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ARS Home » Plains Area » Brookings, South Dakota » Integrated Cropping Systems Research » Research » Publications at this Location » Publication #160025


item Pikul Jr, Joseph

Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 1/30/2004
Publication Date: 3/3/2004
Citation: Pikul Jr, J.L. 2004. Impact of diversified rotation on corn n uptake, yield, and soil quality. Proceedings, 2004 Great Plains Soil Fertility Conference, Denver, CO.

Interpretive Summary: Diversified crop rotations have potential to increase N-fertilizer use efficiency (NUE) and reduce fertilizer N 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. After four years of no tillage, there were no significant differences among crop rotations in soil C. However, soil productivity is related to quantity and quality of soil organic matter. The ratio of soil C:N has consistently narrowed on all rotations and this may be a consequence of no tillage. The similarity of NUE 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 C:N 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: 1) N-fertilizer use efficiency (NUE) of corn, 2) water use efficiency (WUE) of corn, and 3) temporal change in soil quality attributes. An experiment was started in 1997 on a Barnes clay loam (fine-loamy, mixed, superactive, frigid Calcic Hapludoll) near Brookings, South Dakota. All rotations are 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 has been 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. There were no differences (in 2003) among rotations in soil organic matter (loss on ignition), however particulate organic matter (POM) was significantly (p=0.002) greater under CSHAA compared with other rotations. Diversified rotations have potential to increase corn yield and efficiency of water and N use. Further, increased rotation diversity improved some soil attributes associated with soil quality.