Abstract
Summer dry spells in some areas of southern Ontario during the last decade have increased interest in supplemental irrigation. Field studies were conducted in a 2500 heat unit area of southern Ontario on Orthic/Brunisolic Grey Brown Luvisol soils to determine the yield response of field corn (Zea mays L.) to irrigation in midsummer when combined with increased plant density and N rates. The yield responses, phenological records and soil moisture measurements are to be used in the calibration and validation of a corn yield estimation model, to be published in a subsequent paper. Two to four irrigations were applied each year using the line method when soil moisture pressure potential reached −40 to −60 kPa at 22.5 cm depth. Development stages were unaffected by irrigation. Yield increases from irrigation were directly proportional to water applied in midsummer and the intensity of dry weather. Yields increased with plant density in 4 of the 5 yr and were usually consistent over irrigation levels. Additional nitrogen above the recommended rate increased yields in 1982 and 1983, decreased yields in 1981, and resulted in no differences the other two years. In years of positive response to extra nitrogen, there was usually a greater response with irrigation and the responses were greatest at high plant density and for the longer season hybrids. Harvest indices decreased as irrigation amount increased and were exceptionally high in 1983.Key words: Corn, Zea mays L., line-source irrigation, plant population, nitrogen, harvest index
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Claims 10
Claim · model-written summary
Irrigation did not affect corn development stages.
- Taxon
- CORN
Zea mays subsp. mayst0 - Treatment
- irrigatione0
- Outcome
- Development stagese0
- Direction
- unaffectede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Development stages were unaffected by irrigation”
t0“CORN”
Claim · model-written summary
Corn yield increases from irrigation scaled with midsummer water applied and dry-weather intensity.
- Taxon
- CORNZea mays subsp. mayst0
- Treatment
- irrigatione0
- Outcome
- Yield increasese0
- Direction
- increasese0
- Qualifier
- directly proportional to water applied in midsummer and the intensity of dry weathere0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Yield increases from irrigation were directly proportional to water applied in midsummer and the intensity of dry weather”
t0“CORN”
Claim · model-written summary
Higher plant density increased corn yields in four of five years.
- Taxon
- CORNZea mays subsp. mayst0
- Treatment
- plant densitye0
- Outcome
- Yieldse0
- Direction
- increasede0
- Value
- 4 of the 5 yre0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Yields increased with plant density in 4 of the 5 yr and were usually consistent over irrigation levels”
t0“CORN”
Claim · model-written summary
Extra nitrogen increased corn yields in 1982 and 1983.
- Taxon
- CORNZea mays subsp. mayst0
- Treatment
- Additional nitrogen above the recommended ratee0
- Outcome
- yieldse0
- Direction
- increasede0
- Qualifier
- 1982 and 1983e0
- Comparator
- recommended ratee0
Not reportedSetting
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Additional nitrogen above the recommended rate increased yields in 1982 and 1983, decreased yields in 1981, and resulted in no differences the other two years”
t0“CORN”
Claim · model-written summary
Extra nitrogen decreased corn yields in 1981.
- Taxon
- CORNZea mays subsp. mayst0
- Treatment
- Additional nitrogen above the recommended ratee0
- Outcome
- yieldse0
- Direction
- decreasede0
- Qualifier
- 1981e0
- Comparator
- recommended ratee0
Not reportedSetting
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Additional nitrogen above the recommended rate increased yields in 1982 and 1983, decreased yields in 1981, and resulted in no differences the other two years”
t0“CORN”
Claim · model-written summary
Extra nitrogen no differences corn yields in the other two years.
- Taxon
- CORNZea mays subsp. mayst0
- Treatment
- Additional nitrogen above the recommended ratee0
- Outcome
- yieldse0
- Direction
- no differencese0
- Qualifier
- the other two yearse0
- Comparator
- recommended ratee0
Not reportedSetting
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Additional nitrogen above the recommended rate increased yields in 1982 and 1983, decreased yields in 1981, and resulted in no differences the other two years”
t0“CORN”
Claim · model-written summary
Positive yield responses to extra nitrogen were usually greater with irrigation.
- Taxon
- CORNZea mays subsp. mayst0
- Treatment
- extra nitrogene0
- Outcome
- responsee0
- Direction
- greatere0
- Qualifier
- with irrigatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In years of positive response to extra nitrogen, there was usually a greater response with irrigation”
t0“CORN”
Claim · model-written summary
Responses to extra nitrogen were greatest at high plant density and for longer season hybrids.
- Taxon
- CORNZea mays subsp. mayst0
- Treatment
- extra nitrogene1
- Outcome
- responsese0
- Direction
- greateste0
- Qualifier
- high plant density and for the longer season hybridse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the responses were greatest at high plant density and for the longer season hybrids”
e1“positive response to extra nitrogen”
t0“CORN”
Claim · model-written summary
Corn harvest indices declined as irrigation amount rose.
- Taxon
- CORNZea mays subsp. mayst0
- Treatment
- irrigatione0
- Outcome
- Harvest indicese0
- Direction
- decreasede0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Harvest indices decreased as irrigation amount increased”
t0“CORN”
Claim · model-written summary
Corn harvest indices were exceptionally high in 1983.
- Taxon
- CORNZea mays subsp. mayst0
- Outcome
- Harvest indicese0
- Direction
- exceptionally highe0
- Qualifier
- 1983e0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Harvest indices decreased as irrigation amount increased and were exceptionally high in 1983”
t0“CORN”
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