Nitrogen fertilizers and the amount of vitamins in plants: A review

Mozafar, A.

doi:10.1080/01904169309364698

Cited by 165 publications

(116 citation statements)

References 73 publications

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“…Segura F1 (Lošák et al 2011) the content of ascorbic acid was found to be higher in all the fertilised treatments (772-789 mg/kg FM) as compared to the unfertilised treatment (511 mg/kg FM). Previous studies differ in their conclusions regarding the effect of nitrogenous fertilisation on the content of vitamin C. Mozafar (1993) reported Mean values of kohlrabi bulb nitrates (n = 4). Different small letters indicate significant differences at the level of α = 0.05 among individual treatments within the same year and different uppercase letters (A, B) indicate significant differences at the level of α = 0.05 among individual years; FM -fresh matter Mean values of kohlrabi bulb ascorbic acid (n = 4).…”

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confidence: 75%

The effect of fertilisation with digestate on kohlrabi yields and quality

Lošák¹,

Hlušek²,

Válka³

et al. 2016

PLANT SOIL ENVIRON

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The number of biogas stations in the Czech Republic has recently increased considerably; as of 1 January 2014 some 500 biogas plants were registered of which 378 are agricultural biogas plants with installed electric energy of 392 MW. The estimated annual digestate production ranges around 7.9 mil t and the biogas stations are deployed irregularly in the regions. On that account practical problems frequently arise how to utilise the digestate effectively and/or where to apply it (in compliance with legislation -for example: The Nitrates Directive and Restrictions in the Vulnerable Areas). Considering the fact that digestate is produced during the whole year, possibilities are being sought of using it not only to fertilise arable crops but also vegetables. Whereas information on using digestate to fertilise arable crops is relatively abundant, in the case of vegetables it is vice versa (Dostál et al. 2015).Manures from stables, crop residues, wastes from the food industry, municipal wastes, and dedicated energy crops are the main feedstocks for anaerobic digestion (AD) in biogas plants. The residual product of AD, called digestate (= biogas effluents = biogas residues, or biogas slurry, when animal manures are digested), is usually used as (1) untreated control; (2) digestate; (3) digestate + phosphorus (P). The nitrogen (N) rate was the same in treatments 2-3. There were significant differences between years in all parameters. The weight of single kohlrabi bulbs in the unfertilised control was significantly lower in both years (33.1-46.9%) than in the digestate treatment (100%). Digestate supplemented with P (treatment 3) increased the bulb yield significantly by 11.0-14.3% compared with pure digestate (treatment 2). In both years the content of bulb nitrates (mg NO 3 -/kg FM (fresh matter)) was significantly the lowest in the unfertilised control (135 and 163, respectively). After digestate applications the nitrates content (mg NO 3 -/kg FM) increased significantly in both years, i.e. to 315-327 (2014) and to 486-509 (2015) compared to unfertilised control. In two years the content of ascorbic acid (mg/kg FM) did not differ among the three treatments (274-288 in 2014 and 311-329 in 2015). Digestates can be recommended for kohlrabi fertilisation prior to planting.

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confidence: 75%

The effect of fertilisation with digestate on kohlrabi yields and quality

Lošák¹,

Hlušek²,

Válka³

et al. 2016

PLANT SOIL ENVIRON

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“…Nitrogen fertilizers are also known to increase plant foliage and thus may reduce the light intensity and accumulation of AA in shaded parts. Since excess use of nitrogen fertilizers increases the concentration of NO 3 and simultaneously decreases that of AA, it may have a double negative effect on the quality of plant foods (Mozafar, 1993).…”

Section: Variation Among Species and Cultivarsmentioning

confidence: 99%

Preharvest and postharvest factors influencing vitamin C content of horticultural crops

Lee

Kader

2000

Postharvest Biology and Technology

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Vitamin C, including ascorbic acid and dehydroascorbic acid, is one of the most important nutritional quality factors in many horticultural crops and has many biological activities in the human body. The content of vitamin C in fruits and vegetables can be influenced by various factors such as genotypic differences, preharvest climatic conditions and cultural practices, maturity and harvesting methods, and postharvest handling procedures. The higher the intensity of light during the growing season, the greater is vitamin C content in plant tissues. Nitrogen fertilizers at high rates tend to decrease the vitamin C content in many fruits and vegetables. Vitamin C content of many crops can be increased with less frequent irrigation. Temperature management after harvest is the most important factor to maintain vitamin C of fruits and vegetables; losses are accelerated at higher temperatures and with longer storage durations. However, some chilling sensitive crops show more losses in vitamin C at lower temperatures. Conditions favorable to water loss after harvest result in a rapid loss of vitamin C especially in leafy vegetables. The retention of vitamin C is lowered by bruising, and other mechanical injuries, and by excessive trimming. Irradiation at low doses (1 kGy or lower) has no significant effects on vitamin C content of fruits and vegetables. The loss of vitamin C after harvest can be reduced by storing fruits and vegetables in reduced O 2 and/or up to 10% CO 2 atmospheres; higher CO 2 levels can accelerate vitamin C loss. Vitamin C of produce is also subject to degradation during processing and cooking. Electromagnetic energy seems to have advantages over conventional heating by reduction of process times, energy, and water usage. Blanching reduces the vitamin C content during processing, but limits further decreases during the frozen-storage of horticultural products.

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“…Comprehensive studies have shown clear advantages for several parameters describing a higher product quality of organic produce compared to products derived from mainstream agriculture (Baker et al 2002;Benbrook 2015). The limited availability and uptake of nitrogen is considered as responsible for the often higher contents of secondary metabolites as beneficial ingredients in organic products compared to conventional (Mozafar 1993;Brandt and Molgaard 2001;Köpke 2005). …”

Section: Food Quality and Healthmentioning

confidence: 99%