were between $75 to $81/acre/year. Soil water content was reduced 15% with conventional tillage or deep tillage compared to strict no-tillage, suggesting that cotton rooting was increased by these systems. Oat increased cotton stands an average of 25% and seed-cotton yield by 7% compared to ryegrass. Strict no-tillage resulted in the lowest yields; 30% less than the overall mean (3295 lb seed-cotton/acre). Non-inversion deep tillage in no-till (especially paratill) following oat was the best tillage system combination (3535 lb seed-cotton/acre) but deep tillage did not increase cotton yields in conventional tillage systems. Integrating winter-annual grazing can be achieved in the Coastal Plain using non-inversion deep tillage following oat in a conservation tillage system, providing producers extra income while protecting the soil resource.