Abstract
Abstract The use of winter legume cover crops for erosion control and to provide additional N to the soil is well established. Other potential benefits to legume cover crops besides N additions have been recognized, but have not been quantified. The objective of this study was to separate the fixed‐N effects from the rotation effects in a winter legume cover cropping system. A field study was initiated in 1989 on a Norfolk loamy sand (fine, loamy, siliceous, thermic Typic Kandiudult) in east‐central Alabama. Corn ( Zea mays L.) was grown following (i) ‘Tibbee’ crimson clover ( Trifolium incarnatum L.), (ii) a partially ineffective‐nodulating crimson clover, CH‐1, (iii) rye ( Secale cereale L.), and (iv) winter fallow. The plots were split into four rates of fertilizer N (0, 56, 112, and 168 kg N ha −1 ) in a split‐plot experimental plan. An evaluation of different methods of distinguishing fixed‐N vs. rotation effects of the winter annual legume cover crop to a subsequent corn crop was made. Regression analysis of the effect of N application rates on N 2 fixation by crimson clover (fertilized with 45 kg N ha −1 ) indicated that CH‐1 clover biomass contained approximately 40 and 101 kg N ha −1 and Tibbee clover contained approximately 51 and 119 kg N ha −1 in 1990 and 1991, respectively. In both years of the study, crimson clover substantially increased corn yield compared with winter fallow, with a yield increase at the highest fertilizer N application level of 7 and 22% for 1990 and 1991, respectively. Estimates of yield increases due to rotation ranged from negative to 40%. The data indicated that winter cover crops improve corn yield and that besides soil N availability, there was very little difference between the beneficial effects of clover and the rye cover crops to corn.
Abstract from the paper’s OpenAlex record, shown for indexing and research. Copyright remains with the authors or the publisher. Read at the source ↗
The text the model read, with the source record’s inline markup (italics, sub- and superscripts) rendered and its character entities decoded; quote offsets refer to the raw text.
Claims 7
Claim · model-written summary
Crimson clover substantially increased corn yield compared with winter fallow in both years.
- Treatment
- crimson clovere1
- Outcome
- corn yielde1
- Direction
- increasede1
- Qualifier
- substantiallye1
- Comparator
- winter fallowe1
Zea maysOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Corn ( Zea mays L.) was grown following”
e1“In both years of the study, crimson clover substantially increased corn yield compared with winter fallow”
Claim · model-written summary
Crimson clover increased corn yield by 7 and 22% at the highest fertilizer N level in 1990 and 1991.
- Treatment
- crimson clovere1
- Outcome
- yield increasee2
- Direction
- increasee2
- Value
- 7 and 22%e2
- Qualifier
- at the highest fertilizer N application levele2
- Comparator
- winter fallowe1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Corn ( Zea mays L.) was grown following”
e1“In both years of the study, crimson clover substantially increased corn yield compared with winter fallow”
e2“with a yield increase at the highest fertilizer N application level of 7 and 22% for 1990 and 1991”
Claim · model-written summary
Estimated yield increases due to rotation ranged from negative to 40%.
- Treatment
- rotatione3
- Outcome
- yield increasese3
- Direction
- increasese3
- Value
- 40%e3
- Qualifier
- ranged from negative to 40%e3
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Corn ( Zea mays L.) was grown following”
e3“Estimates of yield increases due to rotation ranged from negative to 40%”
Claim · model-written summary
Winter cover crops improve corn yield.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Corn ( Zea mays L.) was grown following”
e4“The data indicated that winter cover crops improve corn yield”
Claim · model-written summary
Beyond soil N availability, clover and rye cover crops gave very little difference in their beneficial effects on corn.
- Treatment
- clovere5
- Outcome
- beneficial effectse5
- Direction
- very little differencee5
- Comparator
- rye cover cropse5
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Corn ( Zea mays L.) was grown following”
e5“besides soil N availability, there was very little difference between the beneficial effects of clover and the rye cover crops to corn”
Claim · model-written summary
Crimson clover biomass contained approximately 40 and 101 kg N per hectare.
- Taxon
- Trifolium incarnatum
Trifolium incarnatume6 - Outcome
- clover biomasse7
- Value
- 40 and 101 kg N hae7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e6“Trifolium incarnatum L.”
e7“clover biomass contained approximately 40 and 101 kg N ha”
Claim · model-written summary
Tibbee crimson clover contained approximately 51 and 119 kg N per hectare in 1990 and 1991.
- Taxon
- Trifolium incarnatumTrifolium incarnatume6
- Material
- Tibbeee7
- Outcome
- clover containede7
- Value
- 51 and 119 kg N hae7
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e6“Trifolium incarnatum L.”
e7“and Tibbee clover contained approximately 51 and 119 kg N ha”
The same questions in other papers
cover crop · yield · Zea mays (maize)Positive and negative results
103 papers in the same direction as this paper · 104 in the opposite direction · 14 reporting no difference from an alternative
- negative
- negative
- positive
218 papers more in this group
See all 222 papers →rotation · yield · Zea mays (maize)Positive and negative results
253 papers in the same direction as this paper · 52 in the opposite direction · 16 reporting no difference from an alternative
- positive
- negative
- negative
318 papers more in this group
See all 322 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.