Bioenergy sorghum ( L. Moench) is a promising crop for contributing to the United States bioenergy supply. However, the varying limitations of the marginal lands targeted for its cultivation present a management challenge. This two-year study aimed to investigate how the limitations associated with marginal cropland impact the effects of nitrogen fertilization on the yield of bioenergy sorghum and the uptake of 11 macro- (N, P, K, Ca, Mg, and S) and micronutrients (Fe, Mn, Zn, Cu, and B). The study contrasted prime cropland in central Illinois (Urbana) with three marginal cropland sites in southern (Ewing) and central Illinois (Fairbury and Pesotum). These marginal cropland sites are characterized by varying limitations, including low soil fertility (P and K limitations), leaching and erosion, and flooding, respectively. Four nitrogen rates (0, 56, 112, and 168 kg N ha) were tested under eight environments. The average yields and ranges of sorghum biomass were 20.2 (17.0–23.2) Mg ha in Urbana, 18.1 (13.1–19.8) Mg ha in Ewing, 13.8 (9.0–17.3) Mg ha in Fairbury, and 23.3 (14.6–33.0) Mg ha in Pesotum. Optimal N rates were 56 N in Pesotum and 112 N in Urbana, Ewing, and Fairbury. Tissue macronutrient contents in Urbana were generally higher than in the marginal croplands, while micronutrient contents did not show discernible trends. Increasing N rate generally correlated with the macronutrient removal except in Ewing. Comparable sorghum biomass yields were observed between prime and marginal croplands (averaging 18.3 Mg ha), but optimal N rates varied between 56 N and 112 N. This suggests that yield gaps can be narrowed by applying the optimal N rates for the respective locations. However, increased removals of macronutrients, especially P and K, with increasing yields indicate the need to revise fertilizer recommendations, particularly for soils deficient in these nutrients. Our study suggests that while sorghum production on marginal cropland is feasible, N management needs to be adapted to the unique limitations associated with various types of marginal cropland.

中文翻译：

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优化伊利诺伊州生物能源高粱生产力和养分去除：不同边缘条件下氮肥的影响


生物能源高粱（L. Moench）是一种有前景的作物，可为美国生物能源供应做出贡献。然而，用于耕种的边际土地的不同限制带来了管理挑战。这项为期两年的研究旨在调查与边际农田相关的限制如何影响氮肥对生物能源高粱产量以及 11 种常量营养素（N、P、K、Ca、Mg 和 S）和微量营养素的吸收的影响（铁、锰、锌、铜和硼）。该研究将伊利诺伊州中部（厄巴纳）的主要农田与伊利诺伊州南部（尤因）和中部（费尔伯里和比索图姆）的三个边缘农田进行了对比。这些边缘农田地点具有不同的限制，包括土壤肥力低（磷和钾限制）、淋滤和侵蚀以及洪水。在八个环境下测试了四种施氮量（0、56、112 和 168kgN ha）。高粱生物量的平均产量和范围为厄巴纳 (Urbana) 20.2 (17.0–23.2) 镁·公顷 (Mg ha)、尤因 (Ewing) 18.1 (13.1–19.8) 镁·公顷 (Mg ha)、费尔伯里 (Fairbury) 13.8 (9.0–17.3) 镁·公顷 (Mg ha) 和 23.3 (14.6–33.0) 镁·公顷哈比索图姆。 Pesotum 的最佳施氮量为 56N，厄巴纳 (Urbana)、尤因 (Ewing) 和费尔伯里 (Fairbury) 的最佳施氮量为 112N。厄巴纳的组织大量营养素含量普遍高于边缘农田，而微量营养素含量没有显示出明显的趋势。除尤文外，氮肥施用量的增加通常与常量营养素的去除相关。在主要农田和边际农田之间观察到可比的高粱生物量产量（平均 18.3 毫克公顷），但最佳施氮量在 56N 和 112N 之间变化，这表明通过对各个地点应用最佳施氮量可以缩小产量差距。 然而，大量营养素（尤其是磷和钾）的去除量随着产量的增加而增加，表明需要修改肥料建议，特别是对于缺乏这些营养素的土壤。我们的研究表明，虽然边际农田生产高粱是可行的，但氮肥管理需要适应与各种类型边际农田相关的独特限制。