Producing Nitrate-free Endive Heads: Effect of Nitrogen Form on Growth, Yield, and Ion Composition of Endive

In a growth chamber, endive (Cichorium endivia L. var. crispum Hegi) plants were grown using a solution culture method to evaluate the influence of four ammonium : nitrate (NH4-N : NO3-N) percentage ratios (100:0, 70:30, 30:70, and 0:100) on growth (leaf area, dry mass, crop growth rate, relative growth rate, and net assimilation rate), yield characteristics (head and root fresh mass and root length), quality (dry matter, nitrogen, and nitrate), and inorganic ion content. No symptoms of NH4+ toxicity were detected in endive plants 8 weeks after beginning nutrient treatments. Moreover, by feeding N in mixed form, the growth indices increased compared to indices from feeding with any of the two N forms alone. Ammonium-fed plants produced nitrate-free heads with a fresh mass (171 g) similar to nitrate-fed plants. Compared to the other treatments, the heads of NH4+-fed plants were darker green and more succulent. Mixed N improved yield but caused a remarkable accumulation of nitrate in heads. Following an increase in NO3-N from 30% to 70% in the nutrient solution, head fresh mass rose from 196 to 231 g and NO3- concentration more than doubled (from 2.4 to 6.1 g·kg-1 fresh mass). With 100% of NO3-N, NO3- concentration was 5.5 g·kg-1 fresh mass. With higher NO3-N percentages in the nutrient solution, the difference in the concentration of inorganic cations and anions increased, but K+ concentration was also high in ammonium-fed plants (on average 77 g·kg-1 dry mass). Head total N accumulation was increased by the presence of NH4+ in the nutrient solution and decreased with 100% NO3-N. From the commercial viewpoint, the produce obtained from 100% NH4-N was good, with the value-added factor of the absence of nitrate. This may be an extremely remarkable factor because of the commercial limits on the allowable nitrate content in leafy vegetables already enforced by many European countries and those the European Union is going to adopt in a directive.

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An Exploration of Seaweed Polysaccharides Stimulating Denitrifying Bacteria for Safer Nitrate Removal

Molecules ◽

10.3390/molecules26113390 ◽

2021 ◽

Vol 26 (11) ◽

pp. 3390

Author(s):

Hui Zhang ◽

Lin Song ◽

Xiaolin Chen ◽

Pengcheng Li

Keyword(s):

Growth Rate ◽

Bacillus Subtilis ◽

Nitrate Removal ◽

Denitrifying Bacteria ◽

Soil Salinization ◽

Nitrate Content ◽

Weak Efficiency ◽

N Accumulation ◽

N Removal ◽

Intensively Managed

Excessive use of nitrogen fertilizer in intensively managed agriculture has resulted in abundant accumulation of nitrate in soil, which limits agriculture sustainability. How to reduce nitrate content is the key to alleviate secondary soil salinization. However, the microorganisms used in soil remediation cause some problems such as weak efficiency and short survival time. In this study, seaweed polysaccharides were used as stimulant to promote the rapid growth and safer nitrate removal of denitrifying bacteria. Firstly, the growth rate and NO3−-N removal capacity of three kinds of denitrifying bacteria, Bacillus subtilis (BS), Pseudomonas stutzeri (PS) and Pseudomonas putida (PP), were compared. The results showed that Bacillus subtilis (BS) had a faster growth rate and stronger nitrate removal ability. We then studied the effects of Enteromorpha linza polysaccharides (EP), carrageenan (CA), and sodium alginate (AL) on growth and denitrification performance of Bacillus subtilis (BS). The results showed that seaweed polysaccharides obviously promoted the growth of Bacillus subtilis (BS), and accelerated the reduction of NO3−-N. More importantly, the increased NH4+-N content could avoid excessive loss of nitrogen, and less NO2−-N accumulation could avoid toxic effects on plants. This new strategy of using denitrifying bacteria for safely remediating secondary soil salinization has a great significance.

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Nutrient Solution Deprivation as a Tool to Improve Hydroponics Sustainability: Yield, Physiological, and Qualitative Response of Lettuce

Agronomy ◽

10.3390/agronomy11081469 ◽

2021 ◽

Vol 11 (8) ◽

pp. 1469

Author(s):

Michele Ciriello ◽

Luigi Formisano ◽

Antonio Pannico ◽

Christophe El-Nakhel ◽

Giancarlo Fascella ◽

...

Keyword(s):

Nutrient Solution ◽

Potential Effect ◽

Quality Parameters ◽

Leafy Vegetables ◽

Nitrate Content ◽

Yield Reduction ◽

Quality Performance ◽

Floating Raft ◽

Amino Acids Profile ◽

Excessive Nutrients

Hydroponics growing systems often contain excessive nutrients (especially nitrates), which could lead to a quality loss in ready-to-eat leafy vegetables and posing a health risk to consumers, if managed inadequately. A floating raft system was adopted to assay the production and quality performance of lettuce (Lactuca sativa L. cv ‘Maravilla De Verano Canasta’) deprived of the nutrient solution by replacement with only water, three and six days before harvest. Yield and quality parameters, mineral composition, pigments, organic acids, amino acids profile, soluble proteins, and carbohydrate content were determined. Nutrient solution deprivation six days before harvest resulted in a significant reduction in leaf nitrate (−53.3%) concomitant with 13.8% of yield loss, while plants deprived of nutrient solution three days before harvest increased total phenols content (32.5%) and total ascorbic acid (102.1%), antioxidant activity (82.7%), anthocyanins (7.9%), sucrose (38.9%), starch (19.5%), and γ-aminobutyric acid (GABA; 28.2%), with a yield reduction of 4.7%, compared to the control. Our results suggest that nutrient solution deprivation three days before harvest is a successful strategy to reduce nitrate content and increase the nutritional quality of lettuce grown in floating raft systems with negligible impact on yield. These promising results warrant further investigation of the potential effect of nutrient solution deprivation on the quality attributes of other leafy vegetables cultivated in floating raft systems and in a “cascade” growing system.

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Evaluation of the Non-destructive Method Efficiency of Estimating Nitrogen Content in Jambu Plants Grown in Hydroponic System

Journal of Agricultural Studies ◽

10.5296/jas.v8i2.16380 ◽

2020 ◽

Vol 8 (2) ◽

pp. 466

Author(s):

Italo Marlone Gomes Sampaio ◽

Mário Lopes da Silva Júnior ◽

Erika Da Silva Chagas ◽

Ricardo Falesi Palha de Moraes Bittencourt ◽

Vivian Christine Nascimento Costa ◽

...

Keyword(s):

Nitrogen Content ◽

Nutrient Solution ◽

Linear Models ◽

Nitrogen Concentration ◽

Chlorophyll Concentration ◽

Technical Information ◽

Dry Mass ◽

Leafy Vegetables ◽

Total Chlorophyll ◽

N Content

Jambu is considered a leafy vegetable with expressive relevance in the regions that compose the Brazilian Amazon. However, there are challenges regarding its cultivation, particularly for the nutritional management, since there is little technical information that allows an increase in the efficiency of its production. In this sense, nitrogen (N) gains prominence, since it is related to the increased yield and quality of leafy vegetables, therefore its monitoring of N content in plants is necessary. The objective of this study was to evaluate the efficiency of using the SPAD index to estimate the N content of jambu leaves, total chlorophyll concentration, as well as its relationship with dry mass accumulation due to the increase of nitrogen concentration in the nutrient solution. The design used was completely randomized with eight replications. The treatments were six nitrogen concentrations in the nutrient solution (11, 13, 15, 17, 19 and 21 mmol L-¹). After 21 days of transplantation, the SPAD index was measured. Then, these plants were collected to quantify the total chlorophyll, dry mass and nitrogen content. In general, the variables were explained by increasing linear models. There was a positive correlation between the SPAD index and the other characteristics evaluated. Based on the results, the best response at the concentration of 21 mmol L-¹ in the nutrient solution stands out. In addition, the SPAD index has potential to be used in the diagnosis of nitrogen status in jambu leaves.

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Impact of Light Intensity and Nitrogen of Nutrient Solution on Nitrate Content in Three Lettuce Cultivars Prior to Harvest

Journal of Agricultural Science ◽

10.5539/jas.v10n6p99 ◽

2018 ◽

Vol 10 (6) ◽

pp. 99 ◽

Cited By ~ 5

Author(s):

Khurshid Ahmed Khan ◽

Zhengnan Yan ◽

Dongxian He

Keyword(s):

Light Intensity ◽

Nutrient Solution ◽

Nitrogen Supply ◽

Leafy Vegetables ◽

Photon Flux ◽

Photon Flux Density ◽

Nitrate Content ◽

High Accumulation ◽

Important Indicator ◽

Fluorescent Lamps

Nitrate smoothly accumulates in leafy vegetables and poses serious health hazards if connected excessively in the human diet. The objective of this study was to improve the cultivation method of low nitrate lettuce grown in plant factory. A substantial decrease of nitrate content (NO3-) in three lettuce cultivars were subjected by short-term pre-harvest treatment combined with lowing nitrogen supply of nutrient solution to half concentration and high photosynthetic photon flux density (PPFD) by LED lighting. The lettuce (Lactuca sativa L. cv. Frill ice, Lvzhu, Ziwei) were hydroponically grown in full strength of nutrient solution based on Yamasaki formula up to harvest time within a controlled environment under two light sources using fluorescent lamps and LEDs. The results demonstrated that a subsequent 3-days treatment of additional PPFD from 250 µmol m-2 s-1 to 350 µmol m-2 s-1 from 18 days after transplanting and half concentrations of nitrogen (NO3--N) in nutrient solution which is composition to standard resulted in the decrease of nitrate content as compared to plants grown under initial PPFD and full concentration of NO3--Ncomposition. The gradual decrease in nitrate content was accompanied by an increased concentration of nutritionally carbohydrates. Another important indicator of nutritional quality such as vitamin C content exhibited some variation, fresh weight of cultivars in cv. Frill ice and Ziwei observed higher with fluorescent lamps and for cv. Lvzhu with LED treatment section followed by lowest nitrate content of fresh leaves, respectively. Further, presented results disclosed that to avoid high accumulation of nitrate in leafy vegetables, the strategy of lowering nitrogen supply and increasing light intensity prior to harvest benefiting growers and consumers by improving quality of the product also making it consumer friendly.

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Rocket plants in response to nitrogen concentration in nutrient solution

Horticultura Brasileira ◽

10.1590/s0102-0536-20210316 ◽

2021 ◽

Vol 39 (3) ◽

pp. 341-345

Author(s):

Paulo Henrique S Silva ◽

Arthur Bernardes Cecílio Filho ◽

Isaias dos S Reis ◽

Carolina S Nascimento ◽

Camila S Nascimento

Keyword(s):

Nutrient Solution ◽

Block Design ◽

Nitrogen Concentration ◽

Dry Mass ◽

Nitrate Content ◽

Hydroponic System ◽

N Concentration ◽

Randomized Block Design ◽

Number Of Leaves

ABSTRACT Nitrogen (N) is the second most accumulated nutrient in rocket. This nutrient greatly affects growth, productivity and quality of the vegetable. Rocket is the second most widely grown leafy vegetable in hydroponic system; however, no studies on how N concentration in nutrient solution affects this crop can be found in literature. We studied four concentrations (79.2; 118.8; 158.4 and 237.6 mg L-1 of N) in a randomized block design with five replicates. Maximum number of leaves, leaf area, dry mass and productivity of rocket cv. ‘Folha larga’ were obtained with the highest N concentration. The rocket quality, evaluated by the nitrate content, was maximum with 210.2 mg L-1 of N and its value in the concentration which maximized productivity is in the acceptable range for vegetables; so, it is recommended to grow rocket with 237.6 mg L-1 of N in the nutrient solution.

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Effect of Molybdenum Rate on Yield and Quality of Lettuce, Escarole, and Curly Endive Grown in a Floating System

Agronomy ◽

10.3390/agronomy8090171 ◽

2018 ◽

Vol 8 (9) ◽

pp. 171 ◽

Cited By ~ 14

Author(s):

Alessandra Moncada ◽

Alessandro Miceli ◽

Leo Sabatino ◽

Giovanni Iapichino ◽

Fabio D’Anna ◽

...

Keyword(s):

Nutrient Solution ◽

Nutritional Quality ◽

Growth Yield ◽

Leafy Vegetables ◽

Morphological Alteration ◽

Nitrate Content ◽

Yield And Quality ◽

Floating System ◽

Four Levels

Molybdenum (Mo) is required in enzymes involved in a number of different metabolic processes, and is crucial for the survival of plants and animals. The influence of nutrient solutions containing four levels of molybdenum (0, 0.5, 1.5, and 3.0 µmol/L) on growth, yield, and quality of lettuce, escarole, and curly endive grown in a hydroponic floating system was evaluated. Biometric, nutrient, and quality analyses were conducted to assess the response of each species to Mo. The results demonstrated that molybdenum is essential for harvesting marketable plants. Lettuce, escarole, and curly endive plants differed significantly in their response to molybdenum fertilization. The increase of Mo concentration in the nutrient solution was not harmful for plants and had no influence on yield and morphological traits of the leafy vegetables; however, it significantly affected some quality characteristics. Mo fertilization raised the nutritional quality by increasing ascorbic acid content up to 320.2, 139.0, and 102.1 mg kg−1 FW (fresh weight), and reducing nitrate content down to 1039.2, 1047.3, and 1181.2 mg kg−1 FW for lettuce, escarole, and curly endive, respectively. The addition of Mo in the nutrient solution increased the Mo content of plants up to 0.50, 4.02, and 2.68 μg g−1 FW for lettuce, escarole, and curly endive, respectively. Increasing Mo supply to lettuce, escarole, and curly endive up to 3.0 µmol L−1 could lead to a higher nutritional quality with no significant morphological alteration or yield loss.

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High NH4+/NO3− Ratio Inhibits the Growth and Nitrogen Uptake of Chinese Kale at the Late Growth Stage by Ammonia Toxicity

Horticulturae ◽

10.3390/horticulturae8010008 ◽

2021 ◽

Vol 8 (1) ◽

pp. 8

Author(s):

Yudan Wang ◽

Xiaoyun Zhang ◽

Houcheng Liu ◽

Guangwen Sun ◽

Shiwei Song ◽

...

Keyword(s):

Nutrient Solution ◽

Nitrogen Uptake ◽

Growth Stage ◽

Ph Value ◽

Ammonia Toxicity ◽

N Accumulation ◽

Ammonium Toxicity ◽

Total N ◽

Chinese Kale ◽

Late Growth

The aim of this study was to determine the effects of various NH4+/NO3− ratios in a nutrient solution on the growth and nitrogen uptake of Chinese kale under hydroponic conditions. The four NH4+/NO3− ratios in the nutrient solution were CK (0/100), T1 (10/90), T2 (25/75), and T3 (50/50). An appropriate NH4+/NO3− ratio (10/90, 25/75) promoted the growth of Chinese kale. T2 produced the highest fresh and dry weight among treatments, and all indices of seedling root growth were the highest under T2. A high NH4+/NO3− ratio (50/50) promoted the growth of Chinese kale seedlings at the early stage but inhibited growth at the late growth stage. At harvest, the nutrient solution showed acidity. The pH value was the lowest in T3, whereas NH4+ and NH4+/NO3− ratios were the highest, which caused ammonium toxicity. Total N accumulation and N use efficiency were the highest in T2, and total N accumulation was the lowest in T3. Principal component analysis showed that T2 considerably promoted growth and N absorption of Chinese kale, whereas T3 had a remarkable effect on the pH value. These findings suggest that an appropriate increase in NH4+ promotes the growth and nutrient uptake of Chinese kale by maintaining the pH value and NH4+/NO3− ratios of the nutrient solution, whereas excessive addition of NH4+ may induce rhizosphere acidification and ammonia toxicity, inhibiting plant growth.

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Fertilization of Two Container-grown Woody Ornamentals Based on Their Specific Nitrogen Accumulation Patterns

HortScience ◽

10.21273/hortsci.40.2.451 ◽

2005 ◽

Vol 40 (2) ◽

pp. 451-456 ◽

Cited By ~ 1

Author(s):

David R. Sandrock ◽

Anita N. Azarenko ◽

Timothy L. Righetti

Keyword(s):

Growth Rate ◽

N Uptake ◽

N Fertilization ◽

Silica Sand ◽

Production Cycle ◽

Nitrogen Accumulation ◽

N Accumulation ◽

Total N ◽

Slow Growth Rate ◽

Sliding Scale

Nitrogen accumulation patterns were established for Weigela florida (Bunge.) A. DC. `Red Prince' (fast growth rate) and Euonymus alatus (Thunb.) Sieb. `Compactus' (slow growth rate). From these, daily and biweekly N delivery schedules were designed to match N supply with N accumulation patterns of each taxon. Delivery schedules were sliding scales in that total N applied was controlled by independent increases (or decreases) of N concentration and solution volume. Daily and biweekly N delivery schedules were tested against a constant N rate (200 mg·L-1) and Osmocote 18N-2.6P-9.9K (The Scotts Co., Marysville, Ohio). Plants were grown in 3.8-L containers in 7 douglas fir bark: 2 sphagnum peatmoss: 1 silica sand (0.65 mm; by volume) outdoors in full sun on a gravel pad for 142 d. Within each taxon, Weigela and Euonymus grown with sliding-scale N fertilization schedules had similar total dry weights, leaf areas, and total plant N contents to plants grown with a constant N rate (200 mg·L-1) or Osmocote 18N-2.6P-9.9K. Sliding-scale liquid fertilization based on plant N requirements introduced less total N to the production cycle and resulted in higher N uptake efficiency than fertilization with a constant N rate of 200 mg·L-1. In general, liquid N fertilizer treatments resulted in plants with higher shoot to root ratios than plants treated with Osmocote 18N-2.6P-9.9K. Weigela and Euonymus treated with biweekly schedules were similar to plants treated with daily schedules (same total amount of N delivered with each treatment).

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Comparative Growth and Ions Response to Phosphorus Application for Two Brassica Species under Salt Stress

Asian Soil Research Journal ◽

10.9734/asrj/2020/v3i430079 ◽

2020 ◽

pp. 24-31

Author(s):

Badar-uz- Zaman ◽

Sundas Nawaz

Keyword(s):

Salt Stress ◽

Nutrient Solution ◽

Brassica Species ◽

Dry Mass ◽

Stress Conditions ◽

Fresh Mass ◽

Control Root ◽

Genetic Level ◽

Phosphorus And Potassium ◽

Phosphorus Application

The genetic level differences between Brassica species can have potential impact on their performance under salt stress conditions together with Phosphorus and Potassium applications. In this study we hypothesized that certain level of salt stress mitigation can be done with applications of Phosphorus and Potassium solutions. Germinated seeds of Brassica juncea (var. Khanpur raya) and B. napus (Faisal canola), raised to 10 days seedlings stage and transferred to continuously aerated nutrient solution For salt stress, applied NaCl @60 mM in the nutrient solution’ also applied phosphorus as potassium di hydrogen phosphate (PDP) @ 0 and 10 mM in triplicates. Khanpur raya and Faisal canola responded significantly (p< 0.01) to the application of PDP for growth and ions relations under salt stress and non-stress. Under stress conditions, shoot fresh mass (SFM) of Khanpur raya increased 10 percent with 10 mM of applied PDP than its control whereas SFM of Faisal canola increased 8 percent than its control. Root fresh mass (RFM) of Khanpur raya increased 8 percent with 10 mM of applied PDP than its control whereas RFM of Faisal canola increase 10 percent than its control. Dry mass of Khanpur raya increased 11 percent with 10 mM of applied PDP than its control whereas SDM of Faisal canola increased 6 percent than its control. Root dry mass (RDM) of Khanpur raya increased 18 percent with 10 Mm of applied PDP than its control whereas RDM of Faisal canola increased 19 percent than its control. In Khanpur raya Na+ /K+ ratio decreased 21 percent than the control, whereas this ratio decreased 24 percent in Faisal canola than its control. Under salt stress, physiological P-use in shoot and root of Khanpur raya increased 11 and 8 percent respectively than that of Faisal canola.

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Growth Rate and Nutrient Uptake of Basil in Small-scale Hydroponics

HortScience ◽

10.21273/hortsci14727-19 ◽

2020 ◽

Vol 55 (4) ◽

pp. 507-514

Author(s):

Elisa Solis-Toapanta ◽

Paul Fisher ◽

Celina Gómez

Keyword(s):

Growth Rate ◽

Nutrient Uptake ◽

Nutrient Solution ◽

Indoor Environment ◽

Nutrient Concentration ◽

Management Strategies ◽

Dry Mass ◽

Small Scale ◽

Hydroponic Systems ◽

Over Time

To identify practices that may simplify the use of small-scale hydroponic systems for indoor gardening, we compared two nutrient solution management treatments for basil (Ocimum basilicum) production. Experiments were conducted for 8 weeks to evaluate the effect of biweekly replacement of the nutrient solution (W) vs. biweekly fertilizer addition without nutrient solution replacement (W/O) on growth and nutrient uptake of basil ‘Genovese Compact’ grown in either a greenhouse or an indoor environment. Greenhouse day/night temperature was 29/24 ± 4 °C, relative humidity (RH) was 65 ± 4%, and daily light integral (DLI) was 26.1 mol·m‒2·d‒1. The indoor environment had a constant ambient temperature of 21 °C, RH of 65%, and DLI of 9 mol·m‒2·d‒1 provided by broadband white lamps. Four plants were grown in 7.6-L replicate hydroponic systems, with 178 mg·L‒1 N from a complete nutrient solution in two experimental runs. Shoot fresh and dry mass, leaf number, and leaf area showed an increasing quadratic trend over time when plants were grown in the greenhouse. In contrast, growth over time was linear for plants grown indoors. Within each environment, solution management treatment did not affect growth, indicating that the simpler W/O strategy was adequate under these conditions. Plants grown in the greenhouse required more frequent refill water applications compared with indoors, which resulted in three to four times more refill water applied. Because indoor-grown plants had a decreased growth rate, nutrient uptake rate, and volume of water applied compared with plants grown in the greenhouse, electrical conductivity (EC) for the W/O treatment increased over time. Final nutrient solution concentration was highest for indoor-grown plants under the W/O treatment, and final tissue nutrient concentration was higher for plants grown indoors compared with the greenhouse. Final nutrient uptake (dry mass × nutrient concentration) was higher for plants grown in the greenhouse rather than indoors. Considering that EC increased in the solution of indoor-grown plants under W/O, an appropriate strategy using this treatment would require reducing fertilizer input indoors. To refine simple and robust fertilizer management strategies for indoor gardeners, further research is needed to test variables such as different plant species, cultivars, and water qualities.

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