Abstract
Many growers continue to have interest in double-cropping hard red winter wheat {Triticum aestivum {L.} em Thell}, soybean {Glycine max L. Merr.}, and grain sorghum {Sorghum bicolor {L.} Moench} in the eastern part of Oklahoma. Fall, winter, and spring precipitation is usually sufficient in this part of the state to produce wheat. Removal of water from the soil profile by the wheat crop and erratic distribution of rainfall during the summer months, however, often results in soil moisture deficits during the reproductive growth stages of both doublecropped soybean and grain sorghum. An eight-year {1981-1988} field study was conducted at the. Oklahoma Vegetable Research Station, Bixby, Oklahoma, on a Wynona silt loam soil {Cumulic Haplaquoll} with 0-1% slope. The objective of the field investigation was to evaluate the long-term yields of mono- and double-cropped wheat, soybean, and grain sorghum. All wheat was produced under rainfed conditions while soybean and grain sorghum were produced under both conventional and no-till systems and under irrigated and rainfed conditions in eastern Oklahoma. Over the 8-yr study period, monocropped wheat yielded an average of 2970 compared with an average of 2405 kg ha^-1 for all double-cropped wheat. When the data for wheat yields were pooled and analyzed over years, there was a significant {P < 0.01} cropping system {C} x year {Y} interaction. The higher yields under monocropping were expected as monocropped wheat is planted around the first to third week of October and benefits from more fall growth and tillering compared with early November to early December planting and less tillering of the doublecropped wheat. Irrigated monocropped soybean yielded an average of 3110 compared with 2720 kg ha^-1 for rainfed, monocropped soybean, and irrigated double-cropped yielded an average of 2250 compared with 1940 kg ha- 1 for rainfed, double-cropped soybean. When the data for soybean yields were pooled and analyzed over years there were significant water (W) x Y, C x Y, and W x C x Y interactions. When compared with rainfed conditions the application of supplemental irrigation consistently increased soybean yields under monocropping. Under double-cropping, irrigation increased yields in five out of eight years. These results are most likely responsible for the significant interaction effects of C x W x Y interaction. Irrigated conventionally tilled monocropped grain sorghum averaged 6220 compared with 6010 kg ha- 1 for rainfed conventionally tilled monocropped grain sorghum. Irrigated no-till double-cropped sorghum yielded an average of 5300 compared with 4360 kg ha- 1 for rainfed no-till double-cropped sorghum. When the data for grain sorghum were pooled and analyzed over years, there were significant (P < 0.01) C x W, W x Y, C x Y, and W x C x Y interactions. The C x W, W x Y, and C x Y interactions can be attributed to the contrasting yield differences between rainfed and irrigated treatments over years for different cropping systems. These interaction effects were due to wide variation in amounts and distributions of rainfall during the 8-yr period. The significance of the three-factor interaction (C x W x Y) for both soybean and grain sorghum implies that the two-factor interaction effect of C x W was not the same for yields in all the eight years.
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Claims 10
Claim · model-written summary
Monocropped wheat yielded higher than double-cropped wheat (2970 versus 2405 kg/ha on average).
- Taxon
- wheat
Triticum aestivume1 - Treatment
- monocroppinge2
- Outcome
- yieldse2
- Direction
- highere2
- Value
- 2970e3
- Comparator
- all double-cropped wheate3
- Setting
- Bixby, Oklahomae0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“field study was conducted at the. Oklahoma Vegetable Research Station, Bixby, Oklahoma”
e1“Many growers continue to have interest in double-cropping hard red winter wheat”
e2“The higher yields under monocropping were expected”
e3“monocropped wheat yielded an average of 2970 compared with an average of 2405 kg ha^-1 for all double-cropped wheat”
Claim · model-written summary
The cropping system by year interaction was significant for wheat yields.
- Taxon
- wheatTriticum aestivume1
- Outcome
- wheat yieldse2
- Qualifier
- cropping system {C} x year {Y} interactione2
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Many growers continue to have interest in double-cropping hard red winter wheat”
e2“When the data for wheat yields were pooled and analyzed over years, there was a significant {P < 0.01} cropping system {C} x year {Y} interaction”
Claim · model-written summary
Irrigated monocropped soybean yielded higher than rainfed monocropped soybean (3110 versus 2720 kg/ha on average).
- Taxon
- soybean
Glycine maxe4 - Treatment
- Irrigated monocropped soybeane4
- Outcome
- yieldede4
- Direction
- higherinferrede4
- Value
- 3110e4
- Comparator
- rainfed, monocropped soybeane4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e4“Irrigated monocropped soybean yielded an average of 3110 compared with 2720 kg ha^-1 for rainfed, monocropped soybean, and irrigated double-cropped yielded an average of 2250 compared with 1940 kg ha- 1 for rainfed, double-cropped soybean”
Claim · model-written summary
Irrigated double-cropped soybean yielded higher than rainfed double-cropped soybean (2250 versus 1940 kg/ha on average).
- Taxon
- soybeanGlycine maxe4
- Treatment
- irrigated double-croppede4
- Outcome
- yieldede4
- Direction
- higherinferrede4
- Value
- 2250e4
- Comparator
- rainfed, double-cropped soybeane4
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e4“Irrigated monocropped soybean yielded an average of 3110 compared with 2720 kg ha^-1 for rainfed, monocropped soybean, and irrigated double-cropped yielded an average of 2250 compared with 1940 kg ha- 1 for rainfed, double-cropped soybean”
Claim · model-written summary
Supplemental irrigation consistently increased soybean yields under monocropping compared with rainfed conditions.
- Taxon
- soybeanGlycine maxe5
- Treatment
- supplemental irrigatione5
- Outcome
- soybean yieldse5
- Direction
- increasede5
- Qualifier
- under monocroppinge5
- Comparator
- rainfed conditionse5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e5“When compared with rainfed conditions the application of supplemental irrigation consistently increased soybean yields under monocropping”
Claim · model-written summary
Under double-cropping, irrigation increased soybean yields in five out of eight years.
- Taxon
- soybeanGlycine maxe4
- Treatment
- irrigatione6
- Outcome
- yieldse6
- Direction
- increasede6
- Qualifier
- in five out of eight yearse6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e4“Irrigated monocropped soybean yielded an average of 3110 compared with 2720 kg ha^-1 for rainfed, monocropped soybean, and irrigated double-cropped yielded an average of 2250 compared with 1940 kg ha- 1 for rainfed, double-cropped soybean”
e6“Under double-cropping, irrigation increased yields in five out of eight years”
Claim · model-written summary
Irrigated monocropped grain sorghum averaged higher than rainfed monocropped grain sorghum (6220 versus 6010 kg/ha).
- Taxon
- grain sorghum
Sorghum bicolore7 - Treatment
- Irrigated conventionally tilled monocroppede7
- Outcome
- averagede7
- Direction
- higherinferrede7
- Value
- 6220e7
- Comparator
- rainfed conventionally tilled monocropped grain sorghume7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e7“Irrigated conventionally tilled monocropped grain sorghum averaged 6220 compared with 6010 kg ha- 1 for rainfed conventionally tilled monocropped grain sorghum”
Claim · model-written summary
Irrigated no-till double-cropped sorghum yielded higher than rainfed no-till double-cropped sorghum (5300 versus 4360 kg/ha).
- Treatment
- Irrigated no-till double-croppede1
- Outcome
- yieldede1
- Direction
- higherinferrede1
- Value
- 5300e1
- Comparator
- rainfed no-till double-cropped sorghume1
SorghumOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Irrigated no-till double-cropped sorghum yielded an average of 5300 compared with 4360 kg ha- 1 for rainfed no-till double-cropped sorghum”
Claim · model-written summary
For soybean yields, water by year, cropping system by year and three-way interactions were significant.
- Taxon
- soybeanGlycine maxe1
- Outcome
- soybean yieldse1
- Qualifier
- water (W) x Y, C x Y, and W x C x Y interactionse1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“When the data for soybean yields were pooled and analyzed over years there were significant water (W) x Y, C x Y, and W x C x Y interactions”
Claim · model-written summary
For grain sorghum yields, C x W, W x Y, C x Y and W x C x Y interactions were significant.
- Taxon
- grain sorghumSorghum bicolore1
- Outcome
- interactionse1
- Qualifier
- C x W, W x Y, C x Y, and W x C x Ye1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“When the data for grain sorghum were pooled and analyzed over years, there were significant (P < 0.01) C x W, W x Y, C x Y, and W x C x Y interactions”
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