Abstract
Leguminous cover crops are considered part of sustainable agricultural systems. With the development of no‐till cropping systems, cover crops have been recognized for their ability to provide N for succeeding crops. The objectives of this study were: (i) to determine the N contribution of summer cover crops and double‐cropped grain crops following winter wheat ( Triticum aestivum L.) and N rates to subsequent maize ( Zea mays L.) crops’ physiological traits and yield, (ii) to calculate the fertilizer N replacement value, and (iii) to perform economic analyses of the cropping systems. Field experiments were conducted during the 2012–2013 and 2013–2014 growing seasons in Kansas. The grain yield of maize in all the cover crop systems and the double‐cropped soybean [ Glycine max (L.) Merr.] system was similar to maize in the fallow system with 45 kg N ha −1 . The mean increase in grain yield as a result of including cowpea [ Vigna unguiculata (L.) Walp.], pigeonpea [ Cajanus cajan (L.) Millsp.], sunn hemp ( Crotalaria juncea L.), double‐cropped soybean, and double‐cropped grain sorghum [ Sorghum bicolor (L.) Moench] in the rotation over the fallow system with 0 kg N ha −1 was 78, 91, 66, 72, and 12%, respectively. Fertilizer N replacement values for cowpea, pigeonpea, sunn hemp, double‐cropped soybean, and double‐cropped grain sorghum were 53, 64, 43, 47, and –5 kg N ha −1 , respectively. We conclude that the inclusion of summer leguminous cover crops in a cropping system has the potential to reduce or supplement N requirements and increase the grain yield of subsequent maize crops.
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Claims 12
Claim · model-written summary
Maize grain yield in all cover crop systems and double-cropped soybean was similar to maize in fallow with 45 kg N/ha.
- Treatment
- cover crop systemse1
- Outcome
- grain yielde1
- Direction
- similare2
- Comparator
- fallow system with 45 kg N ha −1e2
Zea maysOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“The grain yield of maize in all the cover crop systems”
e2“was similar to maize in the fallow system with 45 kg N ha −1”
t0“Response of Maize”
Claim · model-written summary
Including cowpea in the rotation raised maize grain yield by 78 over the 0 kg N fallow.
- Treatment
- cowpeae1
- Outcome
- grain yielde1
- Direction
- increasee1
- Value
- 78e1
- Comparator
- fallow system with 0 kg N ha −1e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“The mean increase in grain yield as a result of including cowpea [ Vigna unguiculata (L.) Walp.], pigeonpea [ Cajanus cajan (L.) Millsp.], sunn hemp ( Crotalaria juncea L.), double‐cropped soybean, and double‐cropped grain sorghum [ Sorghum bicolor (L.) Moench] in the rotation over the fallow system with 0 kg N ha −1 was 78, 91, 66, 72, and 12%, respectively”
t0“Response of Maize”
Claim · model-written summary
Including pigeonpea in the rotation raised maize grain yield by 91 over the 0 kg N fallow.
- Treatment
- pigeonpeae1
- Outcome
- grain yielde1
- Direction
- increasee1
- Value
- 91e1
- Comparator
- fallow system with 0 kg N ha −1e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“The mean increase in grain yield as a result of including cowpea [ Vigna unguiculata (L.) Walp.], pigeonpea [ Cajanus cajan (L.) Millsp.], sunn hemp ( Crotalaria juncea L.), double‐cropped soybean, and double‐cropped grain sorghum [ Sorghum bicolor (L.) Moench] in the rotation over the fallow system with 0 kg N ha −1 was 78, 91, 66, 72, and 12%, respectively”
t0“Response of Maize”
Claim · model-written summary
Including sunn hemp in the rotation raised maize grain yield by 66 over the 0 kg N fallow.
- Treatment
- sunn hempe1
- Outcome
- grain yielde1
- Direction
- increasee1
- Value
- 66e1
- Comparator
- fallow system with 0 kg N ha −1e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“The mean increase in grain yield as a result of including cowpea [ Vigna unguiculata (L.) Walp.], pigeonpea [ Cajanus cajan (L.) Millsp.], sunn hemp ( Crotalaria juncea L.), double‐cropped soybean, and double‐cropped grain sorghum [ Sorghum bicolor (L.) Moench] in the rotation over the fallow system with 0 kg N ha −1 was 78, 91, 66, 72, and 12%, respectively”
t0“Response of Maize”
Claim · model-written summary
Including double‐cropped soybean in the rotation raised maize grain yield by 72 over the 0 kg N fallow.
- Treatment
- double‐cropped soybeane1
- Outcome
- grain yielde1
- Direction
- increasee1
- Value
- 72e1
- Comparator
- fallow system with 0 kg N ha −1e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“The mean increase in grain yield as a result of including cowpea [ Vigna unguiculata (L.) Walp.], pigeonpea [ Cajanus cajan (L.) Millsp.], sunn hemp ( Crotalaria juncea L.), double‐cropped soybean, and double‐cropped grain sorghum [ Sorghum bicolor (L.) Moench] in the rotation over the fallow system with 0 kg N ha −1 was 78, 91, 66, 72, and 12%, respectively”
t0“Response of Maize”
Claim · model-written summary
Including double‐cropped grain sorghum in the rotation raised maize grain yield by 12% over the 0 kg N fallow.
- Treatment
- double‐cropped grain sorghume1
- Outcome
- grain yielde1
- Direction
- increasee1
- Value
- 12%e1
- Comparator
- fallow system with 0 kg N ha −1e1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“The mean increase in grain yield as a result of including cowpea [ Vigna unguiculata (L.) Walp.], pigeonpea [ Cajanus cajan (L.) Millsp.], sunn hemp ( Crotalaria juncea L.), double‐cropped soybean, and double‐cropped grain sorghum [ Sorghum bicolor (L.) Moench] in the rotation over the fallow system with 0 kg N ha −1 was 78, 91, 66, 72, and 12%, respectively”
t0“Response of Maize”
Claim · model-written summary
Fertilizer N replacement value of cowpea for maize was 53.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Fertilizer N replacement values for cowpea, pigeonpea, sunn hemp, double‐cropped soybean, and double‐cropped grain sorghum were 53, 64, 43, 47, and –5 kg N ha −1 , respectively”
t0“Response of Maize”
Claim · model-written summary
Fertilizer N replacement value of pigeonpea for maize was 64.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Fertilizer N replacement values for cowpea, pigeonpea, sunn hemp, double‐cropped soybean, and double‐cropped grain sorghum were 53, 64, 43, 47, and –5 kg N ha −1 , respectively”
t0“Response of Maize”
Claim · model-written summary
Fertilizer N replacement value of sunn hemp for maize was 43.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Fertilizer N replacement values for cowpea, pigeonpea, sunn hemp, double‐cropped soybean, and double‐cropped grain sorghum were 53, 64, 43, 47, and –5 kg N ha −1 , respectively”
t0“Response of Maize”
Claim · model-written summary
Fertilizer N replacement value of double‐cropped soybean for maize was 47.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Fertilizer N replacement values for cowpea, pigeonpea, sunn hemp, double‐cropped soybean, and double‐cropped grain sorghum were 53, 64, 43, 47, and –5 kg N ha −1 , respectively”
t0“Response of Maize”
Claim · model-written summary
Fertilizer N replacement value of double‐cropped grain sorghum for maize was –5 kg N ha −1.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“Fertilizer N replacement values for cowpea, pigeonpea, sunn hemp, double‐cropped soybean, and double‐cropped grain sorghum were 53, 64, 43, 47, and –5 kg N ha −1 , respectively”
t0“Response of Maize”
Claim · model-written summary
Summer leguminous cover crops can reduce or supplement N requirements and increase grain yield of subsequent maize.
- Outcome
- reduce or supplement N requirements and increase the grain yielde1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“the inclusion of summer leguminous cover crops in a cropping system has the potential to reduce or supplement N requirements and increase the grain yield of subsequent maize crops”
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