Abstract
Effect of Nitrogen Fertilization on the Yield and Quality of Field-grown Leaf Lettuce for Spring Harvest Two 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-[NH 4 NO 3 ], calcium nitrate 15.5% N-[Ca(NO 3 ) 2 xH 2 O+NH 4 NO 3 ], ammonium sulphate 20.0% N-[(NH4) 2 SO 4 ], and ENTEC 26% N-[NH 4 NO 3 +(NH 4 ) 2 SO 4 +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 -3 to 100 mg N·dm -3 resulted in a significant increase in the marketable yield of lettuce. At 150 mg N·dm -3 this 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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Claims 8
Claim · model-written summary
ENTEC 26 produced significantly higher lettuce yield than calcium nitrate and ammonium sulphate.
- Taxon
- lettuce
Lactuca sativae0 - Treatment
- ENTEC 26e0
- Outcome
- yields of lettucee0
- Direction
- highere0
- Comparator
- calcium nitrate and ammonium sulphatee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“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.”
Claim · model-written summary
Ammonium nitrate produced significantly higher lettuce yield than calcium nitrate and ammonium sulphate.
- Taxon
- lettuceLactuca sativae0
- Treatment
- ammonium nitratee0
- Outcome
- yields of lettucee0
- Direction
- highere0
- Comparator
- calcium nitrate and ammonium sulphatee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“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.”
Claim · model-written summary
Raising soil nitrogen from 50 to 100 mg N·dm -3 significantly increased marketable lettuce yield.
- Taxon
- lettuceLactuca sativae0
- Treatment
- 100 mg N·dm -3e0
- Outcome
- marketable yielde0
- Direction
- increasee0
- Comparator
- 50 mg N·dm -3e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increasing the concentration of nitrogen in the soil from 50 mg N·dm -3 to 100 mg N·dm -3 resulted in a significant increase in the marketable yield of lettuce”
Claim · model-written summary
Marketable yield at 150 mg N·dm -3 was similar to yield at 100 mg N·dm -3.
Not reportedTaxon
Verbatim
e0“At 150 mg N·dm -3 this yield remained at a level similar to that at 100 mg N·dm -3”
Claim · model-written summary
Ammonium sulphate gave lettuce leaves the lowest mean nitrate content before harvest.
- Taxon
- lettuceLactuca sativae0
- Organ / stage
- leavese0
- Treatment
- ammonium sulphatee0
- Outcome
- nitrate contente0
- Direction
- loweste0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The lettuce fertilized with ammonium sulphate was marked by the lowest mean nitrate content in the leaves before harvest.”
Claim · model-written summary
Increasing nitrogen doses reduced lettuce leaf dry weight content.
- Taxon
- lettuceLactuca sativae0
- Organ / stage
- leavese0
- Treatment
- gradually higher doses of nitrogene0
- Outcome
- dry weight contente0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“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.”
Claim · model-written summary
Increasing nitrogen doses lowered total and reducing sugars in lettuce leaves.
- Taxon
- lettuceLactuca sativae0
- Organ / stage
- leavese0
- Treatment
- gradually higher doses of nitrogene0
- Outcome
- total and reducing sugarse0
- Direction
- lowere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“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.”
Claim · model-written summary
Soil nitrogen for leaf lettuce should not exceed 100 mg N·dm -3 for yield and quality.
Verbatim
e0“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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