Abstract
Because the yield response to K in a wheat ( Triticum aestivum L.)‐soybean [ Glycine max (L.) Merr.] rotation on Atlantic Coastal Plain soils may be influenced by tillage type and K application timing, a study was conducted between 1986 and 1988 on a Bojac loamy sand (coarse‐loamy, mixed, thermic Typic Hapludult) to investigate the effects of tillage, K rate, and K application timing on soil and plant K and crop yields. The experimental design was a split plot, with tillage as the main plot factor and K rate × K application timing as the subplot factor. Tillage treatments were conventional tillage (CT) and no‐till (NT). Potassium fertilizer (KC1) rates of 0, 36, and 72 lb K/acre were applied (i) 100% prior to wheat planting; (ii) 50% prior to wheat planting, 50% at Zadoks 30 growth stage; and (iii) 50% prior to wheat planting, 50% prior to soybean planting. Wheat yields under continuous NT management declined from 84 bu/acre in 1987 to 53 bu/acre in 1988, while CT wheat yields remained constant at 76 bu/acre in 1987 and 75 bu/acre in 1988. No‐till soybeans significantly outyielded CT soybeans by 48 to 33 bu/acre in 1987 and 61 to 46 bu/acre in 1988. Neither wheat nor soybeans responded to K rate or timing of application despite reductions in soil test K to levels diagnosed as insufficient. Leaching losses contributed significantly to declines in soil K, as crop removal accounted for only a portion of the “missing” K. Testing for K on Coastal Plain soils should involve subsoil sampling, since both wheat and soybeans appear capable of procuring considerable amounts of K from deeper than 12 to 18 in. within the profile.
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Claims 9
Claim · model-written summary
Continuous no-till wheat yield declined from 84 bu/acre in 1987 to 53 bu/acre in 1988.
- Taxon
- Wheat
Triticum aestivume0 - Treatment
- continuous NT managemente0
- Outcome
- Wheat yieldse0
- Direction
- declinede0
- Value
- 84 bu/acre in 1987 to 53 bu/acre in 1988e0
- Setting
- Atlantic Coastal Plain soilse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Wheat yields under continuous NT management declined from 84 bu/acre in 1987 to 53 bu/acre in 1988”
e1“Atlantic Coastal Plain soils”
Claim · model-written summary
Conventional tillage wheat yield remained near 76 bu/acre across 1987 and 1988.
- Taxon
- wheatTriticum aestivumt0
- Treatment
- CTe0
- Outcome
- wheat yieldse0
- Direction
- remained constante0
- Value
- 76 bu/acre in 1987 and 75 bu/acre in 1988e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“CT wheat yields remained constant at 76 bu/acre in 1987 and 75 bu/acre in 1988”
t0“Wheat and Soybeans”
Claim · model-written summary
No-till soybean yield significantly exceeded conventional tillage yield in 1987, 48 versus 33 bu/acre.
- Taxon
- soybeans
Glycine maxe0 - Treatment
- No‐tille0
- Outcome
- soybeanse0
- Direction
- outyieldede0
- Value
- 48 to 33 bu/acree0
- Qualifier
- in 1987e0
- Comparator
- CTe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“No‐till soybeans significantly outyielded CT soybeans by 48 to 33 bu/acre in 1987”
Claim · model-written summary
No-till soybean yield significantly exceeded conventional tillage yield in 1988, 61 versus 46 bu/acre.
- Taxon
- soybeansGlycine maxe0
- Treatment
- No‐tille0
- Outcome
- soybeanse0
- Direction
- outyieldede0
- Value
- 61 to 46 bu/acree0
- Qualifier
- in 1988e0
- Comparator
- CTe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“No‐till soybeans significantly outyielded CT soybeans by 48 to 33 bu/acre in 1987 and 61 to 46 bu/acre in 1988”
Claim · model-written summary
Wheat yield did not respond to potassium rate or application timing.
- Taxon
- wheatTriticum aestivume0
- Treatment
- K rate or timing of applicatione0
- Outcome
- wheate0
- Direction
- Neither wheat nor soybeans respondede0
- Qualifier
- despite reductions in soil test K to levels diagnosed as insufficiente0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Neither wheat nor soybeans responded to K rate or timing of application despite reductions in soil test K to levels diagnosed as insufficient”
Claim · model-written summary
Soybean yield did not respond to potassium rate or application timing.
- Taxon
- soybeansGlycine maxe0
- Treatment
- K rate or timing of applicatione0
- Outcome
- soybeanse0
- Direction
- Neither wheat nor soybeans respondede0
- Qualifier
- despite reductions in soil test K to levels diagnosed as insufficiente0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Neither wheat nor soybeans responded to K rate or timing of application despite reductions in soil test K to levels diagnosed as insufficient”
Claim · model-written summary
Leaching contributed significantly to soil potassium loss; crop removal explained only part of the missing potassium.
- Taxon
- wheatTriticum aestivumt0
- Treatment
- Leaching lossese0
- Outcome
- declines in soil Ke0
- Direction
- declinese0
- Qualifier
- crop removal accounted for only a portion of the “missing” Ke0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Leaching losses contributed significantly to declines in soil K, as crop removal accounted for only a portion of the “missing” K”
t0“Wheat and Soybeans”
Claim · model-written summary
Wheat and soybeans appear able to obtain substantial potassium from deeper than 12 to 18 inches in the soil profile.
- Taxon
- wheat and soybeansGlycine maxTriticum aestivume0
- Outcome
- procuring considerable amounts of Ke0
- Qualifier
- deeper than 12 to 18 in. within the profilee0
Not reportedOrgan / stage
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“both wheat and soybeans appear capable of procuring considerable amounts of K from deeper than 12 to 18 in. within the profile”
Claim · model-written summary
Potassium testing on Coastal Plain soils should include subsoil samples.
- Taxon
- Wheat and SoybeansGlycine maxTriticum aestivumt0
- Outcome
- subsoil samplinge0
- Setting
- Coastal Plain soilse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Testing for K on Coastal Plain soils should involve subsoil sampling”
t0“Wheat and Soybeans”
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11 papers in the same direction as this paper · 11 in the opposite direction · 1 reporting no difference from an alternative
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See all 24 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.