Nitrogen Fertilization Effects on Irrigated No-Till Corn Production and Soil Carbon and Nitrogen
- Ardell D. Halvorson * and
- Claudia Pozzi Jantalia
- USDA-ARS, 2150 Centre Ave, Bldg. D, Ste. 100, Fort Collins, CO 80526; C.P. Jantalia, Embrapa Agrobiology, Road BR Km 7, Seropedica, Rio de Janeiro 23890-000, Brazil. Trade names and company names are included for the benefit of the reader and do not imply any endorsement or preferential treatment of the product by the authors or the USDA-ARS. USDA is an equal opportunity provider and employer. Contribution from USDA-ARS, Fort Collins, CO
Converting to no-till (NT) production can affect N requirements for optimizing corn (Zea mays L.) yields while enhancing soil organic carbon (SOC) and N levels. Nitrogen fertilization impacts on irrigated, NT continuous-corn grain, stalk, cob, and stover yields, stover C and N uptake, and C/N ratios were evaluated for 11 yr on a clay loam soil. Changes in SOC and total soil nitrogen (TSN) were also monitored. Grain, stalk, cob, and stover yields increased with increasing N rate, as did N and C uptake. The C/N ratio of stalk residue declined with increasing N rate, but cob C/N ratio was not affected, with an average stover C/N ratio of 68 at the highest N rate. Nitrogen fertilization increased SOC and TSN levels with average SOC and TSN mass rate gains with N application of 0.388, 0.321, and 0.160 Mg SOC ha−1 yr−1 and 0.063, 0.091, and 0.140 Mg TSN ha−1 yr−1 in the 0- to 7.6-, 0- to 15.2-, and 0- to 30.4-cm soil depths, respectively. The SOC and TSN mass rate changes were lower without N application. Increases in TSN appeared to be more rapid than SOC, resulting in a decline in the soil C/N ratio with time. Under irrigated, NT continuous corn production, N fertilization optimized grain and residue yields, with the enhanced benefit of increased SOC and TSN levels in the semiarid central Great Plains. Removal of cobs or partial stover residue as a cellulosic feedstock for ethanol production appears possible without negative effects on soil quality under irrigated, NT corn production.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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