N and P use efficiencies of basil cultivated in organically fertilized growing media
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)
- et al.
The effects of biochar, compost and their mixture and nitrogen fertilizer on yield and nitrogen use efficiency of barley grown on a Nitisol in the highlands of Ethiopia
Science of The Total Environment
(2016) - et al.
Achieving environmentally sustainable growing media for soilless plant cultivation systems – A review
Scientia Horticulturae
(2016) - et al.
Organic versus conventional fertilization effects on sweet basil (Ocimum basilicum L.) growth in a greenhouse system
Industrial Crops and Products
(2015) - et al.
Microbial immobilization of ammonium and nitrate in relation to ammonification and nitrification rates in organic and conventional cropping systems
Soil Biology and Biochemistry
(2003) - et al.
Substrates and fertilizers for organic container production of herbs, vegetables, and herbaceous ornamental plants grown in greenhouses in the United States
Scientia Horticulturae, Recent advances in organic horticulture technology and management - Part 1
(2016) - et al.
Peat particle size effects on spatial root distribution, and changes on hydraulic and aeration properties
Scientia Horticulturae
(2013) - et al.
Chapter 8 - Organic Soilless Media Components
Plant biostimulants: Definition, concept, main categories and regulation
Scientia Horticulturae, Biostimulants in Horticulture
(2015)- et al.
Determination of a Critical Nitrogen Dilution Curve for Winter Wheat Crops
Annals of Botany
(1994) - et al.
Diagnosis tool for plant and crop N status in vegetative stage: Theory and practices for crop N management
European Journal of Agronomy
(2008)
Evolution of hydraulic properties and wettability of organic growing media during cultivation according to irrigation strategies
Sci. Hortic.
Use of plant growth-promoting rhizobacteria (PGPR) and organic fertilization for soilless cultivation of basil
Scientia Horticulturae
Structure and activity of spontaneous fungal communities in organic substrates used for soilless crops
Scientia Horticulturae
Autotrophic Nitrification in Bacteria
Chapter 4 - The significance of nutrient interactions for crop yield and nutrient use efficiency
Plant growth-promoting rhizobacteria act as biostimulants in horticulture
Scientia Horticulturae
Chapter 6 - Nutrition of Substrate-Grown Plants
Qualité de l'eau – Dosage du phosphore – Méthode spectrométrique au molybdate d'ammonium
NF EN ISO
Nutrient Use Efficiency in Plants
Communications in Soil Science and Plant Analysis
Dynamics of nutrient availability in tomato production with organic fertilisers
Biological Agriculture & Horticulture
Dynamics of nitrogen availability in pot grown crops with organic fertilization
Biological Agriculture & Horticulture
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
Experience with selected physical methods to characterize the suitability of growing media for plant growth
Acta Horticulturae
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
Organic Growing Media: Constituents and Properties
Vadose Zone Journal
Physical properties of organic soils and growing media: Water and air storage and flow dynamics
Physical Properties of Organic Soil: Adapting Mineral Soil Concepts to Horticultural Growing Media and Histosol Characterization
Vadose Zone Journal
The wise use of peat in horticulture
Acta Horticulturae
C : N : P stoichiometry in soil: is there a “Redfield ratio” for the microbial biomass?
Biogeochemistry
Organic hydroponics: a US reality challenging the traditional concept of “organic” and “soilless” cultivation
Acta Horticulturae
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