Agroforestry adoptition is gaining considerable traction in the temperate US with growing popularity and government incentives (e.g., the Partnerships for Climate-Smart Commodities Project) for systems with greenhouse gas mitigation potential. The identification of complementary species combinations will accelerate the expansion of temperate agroforestry. Since the mid-19th century, European timber plantations have taken advantage of the late-leafing habit of walnut (Juglans spp.) to grow a spring grain crop between the tree rows. Such alley cropping systems increase land-use efficiency and provide extensive environmental benefits. A parallel but underutilized opportunity in North American involves incorporating eastern black walnut (Juglans nigra L.) cultivars into alley cropping systems (ACS). Eastern black walnut, henceforth referred to as black walnut, is native to North America and exhibits architectural and phenological characters for reduced competition with winter cereal crops grown in alleys. Black walnut also produces nutritious nuts, and cultivars with improved kernel percentage and mass offer potential to cultivate the species as a domesticated orchard crop, as opposed to just the high-quality timber for which it is well-known. However, field observations suggest significant variation in tree architecture and phenology amongst cultivars, which is likely to influence complementarity with winter grains. Comprehensive characterization of trait genetic diversity is needed to best leverage germplasm into productive systems. Here, we review literature related to implementing ACS with consideration of cultivar-dependent traits that may reduce interspecific competition. While the focus is directed toward black walnut, broad characterization of other underutilized fruit/nut species will allow for robust diversification of ACS.

随着越来越受欢迎以及政府对具有温室气体减排潜力的系统的激励措施（例如气候智能型商品合作伙伴项目），农林业的采用在美国温带地区获得了相当大的吸引力。互补物种组合的识别将加速温带农林业的扩张。自 19 世纪中叶以来，欧洲木材种植园利用核桃（Juglans spp.）的晚叶习性在树行之间种植春季谷物作物。这种小巷耕作系统提高了土地利用效率并提供了广泛的环境效益。北美的一个类似但未充分利用的机会是将东部黑核桃 ( Juglans nigra L.) 品种纳入胡同种植系统 (ACS)。东部黑胡桃，以下简称黑胡桃，原产于北美，具有结构和物候特征，可减少与小巷种植的冬季谷物作物的竞争。黑胡桃还生产营养丰富的坚果，具有改善的仁率和质量的品种提供了将该物种作为驯化果园作物种植的潜力，而不仅仅是其闻名的优质木材。然而，实地观察表明品种之间的树木结构和物候存在显着差异，这可能会影响与冬季谷物的互补性。需要对性状遗传多样性进行全面表征，以便最好地利用种质进入生产系统。在这里，我们回顾了与实施 ACS 相关的文献，并考虑了可能减少种间竞争的品种依赖性状。虽然重点是黑胡桃，但其他未充分利用的水果/坚果品种的广泛特征将使 ACS 实现强劲的多样化。