Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/4/2014
Publication Date: 3/28/2014
Citation: Schomberg, H.H., Fisher, D.S., Reeves, D.W., Endale, D.M., Raper, R.L., Jayaratne, K., Gamble, G.R., Jenkins, M. 2014. Grazing winter rye cover crop in a cotton no-till system: yield and economics. Agronomy Journal. 106:1041-1050. DOI:10.2134/agronj13.0434. Interpretive Summary: Although most producers understand the benefits of cover crops to reduce soil erosion and improve soil quality, cover crop use in the US continues to be limited due to cost of establishment and potential for negative effects on the following cash crop. Grazing a rye cover crop with cattle during the spring can provide a farmer economic value to offset the cost of cover crop establishment. We evaluated the effects of grazing a rye cover crop on yield and economic returns in a conservation tillage cotton production system. The research was conducted in the Southern Piedmont near Watkinsville, GA from 2006 through 2009. Drought conditions during the four years resulted in lower than normal and highly variable cotton yields. The rye cover crop provided an average of 2.4 Mg ha-1 of forage for grazing. Cotton lint yield averaged 120 kg ha-1 greater in the non-grazed treatment but grazing did not affect cotton fiber quality. Gross economic returns varied between years with the difference between grazed and non-grazed treatments being $ -26, $355, $164, and $-170 ha-1 for 2006, 2007, 2008, and 2009, respectively with an average value $81 ha-1. A wet spring in the final year resulted in measurable soil compaction and lower yield in the grazed treatment. With good management, grazing has the potential to offset establishment costs of a rye cover crop and increase profits for cotton producers in the Southern Piedmont of the USA. This information will be useful to Extension Agents, NRCS personell, farmers and agricultural consultants. It will also be useful to scientists conducting research on mixed cropping and grazing systems.
Technical Abstract: Winter cover crop adoption in conservation management systems continues to be limited in the US but could be encouraged if establishment costs could be offset. A 4-yr field experiment was conducted near Watkinsville, Georgia in which a rye (Secale cereale L.) cover crop was either grazed by cattle (Bos taurus L.) or unharvested and rolled prior to planting cotton (Gossypium hirsutum L.). Drought conditions experienced during all four years of the study had a large effect on results. Cattle consumed about 2.4 Mg ha-1 of forage annually. Rye residue remaining at cotton planting was greater when non-grazed than when grazed (6.7 vs. 1.7 Mg ha-1). Cotton season average soil water content was greater in two years for the non-grazed treatment. Average lint yield was 120 kg ha-1 greater for the non-grazed treatment and cotton fiber quality parameters were generally better in the non-grazed treatment. The difference between grazed and non-grazed returns varied between years and were $ -26, $355, $164, and $-170 ha-1 for 2006, 2007, 2008, and 2009, respectively with an average value $81 ha-1. Although some negative effects of soil compaction were observed in the final year, returns from grazing have the potential to offset establishment costs of a rye cover crop and increase profits for cotton producers in the Southern Piedmont of the USA.