Principal investigators:

T.J. Arkebauer, K.G. Cassman, R.A. Drijber, A. Dobermann, J.L. Lindquist, J.P. Markwell, L.A. Nelson, J.E. Specht, D.T. Walters, H.Y. Yang

Duration: 1999-present

Funding: Potash & Phosphate Institute (PPI) / Foundation for Agronomic Research (FAR), Fluid Fertilizer Foundation (FFF), Nebraska Corn Board

Contact:

Achim Dobermann

University of Nebraska-Lincoln

Department of Agronomy and Horticulture

Lincoln, 68583-0915

adobermann2@unl.edu

(phone: 402-472-1501)

Project description:

In 1999, an interdisciplinary research team at the University of Nebraska established a field experiment to quantify and understand the yield potential of corn and soybean under irrigated conditions, identify efficient crop management practices to achieve yields that approach potential levels, and determine the energy use efficiency, global warming and soil C-sequestration potential of intensively managed corn systems.

This project is generating the quantitative understanding needed to fine-tune crop management for achieving yields of at least 70 to 80% of the yield potential under practical conditions. Data have been This project is generating the quantitative understanding needed to fine-tune crop management for achieving yields of at least 70 to 80% of the yield potential under practical conditions. Data have been used to developed a more accurate corn growth model, which is being used to create maps of yield potential and optimal planting dates and hybrid choice for corn as well as assessing key scenarios for soil C sequestration in corn-based systems. Knowledge, methods, and models derived from the detailed high-yield studies are applied in statewide research on nutrient recommendations for high corn yields across an agroecological gradient in Nebraska. This will lead to improved fertilizer recommendations, including the development of new fertilizer recommendation software.

Key results:

Present evidence, both in terms of available scientific field research data and understanding of crop physiology embodied in simulation models suggests a corn yield potential of about 300 bu/acre, with an amplitude of perhaps ±30 to 70 bu/acre, depending on location and year. Such ranges have been predicted by the Hybrid-Maize model for different environments and available experimental and yield contest data provide further evidence for this. Moreover, our field experiments and the yields achieved by top producers provide evidence that yield levels of 80 to 90% of Ymax are feasible and highly profitable under production conditions. They require, however, that crop management is based on scientific guidelines that aim at achieving high input use efficiency.

Data collected from 1999 to 2002 suggests that (i) high corn yields require higher plant density (37,000 to 44,000 plants/acre) and greater N and K uptake per unit yield, (ii) existing corn growth simulation models underestimate the actual dry matter production and yield measured at near-optimum growth conditions in the field, (iii) achieving high nitrogen use efficiencies at yield potential levels is possible, but requires a dynamic approach to N management, and (iv) the potential to increase soil carbon sequestration is greatest in continuous corn systems with intensive management. A new corn growth simulation model, Hybrid-Maize, will be released soon for practical use.

Publications:

2005

Doberman, A., D.T. Walters, F. Legoretta, T.J. Arkebauer, K.G. Cassman, R.A. Drijber, J.L. Lindquist, J.E. Spect, and H.S. Yang. 2005. In L.S. Murphy (ed.) Proceedings of the 2005 Fluid Forum, Vol. 22 [CD ROM]. Fluid Fertilizer Foundation, Manhattan,KS. [Full Paper]

2004

Arkebauer, T.J., A. Dobermann, K.G. Cassman, R.A. Drijber, J.L. Lindquist, J.E. Specht, D.T. Walters, and H.S. Yang. 2004. Changes in nitrogen use efficiency and soil quality after five years of managing for high yield corn and soybean. In L.S. Murphy (ed.) Fluid focus: the third decade. Proceedings of the 2003 Fluid Forum, Vol. 21. Fluid Fertilizer Foundation, Manhattan,KS. [Full Paper]

Yang, H.S., A. Dobermann, J.L. Lindquist, D.T. Walters, T.J. Arkebauer, and K.G. Cassman. 2004. Hybrid-Maize - a maize simulation model that combines two crop modeling approaches. Field Crops Res., in press [request reprint from hyang2@unl.edu]

2003

Cassman, K.G., Dobermann, A., Walters, D.T., Yang, H.S., 2003. Meeting cereal demand while protecting natural resources and improving environmental quality. Annu. Rev. Environ. Resour. 28:315-358. [request reprint from adobermann2@unl.edu]

Dobermann, A., T. Arkebauer, K.G. Cassman, R.A. Drijber, J.L. Lindquist, J.E. Specht, D.T. Walters, H. Yang, D. Miller, D.L. Binder, G. Teichmeier, R.B. Ferguson, and C.S. Wortmann. 2003. Understanding corn yield potential in different environments. p. 67-82. In L.S. Murphy (ed.) Fluid focus: the third decade. Proceedings of the 2003 Fluid Forum, Vol. 20. Fluid Fertilizer Foundation, Manhattan,KS. [Full Paper]

2002

Dobermann, A., and K.G. Cassman. 2002. Plant nutrient management for enhanced productivity in intensive grain production systems of the United States and Asia . Plant Soil 247:153-175. [PDF file attached]

Dobermann, A., T. Arkebauer, K.G. Cassman, R.A. Drijber, J. Lindquist, S. Madhavan, J. Markwell, L. Nelson, J.E. Specht, D.T. Walters, H.S. Yang, B. Amos, D.L. Binder, C. Murphy, and G. Teichmeier. 2002. Corn yield potential and optimal soil productivity in irrigated corn/soybean systems. p. 65-85. In L.S. Murphy (ed.) Proceedings of the 2002 Fluid Forum, Vol. 19. Fluid Fertilizer Foundation, Manhattan,KS. [Full Paper]

Dobermann, A., Arkebauer, T.J., Cassman, K.G., Lindquist, J.L., Specht, J.E., Walters, D.T., Yang, H.S., 2002. Understanding and managing corn yield potential. In: Proc. of the Fertilizer Industry Round Table, October 28-30, Charleston, SC. The Fertilizer Industry Round Table, Forest Hill, MD. [Full paper]

Dobermann, A., T.J. Arkebauer, K.G. Cassman, J.L. Lindquist, D.T. Walters, H.S. Yang, B. Amos, D.L. Binder, and G. Teichmeier. 2002. Understanding corn yield potential and optimal soil productivity in irrigated corn systems. p. 260-272. In A.J. Schlegel (ed.) Great Plains Soil Fertility Conference Proceedings, Vol. 9. Kansas State University, Manhattan, KS.

Cassman, K.G., A. Dobermann, and D.T. Walters. 2002. Agroecosystems, nitrogen-use efficiency, and nitrogen management. Ambio 31:132-140. [Full Paper]

2001

Arkebauer, T., K.G. Cassman, A. Dobermann, R.A. Drijber, J. Lindquist, Nelson.L., W.L. Powers, K. Russel, J.E. Specht, and D.T. Walters. 2001. Annual report to the Fluid Fertilizer Foundation: Yield potential and optimal soil productivity in irrigated corn systems of the North Central USA. p. 44-54. In L.S. Murphy (ed.) Proceedings of 2001 Fluid Forum, Vol. 18. Fluid Fertilizer Foundation, Manhattan,KS.

Dobermann, A. 2001. Crop potassium nutrition – implications for fertilizer recommendations. In Proc. of the 31^st North-Central Extension-Industry Soil Fertility Conference, November 14-15, 2001, Des Moines, IA. Potash & Phosphate Institute, Brookings, SD. [Full Paper]

1999

Cassman, K.G. 1999. Ecological intensification of cereal production systems: Yield potential, soil quality, and precision agriculture. Proc. Natl. Academy of Science 96:5952-5959.