Abstract
Cowpea [ Vigna unguiculata (L.) Walp.] is an important component of most traditional cropping systems in the semiarid tropics. It provides both leaf vegetable and/or grain. Dual-purpose production of cowpea is most common in subsistence farming systems. Little is, however, known about the effects of cowpea leaf harvesting on tissue nitrogen composition and productivity of most cowpea-based cropping systems. A four-season study was carried out at the National Dry Land Research Center, Katumani, Kenya, to establish the effects of cowpea leaf harvesting initiation time and frequency on 1) tissue nitrogen content of cowpea and maize in a dual-purpose cowpea–maize intercropping systems; and 2) cowpea and maize yield and the overall productivity of a cowpea–maize intercrop measured by land equivalent ratio (LER). Cowpea leaf harvesting was initiated at 2, 3, or 4 weeks after emergence (WAE) and continued at 7- or 14-day intervals until onset of flowering. Cowpea tissue nitrogen content was highest in the control treatment and lowest in cowpea subjected to leaf harvesting from 2 WAE or at 7-day intervals, whereas maize tissue nitrogen content showed the reverse trend. Harvesting cowpea leaves from 3 WAE or at 7-day intervals gave the highest leaf vegetable yield, whereas grain yields were highest when no leaf harvesting was done. Maize yields were significantly improved by harvesting of leaves of the companion cowpea. Harvesting cowpea leaves for use as leaf vegetable increased productivity per unit area of land as measured by LER with the highest productivity achieved when leaf harvesting was initiated at 4 WAE or done at a 14-day interval.
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Claims 7
Claim · model-written summary
Cowpea tissue nitrogen was highest without leaf harvesting and lowest with early or frequent harvest.
- Taxon
- Cowpea
Vigna unguiculatat0 - Treatment
- leaf harvesting from 2 WAE or at 7-day intervalse0
- Outcome
- Cowpea tissue nitrogen contente0
- Direction
- loweste0
- Comparator
- control treatmente0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cowpea tissue nitrogen content was highest in the control treatment and lowest in cowpea subjected to leaf harvesting from 2 WAE or at 7-day intervals”
t0“Cowpea Leaf Harvesting”
Claim · model-written summary
Maize tissue nitrogen showed the reverse trend from cowpea.
- Treatment
- leaf harvesting from 2 WAE or at 7-day intervalse0
- Outcome
- maize tissue nitrogen contente0
- Comparator
- control treatmente0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Cowpea tissue nitrogen content was highest in the control treatment and lowest in cowpea subjected to leaf harvesting from 2 WAE or at 7-day intervals, whereas maize tissue nitrogen content showed the reverse trend.”
Claim · model-written summary
Cowpea leaf yield was highest when harvest began at 3 WAE or recurred every 7 days.
- Taxon
- cowpeaVigna unguiculatae0
- Treatment
- Harvesting cowpea leaves from 3 WAE or at 7-day intervalse0
- Outcome
- leaf vegetable yielde0
- Direction
- higheste0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Harvesting cowpea leaves from 3 WAE or at 7-day intervals gave the highest leaf vegetable yield”
Claim · model-written summary
Cowpea grain yield was highest with no leaf harvesting.
- Taxon
- CowpeaVigna unguiculatat0
- Treatment
- no leaf harvestinge0
- Outcome
- grain yieldse0
- Direction
- higheste0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“grain yields were highest when no leaf harvesting was done.”
t0“Cowpea Leaf Harvesting”
Claim · model-written summary
Harvesting companion cowpea leaves significantly improved maize yield.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Maize yields were significantly improved by harvesting of leaves of the companion cowpea.”
Claim · model-written summary
Cowpea leaf harvest increased land equivalent ratio.
- Taxon
- cowpeaVigna unguiculatae0
- Treatment
- Harvesting cowpea leavese0
- Outcome
- productivity per unit area of land as measured by LERe0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Harvesting cowpea leaves for use as leaf vegetable increased productivity per unit area of land as measured by LER”
Claim · model-written summary
Intercrop productivity was highest when leaf harvest began at 4 WAE or occurred every 14 days.
- Taxon
- Cowpea–maizeVigna unguiculata
Zea mayst0 - Treatment
- leaf harvesting was initiated at 4 WAE or done at a 14-day intervale0
- Outcome
- productivitye0
- Direction
- higheste0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the highest productivity achieved when leaf harvesting was initiated at 4 WAE or done at a 14-day interval.”
t0“Cowpea–maize”
The same questions in other papers
Vigna unguiculata · yield · Zea mays (maize)Positive and negative results
106 papers in the same direction as this paper · 16 in the opposite direction · 4 reporting no difference from an alternative
- negative
- negative
- negative
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See all 127 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.