Nerlich Annika, Dannehl Dennis
Division Biosystems Engineering, Faculty of Life Sciences, Albrecht Daniel Thaer-Institute of Agricultural and Horticultural Sciences, Humboldt University of Berlin, Berlin, Germany.
Front Plant Sci. 2021 Jan 18;11:601455. doi: 10.3389/fpls.2020.601455. eCollection 2020.
In agriculture, the increasing scarcity of arable land and the increase in extreme weather conditions has led to a large proportion of crops, especially vegetables, being cultivated in protected soilless cultivation methods to provide people with sufficient and high-quality food. Rockwool has been used for decades as a soil substitute in soilless cultivation. Since rockwool is not biodegradable, it is disposed in landfills after its use, which nowadays leads to ecological concerns and drives the search for alternative substrates, especially organic materials. The objectives of this study were to investigate the effects of organic materials (wood chips, sphagnum moss, and hemp fibers) in relation to rockwool substrate on plant growth and quality of lettuce as a result of physical and chemical properties of the mentioned substrates. We were able to show that sphagnum moss is a suitable substitute substrate for lettuce cultivation, contrary to hemp. All investigated substrates presented good physical properties, but differed in their decomposition stability. Within 8 weeks, 30% of the hemp and about 10% of both sphagnum and wood materials were degraded. It was concluded that the increased microbiological activity immobilized nitrogen and led to oxygen deficiency in the rhizosphere and resulted in increased phenolic acid contents in lettuce but poor yield on hemp. Sphagnum caused a pH decrease and accumulation of ammonium in the nutrient solution and allowed the highest yield for lettuce at moderate phenolic acid contents. Low yields were obtained on wood, which could possibly be increased by optimized nutrient solution, so that wood as an alternative to rockwool was not excluded. By applying used organic substrates as soil additives on arable land, the nutrients accumulated in it might fertilize the open field crops, thus saving mineral fertilizers. This, together with the avoidance of waste, would contribute to a greater sustainability.
在农业领域，可耕地日益稀缺以及极端天气条件不断增加，导致很大一部分作物，尤其是蔬菜，采用保护性无土栽培方法种植，以向人们提供充足且优质的食物。岩棉作为无土栽培中的土壤替代品已使用了数十年。由于岩棉不可生物降解，使用后被丢弃在垃圾填埋场，如今这引发了生态问题，并促使人们寻找替代基质，尤其是有机材料。本研究的目的是研究有机材料（木屑、泥炭藓和麻纤维）与岩棉基质相比，因其上述基质的物理和化学性质对生菜生长和品质的影响。我们能够证明，与麻不同，泥炭藓是生菜种植的合适替代基质。所有研究的基质都具有良好的物理性质，但在分解稳定性方面存在差异。在8周内，30%的麻以及约10%的泥炭藓和木材材料被降解。得出的结论是，微生物活性增加固定了氮，导致根际缺氧，进而导致生菜中酚酸含量增加，但麻的产量较低。泥炭藓导致营养液pH值下降和铵积累，并在酚酸含量适中时使生菜产量最高。木材的产量较低，通过优化营养液可能会提高产量，因此不排除木材作为岩棉替代品的可能性。通过将用过的有机基质作为土壤添加剂施用于耕地，其中积累的养分可能会为露地作物施肥，从而节省矿物肥料。这与避免浪费一起，将有助于提高可持续性。
