Abstract
Abstract Most Colorado soils contain adequate levels of plant‐available K. This study investigated the influence of up to 750 kg K ha −1 on four semidormant varieties of alfalfa ( Medicago sativa L.) grown on a soil high in K (Nunn clay loam—Aridic Argiustoll) over 4 years. Fertilizer K significantly increased dry matter yield for the first 2 years and significantly increased the total alfalfa yields for the entire duration of the study. The overall yield response, however, was not cost efficient based on current K fertilizer costs. Along with the yield increases, K fertilizer consistently decreased Na plant concentrations, Na uptake, and soil levels of Na. It is postulated that the additional K suppressed Na uptake which possibly resulted in greater N 2 fixation and dry matter production. A greenhouse study using four rates of K and Mg applied as K 2 SO 4 and MgSO 4 , respectively, showed that both materials equally reduced Na uptake and increased yields of the ‘Baker’ cv. Consequently, the yield response to applied K in the field was not a nutritional response to K but resulted from the suppression of Na uptake. This K‐Na interaction produced significant yield responses in the field and the greenhouse even though the Nunn soil (a fine, montmorillonitic, mesic Aridic Argiustoll) is a non‐sodic soil.
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Claims 13
Claim · model-written summary
Fertilizer K significantly increased alfalfa dry matter yield in the first two years.
- Taxon
- alfalfa
Medicago sativae1 - Treatment
- Fertilizer Ke0
- Outcome
- dry matter yielde0
- Direction
- increasede0
- Qualifier
- first 2 yearse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Fertilizer K significantly increased dry matter yield for the first 2 years”
e1“alfalfa ( Medicago sativa L.) grown on a soil high in K”
Claim · model-written summary
Fertilizer K significantly increased total alfalfa yield across the study.
- Taxon
- alfalfaMedicago sativae0
- Outcome
- total alfalfa yieldse0
- Direction
- increasede0
- Qualifier
- entire duration of the studye0
Not reportedTreatmentComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“significantly increased the total alfalfa yields for the entire duration of the study”
Claim · model-written summary
The alfalfa yield response to K was not cost efficient at current fertilizer prices.
- Taxon
- alfalfaMedicago sativae1
- Outcome
- yield responsee0
- Qualifier
- not cost efficient based on current K fertilizer costse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The overall yield response, however, was not cost efficient based on current K fertilizer costs”
e1“total alfalfa yields”
Claim · model-written summary
K fertilizer consistently decreased plant sodium concentrations.
- Taxon
- alfalfaMedicago sativae1
- Treatment
- K fertilizere0
- Outcome
- Na plant concentrationse0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“K fertilizer consistently decreased Na plant concentrations, Na uptake, and soil levels of Na”
e1“alfalfa ( Medicago sativa L.)”
Claim · model-written summary
K fertilizer consistently decreased plant sodium uptake.
- Taxon
- alfalfaMedicago sativae1
- Treatment
- K fertilizere0
- Outcome
- Na uptakee0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“K fertilizer consistently decreased Na plant concentrations, Na uptake, and soil levels of Na”
e1“alfalfa ( Medicago sativa L.)”
Claim · model-written summary
K fertilizer consistently decreased soil sodium levels.
- Taxon
- alfalfaMedicago sativae1
- Treatment
- K fertilizere0
- Outcome
- soil levels of Nae0
- Direction
- decreasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“K fertilizer consistently decreased Na plant concentrations, Na uptake, and soil levels of Na”
e1“alfalfa ( Medicago sativa L.)”
Claim · model-written summary
Additional K may suppress Na uptake, potentially raising nitrogen fixation and dry matter production.
- Taxon
- alfalfaMedicago sativae1
- Treatment
- additional Ke0
- Outcome
- N 2 fixation and dry matter productione0
- Direction
- greatere0
- Qualifier
- possiblye0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the additional K suppressed Na uptake which possibly resulted in greater N 2 fixation and dry matter production”
e1“alfalfa ( Medicago sativa L.)”
Claim · model-written summary
K2SO4 reduced Na uptake in Baker alfalfa.
- Taxon
- alfalfaMedicago sativae2
- Material
- ‘Baker’ cve0
- Treatment
- K 2 SO 4e1
- Outcome
- Na uptakee0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“both materials equally reduced Na uptake and increased yields of the ‘Baker’ cv”
e1“four rates of K and Mg applied as K 2 SO 4 and MgSO 4”
e2“alfalfa ( Medicago sativa L.)”
Claim · model-written summary
MgSO4 reduced Na uptake in Baker alfalfa.
- Taxon
- alfalfaMedicago sativae2
- Material
- ‘Baker’ cve0
- Treatment
- MgSO 4e1
- Outcome
- Na uptakee0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“both materials equally reduced Na uptake and increased yields of the ‘Baker’ cv”
e1“four rates of K and Mg applied as K 2 SO 4 and MgSO 4”
e2“alfalfa ( Medicago sativa L.)”
Claim · model-written summary
K2SO4 increased Baker alfalfa yield.
- Taxon
- alfalfaMedicago sativae2
- Material
- ‘Baker’ cve0
- Treatment
- K 2 SO 4e1
- Outcome
- yieldse0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“both materials equally reduced Na uptake and increased yields of the ‘Baker’ cv”
e1“four rates of K and Mg applied as K 2 SO 4 and MgSO 4”
e2“alfalfa ( Medicago sativa L.)”
Claim · model-written summary
MgSO4 increased Baker alfalfa yield.
- Taxon
- alfalfaMedicago sativae2
- Material
- ‘Baker’ cve0
- Treatment
- MgSO 4e1
- Outcome
- yieldse0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“both materials equally reduced Na uptake and increased yields of the ‘Baker’ cv”
e1“four rates of K and Mg applied as K 2 SO 4 and MgSO 4”
e2“alfalfa ( Medicago sativa L.)”
Claim · model-written summary
The authors attribute field K yield response to suppressed Na uptake.
- Taxon
- alfalfaMedicago sativae1
- Treatment
- applied Ke0
- Outcome
- yield responsee0
- Qualifier
- suppression of Na uptakee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the yield response to applied K in the field was not a nutritional response to K but resulted from the suppression of Na uptake”
e1“alfalfa ( Medicago sativa L.)”
Claim · model-written summary
The K–Na interaction produced significant field and greenhouse yield responses on non-sodic Nunn soil.
- Taxon
- alfalfaMedicago sativae1
- Treatment
- K‐Na interactione0
- Outcome
- yield responsese0
- Qualifier
- non‐sodic soile0
- Setting
- field and the greenhousee0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“This K‐Na interaction produced significant yield responses in the field and the greenhouse even though the Nunn soil (a fine, montmorillonitic, mesic Aridic Argiustoll) is a non‐sodic soil”
e1“alfalfa ( Medicago sativa L.)”
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