Make a choice: A rapid strategy for minimizing peat in horticultural press pots substrates using a constrained mixture design and surface response approach

Abstract

Peat is the most common used substrate in horticultural seedling production. To reduce peat in horticultural potted plant cultivation systems in general is an obstacle, even within the highly specialized horticultural industry. Next to soil-less cultivation systems as e.g. hydroponics, the horticultural industry is eagerly looking for suitable peat substitutes. The demands on these compounds are high, basically mimicking the physical properties of peat. A 100% replacement of peat for press-pots used in seedling production has not yet been found, and only mixes of peat and substrates exist. Several suitable peat substitutes with different properties are known, that usually are used as a share of a mixed peat-substitute substrate. A constrained mixture design was used to test substrates containing 50% v/v and 25% v/v peat and four peat substitutes (two composts and two wood fibers) for vegetable seedling production. By limiting the maximum quantities of each material to be added, there was no negative effect on the growth of Chinese cabbage (Brassica rapa subsp. pekinensis). This means a reduction in of peat to 25% v/v is possible without a change in substrate quality. The mixture design allowed a quick decision to be made regarding the most suitable peat-reduced mixtures. The surface response approach enabled the experimental results to be easily transferred to horticultural practices, additionally. This flexible and efficient method also allows the predictions to be used to meet specific crop management needs.

Investigating the Effect of Hydrafiber and Biochar as a Substitute for Peat-Based Substrate for Zinnia (Zinnia elegans) and Snapdragon (Antirrhinum majus) Production

“…In the United States, peat moss accounts for more than 80% usage of growing media in horticulture [1]. Peat moss has excellent chemical and physical properties for plant growth and development, such as high water-holding capacity, high cation exchange capacity, high air space, and light weight [2][3][4]. However, while having beneficial properties, peat moss faces issues with rewetting and nutrient leaching due to its hydrophobicity [5].…”

“…However, while having beneficial properties, peat moss faces issues with rewetting and nutrient leaching due to its hydrophobicity [5]. In addition, the extensive exploitation of peatlands for farming and agricultural purposes has raised significant environmental concerns [3,4]. Peatlands are crucial reservoirs of terrestrial carbon and play a pivotal role in the global carbon cycle [5][6][7].…”

“…Biochar (BC) is rich in carbon and made of a variety of renewable feedstocks such as green wastes, coconut coir, rice hull, and wood bark that undergoes pyrolysis at 400 • C Horticulturae 2024, 10, 589 2 of 13 to 1200 • C with absent or limited oxygen [3,4,10]. Recent research has highlighted the potential of BC as a cost-effective and environmentally friendly option for container plant production.…”

“…The raw materials of BC can be made from local industries and farms, which reduces the costs of transportation [4]. Substituting peat moss with BC could reduce peat moss harvesting, and protect the peatland ecosystem [3]. Biochar provides many advantages, including enhancing plant nutrient uptake and water use efficiency and mitigating nutrient leaching [5,8,[11][12][13].…”