Abstract
Nitrogen fertility is an important component of irrigated, short‐season cotton ( Gossypium hirsutum L.) production and is necessary to achieve optimum yield. Excessive N, however, almost invariably results in decreased yield and quality of cotton lint and seed. Use of mepiquat chloride (MC) ( N,N ‐dimethylpiperidinium chloride) for remediation of the detrimental effects of excessive N in cotton has been suggested. A field experiment was conducted for 3 yr to determine if MC applied at selected rates on traditionally nonrank, irrigated, short‐season cotton could influence cotton yield, related agronomic characteristics, and fiber properties at different N fertilizer rates. The experiment was conducted near Altus, OK, on a Tillman‐Hollister clay loam (fine, mixed, thermic Pachic Paleustoll). Cotton lint and seed yield responded positively to the Oklahoma State University recommended rate of 50 lb/acre of fertilizer N in all 3 yr, but negatively at the higher rates in the second and third years. Application of MC did not affect lint yield, seed yield, or lint/seed ratio in any year. Higher N fertilizer rates generally produced taller plants (by as much as 3.2 in.) while MC significantly reduced plant height (by as much as 5.7 in.) during this 3 yr. Percentage first harvest was increased (up to 5.5%) by MC in 1 yr, but was reduced (by as much as 17.4%) by higher N rates. Lint percentages were generally reduced by N fertilizer in all years, but were not affected by MC in any year. Excessive N increased fiber grayness in 1 yr and fiber yellowness in another, but did not affect micronaire, length, uniformity, strength, elongation, or leaf index in any of the 3 yr. Applications of MC increased fiber strength in 1 of 3 yr (by 3.8%). They also affected elongation, fiber grayness, and leaf index in 1 yr apiece but not in the two others. Data from this study indicate that for measured parameters, the only consistent positive effects of MC use under any N fertilization regime was reduced plant height. No significant N × MC rate interactions were noted. Research Question Nitrogen fertility is an important component of irrigated short‐season cotton production and is necessary to achieve optimum yield. Excessive N, however, often results in maturity delays and subsequent decreased yield and quality of fiber and seed. Use of mepiquat chloride (MC) has been suggested to counteract the detrimental effects of excessive N in cotton. The objective of this study was to determine whether MC applied at selected rates on traditionally nonrank, irrigated, short‐season cotton could influence cotton yield, related agronomic characteristics, and fiber properties at different N fertilizer rates. Literature Summary Mepiquat chloride has been used in full‐season, picker‐type cotton production systems with varied success. Application of MC is reported to consistently decrease plant size. Some authors report significant yield increases under certain circumstances; others little or none. Few studies have been published pertaining to irrigated, short‐season cotton as produced on the Rolling Plains of Oklahoma and Texas and to the potential of MC to alleviate detrimental effects of excessive N in that region. Study Description A field experiment was conducted on a Tillman‐Hollister clay loam, near Altus, OK, for 3 yr. The experiment was a randomized complete block design with a factorial arrangement of treatments and four replications. Nitrogen rates of 0, 50, 100, and 200 lb of actual N/acre were applied broadcast preplant and disk incorporated. ‘Paymaster 404’ cotton was seeded each year at 21 lb/acre. Mepiquat chloride rates of 0, 0.022, and 0.044 lb a.i./acre (½ pint and 1 pint/acre of 0.35 lb/gallon material, respectively) were superimposed on N rates and foliar applied at early bloom. Irrigation and insecticides were applied as judged necessary. Applied Questions What are the effects of excessive N in nonrank, irrigated, short‐season cotton production? Cotton lint yield responded positively to 50 lb/acre of fertilizer N in all 3 yr. Excessive accumulation of N at the two higher rates, however, resulted in lint yield reductions by the second and third years of the experiment (Fig. ). Seed yield response followed the same pattern as did lint yield, though seed weight increased faster than lint weight. Plant height increased up to 3.2 in. by N fertilization in these experiments while maturity (as measured by percentage first harvest) declined by as much as 17.4%. Lint percentages declined, thus increasing harvest and ginning costs per bale. Higher N rates increased fiber grayness in 1 yr and fiber yellowness in another, but did not affect micronaire, length, uniformity, strength, elongation, or leaf index in any of the 3 yr. Use of N displayed positive and negative effects. At the modest rate of 50 lb/acre, application of N appears economically justified because of the increased lint and seed yield; whereas, the higher rates do not because of the suppressed yields in years 2 and 3. Excessive N resulted in various other unfavorable effects on the plant, higher costs of production, and the potential for environmental degradation. Oklahoma State University soil test recommendations for N fertilizer management were appropriate for maximizing lint yields over the 3 yr. Could any effects of excessive N be overcome in this production situation with the growth regulator mepiquat chloride? Mepiquat chloride did not influence lint and seed yield or their ratio in any of the 3 yr in this experiment. Applications of MC consistently reduced plant height in all years by as much as 5.7 in. However, since this cotton was not rank initially and since plant height correlated poorly with stripper lint percentage, the reductions in height were of doubtful direct economic value. Use of MC increased earliness by up to 5.5% in 1 yr, but was ineffective in another. Fiber strength was increased by up to 3.8% in 1 yr, but not in the 2 other yr. Fiber elongation was increased (a favorable effect) as was grayness (an unfavorable effect) in 1 yr, but in another year leaf index was increased (an unfavorable effect). Rates of MC did not significantly influence micronaire, length, uniformity, or yellowness. Results from this study conducted on nonrank, irrigated, short‐season cotton indicate that, with the exception of plant height, MC application to any N fertilizer management regime had minimal direct benefit on measured parameters. Effect of N fertilization on lint yield in southwest Oklahoma over a 3‐yr period, in actual units. image
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Claims 18
Claim · model-written summary
Recommended nitrogen increased cotton lint and seed yield in all three years.
- Taxon
- Cotton
Gossypium hirsutume0 - Treatment
- 50 lb/acre of fertilizer Ne0
- Outcome
- lint and seed yielde0
- Direction
- positivelye0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cotton lint and seed yield responded positively to the Oklahoma State University recommended rate of 50 lb/acre of fertilizer N in all 3 yr”
Claim · model-written summary
Higher nitrogen rates reduced cotton lint and seed yield in years two and three.
- Taxon
- CottonGossypium hirsutume0
- Treatment
- higher ratese0
- Outcome
- lint and seed yielde0
- Direction
- negativelye0
- Qualifier
- second and third yearse0
- Comparator
- 50 lb/acre of fertilizer Ne0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cotton lint and seed yield responded positively to the Oklahoma State University recommended rate of 50 lb/acre of fertilizer N in all 3 yr, but negatively at the higher rates in the second and third years”
Claim · model-written summary
Mepiquat chloride did not significantly change cotton lint yield, seed yield or their ratio.
- Taxon
- cottonGossypium hirsutume1
- Treatment
- MCe0
- Outcome
- lint yield, seed yield, or lint/seed ratioe0
- Direction
- did not affecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Application of MC did not affect lint yield, seed yield, or lint/seed ratio in any year”
e1“cotton ( Gossypium hirsutum L.)”
Claim · model-written summary
Higher nitrogen rates increased cotton plant height by up to 3.2 inches.
- Taxon
- cottonGossypium hirsutume1
- Treatment
- Higher N fertilizer ratese0
- Outcome
- plantse0
- Direction
- tallere0
- Value
- 3.2 in.e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Higher N fertilizer rates generally produced taller plants (by as much as 3.2 in.)”
e1“cotton ( Gossypium hirsutum L.)”
Claim · model-written summary
Mepiquat chloride reduced cotton height by as much as 5.7 inches.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“MC significantly reduced plant height (by as much as 5.7 in.)”
e1“cotton ( Gossypium hirsutum L.)”
Claim · model-written summary
Mepiquat chloride increased first harvest percentage by up to 5.5% in one year.
- Taxon
- cottonGossypium hirsutume1
- Treatment
- MCe0
- Outcome
- Percentage first harveste0
- Direction
- increasede0
- Value
- 5.5%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Percentage first harvest was increased (up to 5.5%) by MC in 1 yr”
e1“cotton ( Gossypium hirsutum L.)”
Claim · model-written summary
Higher nitrogen rates reduced first harvest percentage by up to 17.4%.
- Taxon
- cottonGossypium hirsutume1
- Treatment
- higher N ratese0
- Outcome
- Percentage first harveste0
- Direction
- reducede0
- Value
- 17.4%e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Percentage first harvest was increased (up to 5.5%) by MC in 1 yr, but was reduced (by as much as 17.4%) by higher N rates”
e1“cotton ( Gossypium hirsutum L.)”
Claim · model-written summary
Nitrogen fertilizer generally reduced lint percentages.
- Taxon
- cottonGossypium hirsutume1
- Treatment
- N fertilizere0
- Outcome
- Lint percentagese0
- Direction
- reducede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Lint percentages were generally reduced by N fertilizer in all years”
e1“cotton ( Gossypium hirsutum L.)”
Claim · model-written summary
Mepiquat chloride did not affect lint percentages.
- Taxon
- cottonGossypium hirsutume1
- Treatment
- MCe0
- Outcome
- Lint percentagese0
- Direction
- not affectede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Lint percentages were generally reduced by N fertilizer in all years, but were not affected by MC in any year”
e1“cotton ( Gossypium hirsutum L.)”
Claim · model-written summary
Excess nitrogen increased fiber grayness in one year.
- Taxon
- cottonGossypium hirsutume1
- Treatment
- Excessive Ne0
- Outcome
- fiber graynesse0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Excessive N increased fiber grayness in 1 yr”
e1“cotton ( Gossypium hirsutum L.)”
Claim · model-written summary
Excess nitrogen increased fiber yellowness in another year.
- Taxon
- cottonGossypium hirsutume1
- Treatment
- Excessive Ne0
- Outcome
- fiber yellownesse0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Excessive N increased fiber grayness in 1 yr and fiber yellowness in another”
e1“cotton ( Gossypium hirsutum L.)”
Claim · model-written summary
Mepiquat chloride increased fiber strength by 3.8% in one year.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Applications of MC increased fiber strength in 1 of 3 yr (by 3.8%)”
e1“cotton ( Gossypium hirsutum L.)”
Claim · model-written summary
Mepiquat chloride increased fiber elongation in one year.
- Taxon
- cottonGossypium hirsutume2
- Treatment
- MCe1
- Outcome
- Fiber elongatione0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Fiber elongation was increased (a favorable effect)”
e1“Use of MC increased earliness”
e2“cotton ( Gossypium hirsutum L.)”
Claim · model-written summary
Mepiquat chloride increased fiber grayness in one year.
- Taxon
- cottonGossypium hirsutume2
- Treatment
- MCe1
- Outcome
- graynesse0
- Direction
- increasede1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“as was grayness (an unfavorable effect) in 1 yr”
e1“Use of MC increased earliness”
e2“cotton ( Gossypium hirsutum L.)”
Claim · model-written summary
Mepiquat chloride increased leaf index in one year.
- Taxon
- cottonGossypium hirsutume2
- Treatment
- MCe1
- Outcome
- leaf indexe0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“leaf index was increased (an unfavorable effect)”
e1“Use of MC increased earliness”
e2“cotton ( Gossypium hirsutum L.)”
Claim · model-written summary
Mepiquat chloride did not significantly affect micronaire, length, uniformity or yellowness.
- Taxon
- cottonGossypium hirsutume1
- Treatment
- MCe0
- Outcome
- micronaire, length, uniformity, or yellownesse0
- Direction
- did not significantly influencee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Rates of MC did not significantly influence micronaire, length, uniformity, or yellowness”
e1“cotton ( Gossypium hirsutum L.)”
Claim · model-written summary
No significant nitrogen by mepiquat chloride rate interaction was detected.
- Taxon
- cottonGossypium hirsutume1
- Outcome
- N × MC rate interactionse0
- Direction
- No significante0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“No significant N × MC rate interactions were noted”
e1“cotton ( Gossypium hirsutum L.)”
Claim · model-written summary
The authors judged the recommended nitrogen rate economically justified and higher rates unjustified.
- Taxon
- cottonGossypium hirsutume1
- Treatment
- 50 lb/acree0
- Outcome
- application of N appears economically justifiede0
- Qualifier
- the higher rates do note0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“At the modest rate of 50 lb/acre, application of N appears economically justified because of the increased lint and seed yield; whereas, the higher rates do not”
e1“cotton ( Gossypium hirsutum L.)”
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See all 343 papers →8 of 9 groups shown: named compounds and organisms first, then groups whose results differ (checked claim by claim), then those with positive and negative results, then the smaller groups.
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.