|Lee, R - UNIVERSITY OF GEORGIA|
|Pippin, R - UNIVERSITY OF GEORGIA|
Submitted to: Southern Conservation Tillage for Sustainable Agriculture Proceedings
Publication Type: Proceedings
Publication Acceptance Date: June 24, 2002
Publication Date: June 24, 2002
Citation: Lee, R.D., Reeves, D.W., Pippin, R., Walker, J.A. 2002. High-residue conservation system for corn and cotton in georgia. In: Van Santen, E., editor. Proceedings of the 25th Annual Southern Conservation Tillage Conference for Sustainable Agriculture - Making Conservation tillage Conventional: Building a Future on 25 Years of Research. Special Report no. 1, Alabama Agricultural Experiment Station and Auburn University, June 24-26, Auburn, Alabama. p. 327-330. Interpretive Summary: Two limiting factors to crop yields in Georgia are short-term drought and root-restricting hard pans. ARS scientists in cooperation with University of Georgia researchers conducted a study on two Coastal Plain soils to develop a practical high-residue conservation tillage system that reduces risk of short-term drought and improves soil quality for corn and cotton. Combinations of deep tillage from a paratill and KMC in-row subsoiler; cover crops of wheat, black oat, and winter fallow; and no-tillage vs. disking were evaluated. Corn was grown in 1999 and 2000 and cotton in 2001. Corn grain yields at Tifton GA were increased by deep tillage both years and by disking in 2000. Black oat tended to increase corn yield, especially with in-row subsoiling. Cotton yields in 2001 were increased with deep tillage (either in-row subsoiling or paratilling) at both locations. Cotton yields were reduced in no-till when no cover crop was used but were higher under disking without a cover crop. This information can be used by extension, NRCS, and private-sector consultants to reduce risks from adoption of conservation tillage by recommending the use of deep tillage on sandy Coastal Plain soils.
Technical Abstract: Two limiting factors to crop yields in Georgia are short-term drought and root-restricting hard pans. The objectives of this study were to develop a practical high-residue conservation tillage system that reduces risk of short-term drought and improves soil quality for corn (Zea mays L.) and cotton (Gossypium hirsutum L.). A strip-split plot design was used to test the following treatment combinations under irrigation at Tifton and Plains GA in 1999-2001: 1) surface tillage (disk and field cultivate vs. no-till), 2) deep tillage (in-row subsoil, zonal paratill, and no-till), and 3) cover crops (black oat [Avena strigosa Schreb.), wheat (Triticum aestivum L.) and natural winter weed infestations. Corn was grown in 1999 and 2000. Cotton was planted in 2001. Grain yield differences were obtained only at the Tifton location. Corn grain yields were significantly higher (P 0.10) in the deep tillage plots compared to no deep tillage in both years and with surface tillage of residue in 2000. There was a strong trend for corn following a black oat cover crop to have the highest yields both years at Tifton, especially with in-row subsoiling. Cotton yields in 2001 were significantly higher with deep tillage (either in-row subsoiling or paratilling) at both locations (P 0.10). There was also an interaction of surface tillage and cover crops in cotton at Tifton. Cotton yields were highest with surface tillage with no cover but lowest in the no-till without a cover crop. These data suggest that without deep tillage, surface tillage, regardless of cover, is needed for best yields of irrigated corn and cotton on Tifton soils.