Intermediate wheatgrass [Thinopyrum intermedium (Host) Barkworth & D.R. Dewey] is a cool‐season perennial forage grass, whose grain is commercialized in the United States as “Kernza.” Its extensive root system may help in reducing soil erosion, water pollution, and C emissions. Nitrogen fertilization and forage harvest intensity may affect the belowground biomass and nonstructural carbohydrate (NSC) concentrations, which may affect growth in subsequent years. We compared N doses and forage harvest treatments in a replicated complete block experiment in three environments (location‐years: Arlington, WI, 2016 and 2017; and St. Paul, MN, 2016). Seeds were sown in the fall, Kernza grain was harvested in the following summer, and rhizomes and roots were sampled in fall to a depth of 0.1 m over 2 yr. The water‐soluble carbohydrates (WSC) accounted for 97–99% of NSC, across environments. The WSC concentration was higher in rhizomes than in roots in both years, but WSC mass was higher in roots than rhizomes due to greater root biomass. Nitrogen generally did not change NSC concentrations across years, but reduced WSC in rhizome the second year in WI. Forage harvest did not affect NSC concentrations across locations and years. Belowground biomass to 1‐m depth in the fall of the second year in Wisconsin averaged 478.3 g m⁻² regardless of treatment. Summer forage yield in the following year was positively associated with root biomass in the fall. These results suggest that harvesting forage in a Kernza dual‐use system is not detrimental to intermediate wheatgrass above‐ and belowground productivity.

中文翻译：

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氮和牧草的收获如何影响两用克恩萨州中级小麦草的地下生物量和非结构性碳水化合物？

中间麦草[中间偃麦草（主持人Barkworth和DR Dewey）是一种凉爽的多年生牧草，其谷物在美国以“ Kernza”的形式商业化。其广泛的根系可能有助于减少水土流失，水污染和碳排放。氮肥和牧草的收获强度可能会影响地下生物量和非结构性碳水化合物（NSC）的浓度，这可能会影响随后几年的生长。我们在三种环境中重复进行的完全区组试验中比较了N剂量和牧草收获的处理方法（地点年份：威斯康星州阿灵顿，2016年和2017年；圣保罗，明尼苏达州，2016年）。秋季播种，第二年夏天收获克恩察籽粒，并在2年内秋季取样根茎和根，深度为0.1 m。在整个环境中，水溶性碳水化合物（WSC）占NSC的97–99％。两年中，根茎中的WSC浓度均高于根，但由于根生物量较高，根中的WSC量高于根茎。氮通常在数年内不会改变NSC的浓度，但在WI的第二年降低了根茎中的WSC。牧草收获不会影响各地和年份的NSC浓度。在第二年秋天，威斯康星州地下生物量达到1米深度，平均为478.3克^−2，无论处理如何。第二年的夏季牧草产量与秋季的根生物量呈正相关。这些结果表明，在克恩扎（Kernza）双重用途系统中收获草料对中间和地下地下小麦草的生产力无害。