Siv Mari Aurdal
Postdoktor
(+47) 986 95 126
siv.aurdal@nibio.no
Sted
Ås - Bygg O43
Besøksadresse
Oluf Thesens vei 43, 1433 Ås (Varelevering: Elizabeth Stephansens vei 21)
Sammendrag
This study evaluates the effectiveness of various peat-free and peat-reduced growing media on the growth and yield of tomatoes and carrots, with the aim to develop sustainable alternatives to traditional peat-based substrates in horticulture. Thirty different growing media mixtures were tested, incorporating materials such as wood fiber, compost, biochar, bio-ash, and struvite, with the goal of identifying viable alternatives to peat. The experiments were conducted in greenhouse conditions, and the performance of these mixtures was assessed based on yield and overall vitality of tomato and carrot plants. The results revealed that fully peat-free mixtures generally underperformed compared to peat-based references. However, some peat-reduced mixtures with 30% peat in combination with wood fiber, compost, struvite or bio-ash demonstrated promising results. Bio-ash and struvite were evaluated as phosphorus sources, with findings suggesting that both materials can enhance substrate fertility when combined with appropriate nitrogen fertilizers. The effect of biochar was not very pronounced in general. Moreover, the addition of biochar was associated with a disappearance of plant-available nitrogen from the growing media, which likely contributed to its limited effectiveness in improving crop performance. The study underscores the continual challenge of completely phasing out peat in growing media for horticulture but highlights the potential of reducing it greatly and integrating more sustainable materials such as wood fiber and recycled materials such as compost, bio-ash and struvite. The results suggest that with further refinement, specific combinations of these materials could be developed into optimized substrate mixtures for sustainable horticultural practices without compromising productivity.
Forfattere
Siv Mari AurdalSammendrag
This paper is a historical review of scientific progress on horticultural growing media, with particular attention to the role of peat and the recurring search for sustainable alternatives. It is well established that peat became the cornerstone of horticultural growing media because it offered a unique combination of nutrient control, pH buffering, water retention, absence of harmful microorganisms, and structural stability. Equally evident are the environmental concerns and sustainability goals that have driven the search for alternative materials since the 1980s. This historical review traces the evolution of growing media from the early 20th century to the mid-2020s, focusing on how peat came to dominate and why its substitution has proven so difficult. Drawing on a wide range of literature, including peer-reviewed experimental studies, historical sources, symposia proceedings, institutional reports, and synthesis articles, the historical development of growing media science and practice across each decade is outlined. Attention is given to various composts, coir, wood fiber, bark, and biochar and challenges with these materials related to product standardization for end-user reliability. While many alternatives show potential, particularly as partial components or as stand-alone media under certain conditions, no single material currently offers a fully viable replacement for peat. Instead, the most promising direction appears to be peat-reduced mixtures optimized for both functionality and sustainability. By understanding how growing media science has evolved and where it has struggled, this paper identifies lessons critical to navigating the ongoing transition toward more sustainable and functional systems.
Sammendrag
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