|Morrison Jr, John|
Submitted to: Annual Southern Conservation Tillage Conference for Sustainable Agriculture
Publication Type: Abstract Only
Publication Acceptance Date: July 9, 2001
Publication Date: July 9, 2001
Citation: Torbert, H.A., Potter, K.N., Morrison, J.E. Tillage systems and N fertilizer practices effect on corn yields in the Texas Blackland Prairie. Proceedings of the 24th Annual Southern Conservation Tillage Conference for Sustainable Agriculture. 2001. p. 61. Technical Abstract: In 1994, an experiment was established to determine plant response to N fertilizer rate and timing within three tillage systems within the Blackland Prairie of Texas. A split plot experiment with 4 replications was established with corn on a Houston Black clay. The main plots were a chisel tillage system without beds, a chisel tillage system with raised wide beds, and a no tillage system with raised wide beds. The subplots were seven soil fertility treatments, consisting of four fertility rates (0, 56, 112, and 168 kg N ha**-1) applied at planting and three fertilizer application timing treatments (fall, at planting, and split between at planting and 30 d later). Plant samples were collected for grain yield, biomass production, and N uptake. During this study, there were two years of low rainfall conditions and two years of high rainfall conditions. The highest yields were observed with the no tillage system, with large differences observed between no tillage and the other tillage systems in low rainfall years. In wet years, grain yields and N uptake increased with N application up to 168 kg N ha**-1, while little effect was observed in the dry years. There was no indication of N limitations in the no-till system compared to the other tillage systems, indicating that there was no need to increase N application rates. While no benefit was realized from split application of N after planting, reductions in corn yields were observed with fall application of N in wet years. Fall application of N reduced yields 30% when compared with fertilizer application at planting. Highest yields were observed with the no-till system indicating that a conservation tillage system may be the most reliable system in Vertisols.