Soilless Culture—An Intensive Production Method on Its Way to Sustainability

A special issue of Horticulturae (ISSN 2311-7524). This special issue belongs to the section "Protected Culture".

Deadline for manuscript submissions: closed (30 September 2023) | Viewed by 24129

Printed Edition Available!
A printed edition of this Special Issue is available here.

Special Issue Editors


E-Mail Website
Guest Editor
INRES—Institute of Crop Science and Resource Conservation, Division of Horticultural Sciences, University of Bonn, 53121 Bonn, Germany
Interests: vegetables; climate change; horticulture; soilless culture; growing media; protected cultivation; greenhouse production
Special Issues, Collections and Topics in MDPI journals

E-Mail Website
Guest Editor
MED—Mediterranean Institute for Agriculture, Environment and Development, Departamento de Fitotecnia, Escola de Ciências e Tecnologia, Universidade de Évora, Pólo da Mitra, Ap. 94, 7006-554 Évora, Portugal
Interests: vegetable crops; vegetable production systems; greenhouse and open-field systems; fertigation; root dynamics; salinity; organic fertilization and soilless cultivation
Special Issues, Collections and Topics in MDPI journals

E-Mail
Guest Editor
Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
Interests: horticulture; plant production systems; water quality; cropping systems; water purification; hydroponics; soilless culture

Special Issue Information

Dear Colleagues,

The prognosis suggests that the area of soilless culture will be dramatically increased in the future, both in protected and open field horticulture. This will be associated with the increased use of growing media in nurseries, herbaceous plants, such as vegetables, ornamentals, medicinal and aromatic plants, and some small fruits and woody crops. Soilless cultures are called intensive-sustainable systems. However, are they sustainable or on their way to being sustainable?

Today, solutions are needed to reduce or replace peat, increase nutrient and water use efficiency, and introduce circular waste flows. Using locally available and renewable raw materials, appropriate substrate mixtures, biostimulants, and adapted high techniques, such as Artificial Intelligence and the Internet of Things, could help us to construct a new strategy for cultivating soilless plants. This Special Issue aims to focus on recent progress in solutions to increase the sustainability of production in intensive horticulture without compromising yield and quality. Another objective will be to examine recent advances in the characterization and utilization of novel growing materials for plant production systems. On the other hand, reducing production costs is needed in these systems. Therefore, we welcome high-quality research publications and reviews covering all related topics in soilless culture and growing media and closely related research areas.

Prof. Dr. Nazim Gruda
Prof. Dr. Rui Manuel Almeida Machado
Dr. Erik van Os
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Horticulturae is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2200 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • abiotic and biotic stress management
  • artificial intelligence and the Internet of Things
  • biofortification
  • biostimulants for soilless culture systems
  • carbon footprints, lifecycle analysis, climate change, and intensive sustainable systems
  • compost utilization in growing media
  • circular growing media, alternative to peat and mineral wool
  • developments in remote growing
  • fertilization: threshold limits of sodium, etc.
  • green roof technology, vertical farming, and how to restrict costs and increase profitability
  • growing media analysis, formulation, and characterization and engineering
  • growing systems for new soilless crops, such as cannabis, freesia, and berries
  • novel inorganic and organic materials, such as waste and digestates, sphagnum moss, biochars, and hydrochars
  • organic soilless production
  • organic waste management and circular horticulture
  • organic fertilizers
  • pathogen elimination and cleaning pipework
  • plant propagation
  • recirculation of nutrient solution
  • root-medium properties, architecture, and plant nutrition
  • soilless culture and understanding of crop physiology and quality aspects
  • stability and biodegradation of growing media
  • water quality
  • water-/nutrient-use efficiency, automation

Published Papers (12 papers)

Order results
Result details
Select all
Export citation of selected articles as:

Editorial

Jump to: Research

5 pages, 200 KiB  
Editorial
Is Soilless Culture a Sustainable Form of Agriculture?
by Nazim S. Gruda, Rui M. A. Machado and Erik A. van Os
Horticulturae 2023, 9(11), 1190; https://doi.org/10.3390/horticulturae9111190 - 31 Oct 2023
Viewed by 1161
Abstract
A soilless culture system (SCS) is a technique used for plant production that has recently become increasingly popular [...] Full article

Research

Jump to: Editorial

14 pages, 1771 KiB  
Article
Using Respirometry to Investigate Biological Stability of Growing Media in Aerobic Conditions
by Sonia Newman, Paul Alexander, Neil Bragg and Graham Howell
Horticulturae 2023, 9(12), 1258; https://doi.org/10.3390/horticulturae9121258 - 23 Nov 2023
Viewed by 890
Abstract
Materials used to replace peat in growing media include wood fibre (WF), often used in combination with composted bark (BC), coir (CR), green compost (GC), and anaerobic digestate fibre (AD). The physical and chemical properties of these materials are relatively well characterised; however, [...] Read more.
Materials used to replace peat in growing media include wood fibre (WF), often used in combination with composted bark (BC), coir (CR), green compost (GC), and anaerobic digestate fibre (AD). The physical and chemical properties of these materials are relatively well characterised; however, biological properties are less well understood. Biological stability of growing media is an important factor in plant performance. The aim of this research was to identify whether dynamic respirometry methods are suitable for measuring growing media stability and to assess the effect of blending two raw materials in a mix. Raw materials were run for 42 days in aerated conditions at 35 °C. Except for AD, individually run samples were considered stable, with CO2 production over 7 days ranked BC < CR < WF < GC << AD in the early stages of the test. The AD was run at two moisture levels, with greater biological activity at lower moisture content. In the most active mixture, AD and WF, there was an increase of activity when nutrients were added at 28 days, indicating major elements were limiting microbial activity. There were interaction effects in sample mixtures, with the CO2 production of WF + GC, WF + CR greater than the sum of the CO2 production from the separate components. Full article
Show Figures

Figure 1

0 pages, 1143 KiB  
Article
Reusing Coir-Based Substrates for Lettuce Growth: Nutrient Content and Phytonutrients Accumulation
by Rui M. A. Machado, Isabel Alves-Pereira, Inês Alves, Rui M. A. Ferreira and Nazim S. Gruda
Horticulturae 2023, 9(10), 1080; https://doi.org/10.3390/horticulturae9101080 - 27 Sep 2023
Viewed by 1219
Abstract
This research aimed to assess the influence of reusing coir-based substrates on growth, nutrient content, and phytonutrients accumulation in lettuce. The experiment included a new coir pith and four coir-based mixes (1) coir, biochar, and perlite; (2) coir, compost, and perlite; (3) coir, [...] Read more.
This research aimed to assess the influence of reusing coir-based substrates on growth, nutrient content, and phytonutrients accumulation in lettuce. The experiment included a new coir pith and four coir-based mixes (1) coir, biochar, and perlite; (2) coir, compost, and perlite; (3) coir, biochar, and pine bark; and (4) coir, compost, and pine bark. All mixes had been previously utilized to grow transplanted spinach and possessed identical ratios of 78:12:10% (v/v) among their components. Lettuce (Lactuca sativa L. cv. ‘Godzilla’) seedlings were transplanted into Styrofoam plant boxes. Each day, the planting boxes received a nutrient solution via drip irrigation. Plants grown in reused mixes had similar macronutrient concentrations as those grown in coir for the first time, except for N and K in the third mix. Plants grown in reused mixtures had similar yields as those in new coir. Lettuce heads yielded 4.6–4.9 kg/m2, while plants grown in reused mixtures had equal or higher total phenols than those in new coir. Ascorbic acid content was higher in plants cultivated in reused mixes. Coir-based growing media can be reused for another short-cycle crop, like lettuce, without yield loss or phytonutrients decrease. Full article
Show Figures

Figure 1

23 pages, 5904 KiB  
Article
Peat Substitution in Horticulture: Interviews with German Growing Media Producers on the Transformation of the Resource Base
by Olivier Hirschler and Daniela Thrän
Horticulturae 2023, 9(8), 919; https://doi.org/10.3390/horticulturae9080919 - 11 Aug 2023
Viewed by 3202
Abstract
Peat is the major constituent of horticultural growing media. Due to its high climate footprint, its extraction and use are controversial and the need to limit its use is widely recognised. The Peat Use Reduction Strategy of the German government aims to phase [...] Read more.
Peat is the major constituent of horticultural growing media. Due to its high climate footprint, its extraction and use are controversial and the need to limit its use is widely recognised. The Peat Use Reduction Strategy of the German government aims to phase out its use and replace it with renewable materials. Despite large potential, stakeholders consider the availability of peat substitutes in sufficient quantity and quality as a critical issue. The goal of this research is to systematically investigate the challenges and opportunities for substituting peat in the resource base of the growing media industry. Based on deep-dive interviews with German growing media producers, the factors determining the supply and use of the main growing media constituents—peat, green compost, wood fibres, composted bark and coir products—were analysed. The results show the critical role of the processing infrastructure on transportation distances and the quality and quantity of the market supply. Additionally, competition with other sectors affects the availability of materials for the growing media industry. Moreover, peat is still economically advantageous compared with its substitutes. Even if this advantage declines due to consumer awareness and the end of domestic extraction, the end of peat use would probably imply new policy measures. Full article
Show Figures

Graphical abstract

20 pages, 3470 KiB  
Article
Performance Evaluation of a Cascade Cropping System
by Eleni Karatsivou, Angeliki Elvanidi, Sofia Faliagka, Ioannis Naounoulis and Nikolaos Katsoulas
Horticulturae 2023, 9(7), 802; https://doi.org/10.3390/horticulturae9070802 - 13 Jul 2023
Cited by 2 | Viewed by 988
Abstract
Minimum environmental impact and improved resource efficiency is attainable for soilless cascade systems where the nutrient solution drained from a primary (donor) crop is reused to fertigate a secondary (receiver) crop. However, it is not clear whether the nutrient solution drained from the [...] Read more.
Minimum environmental impact and improved resource efficiency is attainable for soilless cascade systems where the nutrient solution drained from a primary (donor) crop is reused to fertigate a secondary (receiver) crop. However, it is not clear whether the nutrient solution drained from the primary crop can completely satisfy the needs of a secondary crop and if the productivity of the secondary crop is compromised. To test this hypothesis, a prototype soilless cascade system was developed and evaluated. To assess the performance of the system in terms of yield, water and nutrient productivity, a tomato crop was used as the primary crop, while lettuce, spinach and parsley were tested as secondary crops under different drainage management strategies. Measurements of plant growth, crop fresh and dry matter production, leaf chlorophyll and nutrient content, and photosynthesis rate were performed in the secondary crops. In addition, the water productivity and nutrient use efficiency for the fertigation of the primary and secondary crops were recorded. The results showed that the yield of the cascade spinach crop increased by up to 14% compared to the control treatment (monoculture of secondary crop fertigated by standard nutrient solution). The yield of the lettuce and parsley crop was not affected by the reuse of the tomato crop drainage solution. The water productivities of the lettuce, spinach and parsley plants fertigated with pure drainage solution were 50%, 30% and 14% higher than in the control treatment, respectively. The nitrogen and phosphorus use efficiency was improved by more than 50% compared to the control treatments. Full article
Show Figures

Figure 1

17 pages, 1698 KiB  
Article
Estimating Nitrogen Release from Organic Fertilizers for Soilless Production by Analysis of C and N Pools
by Dieter Lohr, Nazim S. Gruda and Elke Meinken
Horticulturae 2023, 9(7), 767; https://doi.org/10.3390/horticulturae9070767 - 4 Jul 2023
Cited by 1 | Viewed by 1147
Abstract
The use of organic fertilizers in soilless pot plant production has sharply increased in recent years. However, there is still a lack of methods for characterizing the N release from organic fertilizers. This bears the risk of an inadequate nutrient supply and, thus, [...] Read more.
The use of organic fertilizers in soilless pot plant production has sharply increased in recent years. However, there is still a lack of methods for characterizing the N release from organic fertilizers. This bears the risk of an inadequate nutrient supply and, thus, a waste of resources. Therefore, the current research analyzed fourteen commercial organic fertilizers for various C and N pools by extraction in cold and hot water, acid hydrolysis, and thermal fractionation. Furthermore, we conducted an incubation test using a growing medium (80 vol% peat plus 20 vol% green waste compost) and fitted the nitrogen release to different kinetic models. Finally, we calculated the correlations among the best-suited kinetic model parameters and the C and N pools. The C and N pools soluble in water and weak hydrochloride acid varied significantly among the fourteen fertilizers but were closely correlated with each other. The N release from most organic fertilizers could be described very well using the Gompertz function (R² > 0.9), and the parameters of the Gompertz function showed significant correlations with the C and N pools. Hydrolyzable C and N pools provided valuable information about the N release characteristics of organic fertilizers. Full article
Show Figures

Figure 1

19 pages, 2392 KiB  
Article
Biodegradable Food Packaging of Wild Rocket (Diplotaxis tenuifolia L. [DC.]) and Sea Fennel (Crithmum maritimum L.) Grown in a Cascade Cropping System for Short Food Supply Chain
by Perla A. Gómez, Catalina Egea-Gilabert, Almudena Giménez, Rachida Rania Benaissa, Fabio Amoruso, Angelo Signore, Victor M. Gallegos-Cedillo, Jesús Ochoa and Juan A. Fernández
Horticulturae 2023, 9(6), 621; https://doi.org/10.3390/horticulturae9060621 - 26 May 2023
Viewed by 1725
Abstract
The environmental impact of food products is significantly affected by their packaging. Therefore, this study aimed to assess the effect of PLA (polylactic acid) film, as an alternative to petroleum-based bags, on the shelf-life of fresh-cut wild rocket and sea fennel grown in [...] Read more.
The environmental impact of food products is significantly affected by their packaging. Therefore, this study aimed to assess the effect of PLA (polylactic acid) film, as an alternative to petroleum-based bags, on the shelf-life of fresh-cut wild rocket and sea fennel grown in a cascade cropping system (CCS). To this end, wild rocket (main crop) was cultivated using either peat or compost as a growing medium. Sea fennel (secondary crop) was subsequently grown in a floating system with leachates from the primary crop as a nutrient solution. The leaves of both crops were harvested and packaged in OPP- (oriented polypropylene) or PLA-based bags and stored for 7 days at 4 °C. The leaves of wild rocket and sea fennel showed lower dehydration and lower respiration when compost was used as a growing medium or leachate. Wild rocket in compost increased in nitrate and vitamin C contents at harvest while leachates had scarce influence on their contents in sea fennel. After storage, regardless of the crop, no relevant detrimental changes were observed on leaves packaged with PLA, being a product microbiologically safer when compared to OPP. The bag type had almost no influence on most relevant phytochemical compounds. In conclusion, the use of a PLA-based film on minimally processed wild rocket and sea fennel leaves is a sustainable alternative to petroleum-based plastic for a short food supply chain. Full article
Show Figures

Figure 1

15 pages, 2609 KiB  
Article
Testing the Greenhouse Emission Model (GEM) for Pesticides Applied via Drip Irrigation to Stone Wool Mats Growing Sweet Pepper in a Recirculation System
by E. Louise Wipfler, Jos J. T. I. Boesten, Erik A. van Os and Wim H. J. Beltman
Horticulturae 2023, 9(4), 495; https://doi.org/10.3390/horticulturae9040495 - 14 Apr 2023
Viewed by 1560
Abstract
Pesticide emissions to surface water from greenhouses with crops grown on substrates in open or closed systems may be significant. It is important, therefore, to test models such as the Greenhouse Emission Model (GEM), which was developed to assess these emissions as part [...] Read more.
Pesticide emissions to surface water from greenhouses with crops grown on substrates in open or closed systems may be significant. It is important, therefore, to test models such as the Greenhouse Emission Model (GEM), which was developed to assess these emissions as part of the Dutch authorization procedure for use of plant protection products in greenhouses. GEM was tested using an experiment in which imidacloprid and pymetrozine were applied via drip irrigation to stone wool mats growing sweet pepper. The irrigation system in such greenhouses consists of a mixing tank to prepare the nutrient solution and a series of tanks to treat and recirculate the drain water back to the mixing tank. Emissions may occur because (part of) this recirculation water may be discharged or leached to the surface water. GEM assumes that all tanks are perfectly mixed. GEM further assumes that the water in these mats is perfectly mixed and that the pesticide behavior can be simulated by assuming one perfectly mixed reservoir. The model predicted breakthrough of both pesticides out of the mats earlier than measured, and the measured maximum concentrations were approximately two times lower than predicted. We considered a series of possible causes, including a smaller water volume in the mats, a higher plant uptake factor, and sorption to the stone wool. The model performance improved by representing the mats as a sequence of two equally large tanks with plant uptake restricted to the first tank. We recommend to study the solute transport process and the distribution of plant roots in the mats in more detail to further underpin the hypothesis used and improve the model. After this first validation, the GEM model might also be used in other countries to forecast emissions of PPPs to surface water. Full article
Show Figures

Graphical abstract

16 pages, 1447 KiB  
Article
Impact of Sodium Hypochlorite Applied as Nutrient Solution Disinfectant on Growth, Nutritional Status, Yield, and Consumer Safety of Tomato (Solanum lycopersicum L.) Fruit Produced in a Soilless Cultivation
by Maira Lykogianni, Eleftheria Bempelou, Ioannis Karavidas, Christos Anagnostopoulos, Konstantinos A. Aliferis and Dimitrios Savvas
Horticulturae 2023, 9(3), 352; https://doi.org/10.3390/horticulturae9030352 - 7 Mar 2023
Cited by 4 | Viewed by 3572
Abstract
Soilless crop production is spread worldwide. It is a cultivating technique that enhances yield quality and quantity, thus contributing to both food safety and food security. However, in closed-loop soilless crops, the risk of spreading soil-borne pathogens through the recycled nutrient solution makes [...] Read more.
Soilless crop production is spread worldwide. It is a cultivating technique that enhances yield quality and quantity, thus contributing to both food safety and food security. However, in closed-loop soilless crops, the risk of spreading soil-borne pathogens through the recycled nutrient solution makes the establishment of a disinfection strategy necessary. In the current study, sodium hypochlorite was applied to the recycled nutrient solution as a chemical disinfectant to assess its impact on plant growth, leaf gas exchange, fruit yield, tissue mineral composition, and possible accumulation of chlorate and perchlorate residues in tomato fruits. The application of 2.5, 5, and 7.5 mg L−1 of chlorine three times at fortnightly intervals during the cropping period had no impact on plant growth or gas exchange parameters. Furthermore, the application of 2.5 mg L−1 of chlorine led to a significant increase in the total production of marketable fruits (total fruit weight per plant). No consistent differences in nutrient concentrations were recorded between the treatments. Moreover, neither chlorate nor perchlorate residues were detected in tomato fruits, even though chlorate residues were present in the nutrient solution. Therefore, the obtained tomatoes were safe for consumption. Further research is needed to test the application of chlorine in combination with crop inoculation with pathogens to test the efficiency of chlorine as a disinfectant in soilless nutrient solutions. Full article
Show Figures

Graphical abstract

14 pages, 8764 KiB  
Article
Bio-Fertilizers Reduced the Need for Mineral Fertilizers in Soilless-Grown Capia Pepper
by Hayriye Yildiz Dasgan, Mehmet Yilmaz, Sultan Dere, Boran Ikiz and Nazim S. Gruda
Horticulturae 2023, 9(2), 188; https://doi.org/10.3390/horticulturae9020188 - 2 Feb 2023
Cited by 14 | Viewed by 2320
Abstract
Soilless cultivation is extensively used in the greenhouse industry. Recently, hydroponic cultivation of capia pepper has become popular among growers. Capia pepper is harvested at the red maturity stage, and intensive mineral fertilizers are usually used for soilless cultivation. This study was performed [...] Read more.
Soilless cultivation is extensively used in the greenhouse industry. Recently, hydroponic cultivation of capia pepper has become popular among growers. Capia pepper is harvested at the red maturity stage, and intensive mineral fertilizers are usually used for soilless cultivation. This study was performed in a greenhouse during spring under Mediterranean climatic conditions. The effects of bacteria and mycorrhiza on capia pepper plant growth, yield, fruit quality, and nutrition were investigated. Furthermore, the synergistic effects of these two bio-fertilizers were investigated. Our objective was to replace 20% of mineral fertilizers with bio-fertilizers in a soilless culture system. The use of 80% mineral fertilizers, in combination with mycorrhiza and bacteria, provided a 32.4% higher yield than the control (100% mineral fertilizer without bio-fertilizers). Moreover, the concentrations of N, P, K, Ca, Mg, Fe, Mn, Zn, and Cu in the leaves of pepper plants fed with the reduced mineral fertilizers combined with bio-fertilizers were higher than that of the control. In addition, fruit parameters, such as fruit weight, diameter, volume, the electric conductivity of the fruit juice, and total soluble solids, were significantly higher in this treatment compared to the control. Using 80% mineral fertilizer with only bacteria provided a 24.2% higher yield than the control. In conclusion, mineral fertilizers were successfully reduced by 20% using bacteria and mycorrhiza. These results provide an eco-friendly approach to a sustainable environment. Full article
Show Figures

Figure 1

11 pages, 1063 KiB  
Article
Effects of Mixes of Peat with Different Rates of Spruce, Pine Fibers, or Perlite on the Growth of Blueberry Saplings
by Laima Česonienė, Ričardas Krikštolaitis, Remigijus Daubaras and Romas Mažeika
Horticulturae 2023, 9(2), 151; https://doi.org/10.3390/horticulturae9020151 - 24 Jan 2023
Cited by 1 | Viewed by 1566
Abstract
Investigations of substrates for growing plant saplings is the basis for the search for new components. Currently, large numbers of saplings are grown for blueberry plantations. Studies on the use of various organic and inorganic components in substrates is relevant in order to [...] Read more.
Investigations of substrates for growing plant saplings is the basis for the search for new components. Currently, large numbers of saplings are grown for blueberry plantations. Studies on the use of various organic and inorganic components in substrates is relevant in order to reduce the amount of excavated peat. The goal of this study was to analyze the effects of mixes of peat with different rates of spruce, pine fibers and perlite on the growth of blueberry saplings. To define the suitability of substrates, plant vigor assessments of the cultivar ‘Duke’, including plant height and leaf weight, as well as the chlorophyll fluorescence, content of extractable macronutrients and organic carbon in leaves, were investigated. The best effect on the growth of blueberry saplings, the optimal content of macronutrients in the leaves, was shown for substrates in which a part of the peat was replaced by 15–45% v/v of pine wood fiber and by 15–30% v/v of spruce wood fiber. Pine bark fiber in the mix should not exceed 30% v/v. The addition of spruce bark fibers in the different rates had a negative effect on the vegetative growth of the saplings. The quantity of peat in the substrates can also be significantly reduced by adding 15–45% v/v of perlite. These results confirm that pine and spruce fibers or perlite in substrates for blueberry sapling growing could reduce the demand for peat and should significantly contribute to the preservation of unique wetland ecosystems. Full article
Show Figures

Figure 1

15 pages, 1050 KiB  
Article
Coir-Based Growing Media with Municipal Compost and Biochar and Their Impacts on Growth and Some Quality Parameters in Lettuce Seedlings
by Tiago Carreira Martins, Rui M. A. Machado, Isabel Alves-Pereira, Rui Ferreira and Nazim S. Gruda
Horticulturae 2023, 9(1), 105; https://doi.org/10.3390/horticulturae9010105 - 12 Jan 2023
Cited by 6 | Viewed by 2692
Abstract
The purpose of this study was to develop substrates with little or no peat by combining coir-based growing media with municipal compost and/or acacia biochar, two locally produced renewable resources, and to assess their effects on lettuce seedling emergence and growth, as well [...] Read more.
The purpose of this study was to develop substrates with little or no peat by combining coir-based growing media with municipal compost and/or acacia biochar, two locally produced renewable resources, and to assess their effects on lettuce seedling emergence and growth, as well as their content in photosynthetic pigments and total phenols. Two experiments were carried out, the first with six mixes using compost and biochar blended with perlite, pine bark, and blonde peat to adjust some physicochemical characteristics. The mixes of coir: compost: pine bark: blonde peat (73:12:5:10, v/v) and coir: compost: biochar: blonde peat (73:12:10:5, v/v) had physicochemical characteristics closer to or within the normal range of the substrates. The presence of 12% compost and 10% biochar in the mixtures had no adverse effect on lettuce seed germination and cumulative seed emergence, which ranged from 90 to 99%. The seedling growth in those mixes was vigorous and higher than in other mixtures. Coir-based growing media with municipal solid waste compost and compost plus biochar can reduce the use of peat to a percentage of 5–10% v/v and the use of 17–22% v/v of locally produced renewable resources. In addition, mixtures affected the total phenol content in the lettuce leaves. Future research is needed to assess the behavior of seedlings after their transplantation. Full article
Show Figures

Figure 1

Back to TopTop