|Frederick, James - CLEMSON UNIV|
Submitted to: Annual Southern Conservation Tillage Conference for Sustainable Agriculture
Publication Type: Proceedings
Publication Acceptance Date: March 15, 1997
Publication Date: N/A
Interpretive Summary: Stubble is plant debris that remains in the field after harvest and is important for optimum conservation tillage crop production. Wheat is a common winter crop in the southeastern USA that leaves substantial amounts of stubble when only the seeds are harvested. Flax is a potentially new winter crop for the area. Following a flax crop, there is almost no stubble remaining because the straw is harvested for its fiber. We conducted this study to determine the effect of winter cash crop on a succeeding cotton crop that was grown with conservation tillage techniques. We found that for non-irrigated production, there was no difference in yield between cotton grown after flax and cotton grown after wheat. When irrigated, cotton lint yield following a wheat crop was higher than lint yield following a flax crop. Scientists designing production systems for southeastern USA farmers can use this information to develop strategies for summer crops that are grown after winter crops that leave few residues on the soil surface.
Technical Abstract: Flax (Linum usitatissum) is a potential winter crop for production in the southeastern USA. Both the seed and the straw of flax are harvested; thus, few residues are left after flax harvest to protect the soil surface. Our objective was to compare conservation tillage cotton (Gossypium hirsutum) production following flax to production following winter wheat (Triticum aestivum), with and without supplemental irrigation. Adjacent irrigated and rainfed experiments were conducted on a Goldsboro sandy loam soil. Wheat and flax were planted in November 1992 and 1994. Spring N rate treatments applied to the winter crop were 0, 20, 40, and 60 lb N/ac. Cotton was planted immediately after winter crop harvest in June 1993 and 1995. Supplemental irrigation was applied with a traveling gun system to the irrigated study when tensiometers at the 9-in. depth in the irrigated plots reached -30 centibars. Rainfed cotton yields averaged 557 lb lint/ac, and neither year nor winter crop had a significant impact on yield. Irrigated cotton yield was greater in 1994 (893 lb lint/ac) than in 1996 (617 lb lint/ac). In the irrigated experiment, cotton following wheat yielded 84 lb lint/ac more than cotton following flax. Innovative production strategies are needed to improve the yield of double-cropped cotton produced with conservation tillage, especially when it is double cropped with low residue crops like flax.