Research Project:
INTEGRATED SOIL, CROP AND PEST MANAGEMENT FOR SUSTAINABLE AGRICULTURE
Location: Brookings, South Dakota
Title: CORN N UPTAKE AND YIELD IN DIVERSIFIED ROTATIONS UNDER NO TILLAGE
Author
Submitted to: Soil/Water Research, Progress Report
Publication Type:
Experiment Station
Publication Acceptance Date: March 25, 2004
Publication Date: March 25, 2004
Publisher's URL: http://plantsci.sdstate.edu/soilreports/
Citation: Pikul Jr, J.L. 2004. Corn N uptake and yield in diversified rotations under no tillage. In Soil Water Science Research in the Plant Science Department, 2003 Annual Report. South Dakota State University. Brookings, SD.
Interpretive Summary: Diversified crop rotations have potential to increase nitrogen use efficiency and reduce fertilizer nitrogen requirements for corn, but there is a poor understanding of associated effects on soil condition. Long-term field experiments provide benchmarks on crop response, soil quality, and the time frame associated with change. There was a significant corn-yield response to rotation. Greatest corn yield was under a corn-soybean-wheat rotation and this yield was significantly greater than under continuous corn and corn-soybean. After four years of no tillage, there were no significant differences among crop rotations in soil carbon. However, soil productivity is related to quantity and quality of soil organic matter. The ratio of soil carbon to nitrogen has consistently narrowed on all rotations and this may be a consequence of no tillage. The similarity of nitrogen use values among rotations, except continuous corn, suggests that there were no differences in the amount of nitrogen transformed (mineralized) from organic to inorganic forms during the growing season, and this finding might reflect that the soil is in transition (unstable carbon to nitrogen ratio) and will require several more years before a rotation benefit is realized.
Technical Abstract: Increased length of rotation and increased crop diversity may improve efficiency of water and nitrogen (N) use by corn (Zea mays L.) and soil quality. Objectives were to determine the effect of diversified crop rotation on soil carbon sequestration, N-fertilizer use efficiency (NUE) of corn, and water use efficiency (WUE) of corn. An experiment was started in 1997 on a Barnes clay loam (fine-loamy, mixed, superactive, frigid Calcic Hapludoll) near Brookings, South Dakota. All rotations were under no tillage. Rotations were continuous corn (CC), corn-soybean [Glycine max (L.) Merr.] (CS), a 3-year rotation of corn-soybean-oat/pea (Avena sativa L. and Pisum sativum L. mix) hay (CSH), a 3-year rotation of corn-soybean-spring wheat (Triticum aestivum L.) (CSW), and a 5-year rotation of corn-soybean-oat/pea hay companion seeded with alfalfa (Medicago sativa L.)-alfalfa-alfalfa (CSHAA). Fertilizer N was applied at the same rate to all rotations. Average (years) starter N was 16 kg N/ha, with an additional 62 kg N/ha side dressed as ammonia nitrate. Average corn grain yield (1998-2003) was significantly (p=0.001) greater under CSW (6790 kg/ha) compared with CC (4000 kg/ha). Yield was not different among CSH, CSW, and CSHAA rotations. Water use efficiency was significantly (p=0.001) greater under CSH and CSW and ordered as CSW>CSH>CS=CSHAA>CC. Nitrogen use efficiency was significantly (p=0.002) less under CC compared with other rotations. There were no differences among rotations in total soil C and N in the top 15 cm. Average (rotations) C:N ratio significantly narrowed across years. Diversified rotations have potential to increase corn yield and efficiency of water and N use.
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