Effects of constant versus fluctuating red–blue LED radiation on yield and quality of hydroponic purple-leaf lettuce

The aim of this work was to study whether the application of a directly brewed compost extract (added in the nutrient solution or by microsprinkler) could be used to improve the yield and quality of baby leaf red lettuce growing in a floating system, and to control the incidence of Pythium irregulare. Its effect on the quality of fresh-cut red lettuce was also studied. For this, two experiments were carried out over two growing cycles (winter–spring and autumn). The results showed that the use of compost extract added to the nutrient solution improved baby leaf lettuce growth and quality, reducing the nitrate content and enhancing the content of potentially health-promoting compounds such as phenols and flavonoids and the antioxidant capacity. Microbial quality was maintained during storage and the compost extract had no negative effect on the microbial load of the final product. In addition, application of the compost decreased the population of P. irregulare in the water. It is concluded that the application of directly brewed compost extract is of potential use in a sustainable soilless production system for baby leaf red lettuce, since it improves the yield and quality of the product and is able to control the incidence of P. irregulare.

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Effect of Gibberellic Acid on Growth, Yield, and Quality of Leaf Lettuce and Rocket Grown in a Floating System

Agronomy ◽

10.3390/agronomy9070382 ◽

2019 ◽

Vol 9 (7) ◽

pp. 382 ◽

Cited By ~ 19

Author(s):

Alessandro Miceli ◽

Alessandra Moncada ◽

Leo Sabatino ◽

Filippo Vetrano

Keyword(s):

Gibberellic Acid ◽

Nutrient Solution ◽

Production Systems ◽

Growth Yield ◽

Mineral Nutrient ◽

Yield And Quality ◽

Floating System ◽

Use Efficiency ◽

Leaf Lettuce

Gibberellins (GAs) are growth hormones strongly involved in a wide variety of physiological activities. Currently, gibberellins are commercially used to enhance phenotypic characteristics, earliness, and productivity of many vegetable and ornamental crops. In this work, the efficacy of supplementation of low levels of gibberellic acid (0, 10−8, 10−6, and 10−4 M GA3) through the mineral nutrient solution of a floating system on yield and quality of leaf lettuce and rocket plants was tested. The marketability of plants was lost when 10−4 M GA3 was added to the mineral nutrient solution. This study demonstrated that the addition of 10−4 M GA3 exceeded the acceptable threshold for use in hydroponics production systems. Below the concentration of 10−4 M, the presence of GA3 in the mineral nutrient solutions (MNS), especially at 10−6 M GA3, stimulated plant growth and enhanced the yield. Various morphological and physiological traits were enhanced by GA3 treatments (biomass accumulation, leaf expansion, stomatal conductance, water use efficiency (WUE), Nitrogen use efficiency (NUE), etc.), with superimposable trends in both lettuce and rocket. The addition of 10−6 M GA3 to the nutrient solution of a hydroponic floating system can promote growth and quality of lettuce and rocket plants.

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Effect of Nitrogen Fertilization on the Yield and Quality of Field-grown Leaf Lettuce for Spring Harvest

Vegetable Crops Research Bulletin ◽

10.2478/v10032-009-0025-8 ◽

2009 ◽

Vol 71 (1) ◽

pp. 41-49 ◽

Cited By ~ 2

Author(s):

Piotr Chohura ◽

Eugeniusz Kołota

Keyword(s):

Ammonium Nitrate ◽

Ammonium Sulphate ◽

Nitrogen Fertilization ◽

Field Experiments ◽

Calcium Nitrate ◽

Nitrate Content ◽

Yield And Quality ◽

Leaf Lettuce ◽

Spring Harvest

Effect of Nitrogen Fertilization on the Yield and Quality of Field-grown Leaf Lettuce for Spring HarvestTwo field experiments with leaf lettuce were carried out in 2006-2008. Each of them was set up in a random sub-block design in 3 replications and a two-factorial system. The first factor represented different nitrogen doses that were used to obtain the required N level in the soil prior to planting the seedlings, the levels being: 50, 100 and 150 mg N·dm-3. The second factor incorporated 4 nitrogenous fertilizers which were different in terms of chemical composition, and, more importantly, contained different nitrogen forms for introduction to the soil: ammonium nitrate 34% N-[NH4NO3], calcium nitrate 15.5% N-[Ca(NO3)2xH2O+NH4NO3], ammonium sulphate 20.0% N-[(NH4)2SO4], and ENTEC 26% N-[NH4NO3+(NH4)2SO4+0.8% DMPP]. Two varieties of leaf lettuce were used: Casabella (of the type Lollo Bionda) with green leaves, and Klausia (of the type Lollo Rosa) with red leaves. The best sources of nitrogen for the lettuce plants were the fertilizers ENTEC 26 and ammonium nitrate, which in contrast to calcium nitrate and ammonium sulphate made it possible to obtain significantly higher yields of lettuce. Irrespective of the kind of the nitrogenous fertilizer used, increasing the concentration of nitrogen in the soil from 50 mg N·dm-3to 100 mg N·dm-3resulted in a significant increase in the marketable yield of lettuce. At 150 mg N·dm-3this yield remained at a level similar to that at 100 mg N·dm-3. The lettuce fertilized with ammonium sulphate was marked by the lowest mean nitrate content in the leaves before harvest. The use of gradually higher doses of nitrogen resulted in a reduced dry weight content and lower levels of total and reducing sugars in lettuce leaves. With respect to yield size and quality, the recommended concentration of nitrogen in the soil for leaf lettuce should not exceed 100 mg N·dm-3.

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Yield and quality of greenhouse multi-leaf lettuce cultivars grown in soil and soilless culture under Mediterranean conditions

Italus Hortus ◽

10.26353/j.itahort/2020.3.1830 ◽

2020 ◽

Vol 27 (3) ◽

pp. 18-30

Author(s):

Maria Gonnella ◽

Massimiliano Renna ◽

Francesco Serio

Keyword(s):

Soilless Culture ◽

Yield And Quality ◽

Leaf Lettuce ◽

Mediterranean Conditions

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Influence of the substrate on the yield and quality of microgreens of vegetable plants

Collected Works of Uman National University of Horticulture ◽

10.31395/2415-8240-2021-99-1-169-180 ◽

2021 ◽

Vol 1 (99) ◽

pp. 169-180

Author(s):

A. V. Vakhovska ◽

Keyword(s):

Strong Relationship ◽

Mineral Wool ◽

High Yield ◽

Biochemical Processes ◽

Yield And Quality ◽

Important Trait ◽

Leaf Lettuce ◽

Physiological And Biochemical ◽

Time Of Harvest

Research on the effect of the substrate on growth rates, physiological and biochemical processes, yield and quality of lettuce, radish, mustard during the forcing of microgreens in greenhouses showed a positive result. For research, the generally accepted methods were used: laboratory, mathematical-statistical, physical. Evaluation of substrates for growing microgreens of lettuce, radish, mustard indicates that they are suitable for forcing in greenhouses. It was found that the duration of the growth phases of microgreens depends on the substrate. For lettuce, radish and mustard, the appearance of the root occurred on the second day. Greens were collected in 2020 for 8–10 days, in 2021 – for 7–8 days, which is influenced by the length of daylight hours and the ambient temperature. When growing microgreens of lettuce on mineral wool, the height of the plants was 4.48 cm.Radish and mustard had the tallest plants when grown on coconut substrate – 6.36 cm and 6.78 cm. The mass of 1000 pcs. plants is an important trait, which in turn determines the quality of microgreens. Maximum weight 1000 pcs. when grown on a coconut substrate, lettuce – 13.75 g, radishes – 69.61 g, mustard on mineral wool – 35.58 g. A high yield of leaf lettuce during the years of research was obtained when grown on a coconut substrate – 1.62 kg/m2, which significantly exceeded the control by 0.1 kg/m2. A high yield of radish was obtained when grown on a coconut substrate – 5.41 kg/m2, which significantly exceeds the control by 3.83 kg/m2. The mustard yield when using coconut substrate was 4.90 kg/m2, which is 3.38 kg/m2 higher than the control. Correlation analysis proves that for all the studied plants at the time of harvest, there is a direct strong relationship between the mass and its height, and its coefficient is r = 0.98.

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