Abstract
Incorporation of crop residues after harvest may improve nitrogen (N) retention of tropical soils. A maize-groundnut rotation experiment was established in an Ultisol to study the recovery by the crop-soil system of N from mineral fertilizer and from the first maize residue. Out of the recommended N fertilizer for maize (150 kg N ha-1), 60 kg N ha -1 was applied in the form of ammonium sulphate (9.82 atom percent 15N excess) to the first maize crop and traced (for four crops) in the subsequent cropping system, with or without incorporation of crop residues. Similarly, N in the labelled residues of the first crop (maize) was also traced in the soil-crop system with incorporation of unlabelled crop residues. Recovery of fertilizer 15N by the first crop ranged from 20 to 22%. In the subsequent four crops, this value averaged 2% (but ranged from 0.4 to 6%). The proportion of fertilizer N retained in the soil (0-50 cm) after harvest of the first crop was 35 to 44% whereas after harvest of the subsequent crops, this proportion was 30 (but ranged from 24 to 34%) in crop residue treated plots and 22% (but ranged from 18 to 27%) in plots where crop residues were removed. Maize residue-N recovery in the subsequent three crops averaged only 5% (but ranged from 1 to 11%), being highest in the crop after crop residue incorporation. The corresponding recovery in the soil (0-50 cm) averaged across crops was 46% (but ranged from 40 to 52%). In tropical regions with high rainfall, conserving and decreasing soil N losses from mineral fertilizers could be achieved (in the long term) by the combined application of crop residues with mineral fertilizer.
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Claims 8
Claim · model-written summary
Fertilizer 15N recovery by the first maize crop was 20 to 22%.
- Treatment
- ammonium sulphatee1
- Outcome
- Recovery of fertilizer 15Ne0
- Value
- 20 to 22%e0
- Setting
- Humid Tropics of Malaysiat0
Zea maysOrganisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Recovery of Nitrogen from Maize Residue and Inorganic Fertilizer in a Maize‐Groundnut Rotation System in Humid Tropics of Malaysia”
e0“Recovery of fertilizer 15N by the first crop ranged from 20 to 22%”
e1“Out of the recommended N fertilizer for maize (150 kg N ha-1), 60 kg N ha -1 was applied in the form of ammonium sulphate (9.82 atom percent 15N excess) to the first maize crop and traced”
Claim · model-written summary
Fertilizer 15N recovery averaged 2% in the subsequent four crops.
- Outcome
- Recovery of fertilizer 15Ne2
- Value
- 2%e2
- Qualifier
- ranged from 0.4 to 6%e2
- Setting
- Humid Tropics of Malaysiat0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Recovery of Nitrogen from Maize Residue and Inorganic Fertilizer in a Maize‐Groundnut Rotation System in Humid Tropics of Malaysia”
e2“Recovery of fertilizer 15N by the first crop ranged from 20 to 22%. In the subsequent four crops, this value averaged 2% (but ranged from 0.4 to 6%)”
Claim · model-written summary
The proportion of fertilizer N retained in the soil after harvest of the first crop was 35 to 44%.
- Outcome
- proportion of fertilizer N retained in the soil (0-50 cm)e3
- Value
- 35 to 44%e3
- Qualifier
- after harvest of the first crope3
- Setting
- Humid Tropics of Malaysiat0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Recovery of Nitrogen from Maize Residue and Inorganic Fertilizer in a Maize‐Groundnut Rotation System in Humid Tropics of Malaysia”
e3“The proportion of fertilizer N retained in the soil (0-50 cm) after harvest of the first crop was 35 to 44% whereas after harvest of the subsequent crops, this proportion was 30 (but ranged from 24 to 34%) in crop residue treated plots and 22% (but ranged from 18 to 27%) in plots where crop residues were removed”
Claim · model-written summary
With crop residue treatment, the proportion of fertilizer N retained in the soil after the subsequent crops was higher (30%) than in plots where residues were removed.
- Treatment
- crop residuee3
- Outcome
- proportion of fertilizer N retained in the soil (0-50 cm)e3
- Direction
- higherinferrede3
- Value
- 30e3
- Qualifier
- 24 to 34%e3
- Comparator
- plots where crop residues were removede3
- Setting
- Humid Tropics of Malaysiat0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Recovery of Nitrogen from Maize Residue and Inorganic Fertilizer in a Maize‐Groundnut Rotation System in Humid Tropics of Malaysia”
e3“The proportion of fertilizer N retained in the soil (0-50 cm) after harvest of the first crop was 35 to 44% whereas after harvest of the subsequent crops, this proportion was 30 (but ranged from 24 to 34%) in crop residue treated plots and 22% (but ranged from 18 to 27%) in plots where crop residues were removed”
Claim · model-written summary
Without crop residue incorporation, the proportion of fertilizer N retained in the soil after the subsequent crops was 22%.
- Treatment
- crop residues were removede3
- Outcome
- proportion of fertilizer N retained in the soil (0-50 cm)e3
- Value
- 22%e3
- Qualifier
- 18 to 27%e3
- Setting
- Humid Tropics of Malaysiat0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Recovery of Nitrogen from Maize Residue and Inorganic Fertilizer in a Maize‐Groundnut Rotation System in Humid Tropics of Malaysia”
e3“The proportion of fertilizer N retained in the soil (0-50 cm) after harvest of the first crop was 35 to 44% whereas after harvest of the subsequent crops, this proportion was 30 (but ranged from 24 to 34%) in crop residue treated plots and 22% (but ranged from 18 to 27%) in plots where crop residues were removed”
Claim · model-written summary
Maize residue-N recovery in the subsequent three crops averaged 5%, highest in the crop after residue incorporation.
- Treatment
- crop residue incorporatione4
- Outcome
- Maize residue-N recoverye4
- Direction
- higheste4
- Value
- 5%e4
- Qualifier
- in the subsequent three cropse4
- Setting
- Humid Tropics of Malaysiat0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Recovery of Nitrogen from Maize Residue and Inorganic Fertilizer in a Maize‐Groundnut Rotation System in Humid Tropics of Malaysia”
e4“Maize residue-N recovery in the subsequent three crops averaged only 5% (but ranged from 1 to 11%), being highest in the crop after crop residue incorporation”
Claim · model-written summary
Maize residue-N recovery in the soil (0-50 cm) averaged 46% across crops.
- Outcome
- recovery in the soil (0-50 cm)e5
- Value
- 46%e5
- Qualifier
- averaged across cropse5
- Setting
- Humid Tropics of Malaysiat0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Recovery of Nitrogen from Maize Residue and Inorganic Fertilizer in a Maize‐Groundnut Rotation System in Humid Tropics of Malaysia”
e5“The corresponding recovery in the soil (0-50 cm) averaged across crops was 46% (but ranged from 40 to 52%)”
Claim · model-written summary
Combined application of crop residues with mineral fertilizer could conserve soil N and decrease N losses from mineral fertilizers in tropical regions with high rainfall, in the long term.
- Treatment
- combined application of crop residues with mineral fertilizere6
- Outcome
- conserving and decreasing soil N losses from mineral fertilizerse6
- Qualifier
- in the long terme6
- Setting
- In tropical regions with high rainfalle6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t0“Recovery of Nitrogen from Maize Residue and Inorganic Fertilizer in a Maize‐Groundnut Rotation System in Humid Tropics of Malaysia”
e6“In tropical regions with high rainfall, conserving and decreasing soil N losses from mineral fertilizers could be achieved (in the long term) by the combined application of crop residues with mineral fertilizer”