Kernza intermediate wheatgrass is a new perennial grain crop with the potential to produce high nutritive value forage when intercropped with legumes. Understanding the potential benefits of intercropping systems requires considering the interaction between different legume species intercropped, intermediate wheatgrass row spacing, and environments encompassing spatial and temporal variation. We aimed to evaluate the effect of these factors on the biomass allocation to harvestable (grain, intermediate wheatgrass forage, legume forage) and non-harvestable (weed biomass) outputs. In four environments, given by the combination of two sites (Wisconsin, USA) and two establishment years, we sowed intermediate wheatgrass in two row spacings in eight cropping systems: three intermediate wheatgrass monocultures [control without N fertilization, intermediate wheatgrass fertilized with 45 or 90 kg N ha as urea], and four intermediate wheatgrass-legume intercrops (intermediate wheatgrass with alfalfa, Berseem clover, Kura clover, or red clover). We evaluate grain yields, intermediate wheatgrass and legume forage, and weed biomass over three consecutive years. Our results suggest that intercropping legumes does not affect Kernza grain yield in the first grain production year, which is the year with the highest yield potential. In subsequent production years, grain yields were lower in red clover intercrops than in intermediate wheatgrass monoculture control or fertilized, depending on the environment. Among the legumes tested in our study, red clover and alfalfa were suitable for increasing total biomass production in most of the environments and red clover reduced weed biomass compared to intermediate wheatgrass monocultures. Our results encourage intercropping legumes with intermediate wheatgrass because of the increase in forage yield and quality. These benefits can compensate for lower Kernza grain yields commonly observed in the second and third production years. Our study provides valuable insights into the intermediate wheatgrass potential as a dual-use crop for grain and forage production. Improving our understanding of the factors that influence grain yield and forage production such as post-harvest management, multiple forage harvests or grazing, may optimize the productivity and sustainability of these cropping systems.

中文翻译：

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饲料增加还是谷物忧郁？豆类选择塑造 Kernza 中间小麦草两用作物性能


Kernza 中间小麦草是一种新的多年生谷物作物，与豆类间作时具有生产高营养价值饲料的潜力。了解间作系统的潜在效益需要考虑间作的不同豆类物种、中间小麦草行距以及包含空间和时间变化的环境之间的相互作用。我们的目的是评估这些因素对可收获（谷物、中间小麦草饲料、豆类饲料）和不可收获（杂草生物量）产出的生物量分配的影响。在四种环境中，结合两个地点（美国威斯康星州）和两个种植年份，我们在八个种植系统中以两行间距播种中型小麦草：三种中型小麦草单一栽培[对照不施氮肥，中型小麦草施肥 45 或90 千克 N·公顷（作为尿素）]，以及四种中间小麦草-豆科间作作物（中间小麦草与苜蓿、Berseem 三叶草、库拉三叶草或红三叶草）。我们连续三年评估了谷物产量、中间小麦草和豆科饲料以及杂草生物量。我们的研究结果表明，间作豆类不会影响粮食生产第一年（即产量潜力最高的年份）Kernza 的粮食产量。在随后的生产年份中，红三叶草间作作物的谷物产量低于中间小麦草单一栽培对照或施肥的谷物产量，具体取决于环境。在我们研究中测试的豆类中，红三叶草和苜蓿适合在大多数环境中增加总生物量生产，并且与中间小麦草单一栽培相比，红三叶草减少了杂草生物量。 我们的研究结果鼓励豆类与中间小麦草间作，因为可以提高饲料产量和质量。这些效益可以弥补第二和第三生产年常见的肯扎谷物产量较低的情况。我们的研究为中间小麦草作为谷物和饲料生产的双重用途作物的潜力提供了宝贵的见解。提高我们对影响粮食产量和饲料生产的因素（例如收获后管理、多次饲料收获或放牧）的了解，可能会优化这些种植系统的生产力和可持续性。