Author
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Yost, Matt |
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RANDALL, B - Dow Agro Sciences |
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Kitchen, Newell |
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HEATON, E - Iowa State University |
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MYERS, ROBERT - University Of Missouri |
Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 1/6/2017 Publication Date: 1/12/2017 Citation: Yost, M.A., Randall, B.K., Kitchen, N.R., Heaton, E.A., Myers, R.L. 2017. Yield potential and nitrogen requirements of Miscanthus × giganteus on eroded soil. Agronomy Journal. 109(2):684-695. doi: 10.2134/agronj2016.10.0582. Interpretive Summary: Giant Miscanthus is one of the most productive renewable energy feedstock options and also is emerging as an industrial crop for use as soluble fiber. Several studies in the United States and Europe have measured yield and nitrogen fertilizer requirements of Miscanthus on marginal or eroded soils. However, none of these studies have been conducted on eroded soils with a restrictive claypan, which typically have low organic matter, high nitrogen loss, and variable water availability. Research was conducted at four sites near Columbia, Missouri during 2013 to 2015 to determine yield and nitrogen requirements of young (1 to 3 years old) and mature (6 to 8 years old) stands. Results indicated that: i) miscanthus yield on eroded claypan soil was similar to that on many other eroded and some productive soils in the United States; ii) a priming fertilizer strategy (more fertilizer upfront and less later) had no advantages over constant annual rates; iii) 67 kg N ha-1 yr-1 was the lowest rate that maximized yield; and iv) leaf chlorophyll concentration is an accurate indicator of response to nitrogen fertilizer. These results demonstrate that miscanthus can be productive on eroded claypan soils and that the infrequent yield response to nitrogen fertilization can be predicted. This information will enable consultants and producers to accurately predict when miscanthus requires nitrogen fertilization, thereby saving resources, improving profits, and reducing environmental harm of excessive nitrogen. Technical Abstract: Miscanthus × giganteus yield and fertilizer N requirements have been well studied in Europe and parts of the United States, but few reports have investigated its production on eroded claypan soils economically marginal for grain crops. This study was conducted to evaluate yield potential and fertilizer N strategies for young and mature M. × giganteus on eroded soils. Constant (medium, high) and priming (low, medium, high) fertilizer N rates were applied during 2013 to 2015 at three locations to young stands planted in 2012. Constant rates (low, medium, high) also were applied to one mature stand planted in 2007. Winter biomass yield (13.3-23.8 Mg/ha) was comparable to more productive soils and increased with N fertilization at only two sites with young stands. At one location, yield increased by 44, 48, and 82% with fertilization in 2013, 2014, and 2015, respectively, while the other location increased by 43% only in 2015. At both locations, the medium constant rate (67 kg N/ha/yr) was the lowest rate that maximized total yield across three years. This rate was efficient as it did not increase N removal in harvested biomass. Fertilization always increased leaf chlorophyll concentration (LCC) and site-years with relative LCC <0.85 had yield response to N, while those at or above this level did not. Nitrogen fertilization is not always needed for M. × giganteus on eroded soils low in organic matter and relative LCC should accurately identify when fertilization is required. |