Tillage systems for cotton-peanut rotations following winter-annual grazing: impact on soil carbon, nitrogen and physical properties

Authors: SIRI-PRIETO, G - U DE LA REP O DEL URUGUAY; Reeves, Donald; Raper, Randy

Submitted to: Soil & Tillage Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/21/2006
Publication Date: 8/10/2007
Citation: Siri-Prieto, G., Reeves, D.W., Raper, R.L. 2007. Tillage systems for cotton-peanut rotations following winter-annual grazing: impact on soil carbon, nitrogen and physical properties. Soil & Tillage Research. 96:260-268.

Interpretive Summary: Southern producers are interested in systems that integrate winter-grazing of cattle with summer crops like cotton and peanut to generate additional income. But grazing can result in excessive soil compaction from cattle trampling. 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 and peanut with winter-annual cattle grazing. They grazed oat and ryegrass during winter with stocker cattle and tested four tillage systems in a cotton-peanut rotation following grazing each year. They measured soil compaction, water infiltration, and soil carbon (organic matter) at the end of the study. No-tillage resulted in the greatest soil compaction and lowest infiltration. Non-inversion tillage with a bent-leg subsoiler (paratilling) prior to cotton or peanut planting, especially without surface-soil tillage, reduced soil compaction up to 16-inches deep, increased infiltration by 83%, and increased soil carbon 38% near the soil surface after 3-yr, suggesting an improvement in soil quality. Integrating winter-annual grazing using paratilling in a conservation tillage system proved successful in improving soil physical properties and increasing soil carbon. This information can be used by extension specialists, USDA-NRCS, crop consultants, and producers to promote the use of environmentally and economically sustainable conservation practices on over 4 million acres of cotton and peanut in the Southeast.

Technical Abstract: Integrating livestock with cotton (Gossypium hirsutum L.) and peanut (Arachis hypogaea L.) production systems by grazing winter-annuals can offer additional income for producers provided it does not result in excessive soil compaction. We conducted a 3-yr field study on a Dothan loamy sand (fine-loamy, kaolinitic, thermic Plinthic Kandiudults) in south Alabama USA to determine the influence of tillage system prior to cotton-peanut planting on soil properties following winter-annual grazing. Two winter annual forages [oat (Avena sativa L.) and annual ryegrass (Lolium mutiflorum L.)] and four tillage practices [chisel + disk, non-inversion deep tillage (paratill) with and without disking and no-till] were evaluated in a strip-plot design of four replications. We evaluated cone index, bulk density, infiltration, soil organic carbon (SOC), and total nitrogen (N). Paratilling prior to cotton or peanut planting, especially without surface-soil tillage, reduced compaction initially to 40-cm and residually to 30-cm through the grazing period in winter. There were no significant differences in cone index, bulk density, or infiltration between forage species. No-tillage resulted in the greatest bulk density (1.65 Mg m-3) and lowest infiltration (36% of water applied), while paratilling increased infiltration in no-tillage to 83%. Paratilling also increased SOC 38% and N 56% near the soil surface (0-5 cm) after 3-yr, suggesting an improvement in soil quality. For coastal plain soils, integrating winter annual grazing in a cotton-peanut rotation using deep tillage (paratill) in a conservation tillage system can improve soil quality by reducing cone index, increasing infiltration, and increasing SOC in the soil surface.