Abstract
A large amount of nitrogen (N) fertilizers poured into the fields severely pollute the environment. Reasonable application of N fertilizer has always been the research hotpot. The effects of N management on maize N utilization and residual nitrate N in soil under maize/soybean and maize/ sweet potato relay strip intercropping systems were reported in a field experiment in southwest China. It was found that maize N accumulation, N harvest index, N absorption efficiency, N contribution proportion after the anthesis stage in maize/soybean relay strip intercropping were increased by 6.1%, 5.4%, 4.3%, and 15.1% than under maize/sweet potato with an increase of 22.6% for maize yield after sustainable growing of maize/soybean intercropping system. Nitrate N accumulation in the 0-60 cm soil layer was 12.9% higher under maize/soybean intercropping than under maize/sweet potato intercropping. However, nitrate N concentration in the 60-120 cm soil layer when intercropped with soybean decreased by 10.3% than when intercropped with sweet potato, indicating a decrease of N leaching loss. Increasing of N application rate enhanced N accumulation of maize and decreased N use efficiency and significantly increased nitrate concentration in the soil profile except in the 60-100 cm soil layer, where no significant difference was observed with nitrogen application rate at 0 to 270 kg · hm(-2). Further application of N fertilizer significantly enhanced nitrate leaching loss. Postponing N application increased nitrate accumulation in the 60-100 cm soil layer. The results suggested that N application rates and ratio of base to top dressing had different influences on maize N concentration and nitrate N between maize/soybean and maize/sweet potato intercropping. Maize N concentration in the late growing stage, N harvest index and N use efficiency under maize/soybean intercropping increased (with N application rate at 180-270 kg · hm(-2) and ratio of base to top dressing = 3:2:5) and decreased nitrate leaching loss with yield reaching 7757 kg · hm(-2) on average. However, for maize/sweet potato, N concentration and use efficiency and maize yield increased significantly with N application rate at 180 kg · hm(-2) and ratio of base to top dressing = 5:5 than that under other treatments with yield reaching 6572 kg · hm(-2). Under these circumstances, it would be possible to realize maize high yield, high efficiency and safety of N man- agement under maize/soybean and maize/sweet potato relay strip intercropping systems.
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Claims 17
Claim · model-written summary
Maize nitrogen accumulation was 6.1% higher with soybean than sweet potato relay intercropping.
- Treatment
- maize/soybean relay strip intercroppinge0
- Outcome
- maize N accumulatione0
- Direction
- increasede0
- Value
- 6.1%e0
- Comparator
- maize/sweet potatoe0
Zea maysOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“maize N accumulation, N harvest index, N absorption efficiency, N contribution proportion after the anthesis stage in maize/soybean relay strip intercropping were increased by 6.1%, 5.4%, 4.3%, and 15.1% than under maize/sweet potato”
Claim · model-written summary
Maize nitrogen harvest index was 5.4% higher with soybean than sweet potato.
- Treatment
- maize/soybean relay strip intercroppinge0
- Outcome
- N harvest indexe0
- Direction
- increasede0
- Value
- 5.4%e0
- Comparator
- maize/sweet potatoe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“maize N accumulation, N harvest index, N absorption efficiency, N contribution proportion after the anthesis stage in maize/soybean relay strip intercropping were increased by 6.1%, 5.4%, 4.3%, and 15.1% than under maize/sweet potato”
Claim · model-written summary
Maize nitrogen absorption efficiency was 4.3% higher with soybean than sweet potato.
- Treatment
- maize/soybean relay strip intercroppinge0
- Outcome
- N absorption efficiencye0
- Direction
- increasede0
- Value
- 4.3%e0
- Comparator
- maize/sweet potatoe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“maize N accumulation, N harvest index, N absorption efficiency, N contribution proportion after the anthesis stage in maize/soybean relay strip intercropping were increased by 6.1%, 5.4%, 4.3%, and 15.1% than under maize/sweet potato”
Claim · model-written summary
Postanthesis nitrogen contribution proportion was 15.1% higher with soybean than sweet potato.
- Treatment
- maize/soybean relay strip intercroppinge0
- Outcome
- N contribution proportion after the anthesis stagee0
- Direction
- increasede0
- Value
- 15.1%e0
- Comparator
- maize/sweet potatoe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“maize N accumulation, N harvest index, N absorption efficiency, N contribution proportion after the anthesis stage in maize/soybean relay strip intercropping were increased by 6.1%, 5.4%, 4.3%, and 15.1% than under maize/sweet potato”
Claim · model-written summary
Maize yield rose 22.6% after sustained maize–soybean intercropping.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“an increase of 22.6% for maize yield after sustainable growing of maize/soybean intercropping system”
Claim · model-written summary
Topsoil nitrate accumulation was 12.9% higher with soybean than sweet potato intercropping.
- Treatment
- maize/soybean intercroppinge0
- Outcome
- Nitrate N accumulation in the 0-60 cm soil layere0
- Direction
- highere0
- Value
- 12.9%e0
- Comparator
- maize/sweet potato intercroppinge0
Not reportedTaxon
Verbatim
e0“Nitrate N accumulation in the 0-60 cm soil layer was 12.9% higher under maize/soybean intercropping than under maize/sweet potato intercropping”
Claim · model-written summary
Deep soil nitrate concentration decreased 10.3% with soybean rather than sweet potato intercropping.
- Treatment
- intercropped with soybeane0
- Outcome
- nitrate N concentration in the 60-120 cm soil layere0
- Direction
- decreasede0
- Value
- 10.3%e0
- Comparator
- intercropped with sweet potatoe0
Not reportedTaxon
Verbatim
e0“nitrate N concentration in the 60-120 cm soil layer when intercropped with soybean decreased by 10.3% than when intercropped with sweet potato”
Claim · model-written summary
Higher nitrogen rates increased maize nitrogen accumulation.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Increasing of N application rate enhanced N accumulation of maize”
Claim · model-written summary
Higher nitrogen rates reduced maize nitrogen use efficiency.
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Increasing of N application rate enhanced N accumulation of maize and decreased N use efficiency”
Claim · model-written summary
Higher nitrogen rates increased nitrate concentration through most of the soil profile.
- Treatment
- Increasing of N application ratee0
- Outcome
- nitrate concentration in the soil profilee0
- Direction
- increasede0
- Qualifier
- except in the 60-100 cm soil layere0
Not reportedTaxonComparator
Verbatim
e0“Increasing of N application rate enhanced N accumulation of maize and decreased N use efficiency and significantly increased nitrate concentration in the soil profile except in the 60-100 cm soil layer”
Claim · model-written summary
At 0–270 kg per hectare, nitrogen rate did not significantly alter nitrate in the 60–100 cm layer.
- Treatment
- nitrogen application rate at 0 to 270 kg · hm(-2)e0
- Outcome
- 60-100 cm soil layere0
- Direction
- no significant differencee0
Not reportedTaxonComparator
Verbatim
e0“in the 60-100 cm soil layer, where no significant difference was observed with nitrogen application rate at 0 to 270 kg · hm(-2)”
Claim · model-written summary
Further nitrogen fertilizer significantly increased nitrate leaching loss.
Not reportedTaxonComparator
Verbatim
e0“Further application of N fertilizer significantly enhanced nitrate leaching loss”
Claim · model-written summary
Postponing nitrogen application increased nitrate accumulation in the 60–100 cm layer.
- Treatment
- Postponing N applicatione0
- Outcome
- nitrate accumulation in the 60-100 cm soil layere0
- Direction
- increasede0
Not reportedTaxonComparator
Verbatim
e0“Postponing N application increased nitrate accumulation in the 60-100 cm soil layer”
Claim · model-written summary
Specified soybean intercropping nitrogen management increased late maize nitrogen concentration, harvest index, and use efficiency.
- Treatment
- N application rate at 180-270 kg · hm(-2) and ratio of base to top dressing = 3:2:5e0
- Outcome
- Maize N concentration in the late growing stage, N harvest index and N use efficiencye0
- Direction
- increasede0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Maize N concentration in the late growing stage, N harvest index and N use efficiency under maize/soybean intercropping increased (with N application rate at 180-270 kg · hm(-2) and ratio of base to top dressing = 3:2:5)”
Claim · model-written summary
That soybean intercrop management reduced nitrate leaching and averaged 7757 kg per hectare yield.
- Outcome
- nitrate leaching losse0
- Direction
- decreasede0
- Qualifier
- yield reaching 7757 kg · hm(-2) on averagee0
Not reportedTaxonTreatmentComparator
Verbatim
e0“decreased nitrate leaching loss with yield reaching 7757 kg · hm(-2) on average”
Claim · model-written summary
For maize–sweet potato, specified nitrogen management significantly increased maize nitrogen concentration and use efficiency.
- Treatment
- N application rate at 180 kg · hm(-2) and ratio of base to top dressing = 5:5e0
- Outcome
- N concentration and use efficiencye0
- Direction
- increasede0
- Comparator
- other treatmentse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“N concentration and use efficiency and maize yield increased significantly with N application rate at 180 kg · hm(-2) and ratio of base to top dressing = 5:5 than that under other treatments”
t0“maize nitrogen utilization”
Claim · model-written summary
For maize–sweet potato, specified nitrogen management significantly increased maize yield to 6572 kg per hectare.
- Treatment
- N application rate at 180 kg · hm(-2) and ratio of base to top dressing = 5:5e0
- Outcome
- maize yielde0
- Direction
- increasede0
- Value
- 6572 kg · hm(-2)e0
- Comparator
- other treatmentse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“maize yield increased significantly with N application rate at 180 kg · hm(-2) and ratio of base to top dressing = 5:5 than that under other treatments with yield reaching 6572 kg · hm(-2)”
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See all 834 papers →8 of 11 groups shown: named compounds and organisms first, then groups whose results differ (checked claim by claim), then those with positive and negative results, then the smaller groups.
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.