Tuesday, November 6, 2007
151-10

Spatial Yield Response of Corn and Cotton on a Coastal Plain Loamy Sand.

Philip Bauer1, James Frederick2, Warren Busscher1, and Jeffrey Novak1. (1) USDA-ARS, USDA/ARS Coastal Plains Research Center, 2611 W. Lucas St., Florence, SC 29501-1241, (2) Clemson University, Pee Dee Res. & Education Ctr., 2200 Pocket Rd., Florence, SC 29506-9706

A substantial amount of the yield variation in many coastal plain fields in the southeast is related to soil differences in and around poorly drained depression areas. We conducted a six-year study to evaluate the influence of management system and soil map unit on corn (Zea mays L.) and cotton (Gossypium hirsutum L.) yields. A 5.7-ha field was split approximately in half in 1997 with conventional management used on one-half of the field and conservation management on the other half. From 1999 through 2004, corn and cotton were rotated annually on the field. Crop yield was measured using yield monitors. Although differences in yield occurred between conventional and conservation management on specific soils for both crops, spatial yield trends were similar for the two management systems. The two crops had opposite spatial yield trends. Corn yields tended to be highest on soils near the depression area while cotton yields were highest on soils furthest from the depression area. The contrasting spatial yield response of these two crops appeared at least partially due water availability during the months when yield was most vulnerable to water deficit stress. Averaged over the three years that corn was grown, potential evapotranspiration (ET) was 86 mm greater than rainfall during June and July. For cotton, potential ET was only 14.6 mm greater than rainfall during July and August. These results are useful for developing site-specific management principles for these two crops in the southeastern coastal plain.