|Frederick, James - CLEMSON UNIV|
Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 2, 1996
Publication Date: N/A
Interpretive Summary: Farmers generally till their fields with disks or plows to provide a good seedbed and to loosen the soil before planting wheat in the southeastern United States. However, using these conventional tillage implements that bury all of the previous crop residues can increase soil erosion and decrease the speed in which rainfall can enter the soil. New conservation tillage planters are available that can perform well even when the previou crop residues are still on the soil surface, but very little information is available about the best way to use them for producing wheat. We found that as long as a tool that loosened the soil without disturbing surface residues was used before planting, wheat yield with conservation tillage was the same (wet year) or 25% higher (dry year) as conventional tillage yield. This information is important to extension personnel and wheat farmers and because it provides a method of producing wheat that will decrease soil erosion and may increase yield.
Technical Abstract: Little is known about the effects of surface and deep tillage systems on winter wheat development and grain yield on the Coastal Plain. The objectives of this experiment were 1) to determine whether surface tillage affects the grain yield response of winter wheat to deep tillage, and 2) to examine the effects of surface and deep tillage on winter wheat development. The experiment was conducted on a sandy Coastal Plain soil i 1994 and 1995. Treatments were surface residue management (double disked and no surface tillage) and deep tillage (deep tilled and no deep tillage). Averaged over years and levels of deep tillage, the number of emerged seedlings was 16% lower in the plots having no surface tillage (NST) than in the plots which were double disked (DD). With deep tillage, the NST and DD wheat had a similar number of heads per m2, indicating that the NST wheat produced more heads per plant than the DD wheat. Deep tillage increased plant dry weight, kernel number per unit area, and grain yield more for the NST wheat than for the DD wheat. When deep tilled, grain yields of the NST and DD wheat were similar in 1994 but were 25% higher for the NST wheat in the drier year of 1995. Results from this study indicate there may be no need to incorporate surface residues if deep tillage is performed and the proper planting equipment is used to produce winter wheat on the southeastern Coastal plain. Yield increases due to deep tillage in this region appear to be greater for NST wheat than for DD wheat.