Abstract
The long-term effects of low and high NH4+/ NO3- uptake ratios in a system with rigorous control of pH and nitrogen concentration are poorly understood. In two replicate studies, two cultivars of wheat (Triticum aestivum) were grown to maturity with three NH4+/ NO3- ratios in hydroponic solution: 0/100, 25/75, and 85/15%. Nitrogen was controlled at ample levels throughout the 70-d life cycle and pH was controlled at 5.8 ± 0.2. An equimolar ratio of NH4+ to Cl- was used to facilitate charge balance. Nitrogen consumption and transpiration were measured daily. Flag leaves were analyzed at 10-d intervals for total nitrogen, NO3--N, and essential elements. Essential nutrient elements in the biomass and seeds were measured at harvest. Yield components , nitrogen recovery, and nitrogen assimilation were calculated. There was no difference between the NO3- only (0/100) and the low NH4+ (25/75) treatments . The high NH4+ treatment (85/15) did not reduce vegetative biomass, but decreased seed yield and harvest index by 20%. The decrease was associated with a 23% reduction in seed number head-1. The high NH4+ treatment increased percent root mass by 50% and percent sterile heads by 800%, but increased assimilated N in the seeds by 30% and in the biomass by 130%. Supplemental additions of K were effective in preventing the reduction of K concentration in the wheat tissues typically caused by high NH4+, but the high NH4+ treatment decreased the concentrations of Ca, Mn, and Zn, and increased the concentrations of S, P, Fe, and B in the wheat tissue . The uptake of Mg and Cu was similar among all three treatments. Chloride concentrations in the flag leaves increased from 0.8% in the NO3- only treatment to 2.0% in the two NH4+ treatments. This research indicates that hydroponic wheat can be grown to maturity with high levels of NH4+ with a small reduction in grain yield.
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Claims 14
Claim · model-written summary
The nitrate only and low ammonium treatments did not differ.
- Treatment
- low NH4+ (25/75)e0
- Outcome
- no differencee0
- Direction
- no differencee0
- Comparator
- NO3- only (0/100)e0
Not reportedTaxon
Verbatim
e0“There was no difference between the NO3- only (0/100) and the low NH4+ (25/75) treatments”
Claim · model-written summary
High ammonium did not reduce vegetative biomass.
Not reportedTaxonComparator
Verbatim
e0“The high NH4+ treatment (85/15) did not reduce vegetative biomass”
Claim · model-written summary
High ammonium decreased seed yield by 20%.
Not reportedTaxonComparator
Verbatim
e0“The high NH4+ treatment (85/15) did not reduce vegetative biomass, but decreased seed yield and harvest index by 20%”
Claim · model-written summary
High ammonium decreased harvest index by 20%.
Not reportedTaxonTreatmentComparator
Verbatim
e0“decreased seed yield and harvest index by 20%”
Claim · model-written summary
The decrease was associated with 23% fewer seeds per head.
Not reportedTaxonTreatmentComparator
Verbatim
e0“The decrease was associated with a 23% reduction in seed number head-1”
Claim · model-written summary
High ammonium increased percent root mass by 50%.
Not reportedTaxonComparator
Verbatim
e0“The high NH4+ treatment increased percent root mass by 50%”
Claim · model-written summary
High ammonium increased percent sterile heads by 800%.
Not reportedTaxonTreatmentComparator
Verbatim
e0“percent sterile heads by 800%”
Claim · model-written summary
High ammonium increased assimilated nitrogen in seeds by 30%.
Not reportedTaxonTreatmentComparator
Verbatim
e0“increased assimilated N in the seeds by 30%”
Claim · model-written summary
High ammonium increased assimilated nitrogen in biomass by 130%.
Not reportedTaxonTreatmentComparator
Verbatim
e0“in the biomass by 130%”
Claim · model-written summary
Supplemental K prevented the high ammonium associated decline in wheat tissue K.
- Taxon
- wheat
Triticum aestivume0 - Treatment
- Supplemental additions of Ke0
- Outcome
- K concentration in the wheat tissuese0
- Direction
- preventing the reductione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Supplemental additions of K were effective in preventing the reduction of K concentration in the wheat tissues typically caused by high NH4+”
Claim · model-written summary
High ammonium decreased wheat tissue Ca, Mn, and Zn concentrations.
Not reportedTaxonComparator
Verbatim
e0“the high NH4+ treatment decreased the concentrations of Ca, Mn, and Zn”
Claim · model-written summary
High ammonium increased wheat tissue S, P, Fe, and B concentrations.
- Taxon
- wheatTriticum aestivume0
- Outcome
- concentrations of S, P, Fe, and B in the wheat tissuee0
- Direction
- increasede0
Not reportedTreatmentComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“increased the concentrations of S, P, Fe, and B in the wheat tissue”
Claim · model-written summary
Mg and Cu uptake was similar across three treatments.
Not reportedTaxonComparator
Verbatim
e0“The uptake of Mg and Cu was similar among all three treatments”
Claim · model-written summary
Flag leaf chloride rose from 0.8% under nitrate only to 2.0% under ammonium treatments.
- Treatment
- two NH4+ treatmentse0
- Outcome
- Chloride concentrations in the flag leavese0
- Direction
- increasede0
- Value
- 2.0%e0
- Qualifier
- 0.8%e0
- Comparator
- NO3- only treatmente0
Not reportedTaxon
Verbatim
e0“Chloride concentrations in the flag leaves increased from 0.8% in the NO3- only treatment to 2.0% in the two NH4+ treatments”
The same questions in other papers
ammonium · nutrient: content · Triticum aestivum (wheat)Positive and negative results
1 in the opposite direction
- positive
ammonium · yield · Triticum aestivum (wheat)Positive and negative results
1 paper in the same direction as this paper · 1 in the opposite direction
- positive
- negative
ammonium · growth · Triticum aestivum (wheat)Results agree
2 papers in the same direction as this paper
- negative
- negative
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.