Abstract
The European Union has limited the maximum nitrate (NO 3 − ) content allowed for industrial processed spinach ( Spinacia oleracea L.) to 2000 mg/kg fresh weight in order to avoid human pathologies associated with uptake of high amounts of nitrate. Nitrification inhibitors (NIs) 3,4-dimethylpyrazole phosphate (DMPP) and dicyandiamide (DCD) allow changing of the molecular form (NH 4 + or NO 3 − ) in which soil mineral N is available for plants. Enhancing ammonium nutrition has successfully reduced the amount of nitrate accumulated in plants in hydroponic culture. Therefore, fertilizers containing NIs have been proposed to reduce nitrate accumulated by vegetables grown in field conditions. Basammon Stabil® (BS) and Entec 26®-(E26) are commercial fertilizers containing DCD and DMPP respectively. In the present paper, the effect of applying ammonium sulphate nitrate (ASN), BS and E26 at three rates (0, 150 and 250 kg N/ha) to spinach crops cultivated under Mediterranean growing conditions for industrial processing is analysed. During 1998 and 1999, eight field split-plot trials with four replicates were carried out in the Ebro Valley, northern Spain, during different seasons and with various soil types. The fertilizer effects were influenced by the season and the type of soil. In spring, fertilizers containing NIs increased the mineral N (Nmin) in the soil and greatly reduced nitrate accumulation in the crop. In autumn, with less solar radiation, the nitrate accumulation was more than 2000 mg/kg fresh weight on many occasions and the effect of NIs was smaller. The present paper concluded that, under Mediterranean growing conditions, DCD can reduce nitrate accumulation in spinach between 18 and 61% and DMPP between 33 and 84%, without reducing yield or changing other quality characteristics. NIs are especially useful in the spring, when soil temperature is low and solar radiation interception by the crop is high.
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Claims 9
Claim · model-written summary
Fertilizer effects on spinach varied by season and soil type.
- Taxon
- spinach
Spinacia oleraceat0 - Outcome
- fertilizer effectse0
- Qualifier
- season and the type of soile0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The fertilizer effects were influenced by the season and the type of soil.”
t0“spinach”
Claim · model-written summary
In spring, nitrification inhibitor fertilizers increased soil mineral nitrogen.
- Taxon
- spinachSpinacia oleraceat0
- Treatment
- fertilizers containing NIse0
- Outcome
- mineral N (Nmin) in the soile0
- Direction
- increasede0
- Qualifier
- In springe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In spring, fertilizers containing NIs increased the mineral N (Nmin) in the soil”
t0“spinach”
Claim · model-written summary
In spring, nitrification inhibitor fertilizers greatly reduced crop nitrate accumulation.
- Taxon
- spinachSpinacia oleraceat0
- Treatment
- fertilizers containing NIse0
- Outcome
- nitrate accumulation in the crope0
- Direction
- reducede0
- Qualifier
- In springe0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In spring, fertilizers containing NIs increased the mineral N (Nmin) in the soil and greatly reduced nitrate accumulation in the crop.”
t0“spinach”
Claim · model-written summary
In autumn, nitrate accumulation exceeded 2000 mg/kg fresh weight on many occasions.
- Taxon
- spinachSpinacia oleraceat0
- Outcome
- nitrate accumulatione0
- Direction
- more thane0
- Value
- 2000 mg/kg fresh weighte0
- Qualifier
- In autumn, with less solar radiatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In autumn, with less solar radiation, the nitrate accumulation was more than 2000 mg/kg fresh weight on many occasions”
t0“spinach”
Claim · model-written summary
Nitrification inhibitor effects were smaller in autumn.
- Taxon
- spinachSpinacia oleraceat0
- Outcome
- effect of NIse0
- Direction
- smallere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the effect of NIs was smaller”
t0“spinach”
Claim · model-written summary
DCD reduced spinach nitrate accumulation by 18 to 61%.
- Taxon
- spinachSpinacia oleraceae0
- Treatment
- DCDe0
- Outcome
- nitrate accumulatione0
- Direction
- reducee0
- Value
- 18 and 61%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“DCD can reduce nitrate accumulation in spinach between 18 and 61%”
Claim · model-written summary
DMPP reduced spinach nitrate accumulation by 33 to 84%.
- Taxon
- spinachSpinacia oleraceae1
- Treatment
- DMPPe0
- Outcome
- nitrate accumulatione1
- Direction
- reducee1
- Value
- 33 and 84%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“DMPP between 33 and 84%, without reducing yield or changing other quality characteristics.”
e1“DCD can reduce nitrate accumulation in spinach between 18 and 61% and DMPP between 33 and 84%”
Claim · model-written summary
Nitrification inhibitors did not reduce spinach yield or change other quality characteristics.
- Taxon
- spinachSpinacia oleraceae1
- Treatment
- DCDe1
- Outcome
- yield or changing other quality characteristicse0
- Direction
- without reducinge0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“without reducing yield or changing other quality characteristics.”
e1“DCD can reduce nitrate accumulation in spinach between 18 and 61% and DMPP between 33 and 84%”
Claim · model-written summary
Nitrification inhibitors are especially useful in spring under cool soil and high intercepted radiation.
- Taxon
- spinachSpinacia oleraceat0
- Outcome
- especially useful in the springe0
- Qualifier
- soil temperature is low and solar radiation interception by the crop is highe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“NIs are especially useful in the spring, when soil temperature is low and solar radiation interception by the crop is high.”
t0“spinach”
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See all 60 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.