The results of a study conducted in Latvia on the life cycle analysis of substrates have been published in the influential journal of environmental sciences “Journal of Cleaner Production“.
In a study conducted by scientists from Riga Technical University (RTU) titled “Peat Production for Horticulture in the Context of Latvia: Sustainability Assessment Using Life Cycle Analysis Modeling“, it was found that the use of peat substrate in horticulture has up to seven times less overall environmental impact compared to more commonly used horticultural methods and alternative substrates in the European Union. This significant finding suggests that peat may offer a more environmentally favorable solution for growing media, particularly when its full life cycle is considered.
Research has shown that peat substrate can have up to seven times less overall environmental impact compared to other growing media. This suggests that, despite concerns about the sustainability of peat harvesting, its use as a substrate may be more environmentally favorable in certain contexts. Peat is known for its excellent water retention and nutrient-holding capabilities, which makes it highly effective for plant growth.
However, the environmental impact of peat is often debated due to the slow regeneration of peat bogs and the release of stored carbon during extraction. This research highlights that, with responsible management and sustainable harvesting practices, peat substrates could potentially offer a more eco-friendly option than alternative substrates, which may require more energy or resources to produce.
Study highlights
• Sustainable management of the peat extraction for the Latvian context.
• Cradle-to-grave life cycle assessment of peat substrate for horticultural use.
• Comparison with coir pith and rock wool substrates.
• Highest impact from the distribution of the final product and the peat extraction.
• Coir pith has the highest impact, followed by rock wool and peat.
Abstract
The study, published in October in the Journal of Cleaner Production, one of the most influential scientific journals in the field of environmental sciences, was based on a detailed life cycle analysis of the peat substrate. The analysis was carried out at one of Latvia’s largest peat extraction and processing companies. The research underscores the importance of considering the entire life cycle of peat production and its environmental impact, offering valuable insights into the sustainable use of peat in horticulture.
Latvia is one of the European states with the highest percentage of relative cover of peat and peat-topped soils (0–30 cm) (Montanarella et al., 2006). Peatlands in Latvia are not equally distributed in the national territory. In addition, their age and prerequisites for development are different depending on the region.
Study results
Currently, up to 86% of the substrates used in the European Union (EU) for growing food, tree seedlings, and ornamental plants rely on soil fertilizers derived directly from peat. About one-third of this peat is sourced from Latvia. Despite longstanding efforts to find alternatives to peat substrates, these attempts have been largely unsuccessful.
A study conducted by Riga Technical University (RTU) assessed the environmental impacts of horticultural peat substrates and two commonly used alternatives—coconut fiber (coir) and mineral wool substrates—across factors such as human health, climate change, resource use, and ecosystem quality. The study found that the coir substrate had the largest overall environmental impact, scoring 48.51 mPt (milliEcoPoints, an internationally recognized ecological indicator), followed by the mineral wool substrate at 10.6 mPt. In comparison, the peat substrate had an impact of just 6.79 mPt, indicating that peat used in horticulture has up to seven times less environmental impact than coir and one and a half times less than mineral wool.
Peat also demonstrated the best performance regarding greenhouse gas (GHG) emissions associated with global warming. Emissions from coir substrate per cubic meter amounted to 47 kg of CO₂ equivalent, mineral wool substrate emissions were 32.1 kg CO₂ equivalent, while peat substrate emissions were only 20.2 kg CO₂ equivalent. This highlights peat as the more environmentally friendly option, especially in terms of reducing GHG emissions.
“The research makes it possible to justify the sustainability of horticultural peat extraction companies and reaffirms that peat is part of the European Green Deal, helping to achieve climate neutrality goals. There are no suitable substitutes for peat substrate in horticulture.”
This statement emphasizes the importance of peat as a sustainable resource in horticulture, particularly in light of the European Green Deal’s objectives for climate neutrality. The findings suggest that, despite ongoing efforts, no viable alternatives to peat substrates have been found that can match its environmental and horticultural benefits.
Conclusions
This study aims to assess and estimate the potential environmental impacts of the life cycle of peat produced in a Latvian context, comparing it with two other horticultural substrates: coir pith and rock wool. The environmental profile of peat is primarily influenced by three dominant processes: distribution, extraction, and, to a lesser extent, refinement and the use phase. Specifically:
- Distribution to end customers represents the most significant contribution across nearly all environmental impact indicators.
These findings help highlight the role of peat in horticulture and its relatively lower environmental footprint compared to alternative substrates. Further details and analysis of the specific contributions of extraction, refinement, and usage phases would help inform more sustainable horticultural practices.