Abstract
Abstract Even though P and K are both essential nutrients, the response of agronomic crops to P/K interaction under field conditions has not been adequately documented. This research was conducted to examine the influence of a high and low level of P over a wide range of K levels and vice versa on yield and chemical composition of forage sorghum ( Sorghum bicolor L.). In Exp. I, K was applied at rates of 0, 56, 112, and 244 kg/ha and split with P application of 0 and 116 kg/ha. For Exp. II, P was applied at rates of 0,29,58, and 116 kg/ha. For Exp. II, P was applied at rates of 0, 29, 58, and 116 kg/ha and was split with K applications of 0 and 224 kg/ha. These studies were conducted from 1978 thru 1980 on a Davidson clay (Rhodic Paleudult: clayey, kaolinitic, thermic) soil. Potassium application (Exp. I) increased yields only in years with less than optimum moisture conditions and then only when P was applied. When no P was applied, yields decreased with increased K application. Phosphorus (Exp. II) increased yields for each of the 3 years studied. In years with less than optimum moisture conditions, application of K increased yields at the higher P levels. Tissue K concentrations increased with K application while Ca and Mg concentrations decreased with increased K application. However, when P was applied Ca and Mg concentration increased. In the absence of applied P, the decreased in Ca and Mg concentration was related to competition with K for uptake. This competition may be responsible for reduced yields when K application was increased in the absence of applied P. When P was applied (in the presence or absence of applied K), Ca and Mg concentration increased in the tissue. A linear relationship between yield and Mg concentration in the tissue was present.
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Claims 8
Claim · model-written summary
Potassium increased yield only in dry years when P was applied.
- Taxon
- forage sorghumt0
- Treatment
- Potassium applicatione0
- Outcome
- yieldse0
- Direction
- increasede0
- Qualifier
- only in years with less than optimum moisture conditions and then only when P was appliede0
Not reportedComparator
Verbatim
e0“Potassium application (Exp. I) increased yields only in years with less than optimum moisture conditions and then only when P was applied.”
t0“Forage Sorghum”
Claim · model-written summary
Increasing K without P decreased yields.
Verbatim
e0“When no P was applied, yields decreased with increased K application.”
t0“Forage Sorghum”
Claim · model-written summary
Phosphorus increased yields in all three years.
Not reportedComparator
Verbatim
e0“Phosphorus (Exp. II) increased yields for each of the 3 years studied.”
t0“Forage Sorghum”
Claim · model-written summary
K increased yields at high P levels in dry years.
- Taxon
- forage sorghumt0
- Treatment
- application of Ke0
- Outcome
- yieldse0
- Direction
- increasede0
- Qualifier
- higher P levelse0
Not reportedComparator
Verbatim
e0“In years with less than optimum moisture conditions, application of K increased yields at the higher P levels.”
t0“Forage Sorghum”
Claim · model-written summary
Tissue K increased with K application.
Not reportedComparator
Verbatim
e0“Tissue K concentrations increased with K application while Ca and Mg concentrations decreased with increased K application.”
t0“Forage Sorghum”
Claim · model-written summary
Tissue Ca and Mg decreased with K application.
- Taxon
- forage sorghumt0
- Treatment
- increased K applicatione0
- Outcome
- Ca and Mg concentrationse0
- Direction
- decreasede0
Not reportedComparator
Verbatim
e0“Tissue K concentrations increased with K application while Ca and Mg concentrations decreased with increased K application.”
t0“Forage Sorghum”
Claim · model-written summary
Tissue Ca and Mg increased with P application.
Not reportedComparator
Verbatim
e0“when P was applied Ca and Mg concentration increased.”
t0“Forage Sorghum”
Claim · model-written summary
Yield was linearly related to tissue Mg.
Not reportedDirection
Verbatim
e0“A linear relationship between yield and Mg concentration in the tissue was present.”
t0“Forage Sorghum”
The same questions in other papers
potassium · yield · SorghumResults differ
23 papers in the same direction as this paper · 16 in the opposite direction · 1 reporting no difference from an alternative
- positive
- no effect
- no effect
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See all 41 papers →phosphorus · yield · SorghumResults differ
91 papers in the same direction as this paper · 12 in the opposite direction · 1 reporting no difference from an alternative
- positive
- negative
- no effect
101 papers more in this group
See all 105 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.