ENABLING MANAGEMENT RESPONSE OF SOUTHEASTERN AGRICULTURAL CROP AND PASTURE SYSTEMS TO CLIMATE CHANGE
Location: National Soil Dynamics Laboratory
Title: Cover crop biomass harvest influences cotton nitrogen utilization and productivity
Submitted to: International Journal of Agronomy
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 16, 2012
Publication Date: May 21, 2012
Citation: Ducamp, F., Arriaga, F.J., Balkcom, K.S., Prior, S.A., Van Santen, E., Mitchell, C.C. 2012. Cover crop biomass harvest influences cotton nitrogen utilization and productivity. International Journal of Agronomy. Article 420624, 12 pages. doi:10.1155/2012/420624. Available: http://www.hindawi.com/journals/ija/2012/420624/.
Interpretive Summary: Recently, it has been proposed that winter cover crop biomass could be used as an alternative source of energy or for feeding animals. Our objective was to evaluate if such practices could impact nitrogen requirements and cotton yields in a conservation cropping system. Our findings indicated that a rye cover crop can benefit cotton, but the removal of rye residue may lower seed cotton yields during hotter and dryer years. More longer-term studies are required to completely understand the effect of cover crop residue removal in conservation tillage systems.
Winter cover crops planted in cotton (Gossypium hirsutum L.) fields in the southeastern US could be harvested for biofuels or animal feed use. This practice could impact cotton yields and its response to nitrogen (N) fertilization. An experiment in central Alabama examined the effect of rye (Secale cereale L.) residue management (RM) and N rates on cotton productivity during 2006 and 2007. The three RM treatments were: No winter cover crop (NC), rye residue removed (REM) and rye residue retained (RET). Four N rates for cotton (0, 50, 100 and 140 kg ha-1) were also studied. Cotton population, leaf and plant N concentration, cotton biomass and N uptake at first square, and cotton biomass production between first square and cutout were higher for RET, followed by REM and NC. However, leaf N concentration at early bloom and N concentration in the cotton biomass produced between first square and cutout were higher for NC, followed by REM and RET. All cotton growth parameters increased with increasing N rates when averaged across rye RM treatments. Seed cotton yield response to N interacted with year and RM. In 2006, the highest estimated seed cotton yield was about3,950 kg ha-1 for RET and REM, with an application of 140 kg N ha-1. In 2007, maximum predicted seed cotton yields for RET and REM were 2,660 and 2,460 kg ha-1, with an estimated N application of 125 and 106 kg N ha-1, respectively. In both years, the lowest observed seed cotton yields corresponded to NC. These results indicate that rye used as a cover crop can be beneficial for cotton. Rye residue removal may reduce seed cotton yields only during hotter and dryer years. Long-term studies would be required to completely understand the effect of rye residue removal on cotton production under conservation tillage.