Abstract
The effects of the German Fertilizer Application Ordinance (GFO) on crop yield, nitrogen use efficiency and economical performance are highly controversial in science and practice in Germany. This study presents the results of a multi-year field experiment conducted at an experimental farm in southern Germany, in which the effects of different fertilizer systems on crop yield, protein concentration and nitrogen balance were analyzed. At this study site, relatively low N mineralization from the soil N pool was detected. Wheat ( triticum aestivum L.) and barley ( hordeum vulgare L.) showed strong yield declines from annual to multi-annual unfertilized plots, for maize ( zea mays L.), this yield decrease was not observed. The recommendations according to GFO meets the fertilizer requirement at the trial site well. A 20% reduction of fertilization compared to GFO resulted in a 5% yield reduction and a decrease in protein concentration of wheat and barley. According to the quadratic N response function, the GFO treatment was slightly below the economic optimum nitrogen rate (N opt ) for wheat, and close to N opt for winter barley on average over the trial years. For maize, a relatively high yield variability has been observed in the trial period so far. Sensor-based fertilization resulted in very high yields with high N use efficiency (up to 85%). This fertilization system can help to reduce nitrogen input and minimize nitrogen surplus. For wheat and barley, N fertilization and N uptake were well balanced, for maize clearly negative N surpluses were calculated. Despite all the discussion and criticism of GFO, the results of the plot trial show that high yields with high N use efficiency can be achieved with fertilization according to GFO.
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Claims 17
Claim · model-written summary
Low soil nitrogen mineralization was detected at the trial site.
Not reportedTaxon
Verbatim
e0“At this study site, relatively low N mineralization from the soil N pool was detected.”
Claim · model-written summary
Wheat yield declined from annual to multi-annual unfertilized plots.
- Taxon
- Wheat
Triticum aestivume0 - Treatment
- multi-annual unfertilized plotse0
- Outcome
- yielde0
- Direction
- declinese0
- Comparator
- annuale0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Wheat ( triticum aestivum L.) and barley ( hordeum vulgare L.) showed strong yield declines from annual to multi-annual unfertilized plots”
Claim · model-written summary
Barley yield declined from annual to multi-annual unfertilized plots.
- Taxon
- barley
.jpg?width=60)
Hordeum vulgaree0 - Treatment
- multi-annual unfertilized plotse0
- Outcome
- yielde0
- Direction
- declinese0
- Comparator
- annuale0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“Wheat ( triticum aestivum L.) and barley ( hordeum vulgare L.) showed strong yield declines from annual to multi-annual unfertilized plots”
Claim · model-written summary
Maize yield did not show that decline.
Zea maysOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Wheat ( triticum aestivum L.) and barley ( hordeum vulgare L.) showed strong yield declines from annual to multi-annual unfertilized plots, for maize ( zea mays L.), this yield decrease was not observed”
Claim · model-written summary
GFO recommendations met fertilizer requirements at the trial site.
Not reportedTaxon
Verbatim
e0“The recommendations according to GFO meets the fertilizer requirement at the trial site well.”
Claim · model-written summary
A 20% reduction in fertilization relative to GFO reduced yield by 5%.
Not reportedTaxon
Verbatim
e0“A 20% reduction of fertilization compared to GFO resulted in a 5% yield reduction”
Claim · model-written summary
Reduced fertilization decreased wheat protein concentration.
- Taxon
- wheatTriticum aestivume0
- Treatment
- 20% reduction of fertilizatione0
- Outcome
- protein concentratione0
- Direction
- decreasee0
- Comparator
- GFOe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A 20% reduction of fertilization compared to GFO resulted in a 5% yield reduction and a decrease in protein concentration of wheat and barley.”
Claim · model-written summary
Reduced fertilization decreased barley protein concentration.
- Taxon
- barleyHordeum vulgaree0
- Treatment
- 20% reduction of fertilizatione0
- Outcome
- protein concentratione0
- Direction
- decreasee0
- Comparator
- GFOe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“A 20% reduction of fertilization compared to GFO resulted in a 5% yield reduction and a decrease in protein concentration of wheat and barley.”
Claim · model-written summary
GFO fertilization was slightly below the economic optimum nitrogen rate for wheat.
- Taxon
- wheatTriticum aestivume0
- Treatment
- GFO treatmente0
- Outcome
- economic optimum nitrogen ratee0
- Direction
- slightly belowe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the GFO treatment was slightly below the economic optimum nitrogen rate (N opt ) for wheat”
Claim · model-written summary
GFO fertilization was close to the economic optimum for winter barley.
- Taxon
- winter barleyHordeum vulgaree0
- Outcome
- N opte0
- Direction
- close toe0
- Qualifier
- on average over the trial yearse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“close to N opt for winter barley on average over the trial years”
Claim · model-written summary
Maize yield varied considerably over the trial period.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“For maize, a relatively high yield variability has been observed in the trial period so far.”
Claim · model-written summary
Sensor-based fertilization produced high yields.
Not reportedTaxonComparator
Verbatim
e0“Sensor-based fertilization resulted in very high yields with high N use efficiency (up to 85%).”
Claim · model-written summary
Sensor-based fertilization produced high nitrogen use efficiency up to 85%.
Not reportedTaxonComparator
Verbatim
e0“Sensor-based fertilization resulted in very high yields with high N use efficiency (up to 85%).”
Claim · model-written summary
Wheat nitrogen fertilization and uptake were balanced.
- Taxon
- wheatTriticum aestivume0
- Outcome
- N fertilization and N uptakee0
- Direction
- well balancede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“For wheat and barley, N fertilization and N uptake were well balanced”
Claim · model-written summary
Barley nitrogen fertilization and uptake were balanced.
- Taxon
- barleyHordeum vulgaree0
- Outcome
- N fertilization and N uptakee0
- Direction
- well balancede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“For wheat and barley, N fertilization and N uptake were well balanced”
Claim · model-written summary
Maize had negative nitrogen surpluses.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“for maize clearly negative N surpluses were calculated”
Claim · model-written summary
GFO fertilization achieved high yields and high nitrogen use efficiency.
- Treatment
- fertilization according to GFOe0
- Outcome
- high yields with high N use efficiencye0
- Direction
- highe0
Not reportedTaxon
Verbatim
e0“high yields with high N use efficiency can be achieved with fertilization according to GFO”
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See all 566 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.