Submitted to: Communications in Soil Science and Plant Analysis
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/11/2012
Publication Date: 10/23/2012
Citation: Pikul Jr, J.L., Osborne, S.L., Riedell, W.E. 2012. Corn yield and nitrogen-and water-use under no-tillage rotations in the northern corn belt. Communications in Soil Science and Plant Analysis. 43:2722-2734. Interpretive Summary: Diversified crop rotations have potential to increase nitrogen use efficiency (NUE) and reduce fertilizer nitrogen (N) requirements for corn. The similarity of NUE values among rotations, except continuous corn (CC), suggests that the timing and availability of N, presumably from microbial decomposition of organic matter during the growing season, were equal even in those rotations having extended use of legumes. This result was unexpected and might reflect that the soil is still in transition under no tillage and additional years will be required before a rotation benefit is realized. Soil water use efficiency (WUE) was greatest under the three-year rotations of corn-soybean-oat/pea hay (CSH) and corn-soybean-wheat (CSW). On average, WUE of rotated corn was about 50 percent greater than CC. However, in three of eight years there were no differences in WUE among rotations. At corn planting, the five-year rotation of corn-soybean-oat/pea hay companion seeded with alfalfa-alfalfa-alfalfa (CSHAA) had significantly less soil water than all other rotations. However, soil water use between June 1 and Sept 30 among all rotations was not different and largely insignificant in respect to water available for use by corn. Corn predominately used growing season precipitation. Average (years) corn yield was the same under CSH, CSHAA, and CSW, and this yield exceeded corn-soybean (CS) and CC by 8% and 54%, respectively. In years with low spring rainfall, yield advantage of rotation was greatest under CSW (54%) and least under CSHAA (33%). Corn yield under extended rotations (CSH, CSW, and CSHAA) was greater than CC and CS, but lack of early-season rainfall may result in reduced yields under CSHAA.
Technical Abstract: Increased crop diversity and length of rotation may improve corn (Zea mays L.) yield, water and nitrogen use efficiency. The objectives of this study were to determine effects of crop rotation on corn yield, water use, and nitrogen use. No-tillage crop rotations were started in 1997 on a Barnes clay loam (fine-loamy, mixed, superactive, frigid Calcic Hapludoll) near Brookings, SD. 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.) 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 to corn on all rotations at planting (16 kg N/ha) and side dressed (64 kg N/ha). Average corn grain yield (1998-2007) was greatest under CSW (7.38 Mg/ha) and least under CC (4.66 Mg/ha). Yield was not different among CSH, CSW, and CSHAA rotations. Water use efficiency of rotation was ordered as CSW>CSH>CSHAA>CS>CC. Nitrogen use efficiency was greatest under CSW and least under CC. There were no differences in yield advantage (YA) among crop rotations during years with plentiful early-season rainfall (May 1 – July 31). In years with low spring rainfall, YA was greatest under CSW (54%) and least under CSHAA (33%). Corn yield under extended rotations (CSH, CSW, and CSHAA) was greater than CC and CS, but lack of rainfall may result in reduced yields under CSHAA.