Abstract
To optimise the production of Swiss chard, high levels of nitrogen fertiliser are often applied. This may have adverse effects on both the economy of fertilisation and the nutritional value of the human diet. Very little is known about both the optimum levels and influence of different sources of nitrogen on this crop under South African conditions. Glasshouse experiments were therefore conducted to determine the integrated effects of nitrogen level and source on the yield and quality of Swiss chard. Three Swiss chard seedlings were planted in each 4 L pot and later thinned to one plant per pot. Nine nitrogen levels (0, 100, 200, 300, 400, 500, 600, 700 and 800 kg ha-~ N) and six nitrogen sources (ammonium nitrate, calcium nitrate, potassium nitrate, ammonium sulphate, urea ammonium nitrate and urea) were combined in a factorial arrangement with four replications. The number of leaves harvested, leaf area, fresh and dry leaf mass, and leaf nitrogen content increased with increasing nitrogen levels up to 800 kg ha-~ N. Dry leaf mass was significantly higher where urea was applied compared to calcium nitrate. Although the different nitrogen sources did not differ significantly at the corresponding application levels, the nitrate accumulation within Swiss chard leaves was significantly increased with the use of ammonium nitrate.
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Claims 5
Claim · model-written summary
Leaf number, leaf area, and fresh leaf mass increased with nitrogen level up to 800 kg ha-~ N.
- Taxon
- Swiss Chard
Beta vulgaris subsp. vulgarist0 - Treatment
- increasing nitrogen levels up to 800 kg ha-~ Ne0
- Outcome
- number of leaves harvested, leaf area, freshe0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The number of leaves harvested, leaf area, fresh and dry leaf mass, and leaf nitrogen content increased with increasing nitrogen levels up to 800 kg ha-~ N”
t0“Swiss Chard”
Claim · model-written summary
Dry leaf mass and leaf nitrogen content increased with nitrogen level up to 800 kg ha-~ N.
- Taxon
- Swiss ChardBeta vulgaris subsp. vulgarist0
- Treatment
- increasing nitrogen levels up to 800 kg ha-~ Ne0
- Outcome
- dry leaf mass, and leaf nitrogen contente0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The number of leaves harvested, leaf area, fresh and dry leaf mass, and leaf nitrogen content increased with increasing nitrogen levels up to 800 kg ha-~ N”
t0“Swiss Chard”
Claim · model-written summary
Urea produced significantly higher dry leaf mass than calcium nitrate.
- Taxon
- Swiss ChardBeta vulgaris subsp. vulgarist0
- Treatment
- ureae0
- Outcome
- Dry leaf masse0
- Direction
- highere0
- Comparator
- calcium nitratee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Dry leaf mass was significantly higher where urea was applied compared to calcium nitrate”
t0“Swiss Chard”
Claim · model-written summary
Nitrogen sources did not differ significantly at corresponding application levels.
- Taxon
- Swiss ChardBeta vulgaris subsp. vulgarist0
- Treatment
- different nitrogen sourcese0
- Outcome
- did not differ significantlye0
- Direction
- did not differe0
- Comparator
- corresponding application levelse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the different nitrogen sources did not differ significantly at the corresponding application levels”
t0“Swiss Chard”
Claim · model-written summary
Ammonium nitrate significantly increased nitrate accumulation in Swiss chard leaves.
- Taxon
- Swiss chardBeta vulgaris subsp. vulgarise0
- Organ / stage
- leavese0
- Treatment
- ammonium nitratee0
- Outcome
- nitrate accumulation within Swiss chard leavese0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“nitrate accumulation within Swiss chard leaves was significantly increased with the use of ammonium nitrate”
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See all 108 papers →Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.