Department of Plant Sciences, University of Wyoming, 1000 East University Avenue, Laramie, WY 82071, USA.
Environ Entomol. 2021 Aug 12;50(4):832-841. doi: 10.1093/ee/nvab026.
Interseeding cover crops into standing grains can promote both agronomic and environmental benefits within agroecosystems. Producers must decide which cover crops are the best fit for their goals, and whether diverse cover crop mixtures provide benefits that are worth the increased seed cost. Broadcast seeding is an accessible strategy to try interseeding but can lead to patchy establishment; it is unknown how much seed loss is due to seed predators. In a two-year study, six cover crop species-planted as either single species or mixtures-were interseeded into standing corn. We evaluated seed predation at the time of seeding, agronomic impact through cover crop, and weedy biomass at the end of the season, and conservation impact through activity-density of ground beetles (Coleoptera: Carabidae). Cover crop seeds were vulnerable to seed predation, primarily by vertebrate seed predators, and seed loss varied across cover crop species. Cover crop biomass did not differ according to cover crop diversity and weedy biomass was not affected by cover crop presence or species. Cover crop diversity effects on carabid activity-density were inconsistent: carabids were higher in diverse mixtures in 1 year of the study, but only predicted by vegetative cover, not by cover crop, in the second year. Interseeding cover crops into corn has potential benefits for ground beetles, although the value of mixtures must be further explored.
在农业生态系统中，间作覆盖作物可以促进农业和环境效益。生产者必须决定哪种覆盖作物最适合他们的目标，以及多样化的覆盖作物混合物是否提供了值得增加种子成本的好处。撒播是一种可行的间作策略，但可能导致播种不均匀；尚不清楚有多少种子因种子捕食者而损失。在一项为期两年的研究中，将六种覆盖作物（单一种植或混合种植）间作到站立的玉米中。我们评估了播种时的种子捕食情况、通过覆盖作物的农艺影响以及季节结束时的杂草生物量，以及通过地面甲虫（鞘翅目：Carabidae）的活动密度的保护影响。覆盖作物种子易受种子捕食者的侵害，主要是脊椎动物种子捕食者，并且种子损失因覆盖作物种类而异。覆盖作物生物量与覆盖作物多样性无关，杂草生物量不受覆盖作物存在或种类的影响。覆盖作物多样性对步甲类活动密度的影响不一致：在研究的 1 年内，多样化混合物中的步甲类更高，但在第二年仅由植被覆盖预测，而不是由覆盖作物预测。将覆盖作物间作到玉米中对步甲类具有潜在的益处，尽管混合物的价值还需要进一步探索。
