Elsevier

Scientia Horticulturae

Volume 303, 20 September 2022, 111208
Scientia Horticulturae

N and P use efficiencies of basil cultivated in organically fertilized growing media

https://doi.org/10.1016/j.scienta.2022.111208Get rights and content

Highlights

  • Growing media (GM) are the main driver of Basil N- and P- use efficiencies.

  • Peat provided the best growth conditions under organic fertilization.

  • Microbial N competition limited basil growth in woody-based GM.

  • Organic fertilizer localization and PGPR inoculum weakly alleviated N limitation.

  • Peat will be difficult to replace especially with woody constituents in GM.

Abstract

Sustainable production in soilless cultivation systems may be achieved by using recycled organic materials as constituents of growing media (GM) and as organic fertilizers. Synchronizing nutrient releases from organic fertilizer mineralization with plant needs in containerized production is difficult to manage for greenhouse growers. This is further amplified by the diversification of GM constituents, driving microbial activities. We aimed to evaluate how the plant can adapt its nutrition to different organic fertilization strategies and ensure its growth depending on the GM and organic fertilizer types. Ocimum basilicum L. was grown for 60 days in a greenhouse in pots filled with three different GM: 100% peat (Peat); 70% peat and 30% coir fiber (GM1); and 50% coir pith, 25% composted bark, 25% wood fiber (GM2). Two contrasted organic fertilizers were used (horn and a granular fertilizer), mixed to the GM, localized in the pot, or combined with Bacillus sp. inoculation as plant growth-promoting rhizobacteria (PGPR). Standard mineral fertilization mixed to the GM was also used as a control treatment. We investigated basil growth (height, biomass, leaf area, chlorophyll and flavonol contents) as well as nitrogen (N) and phosphorus (P) use efficiencies, from their uptake by the roots to their allocation to the plant organs. Basil performances were mainly affected by the GM type. Peat provided optimal conditions for plant development. In GM1, basil maximized the utilization of available N and P taken up from the GM and reached the highest biomass production. Basil performances were especially low when it was grown on GM2 because of a strong competition for N between microbes and the roots. The fertilizer type, its localization and PGPR inoculation did not affect basil growth or nutrition in peat; these treatments had only little effect on basil grown on GM1 and GM2, and affected its performances differently depending on the GM type. This study provides evidence that fertilization must be thoughtfully managed depending on the GM in organically fertilized systems.

Introduction

The demand for organically grown products has increased in recent years (Treadwell et al., 2007). This growing and highly profitable market promotes the development of certified organic soilless cultivation systems especially in the US but also in Europe for seedlings, microgreens and herbs grown on organic growing media (GM) (Di Gioia and Rosskopf, 2021). However, knowledge on the efficiency of these innovative systems and materials used is still limited (Gruda, 2019). The agronomic quality of GM refers to its ability to maintain good balance between water and air, essentials for the development of the plant rhizosphere (Carlile et al., 2015; Barrett et al., 2016). Peat, whose properties ensure optimal growing conditions, has established itself as a reference organic GM (Clarke, 2008; Gruda, 2019). Nevertheless, its use is questioned because exploiting peatland implies depleting a recognized carbon (C) sink (Leifeld and Menichetti, 2018). Similarly, the use of synthetic fertilizers has a high environmental cost (Von Blottnitz et al., 2006) and is prohibited in organic systems (Di Gioia and Rosskopf, 2021). Consequently, organic fertilizers represent a sustainable alternative to mineral fertilizers (Burnett et al., 2016). Mineral fertilization is well controlled in soilless cultivation, but organic fertilization is much more poorly managed despite the great number of organic fertilizers available on the market (Burnett et al., 2016). Satisfactory microbial activity in GM is essential to ensure organic fertilizer mineralization into available nutrients that can be taken up by the plant (Grunert et al., 2016). However, organic GM (e.g., peat, coir and wood fiber) display specific microbial community structures depending on their origin and manufacturing process (Montagne et al., 2015, 2017). Thus, the processes of organic fertilizer mineralization within GM are complex, varying from a GM to another, with fertilizer types (Dion et al., 2020; Paillat et al., 2020), with the growing environment (Grunert et al., 2019, 2020), and thus, affecting nutrient availability in GM (Paillat et al., 2020). As a result, many growers are uncertain about switching over to organic fertilization because appropriate nutrient supply is difficult to manage when only organic nutrient sources are used (Bergstrand et al., 2019), especially due to a low nutrient buffering capacity of GM in the limited volume of containers (Silber and Bar-Tal, 2019).

Synchronizing nutrient supply with the requirements of plants is one of the core challenges for increasing nutrient use efficiency (Reich, 2017). The nutrient use efficiency is based on: (i) the uptake efficiency (UpE), evaluating the plant ability to acquire nutrients from fertilization (Agegnehu et al., 2016), and (ii) the utilization efficiency (UtE) evaluating the ability of the plant to transform nutrients into biomass or yield (Baligar et al., 2001). The nitrogen (N) nutrition index (NNI) is also used to assess the crop N status, as the ratio of the shoot N concentration to the critical N concentration (Nc) required to achieve maximum crop growth (Lemaire et al., 2008; Rahimikhoob et al., 2020). While nitrogen is essential and often the most limiting element for plant growth, plants can be subjected to multiple nutrient limitations, especially co-limitation of N and P (Reich, 2017). The nutritional efficiency of phosphorus in above-ground production with the use of organic fertilizers is far less documented (Ménard et al., 2014; Bergstrand et al., 2019, 2020), while geological P sources are being depleted and P fertilizer prices are expected to increase (Vaccari, 2009). Thus, characterizing the efficiency of organic P use from fertilization and its interaction with the efficiency of N use by the plant is a major challenge for our future, with a view to preserving resources by optimizing organic fertilization practices.

The objective of this study is to characterize the effect of GM-organic fertilizer couples on plant growth, and on nitrogen and phosphorus use efficiencies. An experiment was conducted under greenhouse conditions, using basil as the plant of interest. The localization of the organic fertilizer and the use of a biostimulant (Bacillus sp. inoculum) were also studied to evaluate a possible improvement of fertilizer use efficiency. The scientific hypotheses were as follows:

  • 1.

    Alternative growing media containing wood fiber affect nutrient availability, leading to lower basil performances.

  • 2.

    Mineral fertilizer allows for higher yields and better nutrient use efficiency than organic fertilizers do. Organic fertilizers were selected based on their contrasted origins (animal or plant), stoichiometric equilibria and physical and chemical recalcitrance (i.e., resistance to microbial biodegradation). Organic fertilizers have specific mineralization behaviors: The nutrient release rates for an organic fertilizer with high physical and chemical recalcitrance (e.g., hoof and horn) slow down plant growth compared to a more easily available organic source of nutrients.

  • 3.

    The localization of the fertilizer reduces nutrient mineralization rates by reducing the exchange surfaces between fertilizers and microorganisms; this makes nutrient release in the rhizosphere and plant needs coincide.

  • 4.

    The biostimulant promotes the decomposition of organic fertilizers that are more resistant to microbial degradation. Bacillus sp. will promote better nutrient mobilization and facilitate nutrient uptake – especially P uptake.

Section snippets

Experimental design and experimental conditions

French sweet Basil (Ocimum basilicum L. cv. “Grand Vert”, Fourche et Compagnie Co.) was grown in a greenhouse to test interactions between three contrasted growing media (GM), two organic fertilizers (Fert.) and three fertilization strategies (Strat.) on basil growth and nutrient use efficiencies.

Basil is a species commonly cultivated in greenhouse conditions, in pots filled with GM, for aromatic or medicinal uses (Garibaldi et al., 1997; Treadwell et al., 2007; Zheljazkov et al., 2008). It was

Chemical parameters of the growing media at the end of the cultivation period

Following the two organic fertilization treatments, pH, electrical conductivity (EC), the ammonium (NH4+ -N), and nitrate (NO3 -N) contents were mainly affected by the GM (main effect, p<0.001) and remained unchanged whatever the organic fertilizer type or the fertilization strategy (Table S2). Following the mineral fertilization treatment (Min), these parameters only slightly but significantly changed in a GM-dependent manner. pH of the GM added with organic fertilizers was significantly

Organic fertilization affected basil growth and nutrition depending on the growing medium

Basil growth performances were higher under mineral fertilization than under organic fertilization whatever the GM, i.e., higher root and shoot biomass values, leaf area, plant height, chlorophyll content, and N & P use efficiencies. The depressive effects of organic versus mineral fertilization has been observed frequently (Succop and Newman, 2004; Bufalo et al., 2015). Higher ammonification over nitrification rates have often been viewed as the main explanation for the lower performances of

Conclusions

This study demonstrates that the use of organic fertilizers as an alternative to mineral fertilizers is promising. Both organic fertilizers often led to comparable plant nutrition efficiencies, while mineral fertilizers led to better development of basil (biomass, leaf area, plant height). Under organic fertilization, the plant growth performances were mainly driven by the GM type. Unsurprisingly, Peat provided the best growth conditions for basil. However, a wiser use of peat by decreasing its

Funding

This research was funded by Premier Tech GC Co. and the French national association of research and technology (Association Nationale de la Recherche et de la Technologie, ANRT) (CIFRE 2017/0752).

CRediT authorship contribution statement

L. Paillat: Conceptualization, Methodology, Investigation, Formal analysis, Writing – original draft, Visualization, Project administration. P. Cannavo: Conceptualization, Validation, Investigation, Writing – review & editing, Supervision, Project administration, Funding acquisition. A. Dourdan: Investigation, Visualization. F. Barraud: Resources. R. Guénon: Conceptualization, Validation, Writing – review & editing, Supervision, Funding acquisition. L. Huché-Thélier: Conceptualization,

Declaration of Competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgments

We are thankful to the following people from EPHor research unit for their help during the experiment: M. Artous, Y. Barraud-Roussel, R. Bouzouidja, J. Courant, E. Dureau, D. Lemesle, C. Levron, C. Mazzega. The experiments were conducted at the PHENOTIC platform with the assistance of R. Gardet, C. Lebigot and D. Sochard. We also thank A. Buchwalter (scientific translator) for reviewing the paper for English usage.

References (80)

  • J.-C. Michel et al.

    Evolution of hydraulic properties and wettability of organic growing media during cultivation according to irrigation strategies

    Sci. Hortic.

    (2017)
  • A. Moncada et al.

    Use of plant growth-promoting rhizobacteria (PGPR) and organic fertilization for soilless cultivation of basil

    Scientia Horticulturae

    (2021)
  • V. Montagne et al.

    Structure and activity of spontaneous fungal communities in organic substrates used for soilless crops

    Scientia Horticulturae

    (2015)
  • J.I. Prosser

    Autotrophic Nitrification in Bacteria

  • M. Reich

    Chapter 4 - The significance of nutrient interactions for crop yield and nutrient use efficiency

  • M. Ruzzi et al.

    Plant growth-promoting rhizobacteria act as biostimulants in horticulture

    Scientia Horticulturae

    (2015)
  • A. Silber et al.

    Chapter 6 - Nutrition of Substrate-Grown Plants

  • AFNOR, 2011. Qualité du sol – Détermination de la capacité d’échange cationique (CEC) effective et des cations...
  • AFNOR, 2009. Qualité de l'eau – Dosage d’éléments choisis par spectroscopie d’émission optique avec plasma induit par...
  • Qualité de l'eau – Dosage du phosphore – Méthode spectrométrique au molybdate d'ammonium

    NF EN ISO

    (2005)
  • AFNOR, 2000a. Amendements du sol et supports de culture – Détermination des propriétés physiques – Masse volumique...
  • AFNOR, 2000b. Amendements organiques et supports de culture – Préparation des échantillons pour les essais physiques et...
  • AFNOR, 2000c. Amendements du sol et supports de culture – Détermination du pH. NF EN 13037....
  • AFNOR, 2000d. Amendements du sol et supports de culture – Détermination de la conductivité électrique. NF EN 13038....
  • AFNOR, 2000e. Amendements du sol et supports de culture – Détermination de la teneur en matières organiques. NF EN...
  • AFNOR, 1998. Qualité du sol – Détermination de la teneur totale en azote par combustion sèche. NF ISO 13878....
  • AFNOR, 1997. Qualité de l'eau – Dosage de l'azote ammoniacal – Méthode par analyse en flux (CFA et FIA) et détection...
  • AFNOR, 1996. Qualité de l'eau – Détermination de l'azote nitreux et de l'azote nitrique et de la somme des deux par...
  • V.C. Baligar et al.

    Nutrient Use Efficiency in Plants

    Communications in Soil Science and Plant Analysis

    (2001)
  • K.-J. Bergstrand et al.

    Dynamics of nutrient availability in tomato production with organic fertilisers

    Biological Agriculture & Horticulture

    (2020)
  • K.-J. Bergstrand et al.

    Dynamics of nitrogen availability in pot grown crops with organic fertilization

    Biological Agriculture & Horticulture

    (2019)
  • N. Bernstein et al.

    Salinity-induced changes in essential oil, pigments and salts accumulation in sweet basil (Ocimum basilicum) in relation to alterations of morphological development

    Annals of Applied Biology

    (2010)
  • C. Blok et al.

    Experience with selected physical methods to characterize the suitability of growing media for plant growth

    Acta Horticulturae

    (2008)
  • A.C. Bunt

    Media and mixes for container grown plants: a manual on the preparation and use of growing media for growing pot plants. Unwyn Hyman Ltd., London.Bunt, A.C., 1984. Physical properties of mixtures of peats and minerals of different particle size and bulk density for potting substrates

    Acta Horticulturae

    (1988)
  • W.R. Carlile et al.

    Organic Growing Media: Constituents and Properties

    Vadose Zone Journal

    (2015)
  • J. Caron et al.

    Physical properties of organic soils and growing media: Water and air storage and flow dynamics

  • J. Caron et al.

    Physical Properties of Organic Soil: Adapting Mineral Soil Concepts to Horticultural Growing Media and Histosol Characterization

    Vadose Zone Journal

    (2015)
  • D. Clarke

    The wise use of peat in horticulture

    Acta Horticulturae

    (2008)
  • C.C. Cleveland et al.

    C : N : P stoichiometry in soil: is there a “Redfield ratio” for the microbial biomass?

    Biogeochemistry

    (2007)
  • F. Di Gioia et al.

    Organic hydroponics: a US reality challenging the traditional concept of “organic” and “soilless” cultivation

    Acta Horticulturae

    (2021)
  • View full text