| Abstrakt: |
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 in Missouri 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-1) 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-1 yr-1) was the lowest rate that maximized total yield across 3 yr. This rate was efficient as it did not increase N removal in harvested biomass. Fertilization always increased leaf chlorophyll concentration (LCC) and siteyears 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 with low organic matter content, and relative LCC can accurately identify when fertilization is required. [ABSTRACT FROM AUTHOR] |
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