Centro de Investigação de Montanha (CIMO), Instituto Politécnico de Bragança, Campus de Santa Apolónia, 5300-253, Bragança, Portugal.
J Environ Manage. 2021 Apr 15;284:112105. doi: 10.1016/j.jenvman.2021.112105. Epub 2021 Feb 7.
The harvesting of hops (Humulus lupulus L.) generates large amounts of nutrient-rich leaves that can be used in composting mixtures to add value to other organic resources on the farm. In this study, hop leaves were mixed with cow manure and wheat straw in several combinations with the aim of establishing guidelines on how farmers can manage the raw materials and better use these valuable organic resources. The composting process was monitored and the quality of the composts evaluated in relation to the effects on lettuce (Lactuca sativa L.) grown in pots over two consecutive cycles. The mixture of hop leaves with cow manure produced a stable compost after nine months of composting which may be used in horticultural crops, irrespective of the proportion of raw materials, due to their low and similar C/N ratios. However, when using mixtures of leaves and straw in proportions of less than 2:1, the composts did not mature properly, showing high C/N ratios. Their application to the soil led to a strong reduction in plant tissue N concentrations, due to biological N immobilization, which significantly reduced lettuce dry matter yield. Thus, to reduce composting time and increase the quality of the compost, the ratio leaves/straw should be as high as possible, at least 2:1. Alternatively, either the composting process should take longer, or the poorly-matured compost be applied far in advance of sowing a crop so that complementary biological processes can take place in the soil, as recorded in the second cycle of lettuce. Ash from hop stems did not benefit the composting process and proved itself not to be worth using in mixtures.
啤酒花（Humulus lupulus L.）的收获会产生大量营养丰富的叶子，可用于堆肥混合物中，为农场中的其他有机资源增值。在这项研究中，将啤酒花叶片与牛粪和小麦秸秆以几种组合混合，目的是为农民如何管理原材料和更好地利用这些有价值的有机资源制定指导方针。监测了堆肥过程，并评估了堆肥对连续两个周期在花盆中生长的生菜（Lactuca sativa L.）的影响。在九个月的堆肥后，啤酒花叶片与牛粪的混合物产生了稳定的堆肥，可用于园艺作物，而不论原材料的比例如何，因为它们的 C/N 比低且相似。然而，当以小于 2:1 的比例使用叶片和秸秆的混合物时，堆肥没有适当成熟，表现出高的 C/N 比。将其应用于土壤会导致由于生物固氮而导致植物组织 N 浓度大幅降低，这显著降低了生菜的干物质产量。因此，为了缩短堆肥时间并提高堆肥质量，叶片/秸秆的比例应尽可能高，至少为 2:1。或者，堆肥过程应延长，或者在播种作物之前尽早施用未成熟的堆肥，以便在土壤中发生互补的生物过程，如在生菜的第二个周期中所记录的那样。啤酒花茎的灰分不能使堆肥过程受益，事实证明它不值得在混合物中使用。
