Abstract
Biological nitrogen fixation (BNF) is of key importance in the N balance of soybean (Glycine max) crops. A number of authors have suggested that a negative balance may occur under high yield conditions. Few studies have measured the contribution of BNF to soil N in the pampas region. The aims of the present study were to compare three BNF determination methods – two isotopic methods using sorghum or a non-nodulating soybean isoline as a reference crop, and one involving the calculation of the difference in N content between the nodulating and non-nodulating soybean isolines – and to estimate the N balance in soybean crops raised under conventional tillage and no tillage practices. The study was performed in 2004-2005; a complete randomised block design was used with three replicates (plot dimensions 3 × 7 m). The different methodologies estimated BNF to account for 45-58% of total plant N, equivalent to 94 to 123 kg N ha-1. Depending on the methodology for estimating the BNF the soil N balance varied between –7 and 22 kg N ha-1. With an average grain yield of 1,618 kg ha-1 and a BNF accounting for approximately 50% of total plant N (i.e.,115 kg N ha-1), the soil N balance was slightly positive (14 kg ha-1) and independent of the tillage practice. The tillage systems had no effect (P < 0.05) on the mass or number of nodules, shoot biomass production at the R1 or R6 growth stages, the N content, BNF, or grain yield. Since the present results were obtained using non-commercial soybean isolines, further research is required to determine the soil N balance when high yielding soybean crops are raised.
Abstract from the paper’s OpenAlex record; open copy licensed cc-by. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 6
Claim · model-written summary
The different BNF methodologies estimated BNF at 45-58% of total plant N.
- Taxon
- soybean
Glycine maxe0 - Outcome
- BNFe1
- Value
- 45-58%e1
- Setting
- pampas regiont0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Biological nitrogen fixation (BNF) is of key importance in the N balance of soybean (Glycine max) crops”
e1“The different methodologies estimated BNF to account for 45-58% of total plant N, equivalent to 94 to 123 kg N ha-1”
t0“soybean crops in the pampas region”
Claim · model-written summary
Soil N balance varied between -7 and 22 kg N ha-1 depending on the BNF estimation method.
- Taxon
- soybeanGlycine maxe0
- Outcome
- soil N balancee2
- Direction
- variede2
- Value
- –7 and 22 kg N ha-1e2
- Qualifier
- Depending on the methodology for estimating the BNFe2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Biological nitrogen fixation (BNF) is of key importance in the N balance of soybean (Glycine max) crops”
e2“Depending on the methodology for estimating the BNF the soil N balance varied between –7 and 22 kg N ha-1”
Claim · model-written summary
With BNF at about 50% of total plant N, the soil N balance was slightly positive (14 kg ha-1) regardless of tillage.
- Taxon
- soybeanGlycine maxe0
- Outcome
- soil N balancee3
- Direction
- slightly positivee3
- Value
- 14 kg ha-1e3
- Qualifier
- independent of the tillage practicee3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Biological nitrogen fixation (BNF) is of key importance in the N balance of soybean (Glycine max) crops”
e3“the soil N balance was slightly positive (14 kg ha-1) and independent of the tillage practice”
Claim · model-written summary
Tillage systems had no effect on nodule mass or number in soybean.
- Taxon
- soybeanGlycine maxe0
- Treatment
- tillage systemse4
- Outcome
- mass or number of nodulese4
- Direction
- no effecte4
- Comparator
- conventional tillagee5
- Setting
- pampas regiont0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Biological nitrogen fixation (BNF) is of key importance in the N balance of soybean (Glycine max) crops”
e4“The tillage systems had no effect (P < 0.05) on the mass or number of nodules, shoot biomass production at the R1 or R6 growth stages, the N content, BNF, or grain yield”
e5“under conventional tillage and no tillage practices”
t0“soybean crops in the pampas region”
Claim · model-written summary
Tillage systems had no effect on shoot biomass production at the R1 or R6 growth stages in soybean.
- Taxon
- soybeanGlycine maxe0
- Organ / stage
- R1 or R6 growth stagese4
- Treatment
- tillage systemse4
- Outcome
- shoot biomass productione4
- Direction
- no effecte4
- Comparator
- conventional tillagee5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Biological nitrogen fixation (BNF) is of key importance in the N balance of soybean (Glycine max) crops”
e4“The tillage systems had no effect (P < 0.05) on the mass or number of nodules, shoot biomass production at the R1 or R6 growth stages, the N content, BNF, or grain yield”
e5“under conventional tillage and no tillage practices”
Claim · model-written summary
Tillage systems had no effect on N content, BNF or grain yield of soybean.
- Taxon
- soybeanGlycine maxe0
- Treatment
- tillage systemse4
- Outcome
- the N content, BNF, or grain yielde4
- Direction
- no effecte4
- Comparator
- conventional tillagee5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Biological nitrogen fixation (BNF) is of key importance in the N balance of soybean (Glycine max) crops”
e4“The tillage systems had no effect (P < 0.05) on the mass or number of nodules, shoot biomass production at the R1 or R6 growth stages, the N content, BNF, or grain yield”
e5“under conventional tillage and no tillage practices”
The same questions in other papers
tillage · symbiosis · Glycine max (soybean)Positive and negative results
3 papers in the same direction as this paper · 15 reporting no difference from an alternative
- positive
- positive
- positive
15 papers more in this group
See all 19 papers →tillage · yield · Glycine max (soybean)Positive and negative results
125 papers in the same direction as this paper · 264 reporting no difference from an alternative
- positive
- positive
- positive
386 papers more in this group
See all 390 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.