Open Access

ARTICLE

Evaluation of N sources, cover crops, and tillage systems for corn grown under organic management

Suarez Tapia A¹, MB Villamil¹, LJ Grabau²

1 Department of Crop Sciences, University of Illinois, 1102 S. Goodwin Ave. Urbana, IL, 61801, USA.
2 Professor, Department of Plant and Soil Sciences, University of Kentucky, 10 1100 Nicholasville Rd, Lexington, KY, USA.

* Corresponding Author:Address Correspondence to: María B. Villamil, Assistant Professor, Department of Crop Sciences, University of Illinois, 1102 S. Goodwin Ave. Urbana, IL, 61801, USA. (217) 333 4690, e-mail:

Phyton-International Journal of Experimental Botany 2014, 83(all), 71-81. https://doi.org/10.32604/phyton.2014.83.071

Abstract

Public demand for healthier foods and more sustainable food systems in the U.S. has triggered market prices and production of organic alternatives of major crops such as corn (Zea mays L.). Two cover crops and their interactions with tillage systems, N sources and N rates were studied to evaluate the possibility of using these agronomic practices to facilitate growing corn under organic management in Kentucky. A split-split plot design in a RCBD with four replications was evaluated in three environments (SP08, UKR08, UKR09). The main plot treatments were cover crops [hairy vetch, HV (Vicia villosa Roth) and rye (Secale cereale L.)], the split plots were tillage systems [no-till (NT) and moldboard plow (MP)], and the split-split plots were the N treatment factorial combinations including two N sources [Louisville Green (LG) and Nature Safe (NF)] at four rates of N (45, 90, 135 and 180 kg N/ha plus a common control). In addition we conducted a laboratory study of nitrate release for the two selected N sources. Results showed the MP/HV combination resulted in the highest yields at all experimental sites followed by HV/NT. Ear leaf N and grain N content were higher under HV compared with rye at all sites. Nature Safe as N source, increased ear leaf N and grain N more than LG in all experimental sites, and increased yield at two of the three environments. Laboratory incubation studies showed that both N sources stopped mineralizing at 28 days after application, releasing, 55 kg N/ha on average. The MP/HV/NF treatment combination was the best management combination for organic corn production in the environments we studied.

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