Abstract
The objective of this study was to quantify the nitrogen and yield advantage of cowpea, soybean and groundnuts to succeeding maize and grain sorghum crops.Treatments at six localities consisted of a crop rotation with annual legumes and maize or grain sorghum.Monoculture maize or grain sorghum with five nitrogen fertilisation levels was also included as treatments at all localities.Nitrate nitrogen in the soils was determined annually just before planting.Maize yields were determined at four localities and grain sorghum yields at two localities.The average nitrogen advantages after cowpeas, soybean and groundnuts were 32, 22 and 7 kg ha 1 respectively.For cowpeas and soybean, 65% and 54% of the variation in nitrogen advantage between years and localities could be accounted for by the yield of the respecti~etegumes.Approximately 10 kg ha 1 nitrogen advantage resulted from both 1 ton ha 1 soybean seed yield and also from 1 ton ha 1 cowpea dry matter yield.Maize yields increased by 27, 51 and 90% after rotation with cowpea, soybean and groundnut, respectively, compared to monoculture maize (with zero N application).For cowpeas the total yield increase could be accounted for by the measured nitrogen enrichment of the soil, but after soybean and groundnuts an additional average maize yield increase of 10% was found.Average grain sorghum yields after cowpeas and soybeans were respectively 7 and 13% higher than the control (monoculture grain sorghum and zero N application).These increases could not be ascribed to nitrogen enrichment of the soil, since no reaction to nitrogen fertilisation levels was found at either locality.Die doel van hierdie ondersoek was om die stikstof-en opbrengsvoordeel te kwantifiseer wat akkerbone, sojabone en grondbone aan mielies en graansorghum in 'n gewasrotasiestelsel lewer .Die behandelings op ses lokaliteite was gewasrotasie tussen eenjarige peulgewasse en mielies of graansorghum.Monokultuur mielies of graansorghum teen vyf stikstofbemestingspeile was ook behandelings op al ses lokaliteite.Nitraatstikstof in die grond is jaarliks direk voor plant bepaal.Mielie opbrengste is op vier lokaliteite bepaal en graansorghum opbrengste op twee lokaliteite.Die gemiddelde stikstofvoordeel na akkerbone, sojabone en grondbone was onderskeidelik 32, 22 en 7 kg ha-1 .Die opbrengs van akkerbone en sojabone kon onderskeidelik 65% and 54% van die variasie in stikstofvoordeel tussen lokaliteite en seisoene verklaar.Ongeveer 10 kg ha-1 stikstofvoordeel ontstaan vanaf elke 1 ton ha-1 sojabone saadopbrengs en ook vanaf elke 1 ton ha-1 akkerbone droemateriaalopbrengs.Mielie opbrengste (0 N toediening) na rotasie met akkerbone, sojabone en grondbone het met onderskeidelik 27, 51 and 90% toegeneem in vergelyking met monokultuur mielies (0 N toediening).Byakkerbone kon die totale opbrengsverhoging aan die verhoogde stikstofvoorsiening toegeskryf word, maar na sojabone en grondbone is 'n addisionele 10% verhoging waargeneem bo en behalwe die effek van stikstof.Graansorghum opbrengs na akkerbone en sojabone was gemiddeld 7 en 13% hoer as die kontrole behandeling (monokultuur graansorghum, 0 N toediening).Hierdie opbrengsverhoging kan nie aan verhoogde stikstofvoorsiening toegeskryf word nie, aangesien daar geen opbrengsreaksie op stikstoftoediening by beide lokaliteite was nie.
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Claims 17
Claim · model-written summary
cowpeas provided an average nitrogen advantage of 32 kg ha 1 to succeeding crops.
- Taxon
- maize and grain sorghum
Sorghum bicolor
Zea mayst0 - Treatment
- cowpease0
- Outcome
- nitrogen advantagese0
- Value
- 32e0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The average nitrogen advantages after cowpeas, soybean and groundnuts were 32, 22 and 7 kg ha 1 respectively.”
t0“maize and grain sorghum”
Claim · model-written summary
soybean provided an average nitrogen advantage of 22 kg ha 1 to succeeding crops.
- Taxon
- maize and grain sorghumSorghum bicolorZea mayst0
- Treatment
- soybeane0
- Outcome
- nitrogen advantagese0
- Value
- 22e0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The average nitrogen advantages after cowpeas, soybean and groundnuts were 32, 22 and 7 kg ha 1 respectively.”
t0“maize and grain sorghum”
Claim · model-written summary
groundnuts provided an average nitrogen advantage of 7 kg ha 1 to succeeding crops.
- Taxon
- maize and grain sorghumSorghum bicolorZea mayst0
- Treatment
- groundnutse0
- Outcome
- nitrogen advantagese0
- Value
- 7e0
Not reportedComparatorDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The average nitrogen advantages after cowpeas, soybean and groundnuts were 32, 22 and 7 kg ha 1 respectively.”
t0“maize and grain sorghum”
Claim · model-written summary
cowpeas yield accounted for 65% of between-year and between-locality variation in nitrogen advantage.
- Taxon
- maize and grain sorghumSorghum bicolorZea mayst0
- Material
- cowpease0
- Outcome
- variation in nitrogen advantagee0
- Value
- 65%e0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“For cowpeas and soybean, 65% and 54% of the variation in nitrogen advantage between years and localities could be accounted for by the yield of the respecti~etegumes.”
t0“maize and grain sorghum”
Claim · model-written summary
soybean yield accounted for 54% of between-year and between-locality variation in nitrogen advantage.
- Taxon
- maize and grain sorghumSorghum bicolorZea mayst0
- Material
- soybeane0
- Outcome
- variation in nitrogen advantagee0
- Value
- 54%e0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“For cowpeas and soybean, 65% and 54% of the variation in nitrogen advantage between years and localities could be accounted for by the yield of the respecti~etegumes.”
t0“maize and grain sorghum”
Claim · model-written summary
One ton of soybean seed yield corresponded to approximately 10 kg ha 1 nitrogen advantage.
- Taxon
- maize and grain sorghumSorghum bicolorZea mayst0
- Material
- soybeane0
- Outcome
- nitrogen advantagee0
- Value
- 10 kg ha 1e0
- Qualifier
- 1 ton ha 1 soybean seed yielde0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Approximately 10 kg ha 1 nitrogen advantage resulted from both 1 ton ha 1 soybean seed yield and also from 1 ton ha 1 cowpea dry matter yield.”
t0“maize and grain sorghum”
Claim · model-written summary
One ton of cowpea dry matter yield corresponded to approximately 10 kg ha 1 nitrogen advantage.
- Taxon
- maize and grain sorghumSorghum bicolorZea mayst0
- Material
- cowpeae0
- Outcome
- nitrogen advantagee0
- Value
- 10 kg ha 1e0
- Qualifier
- 1 ton ha 1 cowpea dry matter yielde0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Approximately 10 kg ha 1 nitrogen advantage resulted from both 1 ton ha 1 soybean seed yield and also from 1 ton ha 1 cowpea dry matter yield.”
t0“maize and grain sorghum”
Claim · model-written summary
Maize yield increased 27 after cowpea rotation versus zero-N maize monoculture.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Maize yields increased by 27, 51 and 90% after rotation with cowpea, soybean and groundnut, respectively, compared to monoculture maize (with zero N application).”
Claim · model-written summary
Maize yield increased 51 after soybean rotation versus zero-N maize monoculture.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Maize yields increased by 27, 51 and 90% after rotation with cowpea, soybean and groundnut, respectively, compared to monoculture maize (with zero N application).”
Claim · model-written summary
Maize yield increased 90% after groundnut rotation versus zero-N maize monoculture.
- Treatment
- groundnute0
- Outcome
- Maize yieldse0
- Direction
- increasede0
- Value
- 90%e0
- Comparator
- monoculture maizee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Maize yields increased by 27, 51 and 90% after rotation with cowpea, soybean and groundnut, respectively, compared to monoculture maize (with zero N application).”
Claim · model-written summary
Measured soil nitrogen enrichment accounted for the full maize yield increase after cowpeas.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“For cowpeas the total yield increase could be accounted for by the measured nitrogen enrichment of the soil”
t0“maize”
Claim · model-written summary
After soybean, maize yield had an additional average 10% increase beyond soil nitrogen enrichment.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“after soybean and groundnuts an additional average maize yield increase of 10% was found”
t0“maize”
Claim · model-written summary
After groundnuts, maize yield had an additional average 10% increase beyond soil nitrogen enrichment.
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“after soybean and groundnuts an additional average maize yield increase of 10% was found”
t0“maize”
Claim · model-written summary
Grain sorghum yield after cowpeas was 7% above zero-N monoculture.
- Taxon
- grain sorghumSorghum bicolore0
- Treatment
- cowpease0
- Outcome
- grain sorghum yieldse0
- Direction
- highere0
- Value
- 7e0
- Comparator
- monoculture grain sorghum and zero N applicatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Average grain sorghum yields after cowpeas and soybeans were respectively 7 and 13% higher than the control (monoculture grain sorghum and zero N application).”
Claim · model-written summary
Grain sorghum yield after soybeans was 13% above zero-N monoculture.
- Taxon
- grain sorghumSorghum bicolore0
- Treatment
- soybeanse0
- Outcome
- grain sorghum yieldse0
- Direction
- highere0
- Value
- 13e0
- Comparator
- monoculture grain sorghum and zero N applicatione0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Average grain sorghum yields after cowpeas and soybeans were respectively 7 and 13% higher than the control (monoculture grain sorghum and zero N application).”
Claim · model-written summary
The sorghum yield increases could not be attributed to soil nitrogen enrichment.
- Taxon
- grain sorghumSorghum bicolort0
- Outcome
- These increasese0
- Qualifier
- nitrogen enrichment of the soile0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“These increases could not be ascribed to nitrogen enrichment of the soil”
t0“grain sorghum”
Claim · model-written summary
Sorghum yields did not respond to nitrogen fertilization levels at either locality.
- Taxon
- grain sorghumSorghum bicolort0
- Treatment
- nitrogen fertilisation levelse0
- Outcome
- reactione0
- Direction
- no reactione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“no reaction to nitrogen fertilisation levels was found at either locality”
t0“grain sorghum”
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