Abstract
Abstract Pearl millet [ Pennisetum glaucum (R.) Br.] is a high‐quality grain crop that can that can be grown without irrigation during hot, dry summers in the southeastern United States. The N rate required for optimum pearl millet grain yield varies widely in published studies, possibly because of variability in residual soil N from the subsoil. Field studies were conducted in the southern Coastal Plain at Tifton, GA, on a Tifton loamy sand (fine‐loamy, siliceous, thermic Plinthic Kandiudult) with nitrate accumulations near subsoil plinthite. The objective was to determine if pearl millet can extract N from acidic, relatively impermeable subsoils. Nitrate N (1 M KCl‐extractable) was 4 mg kg −1 in the surface 0.6 m, 1 mg kg −1 in the next 0.6 m, and 6 mg kg −1 from 1.2 to 1.5 m. We fertilized pearl millet field plots with two levels of N (0 and 168 kg ha −1 ) and studied root development during the growing seasons in 1993 and 1994. Soil cores were taken 40 d after planting to a depth of 1.2 m, separated into 0.3‐m depth segments, and root length density was measured. Roots were found in the deepest segments. Nitrogen fertilization increased the proportion of the root length density found in the surface soil in one year. We also injected 15 N as 60% atom l5 N‐enriched KNO 3 at a depth of 1 m at 30 and 40 d after planting. At physiological maturity, atom % 15 N abundance in the plants ranged from 10.1 to 12.0 where 15 N was injected and was near natural abundance where no 15 N was injected. These results indicate that pearl millet can extract N from 1 to 1.2 m in an acidic and impermeable subsoil.
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Claims 8
Claim · model-written summary
Nitrate N in the surface 0.6 m of soil was 4 mg kg-1.
Verbatim
t0“Grain Pearl Millet”
e0“Nitrate N”
e1“was 4 mg kg −1 in the surface 0.6 m”
Claim · model-written summary
Nitrate N in the next 0.6 m of soil was 1 mg kg-1.
Verbatim
t0“Grain Pearl Millet”
e0“Nitrate N”
e1“1 mg kg −1 in the next 0.6 m”
Claim · model-written summary
Nitrate N from 1.2 to 1.5 m depth was 6 mg kg-1.
Verbatim
t0“Grain Pearl Millet”
e0“Nitrate N”
e1“6 mg kg −1 from 1.2 to 1.5 m”
Claim · model-written summary
Pearl millet roots were found in the deepest soil segments sampled.
Verbatim
t0“Grain Pearl Millet”
e0“Roots were found in the deepest segments”
Claim · model-written summary
Nitrogen fertilization increased the proportion of root length density found in the surface soil in one year.
- Taxon
- Grain Pearl Millett0
- Treatment
- Nitrogen fertilizatione0
- Outcome
- the proportion of the root length density found in the surface soile0
- Direction
- increasede0
- Qualifier
- in one yeare0
Not reportedComparator
Verbatim
t0“Grain Pearl Millet”
e0“Nitrogen fertilization increased the proportion of the root length density found in the surface soil in one year”
Claim · model-written summary
Atom % 15N abundance in plants ranged from 10.1 to 12.0 where 15N was injected.
Verbatim
t0“Grain Pearl Millet”
e0“atom % 15 N abundance in the plants”
e1“ranged from 10.1 to 12.0 where 15 N was injected”
Claim · model-written summary
Atom % 15N abundance in plants was near natural abundance where no 15N was injected.
Verbatim
t0“Grain Pearl Millet”
e0“atom % 15 N abundance in the plants”
e1“was near natural abundance where no 15 N was injected”
Claim · model-written summary
The authors conclude that pearl millet can extract N from 1 to 1.2 m in an acidic, impermeable subsoil.
Verbatim
t0“Grain Pearl Millet”
e0“pearl millet can extract N from 1 to 1.2 m in an acidic and impermeable subsoil”
The same questions in other papers
fertilization · growth · Cenchrus americanus (pearl millet)Positive and negative results
67 papers in the same direction as this paper · 2 in the opposite direction
- negative
- no effect
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See all 70 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.